Author Topic: Upgraded Leak  (Read 2408 times)

Offline bhobba

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Upgraded Leak
« on: December 10, 2013, 07:11:58 PM »
Hi Guys

At the recent AMP GTG at Mike's I was very impressed with a heavily upgraded Leak I heard (see attached pickie).  In fact some thought it the best amp there.  A similar upgraded Leak was the best amp at a GTG earlier in the year in Canberra.

Got one myself to upgrade and thought it might be interesting documenting my experiences upgrading it here.

Got some supposed gun valves from Stevenvalve - they are supposed the bee knees - don't know too much myself - but many here probably do:

3 - 1950s /60s NOS new in box Siemens 5751= E83CC / 12AX7 / ECC83 Triple Mica Tubes.

3 - 1950s /60s NOS new in box Siemens 5814A =E82CC / 12Au7 / ECC82 Triple Mica Tubes.

4 - 1950s /60s NOS Mullard EL84 Tubes.

1 -1950s/60s NOS  Mullard GZ34 Tube.

Can report what they do when I get a bit of time.  At the moment the power chord that came with the Leak needs to have an Australian plug to work.

On another front my Killer DAC has finally been finished  ;D ;D ;D ;D ;D ;D ;D ;D

It's being run in right now and have made arrangements to take my Off-Ramp over to Rawl99 between Christmas and New year for its first serious listen.  The input of the Leak will be adjusted for direct connection to the Killer - love that direct connecting.

Thanks
Bill

Offline Jehuty

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Re: Upgraded Leak
« Reply #1 on: December 10, 2013, 08:53:07 PM »
Hi Bill,

Congratulations on your Leak and I see that you've already got a good selection of valves to run the Leak. A couple of questions if you don't mind, what do you mean by direct connection from the KillerDAC to the Leak? Are you going to use Duelund CAST for the coupling caps?

Cheers,
William
Not all that matters can be measured, not all that can be measured matters.

Offline bhobba

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Re: Upgraded Leak
« Reply #2 on: December 10, 2013, 09:24:40 PM »
Hi Jehunty

Good questions mate.

I use computer audio and there is a high quality dithered volume control in the software I use - Audirvana.   So what you do is get the amps sensitivity adjusted so you don't have to reduce the volume much.   You then direct connect the DAC to your amp and use that volume control.  Provided you keep the reduction less than about 10db its inaudible, and to be blunt beats the hell out of any pre I have ever heard - and best of all the price is right - costing nothing.

Will try to fit Cast in there if there is room - otherwise may have to settle for VSF copper.

Thanks
Bill

Offline Jehuty

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Re: Upgraded Leak
« Reply #3 on: December 10, 2013, 09:41:55 PM »
Hi Bill,

Very interesting! Most of the volume pots I have heard degrades sound quality so I think it's a very good move to direct connect, if it's done correctly.

I think you'd be able to fit Duelund CAST for the coupling caps. The standard value of coupling caps in the Leak 20 is 0.22uF. The size of Duelund CAST for that value is 34mm D x 41mm H and the chassis height of the Leak 20 amp is almost 55mm, so there's enough space to fit them. However, it would be harder if you choose for 0.47uF Duelund CAST considering the dimension is 34mm D x 62mm H.

Good luck with the mods. I would be following closely as I'm modding mine as well.

Cheers,
William
Not all that matters can be measured, not all that can be measured matters.

Offline springcreek

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Re: Upgraded Leak
« Reply #4 on: December 17, 2013, 08:05:52 AM »
Hi Bill

Welcome to the fold mate. You have some wonderful valves there to run with your leak. Did you replace the power supply caps? Might be a very good move given the age of those old electrolytics. 

Glad your Kdac is finally finished....the worlds longest wait it would seem!

I would love to hear the Offramp into the Kdac then into a tricked out leak, that could be a very good combo!

Cheers, Andy

Offline bhobba

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Re: Upgraded Leak
« Reply #5 on: December 17, 2013, 11:39:44 AM »
Hi Guys

Heard the Leak for the first time yesterday on ML2 Limited down at Mikes.

With the supplied tubes one of the best valve amps I have heard - but, as you would expect, not up there with the the heavily modified one I head at the GTG that so impressed me. Lovely sound - but speed was the issue in comparison to the Arion 500's.

Changed to the better valves.  Instantly better - a lot closer to the one at the GTG - but still not quite there yet.  Cleaner and clearer - but again speed didn't quite match the Arion. 

Decided to use Duelund VSF Copper because I don't think the Cast will fit, and have ordered them.  When they arrive will get them installed and have the resistors upgraded and electrolytics replaced then see what that does.

Very promising so far.

Thanks
Bill

Offline bhobba

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Re: Upgraded Leak
« Reply #6 on: December 17, 2013, 11:41:51 AM »
Hi Andy

See the post above.

Yes it has been a long wait for the Killer - but I am sure it will be worth it.

