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General HIFI => Amplification (Pre/Power) => Topic started by: stevenvalve on April 26, 2014, 06:47:34 PM

Title: Leak Stereo 20 Modifications
Post by: stevenvalve on April 26, 2014, 06:47:34 PM
 I have finished the Leak Stereo 20 Modifications, Including 4 new Duelund 0.47 capacitors, I rearranged the component's, and as you can see, it all fits. Is this one of the world best sounding Leak Stereo 20s well we will never know, it may not even end up being the best at the leak shootout down in Canberra. There is never a guarantee, As we all know dollars spent will not guarantee success in this insane hobby. I also have an nice original standard Leak Stereo 20, and decided to compere them, how does this unmodified amp sound in comparison, well it doesn't..... the modified amp slaughters the stock one. It has a smooth grainless sophisticated beauty that unfortunately the standard one does not want to know about. After the GTG, my next move with this amp will be to change it over to triode mode.
Title: Re: Leak Stereo 20 Modifications
Post by: Tuyen on April 26, 2014, 07:14:19 PM
Very tastefully done Steven.  You have bought all remaining stock of duelund vsfs haven't you.  ;D
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on April 27, 2014, 01:15:17 AM
Very tastefully done Steven.  You have bought all remaining stock of duelund vsfs haven't you.  ;D
I would like to buy them all, but you can pay.
Title: Re: Leak Stereo 20 Modifications
Post by: gamve on April 27, 2014, 12:39:44 PM
I Just got some of the new VSF replacements from mike being the RS series copper foil caps
I just Hope the RS does not stand for RAT sh!t. ::)
Title: Re: Leak Stereo 20 Modifications
Post by: mcb on May 04, 2014, 01:34:57 PM
I Just got some of the new VSF replacements from mike being the RS series copper foil caps
I just Hope the RS does not stand for RAT sh!t. ::)

I look forward to your comments, once you have had a chance to give them a good run. 
Title: Re: Leak Stereo 20 Modifications
Post by: PingPing on May 05, 2014, 09:47:08 AM
Super neat job Steven... how does it sound  :)
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on May 05, 2014, 04:22:38 PM
Super neat job Steven... how does it sound  :)
Ping, its the best sounding push pull amp I have heard, the leak is bolted to a set of speakers that are difficult to run, Quad 57s. It certainly has the synergy with Quads. The midrange is incredibly clean and uncoloured, Very Sweet and pretty, But only about 8 to 10 watts and accordingly not the most powerful bass, but adequate. The test will be when it driving other speakers. Here is a standard nicely rebuilt leak, most are not as good as this rebuilt leak, to be truthful most rebuilds are absolute crap, rebuilt by technicians who do not have a clue about good sound.  As you can see mine is very different.
Title: Re: Leak Stereo 20 Modifications
Post by: data on May 08, 2014, 09:59:46 PM
Very different alright!
looks nice with the new arrangement 8)

Looks like another Stereo 20 will be up for grabs, a guy has one in his clearance pile on the SNA classifieds http://www.stereo.net.au/forums/index.php?/topic/65196-downsize-my-vintage-audio-collection/
Hard not to miss with that typical look.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on May 15, 2014, 07:51:18 PM
 This is a very good tube complement for a Leak stereo 20 but it's very system dependent. Siemens 1950-60s, West German 5814A 12au7 in the first position, followed by 2 /12AX7 mullard 1950s 17MM long plates and 4 mullard 1950's FX1 - B?,  EL84 as the power tubes, and almost equally important is 4 Duelund 0.47 VSF capacitors.
Title: Re: Leak Stereo 20 Modifications
Post by: MrRogers on June 07, 2014, 02:19:22 PM
Looking forward to having a listen soon.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on August 05, 2014, 07:09:55 PM
I thought I would do a modification as suggested by Paul, from fallsaudio. Take the green 100R sacrificial resistor out of the Leak Stereo 20, you can see it in the second picture, this is the out voltage from the GZ34 rectifier, run flying leads from each side then fit them to a choke around 5-10 henrys 120Ma + Choke. In my case a vintage UTC CG40. This will drop about 10V give or take, but will also lower the noise. I have finished the mod and I must say the sound is very good. I will evaluate it for a week. Let you know later.
Title: Re: Leak Stereo 20 Modifications
Post by: Jehuty on August 05, 2014, 08:21:22 PM
I thought I would do a modification as suggested by Paul, from fallsaudio. Take the green 100R sacrificial resistor out of the Leak Stereo 20, you can see it in the second picture, this is the out voltage from the GZ34 rectifier, run flying leads from each side then fit them to a choke around 5-10 henrys 120Ma + Choke. In my case a vintage UTC CG40. This will drop about 10V give or take, but will also lower the noise. I have finished the mod and I must say the sound is very good. I will evaluate it for a week. Let you know later.

UTC CG40 is rated 10 henries and 110 ohms, according to zenelectro calculation it's too high. See: http://killerdac.com/forum/index.php/topic,2461.msg16732.html#msg16732

But if it sounds good to you then no need to be concerned about. We should do a chokes war sometime. I got a nice vintage oil filled choke here in my Leak within the spec recommended by zenelectro. Took me sometime to get it because it's hard to find the correct spec but it's well worth the efforts and money.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on August 05, 2014, 11:36:23 PM
I Do what my ears tell me, Or should I say, what the Cello said
Title: Re: Leak Stereo 20 Modifications
Post by: ozmillsy on August 05, 2014, 11:50:10 PM
 ;D

The cello is but 1 view of music.   

