Author Topic: Leak Stereo 20 Modifications  (Read 23479 times)

Offline stevenvalve

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Leak Stereo 20 Modifications
« 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.
« Last Edit: September 18, 2015, 09:54:47 PM by stevenvalve »

Offline Tuyen

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Re: Leak Stereo 20 Modifications
« Reply #1 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

Offline stevenvalve

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Re: Leak Stereo 20 Modifications
« Reply #2 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.

Offline gamve

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Re: Leak Stereo 20 Modifications
« Reply #3 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. ::)

Offline mcb

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Re: Leak Stereo 20 Modifications
« Reply #4 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. 

Offline PingPing

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Re: Leak Stereo 20 Modifications
« Reply #5 on: May 05, 2014, 09:47:08 AM »
Super neat job Steven... how does it sound  :)

Offline stevenvalve

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Re: Leak Stereo 20 Modifications
« Reply #6 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.
« Last Edit: May 15, 2014, 07:53:11 PM by stevenvalve »

Offline data

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Re: Leak Stereo 20 Modifications
« Reply #7 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.

Offline stevenvalve

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Re: Leak Stereo 20 Modifications
« Reply #8 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.
« Last Edit: May 15, 2014, 07:56:23 PM by stevenvalve »

Offline MrRogers

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Re: Leak Stereo 20 Modifications
« Reply #9 on: June 07, 2014, 02:19:22 PM »
Looking forward to having a listen soon.
Audio Origami PU7 "the world's most musical pick-up arm"
Australian Distributer

Offline stevenvalve

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Re: Leak Stereo 20 Modifications
« Reply #10 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.
« Last Edit: August 05, 2014, 07:30:22 PM by stevenvalve »

Offline Jehuty

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Re: Leak Stereo 20 Modifications
« Reply #11 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.
Not all that matters can be measured, not all that can be measured matters.

Offline stevenvalve

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Re: Leak Stereo 20 Modifications
« Reply #12 on: August 05, 2014, 11:36:23 PM »
I Do what my ears tell me, Or should I say, what the Cello said

Offline ozmillsy

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Re: Leak Stereo 20 Modifications
« Reply #13 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) 
It's all about the music,, not the equipment.

Offline Jehuty

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Re: Leak Stereo 20 Modifications
« Reply #14 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
Not all that matters can be measured, not all that can be measured matters.

Offline springcreek

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Re: Leak Stereo 20 Modifications
« Reply #15 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

Offline stevenvalve

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Re: Leak Stereo 20 Modifications
« Reply #16 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.
« Last Edit: September 07, 2014, 05:56:29 PM by stevenvalve »

Offline vitavoxdude

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Re: Leak Stereo 20 Modifications
« Reply #17 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.
We all like different things so lets all agree to disagree and if any common ground is found then worship it.  Mine is the KD hence being present on this forum.

Offline klackto

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Re: Leak Stereo 20 Modifications
« Reply #18 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?

Offline stevenvalve

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Re: Leak Stereo 20 Modifications
« Reply #19 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.
« Last Edit: July 24, 2015, 08:08:41 PM by stevenvalve »