Thanks
Bill


Offline springcreek

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Re: Upgraded Leak
« Reply #7 on: December 17, 2013, 02:22:08 PM »
Nice one Bill

Best to use something other than electrolytics in the power suppy. Solens are good. I'm keen to try nice big vintage PIO and an oil filled choke...but I need to build another chasis for that!

Offline Jehuty

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Re: Upgraded Leak
« Reply #8 on: December 17, 2013, 02:26:41 PM »
Hi Bill and Andy,

Please don't write off electrolytics too soon, they can be good too in the right place. KillerDAC and even Steve's type 50 amp use electrolytics  ;)

Cheers,
William
Not all that matters can be measured, not all that can be measured matters.

Offline springcreek

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Re: Upgraded Leak
« Reply #9 on: December 17, 2013, 09:24:57 PM »
 :o :o :o :o

Offline hedalfa

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Re: Upgraded Leak
« Reply #10 on: December 18, 2013, 08:43:25 AM »
:o :o :o :o

I thought electros were to be removed like the black spot????
« Last Edit: December 18, 2013, 05:29:23 PM by hedalfa »

Offline Jehuty

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Re: Upgraded Leak
« Reply #11 on: December 18, 2013, 05:18:51 PM »
Cheap electros yes, remove them as soon as you can. High quality ones are good though, I remember Steve tried a Solen in place of an electrolytic in his KillerDAC but he didn't like it  ;)
Not all that matters can be measured, not all that can be measured matters.

Offline hedalfa

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Re: Upgraded Leak
« Reply #12 on: December 18, 2013, 05:30:00 PM »
Cheap electros yes, remove them as soon as you can. High quality ones are good though, I remember Steve tried a Solen in place of an electrolytic in his KillerDAC but he didn't like it  ;)


Interesting....

Offline bhobba

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Re: Upgraded Leak
« Reply #13 on: December 22, 2013, 03:34:10 PM »
Hi Guys

Ordered the VSF Copper to replace the .25 coupling caps to the output valves, and Jensons for the power supply electrolytics from Mike.

Had a chat to Steve and Craig whose upgraded Leaks I heard, and they said they used whatever they had lying around such as Allen Bradleys for the resistors and Duelund Alexanders for some of the coupling caps.

I don't have parts lying around so decided on a more scientific approach.  Had a look at the circuit diagram and removed the grid resistor into the input valve because it will be replaced by a pad to adjust sensitivity.  This left some 10k resistors in the signal path at the output valve grids and after the coupling caps - am getting the best resistor I know for that - naked Z-Foils.  The rest will be 2 watt Amtrans carbon films.

Here is an interesting comparison between the two:
http://www.diyaudio.com/forums/tubes-valves/190095-resistor-test-tx7525-amrg-cmf55.html

The Z-Foil sounds really open. Big bass sound, the strings of my stratocaster seemed to come out more out of the speakers, very good separation of the single string, rich in detail, reminded to a piece of wire. They have the tendency not to make sound. On the other hand, they are the most technically sounding resistors. At some cathodes I liked these most, but not at all places. As always a matter of taste.

These black beauties (Amtrans) sounded very open, airy with a little sweet touch, in a musical sense wonderful, but a little sound making. Big bass too. At some places I loved these most, but not everywhere.

I was told an interstage .1uf coupling capacitor wasn't that critical so decided on an Obligato Gold rather than the whole hog of a Duelund.  The 50uf electrolytic bypass capacitors will use Jensens - but may switch to film if space permits.

Small capacitors will be silver mica's.

Hope to get some high end wire from Mike he wires all his speakers with and change terminals etc to Eichmann.

Anyway that's it for now.

Have to wait for the parts to arrive for the new amp to take shape.  Since its Christmas no use ordering now anyway - will wait for the New Year.

But this is only a start - I have been told by Steve and Craig its a never ending process.  Those guys advised doing a bit at a time.  The resistors are relatively cheap (all up cost with Jensons, Obligatos etc only $250.00 or so) so I thought what the heck - go the whole hog to start with then tweak.

Thanks
Bill

Offline Jehuty

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Re: Upgraded Leak
« Reply #14 on: December 22, 2013, 07:20:16 PM »
Hi Bill,

Very nice parts selection there. I bet it would sound great.

Cheers,
William
Not all that matters can be measured, not all that can be measured matters.

Offline bhobba

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Re: Upgraded Leak
« Reply #15 on: March 21, 2014, 08:17:49 PM »
Hi Guys
 
Well the first stage of my Leak upgrade has been finished.
 
This was everything except the power supply electrolytics which will be replaced with Jensens, and the interstage coupling caps that are Russian Paper In Oil at the moment but will be changed to Duelund VSF Copper.
 
This is one fine sounding amp.  It's very transparent an neutral. 
 
I compared it to an upgraded Prima Luna and my initial reaction was the Leak was slightly more neutral and fluid, the Prima Luna Luna slightly more lively and sweet.  The Leak did it for me just a bit better.  But a lot more listening will be required.
 
Thanks
Bill