It cant be the only measure.   Can it?    ???

[listening to Zhu as I type this] 
8) 
Title: Re: Leak Stereo 20 Modifications
Post by: Jehuty on August 05, 2014, 11:56:45 PM
I Do what my ears tell me, Or should I say, what the Cello said

Yes, we all know that but wait until your ears tell you how my nice and correct specced oil filled choke sounds better than your UTC...or you can wait til the cello says the same thing because mine is more ACCURATE  :P :P :P ;D
Title: Re: Leak Stereo 20 Modifications
Post by: springcreek on August 08, 2014, 12:57:08 PM
I am using the same choke as William and it sounds great...very happy camper. These little amps when sorted and just beautiful...I absolutely love mine. In fact I have had no other amp in my system which I would swap the Leak for, though the RCA theatre amps would make me think twice  ;D
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on September 07, 2014, 05:51:04 PM
I have put up some pictures, to show where the wires attach to run a choke on the leak stereo 20, you are just replacing the 100R resistor. That resistor stops some ripple, the choke is a much better idea, much less noise, and theoretically I will sound better if you chose a great sounding choke. A choke is essentially a long wire and will and should sound better than any resistor. After you run the wire, separate it, strip of the insulation, and then cover it with Teflon, Where to mount the choke, now that is a problem.
Title: Re: Leak Stereo 20 Modifications
Post by: vitavoxdude on September 08, 2014, 10:11:08 AM
That Leak is beautifully re built Steve.  I would imagine it would sound really good with some Lowther horns or the like.
Title: Re: Leak Stereo 20 Modifications
Post by: klackto on September 08, 2014, 02:34:16 PM
Beautifully done.
Do we need to keep the DCR of the choke down so as not to drop the HT too much?
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on September 08, 2014, 03:39:04 PM
Beautifully done.
Do we need to keep the DCR of the choke down so as not to drop the HT too much?
I have only dropped about 10 volts, using the 10 henry, 200ma, choke pictured above. I am changing chokes every week to find the right one.  A smaller choke will probably have less effect on the voltage, 2 henry will probably do, what works. As for wire, i have been trying different wire types, Cat 5 sounds very good, it has the great balance when added with the sound of the original leak wiring. And as with the chokes, all dramatically change the sound.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on September 08, 2014, 03:50:14 PM
That Leak is beautifully re built Steve.  I would imagine it would sound really good with some Lowther horns or the like.
Interesting, I have at the insistence of a friend, tried it on my axiom 80s with very good results. Sweet, pretty, warm, involving, with a lot of liquid body. As for lowthers,  this amp will be a very good match for lowthers, because its strengths oppose the lowthers weaknesses.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on September 08, 2014, 03:59:29 PM
I must say, the great thing about the Leak stereo 20, they are cheap to buy, the valves are cheap, the sound when set up correctly is just superb.
Title: Re: Leak Stereo 20 Modifications
Post by: zenelectro on September 08, 2014, 04:24:28 PM
I have only dropped about 10 volts, using the 10 henry, 200ma, choke pictured above. I am changing chokes every week to find the right one.  A smaller choke will probably have less effect on the voltage, 2 henry will probably do, what works. As for wire, i have been trying different wire types, Cat 5 sounds very good, it has the great balance when added with the sound of the original leak wiring. And as with the choke all dramatically changes the sound.

Just measure the DC resistance across the choke with a multimeter. If it is say 100 ohms and you are running say 120mA (30/tube) that will be 0.12 x 100 = 12 volts drop.

The chokes will vary considerably with their DC resistance and a higher current choke that has low DCR will likely give tighter bass.

Another thing to be aware of is that the size of the power supply caps is important, I'm presuming these are the Solens.
The standard caps are 32uF and once you start making this larger the sound will become less 'active' or 'lively'.

Often increasing the size of the caps too much can make the sound worse - depending on what you want. Making them
larger generally makes the amp tighter and cleaner. For guitar amps, if it's a modern clone of a vintage amp, I sometimes
put smaller PS caps in as per original spec and the amp can really come to life. But thats not a hi fi amp so you want lots of
character.

Z
Title: Re: Leak Stereo 20 Modifications
Post by: klackto on September 10, 2014, 12:37:59 PM
Hammond make an open frame choke model 157Q  which is 3.5H,  DCR 98 ohm, 150ma. 400v. 
It's compact enough that it should be just possible to squeeze beneath the chasis.
As much as I like the idea of using a vintage choke (have some squirrelled away in the garage somewhere) , I'd like to keep the Leak looking as stock as possible.
An off board choke with flying leads is out as well as we have an inquisitive cat who has an overwhelming need to investigate anything new in the house. ( As a kitten he'd chew everything, fortunately the Audi Tekne cables I use have a braided metallic sheath that he couldn't quite get through. The vacuum seal on the turntable didn't fare so well  .... but that's a different story!  :o)
Reckon the Hammond choke is worth pursuing?
Title: Re: Leak Stereo 20 Modifications
Post by: klackto on September 14, 2014, 10:04:05 AM
Well, I went ahead & ordered one. Had to order a few other odds & ends and it was pretty cheap (about $27 US) so no great loss if it doesn't sound any good.
I imagine it should offer an improvement over the resistor if not in the same league as a nice vintage choke.
Meanwhile the 33uf Solen power supply caps I put in have settled in nicely .. a worthwhile improvement over the electrolytics I had in there previously.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on September 16, 2014, 01:20:56 PM
I have been trying different chokes in the 100R resistor spot, and a UTC PA40 does sound very good. I will change back to the resistor in the next week just to check.
Title: Re: Leak Stereo 20 Modifications
Post by: klackto on October 05, 2014, 06:18:14 PM
Managed to fit the Hammond choke. Very easy as the mounting holes line upto those of the power transformer. Will let it burn in for a while and report. I'm sure not in the league of a vintage UTC or Chicago but an option for those who want something self contained.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on November 09, 2014, 05:09:27 PM
I have been fiddling with the valve compliment of the Leak Stereo 20. I came across two E80CC pinched waste tubes in my valve room, and checked them out on the net, turns out they can be used as a substitute for 12AU7s, as you know the leak in that first position uses a 12ax7, I had replaced that with a 12au7, so in that position only and leaving the other two mullard long plate 12ax7s, i dropped in one E80CC..... and WoW  just brilliant. The question is will it cause the amp any problems, i will need to be check this over time, especially the mains transformers temperature, but for now the sound is just marvellous. Much better than any tube I have tried in that position. The model I am using is a pinched waste E80CC Special Quality made in Holland in 1957 with the Heleen made delta mark on the bottom of this tube not on the side as with later models, the Best available... they are very tall about twice the height of the normal 12au7 or 12ax7. This model pinched waste E80CC is the best out there, and not cheap, but well worth it. Why is the waste pinched on this tube, because up until around 1958 they could not make the glass sides straight. As to why they sound better, most audiophiles say, the thicker curved glass is the reason.
Title: Re: Leak Stereo 20 Modifications
Post by: zenelectro on November 10, 2014, 05:16:28 AM
Generally speaking if you want to sub a 12au7 for 12ax 7 you should make some circuit changes, they are really different tubes, the au will usually end up running outside it's happy conditions and you won't hear the best it has to offer. The e80cc is a bit different again but ours much more like an au than an ax. If an au sounds good, it's always with trying a bh7, these can sound really good subbing au7's.
If start by making sure the au7 and e80cc are actually even close to working in their proper region.

Surely by now you know how to do this Steven? !!!!  :) :)
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on November 10, 2014, 02:37:15 PM
I have read plenty about this tube, talking to Paul (fallsaudio) he has had a good look and feels this tube is fine to use,  Zen, put your cane away, little tommy tucker will try to be good.
Title: Re: Leak Stereo 20 Modifications
Post by: zenelectro on November 10, 2014, 08:05:26 PM
I have read plenty about this tube, talking to Paul (fallsaudio) he has had a good look and feels this tube is fine to use,  Zen, put your cane away, little tommy tucker will try to be good.

Ok cane away I will be nice to you :)

The AX7 and AU7 are -very- different tubes. Most designs will run an AU7 at 5 to 10 x the current of an AX7. That's a lot.
So if you do a direct sub, the AU7 can easily be almost off the scale with it's operating point. There's a high likely hood that
it won't sound nearly as good as it could. 

The E80 is pretty similar to AU7 so if the circuit is happy with AU7 should be OK with it.


T
Title: Re: Leak Stereo 20 Modifications
Post by: Peter A on November 11, 2014, 10:23:53 PM
Steve,

I have been using Philips E80CC tubes instead of 12AU7 tubes in my Primaluna Two Amp and STC 4212E amps for years.  The E80CC tubes sound great with heaps of authority.  It will transform any tube audio equipment it is used in. 
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on November 11, 2014, 11:14:25 PM
Steve,

I have been using Philips E80CC tubes instead of 12AU7 tubes in my Primaluna Two Amp and STC 4212E amps for years.  The E80CC tubes sound great with heaps of authority.  It will transform any tube audio equipment it is used in.
Why have I not heard of them before, you have been holding out vital valve info. Found 4 more 1961 SQ e80cc straight glass today, gooooooood
Title: Re: Leak Stereo 20 Modifications
Post by: rab on November 12, 2014, 08:38:59 AM
interesting. Would these be a good choice to replace a pair of 12au7s in the output stage ... of a certain Sabre DAC that shall not be named...?  :-o
Title: Re: Leak Stereo 20 Modifications
Post by: klackto on November 12, 2014, 09:20:39 AM
Steven did you make any circuit changes (eg:change cathode resistor) when substituting the 12au7/e80cc for the 12ax7 in the first position?
I've been using Tungsol 5751s for all 3 valves in the driver stage and find them pretty good but I like the idea of lowering the gain a little more. Have some GE branded made in Great Britain (Mullard I presume/hope) 12au7s that I can try.
I do need to get some NOS el84s at some stage as currently only have Russian Mullard reissues.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on November 12, 2014, 02:20:17 PM
Steven did you make any circuit changes (eg:change cathode resistor) when substituting the 12au7/e80cc for the 12ax7 in the first position?
I've been using Tungsol 5751s for all 3 valves in the driver stage and find them pretty good but I like the idea of lowering the gain a little more. Have some GE branded made in Great Britain (Mullard I presume/hope) 12au7s that I can try.
I do need to get some NOS el84s at some stage as currently only have Russian Mullard reissues.
The leak has a massive amount of gain with the 12ax7s, putting in the 12au7 means you are going from about 100 (12ax7)  to 20 (12au7) gain, dropping the gain means a less forced, more relaxed sound, but still having plenty of gain, plus 1950s 12au7 mullard long plates are cheaper than 1950s mullard 12ax7s long plates. Short plate later mullards 1960s are OK. No circuit changes.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on November 12, 2014, 02:21:53 PM
Steven did you make any circuit changes (eg:change cathode resistor) when substituting the 12au7/e80cc for the 12ax7 in the first position?
I've been using Tungsol 5751s for all 3 valves in the driver stage and find them pretty good but I like the idea of lowering the gain a little more. Have some GE branded made in Great Britain (Mullard I presume/hope) 12au7s that I can try.
I do need to get some NOS el84s at some stage as currently only have Russian Mullard reissues.
I have all the tubes you need just ring when ready.
Title: Re: Leak Stereo 20 Modifications
Post by: Peter A on November 12, 2014, 05:56:35 PM
Steve,

The Philips E80CC tubes were in the STC 4212E amps when you heard them.  They are a fantastic tube with balls.  Pity there is not a E8#CC variant for the 12AX7 tube. 

Title: Re: Leak Stereo 20 Modifications
Post by: klackto on November 12, 2014, 07:16:51 PM
I have all the tubes you need just ring when ready.
Thanks, will do!
Been meaning to pay you a visit for ages so will be in touch soon.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on November 14, 2014, 02:16:49 AM
I have been modifying the standard Leak stereo 20, I wanted it to sound good on the cheap, First i fitted 4 Hovland .47 music caps, early one's, then 4-1W Shinkoh resistors 10K. Tonight i dropped in 2 Jensen electrolytic, one dual 100Uf to replace to cap nearest the transformers and one dual 47UF down the other end. That improved the sound dramatically. It now sounds really good.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on November 14, 2014, 02:48:33 AM
I have finally settled on the perfect choke for the full on leak 20. This is the one to get, UTC Special series PA 40. This amp just sounds so good.... to been fair, it's full of the best hand picked stuff so it should sound great, and it does.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on November 14, 2014, 03:47:09 PM
There are plenty of great vintage chokes out there for the leak, or any audio application, UTC generally make great sounding vintage chokes, with this brand its hard to go wrong. This model just works well with the leak. I have no doubt they make others that will work even better, i can only try what i have.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on November 14, 2014, 04:58:28 PM
I have been modifying the standard Leak stereo 20, I wanted it to sound good on the cheap, First i fitted 4 Hovland .47 music caps, early one's, then 4-1W Shinkoh resistors 10K. Tonight i dropped in 2 Jensen electrolytic, one dual 100Uf to replace to cap nearest the transformers and one dual 47UF down the other end. That improved the sound dramatically. It now sounds really good.
  The Leak Stereo 20. Standard this amp was OK sounding, But this exercise shows with just a few well chosen mods and valves, it can be just superb. I have been running this amp all day, It's sounding, just great. The cheaper valves i have chosen for this amp, 1 long plate 12AU7 mullard-1959 in the critical first position, 2 mullard 12AX7 short plates-1960s, 4 Australian EL84s, mullard GZ34. The Leak Stereo 20 is cheap to buy, cheap to modify, and cheap to retube, Most people will never need another amp. For the interested I put a pointer to show where the one watt 10K shinkoh resistors are install.
Title: Re: Leak Stereo 20 Modifications
Post by: kajak12 on November 14, 2014, 09:28:30 PM
I have been modifying the standard Leak stereo 20, I wanted it to sound good on the cheap, First i fitted 4 Hovland .47 music caps, early one's, then 4-1W Shinkoh resistors 10K. Tonight i dropped in 2 Jensen electrolytic, one dual 100Uf to replace to cap nearest the transformers and one dual 47UF down the other end. That improved the sound dramatically. It now sounds really good.
is that for me?
Title: Re: Leak Stereo 20 Modifications
Post by: klackto on January 12, 2015, 01:16:13 AM
Been doing some work on my Stereo 20.
Had fitted  choke previously and also recently changed output valve cathode resistor bypass caps to 30uf Solen PB mounted along 1 side.
Did some more work today nd put in 47uf Jensens for the driver cathode resistor bypasses.
I previously had a combination of Auricap and  Hovland coupling caps such in theory should have worked well in combination but somehow it wasn't quite doing it for me.
The amp lacked the musicality it had when I had Jensen copper foils which were bloody unreliable.
I had some 0.47uf copper foil Ampohm caps that were bought for a project that never eventuated
and ordered some 0.1uf Ampohm tin foils for the driver stage.
I know I committed the cardinal sin of making more than one change at a time, but hey, patience was not always my forte.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on January 12, 2015, 07:00:05 PM
Been doing some work on my Stereo 20.
Had fitted  choke previously and also recently changed output valve cathode resistor bypass caps to 30uf Solen PB mounted along 1 side.
Did some more work today nd put in 47uf Jensens for the driver cathode resistor bypasses.
I previously had a combination of Auricap and  Hovland coupling caps such in theory should have worked well in combination but somehow it wasn't quite doing it for me.
The amp lacked the musicality it had when I had Jensen copper foils which were bloody unreliable.
I had some 0.47uf copper foil Ampohm caps that were bought for a project that never eventuated
and ordered some 0.1uf Ampohm tin foils for the driver stage.
I know I committed the cardinal sin of making more than one change at a time, but hey, patience was not always my forte.
Love that line (patience was not always my forte) I think its always been a problem for most audiophiles. Interesting combination, how does the amp sound now.
Title: Re: Leak Stereo 20 Modifications
Post by: klackto on January 19, 2015, 12:32:41 AM
Finally had a chance to have a decent listen yesterday. Early days but the easiest way to describe the change is that the "inner glow" of music is portrayed more effectively. I had previously had a mod done to the feedback circuit in an attempt to reduce gain but have now returned it to stock.
I'm using the Leak in a second system in a spare bedroom using speakers I knocked up a while back using bamboo ply and diatone clone drivers from eBay.
Title: Re: Leak Stereo 20 Modifications
Post by: klackto on January 19, 2015, 12:39:53 AM
Here's a pic of the speakers.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on January 19, 2015, 01:49:32 AM
I have my second Leak Stereo 20 in my bedroom with the 47 Lab lens speakers. I need good bass and weight with these small fullrange drivers, so i have the speakers right up against the wall,  the sound is just superb
Title: Re: Leak Stereo 20 Modifications
Post by: Jehuty on February 11, 2015, 11:02:52 AM
You have too many Leak amps. Are they really that good? Or is it just a myth? http://www.stereo.net.au/forums/index.php?/topic/78049-the-myth-of-leak-amplifiers/

 :P
Title: Re: Leak Stereo 20 Modifications
Post by: kajak12 on February 13, 2015, 09:31:37 PM
You have too many Leak amps. Are they really that good? Or is it just a myth? http://www.stereo.net.au/forums/index.php?/topic/78049-the-myth-of-leak-amplifiers/

 :P
Trust STEVEM to start the thread lol  :P :P :P :P
Title: Re: Leak Stereo 20 Modifications
Post by: klackto on April 04, 2015, 12:23:31 PM
We were up in the mountains for a weekend in January and I managed to take the time to visit Steven.
Big thanks to Steven and his wife and had a very enjoyable evening catching up and enjoying some great music and fine sound.
While I was there we tried my modified Leak Steven's Quads and while it was pretty good, Steven spotted a potential (no pun intended) problem with a couple of the Ampohm cans possibly shorting against some resistors.
So next day I fire up the soldering iron and reposition the caps so as to give more clearance to the board and when I fire it up there's a high frequency howl on one channel .......... wtf :o ?????
So fast forward a couple of days and find out my brother in Melbourne had a stroke so the whole audio thing was put on hold for a while.
He's now staying us while he is recuperating and yesterday thanks to the rain, I managed to have another look at the stereo 20.
The solens I had fitted for the el84 cathode resistor bypass were supported by stick on pads and cable ties.
Probably due to the amp being moved around one of the caps was loose and had pressed on the 1k resistor to the driver tube and one leg had come away.
I desoldered the resistor and had some 10mm angle aluminium I had bought a while ago as I was never comfortable with those stick on pads and spent a couple of hours attaching the solens much more securely and thankfully all seems well with the Leak again : :)
Hope to make another trip up to the mountains soon.
Title: Re: Leak Stereo 20 Modifications
Post by: klackto on April 04, 2015, 07:10:25 PM
Meant resoldered the resistor .... not desoldered.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on April 07, 2015, 09:00:59 PM
Picked up 4-Jupiter Copper Foil 0.47uF 600VDC. I will remove the 4-Duelund Copper Foil 0.47uF VSF from the leak stereo 20, I will give them a good run in, lets see how good they are.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on April 23, 2015, 06:25:37 PM
Just replaced the 4-Duelund Copper Foil 0.47uF VSF with the 4-Jupiter Copper Foil 0.47uF 600VDC. I ran flying leads so I can try both ends of the caps for best sound, plus easily changing back to other capacitors for evaluation. The amp is running as i type.
Title: Re: Leak Stereo 20 Modifications
Post by: Rob181 on April 25, 2015, 09:24:44 AM
Looking forward to hearing your thoughts...Dueland Vs Jupiter...
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on May 04, 2015, 07:50:47 PM
I have been running in the 4-Jupiter Copper Foil 0.47uF 600VDC capacitors for about a week now, the impression is very good despite the use of silver lead-in and lead-out wires being used on the caps. Can I hear the silver, yes it's particularly obvious in the high frequency's, there is a slight white lean metallic sheen typical of silver, I have been told these caps need a long run in and to expect a marked change, so I will do that before any major comment.  Have they reached 4-Duelund Copper Foil 0.47uF VSF territory, no not yet, but already they outperform them in Clarity and detail, they are particularly good in understanding diction.   
Title: Re: Leak Stereo 20 Modifications
Post by: rab on May 15, 2015, 10:45:56 PM
Thanks Steven, that's very interesting; might have to try some.

Incidentally, here's a blog post of only 1 week ago describing the restoration of a Leak TL10.1:
http://truefi.blogspot.com.au/2015/05/vintage-treasuries-restauration-of-leak.html (http://truefi.blogspot.com.au/2015/05/vintage-treasuries-restauration-of-leak.html)

- r
Title: Re: Leak Stereo 20 Modifications
Post by: ozmillsy on May 22, 2015, 06:23:44 PM
I have been running in the 4-Jupiter Copper Foil 0.47uF 600VDC capacitors for about a week now, the impression is very good despite the use of silver lead-in and lead-out wires being used on the caps. Can I hear the silver, yes it's particularly obvious in the high frequency's, there is a slight white lean metallic sheen typical of silver, I have been told these caps need a long run in and to expect a marked change, so I will do that before any major comment.  Have they reached 4-Duelund Copper Foil 0.47uF VSF territory, no not yet, but already they outperform them in Clarity and detail, they are particularly good in understanding diction.

Hey Steven,  I was browsing around the Soniccraft website, looking for thicker gauge jupiter wire,,  and I noticed these (copper leads, paper in beeswax),,,,,

http://www.soniccraft.com/product_info.php/jupiter-vintage-cu-lead-047uf-600vdc-p-4516 (http://www.soniccraft.com/product_info.php/jupiter-vintage-cu-lead-047uf-600vdc-p-4516)

Quote
The sound is extremely warm and rich with perhaps a bit more detail than many PIOs.

The price looks reasonable enough to try.  Pity they are not in production anymore.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on May 22, 2015, 08:59:15 PM
Well, I have had a good listen to the 4-Jupiter Copper Foil 0.47uF 600VDC capacitors, Just put back the  4-Duelund Copper Foil 0.47uF VSF, Thoughts on the Jupiter Copper Foil 0.47uF capacitors soon. Being a little crazy I have removed the UTC choke and tried some Duelund 50R resistors in it's place, I had to put two in series to get the 100R value, as i type they sound promising,   
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on June 02, 2015, 10:53:19 PM
Well the Jupiter Copper Foil 0.47uF 600VDC capacitors have some great characteristics, including Transparency, speed, detail, they are also fairly open and extended. The weakness, they are a little lean, bright, and white, also they don't have the duelunds lovely lower midrange weight, warmth and energy, they lacked a little timbrel character. I feel that the Jupiters weaknesses stem from the use of the silver lead-out wires, sure these leads will give you clean transparency, but at what cost. Unfortunately most capacitor makers seem to be going down the silver route. They did many things better than the Duelund Copper Foil 0.47uF VSF, but at the end of the day the duelunds had more involvement weight and natural timbre.

There is a caveat, Jupiter sent me an email. quote
The caps are non polar, but to use the outside foil as a shield connect it to the lower impedance side of the circuit.
Chris Young
Jupiter Condenser.
 
Craig has listened to the Jupiter capacitors and feels they sound just superb, but only when they are installed in the right direction, if they are not set in the right direction they will sound ordinary. They are marked with a stripe but that mark is sometimes wrong and reversed in manufacture, (despite what the manufacturer says) unless you can measure them it's hard to know if they are the right way around. I used 4 and that allows for a multitude of wrong combinations. I will send mine to Craig to get right orientation and listen again.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on June 15, 2015, 12:12:23 AM
Some new capacitors for the second Leak Stereo 20, these capacitors are not a red Wima clone. The brand is STLX. Ian will soon explain there claim to fame. I am now running them in.
Title: Re: Leak Stereo 20 Modifications
Post by: brenden on June 15, 2015, 10:48:58 PM
I will post some info later Steve , my internet is down for another week on the computer and doing this on the phone is a pita. These are Rubycon STLX film caps that have a huge amount of lead attachments at different intervals around the foil. This is said to result in vanishingly low impedence .The cost to build would have been horrendous and I am guessing they would have been an unviable commercial product. These are extremely rare and probably shouldnt have let Steve see them cause he wont give them back .......Doh
Title: Re: Leak Stereo 20 Modifications
Post by: ozmillsy on June 16, 2015, 09:11:35 AM
These are extremely rare and probably shouldnt have let Steve see them cause he wont give them back .......Doh

LOL !!   
Title: Re: Leak Stereo 20 Modifications
Post by: Jehuty on June 16, 2015, 09:28:33 AM
These are extremely rare and probably shouldnt have let Steve see them cause he wont give them back .......Doh

You learned the hard way Ian... :-X
Title: Re: Leak Stereo 20 Modifications
Post by: brenden on June 16, 2015, 01:50:11 PM
In all seriousness Steve has been extremely helpful and welcoming, so I am more than happy to share the experience of these great parts.
     I often  aquire  more than I need for future use as well as friends who may like to try something  and that includes the KD guys .When I find a superior part thats uncommon or rare it i like  to grab them while they are there.
     I have 2 more of the rubycons for my own cd .Hopefully more will turn up one day .
Title: Re: Leak Stereo 20 Modifications
Post by: brenden on June 25, 2015, 01:09:27 PM
Here is a diagram someone drew showing how the Rubycon film caps are constructed .I cant imagine this was an easy task .
Title: Re: Leak Stereo 20 Modifications
Post by: omodo on June 25, 2015, 02:06:05 PM
Here is a diagram someone drew showing how the Rubycon film caps are constructed .I cant imagine this was an easy task .

yeah, looks like a difficult drawing...  :P kudos
Title: Re: Leak Stereo 20 Modifications
Post by: brenden on June 25, 2015, 06:12:51 PM
imagine trying to build one ?
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on June 30, 2015, 08:41:28 PM
I have finished the cheaper Modified Leak Stereo 20 for the 47 Lab speakers and have installed ETI Speaker posts and female sockets plus more 2 watt shinkoh resistors.  The finished valve combination. 1 pinch waist D foil getter, E80CC made in Holland. 2 mullard long plate goal post getter, Blackburn made in 1957. 4 mullard 1961 Blackburn made, hole in plate, EL84. 1 Blackburn made GZ34 rectifier. The combination is riveting, so good it's hard to believe there is a better push pull amplifier out there. Not an amp for head bangers, if you what music that is engaging, emotional, and beautiful, this is it. It Just sounds magnificent, Here is a picture.     
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on August 01, 2015, 08:12:59 PM
As readers know i have been fiddling with different chokes on the full-on leak stereo 20, this choke is really good, its a UTC, CG40, but as you can see it's very impractical to use because of the size, eventually i have to fit one somewhere. I could bolt it on the top of the amp, but this amp is nearly mint and that feels like sacrilege, As for which amp I prefer, the answer soon. 
Title: Re: Leak Stereo 20 Modifications
Post by: klackto on August 02, 2015, 10:13:28 AM
I have one of those chokes as well, so I'd be interested to hear your impressions.
Like you though, I'm not sure I could cope with one of those sticking out the top of my Stereo 20.
Hope everything is ok in your neck of the woods ... heard there's been fires up your way.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on August 03, 2015, 06:43:29 PM
I have been trying to tune the 2 leak stereo 20s, interestingly they both prefer the same type of power cord. I have made various types to suit the application, my normal choice is nearly always a solid core wire about the thickness of internal house wire, and in most applications it works well, but not with these leaks. This is the way to do it, They need a copper multi stranded wire, then connect vintage 1930,40,50,60, male wall plugs with the copper or brass prongs, as you know the newer plugs made today are some type of bright metal and sound like sh!t. I used the original old leak English plugs on the amp end, they are brass or copper and do sound very good, so leave them on your leak. Always clean the tarnish from the old plugs with emery paper, finally use ferrite red rollers or similar to lower to noise from the mains. These power cords sound just great with both leaks. Simple cheap and effective power cord. Remember it's always a synergy thing.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on August 13, 2015, 08:44:13 PM
As I have said i finished the budget Modified Leak Stereo 20, but I just had to see if I can tune it to sound as good as the full on amp. Could i make this cheaper Jensen electrolytic based stereo 20 amp sound as good as the full on solen duelund Stereo 20 amp, I needed to make up for the cheaper amps deficiency's because it used electrolytic capacitors. Typically electrolytic capacitors sound thinner, artificial, and slightly anemic compared to the best quality polypropylene or oil caps. One way to accomplish this task is to use different era valves, so i grabbed my obvious choice, some early D getter 1950s Blackburn RX1 EL84s, why, because they sound far fuller liquid richer and fatter that the later 1960 varieties, it turned out an inspiring choice, These early D getter 1950s Blackburn RX1 EL84s really make up for the leanness that invariably manifest itself with the use of electrolytic caps and its comparatively on the cheap, you can buy a set for a lot less than the price of the expensive amps 4 / 0.47 VSF duelunds. Now the amp is very very close to the expensive solen duelund modified amp. The finished valve combination for a budget Leak Stereo 20, 1 pinch waist 1950s D foil getter E80CC made in Holland. 2 mullard long plate goal post getter Blackburn made in 1950s, plus 4 D getter 1950s Blackburn RX1 EL84s, hole in plate. 1 Blackburn made GZ34 rectifier or Amperex GZ34. The valve choice for the full on Duelund Leak Stereo 20 is almost the same but use the later 1960s Blackburn mullard RX2 or RX3  EL84s, with the hole in plate.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on September 14, 2015, 10:29:46 PM
I decided to compare a choke v the 100R resistor on the cheaper leak stereo 20. This leak always sounded a little rough, cause, and ragged, compered to the other leak, so i fitted the choke (as per pictures below) and Wow its so much better in every way, all those problems are now gone, there's now an obvious lack of grain, it's smoother, ordered, and in control, a rightness to the music, you can hear what the removal of noise has done, what's left is all the benefits. There is no more debate, a quality choke is the way to go.
Title: Re: Leak Stereo 20 Modifications
Post by: zenelectro on September 15, 2015, 08:42:24 AM
I decided to compare a choke v the 100R resistor on the cheaper leak stereo 20. This leak always sounded a little rough, cause, and ragged, compered to the other leak, so i fitted the choke (as per pictures below) and Wow its so much better in every way, all those problems are now gone, there's now an obvious lack of grain, it's smoother, ordered, and in control, a rightness to the music, you can hear what the removal of noise has done, what's left is all the benefits. There is no more debate, a quality choke is the way to go.

That seems to be the case - in just about every case.

I just doubled the size of the chokes in my DAC and similar effect. Not as dramatic as resistor to choke but still better.

Q - what are those big yellow caps?

PS Nice work! :)
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on September 17, 2015, 06:36:58 PM
I have just fitted the Jupiter copper foil paper-in-oil capacitors and i have been told that a long run in is needed, i have sent them to Craig have the orientation checked and now it's no excuses time, do they cut it. They are replacing the duelund VSF caps so this will be interesting. The amp is playing music as i type, and the sound is very good.
Title: Re: Leak Stereo 20 Modifications
Post by: brenden on September 17, 2015, 07:13:52 PM
Hi Steve , the  Jupiters  do need over 100hrs  probably 150 .They change a lot during burn in  sometimes sounding thinner and then sounding warmer .Can be a bit disconcerting.
    Burnin of the Duelunds seems to be more linear .But after burnin both sound great.

   Terry , the yellow caps are the Rubycons , designed to have extremely low impedence for high end audio.Not made any  more unfortunately.
Title: Re: Leak Stereo 20 Modifications
Post by: ozmillsy on September 21, 2015, 08:11:00 AM
Do you mean Jensons, or Jupiter's?
Title: Re: Leak Stereo 20 Modifications
Post by: brenden on September 21, 2015, 06:37:59 PM
Yep Jupiters. I was just following steves lead without thinking .lol.

   I had flu and horrible sinus headaches for nearly 2 weeks so please excuse my typos .I am back in the land of the living now.thank god .
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on September 21, 2015, 10:02:46 PM
Do you mean Jensons, or Jupiter's?
You are right, It's Jupiter's, fixed it.
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on September 24, 2015, 07:09:29 PM
The Jupiter Copper Foil 0.47uF 600VDC capacitors have been running for about 5 days and I can say these are one great sounding capacitor, one of the best out there. Upon comparing them to the best I have heard, (Duelund Copper Foil 0.47uF VSF the capacitor), they are very different, but very close in performance, each with its strengths, the Jupiter may be a little leaner, slightly brighter, and whiter, and do not have the duelunds lovely lower midrange on down bloom, weight and warmth, but they have a beautiful upper midrange clarity plus an all over sweetness and lack of distortion. Some audioheads will prefer the Jupiter's detailed smooth clean sweet character, but the final decision is always system dependence. A fine capacitor and with more run in time they can only improve.
Title: Re: Leak Stereo 20 Modifications
Post by: brenden on September 25, 2015, 01:10:14 PM
Hi Steve . This mirrors my experience even though I am  not directly comparing them in the same position .
    I am using the Jupiters as power supply bypasses and the duelunds in the output coupling .at the moment . Both are magic.There is a wonderful calmness and lack of  distortion  with the Jupiters without any loss of dynamics or resolution .
    For me the .01 as a bypass on the power supplies  and Duelund on the output is a match made in heaven , not to mention my other copper foil polystyrenes and pps caps in critical digital areas .They all   contribute  their bit toward incredible digital playback .
  At some stage I will do a direct comparison on the output with the Jupiters and another few top flight caps but for now I dont feel like I am missing  out on anything whatsoever .
   
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on April 23, 2016, 03:02:27 PM
Some new capacitors for the second Leak Stereo 20, these capacitors are not a red Wima clone. The brand is STLX. Ian will soon explain there claim to fame. I am now running them in.
I have changed back to the Jupiters copper foil, i need to put in a lot of miles before i comment on them. Getting this cheaper leak to the same standard as the duelund leak is proving to be a challenge. 
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on November 04, 2017, 02:15:51 PM
I have changed back to the Jupiters copper foil, i need to put in a lot of miles before i comment on them. Getting this cheaper leak to the same standard as the duelund leak is proving to be a challenge.
I have completely rebuilt this Leak in the last month i will post pictures soon. The bottom line seems to be, ONLY THE BEST WILL DO...........
Title: Re: Leak Stereo 20 Modifications
Post by: stevenvalve on November 16, 2017, 11:31:32 PM
Rebuilt this Second Leak Last Month, I really had too, because the second Leak 20, filled with B grade parts just did not have the same Magic as the main Leak, so it was just a case of put in what i had. Everything i installed was spare and i thought why leave 2 Watt resistors like Allen bradley, Shinkok, and old Andionote, and the even the new audionote models sitting unused in a box. I just measured and installed the right values and amazingly i ended up filling all the resistor places in the leak, but with no real tuning pattern just what fitted and to my real surprise the amp sounded superb, just goes to show that 2 watt quality resistors even randomly installed still work better as a hole than the 1 watt standard stuff. Then it was just a case of installing the worlds best capacitors Duelund VSF copper and a few well placed Solen PB 15uf capacitors, plus a partridge 8 Henry 200 ma choke. The sound now is really close to the full on leak stereo 20 but it is still a cheaper rebuild. But really i must say its not that cheap a rebuild anymore. One big problem is the Duelund VSF copper is so much better than anything out there, what does one do.