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Leak Stereo 20

Just tested the 641 box-plate ECC83 and it measures the way known NOS tubes seem to on the Orange, which is around 7-8 on the scale (in fact exactly 7/8, so not a perfect triode match). It is definitely an ECC83! I’m listening to it in the Leak’s input position and it is sounding very nice and not bright as I remembered. Certainly dynamic and tight, and maybe a bit more upfront. It has that wonderful 3d, clean and natural Mullard top-end. I’ll leave it in for a week or two and then go back to the I61 and see which I prefer.

PS I’m really astonished by the bass that comes out of JR149s with this amp, at the level I listen at you’d really think they were an SBL-sized speaker. Obviously there is a volume envelope as nothing alters basic physics, but within that headroom they kick out a surprisingly big and deep sound with wonderfully tight and agile bass.
 
Listening to The Chieftains and Ry Cooder with a Mexican band "San Patricio" (strange musical mix but good) on mine right now at pretty high volume and this is sounding fantastic. You can almost smell the fajitas!

If only there was really matter transportation so I could lend you this modded one for the evening Tony! I think you'd get a shock how much more there is to come from those transformers and that topology;)
 
Just to follow up on the position #1 ECC83 rolling I’m back where I started with an early ‘60s I61 Mullard which in my system, to my taste etc I prefer to both the 641 box-plate or the F92 long-plate. There is not as much in it as I remembered, all are very good, though the I61 just seems to have a bit more acoustic bloom and warmth to the sound, it just sounds that little more natural with jazz/classical to my mind but still plenty of punch. Interesting given the F92 and box-plate are both very rare and valuable valves!

They all measure great, the same as NOS on the Orange so I’m comparing healthy valves. I’m very pleased I bought the little valve tester, it is a useful thing!
 
Nearly 12 months since we saw anything on this thread.
And I was looking for a bit of a locked down project when this came along from the Pink Fish classifieds.









As you can see not 'original' as Mr. Leak intended.
Looks as if a previous owner had tried to split the power supply in two, left and right. Replaced the GZ34 with silicon and emptied their capacitor spares box in there too.
Happy days.
 
Ouch. If it was mine I’d strip it right back to the bare tag board and start again from scratch. Just get everything non-Leak right out of there and bin it! With some time and effort I’m sure it could be turned back into a Stereo 20 assuming the transformers are ok.
 
Wow! Lots of work needed for this one - Do love a good ‘from scratch’ restoration project! Look forward to seeing your progress.
 
Oh wow! That's my first St20 from when I was about 18!. The weird stuff with green and red wires and bare wires etc wasn't me... hadn't seen that before.
I'd have done the mods when I was about 21 (55 now) and you'll find it's all good. No attempt was made to make it look neat. Bypassing all electrolytics with film caps was considered de rigour at the time... I wouldn't bother these days. Resistors are all metal film and will still be fine. Most of the film caps and the green Welwyn wire wounds are Post Office spec and from the Hartlepool GEC factory which made telephone exchanges back then. It employed about 6000 people and no longer exists...
Note for example the red 0.25uF 160V caps bypassing the electrolytic can at bottom right are in series to give the voltage handling.
Parts are strictly what would have been to hand and would do the job... no on-line ordering of parts then and would have been a postal order off to maplins or such like and wait 10 days or more back then... Hence several wirewounds are a larger power handling than was required and physically bigger. Other parts in series or parallel to get value correct.
It was all properly worked out and job was a gud 'n. I see it's been vandalised to make it way inferior by putting it back to standard though.... Presuming no major parts failures you could just have put new valves in and away you go.
Isn't life funny.... you get re acquainted with a real blast from the distant past and are astounded to see that not only did it still exist but had obviously been used as I built it for decades afterwards... only to see it destroyed a moment afterwards...
 
Aha I see there's been an issue with a valve holder flashing over and tracking.... that's no doubt what took it out of service then...
 
Looking good. If needed, I have a spare McMurdo B9A base if you have no luck resurrecting the ‘leaky’ one.

I also have some brass solder tags very close to the originals in size, that just need the curved ends filed flat and solder coated to look as per Leak’s originals, if needed. I have several to replace on my currently on-hold ST20 resto project. Have some rivets too to fix them, but as I have no appropriately sized riveting gun or press I’m using tin snips to create four ‘petals’ in the ends, and folding those over against the rear side of the board, which will hopefully be strong enough to hold in place once the components are soldered in, and be a near invisible repair too.
 
I sold it in a personal emergency in order to buy a rear tyre for my motorbike so I could go and take up a job motorcycle courier in that London.... IIRC for either £60 or £80!
 
Jez,
That is more than coincidence, what a story, thanks! Some history the old girl has.
I am sure some one else has been in there since you. The transformers have been off (one shell is a different colour to the rest) and old copper Marantz screws used in a couple of places.
Another obvious fault is that one of the HT+ red wires is very brittle and failed in two places. One here and again next to the OPT.



You are correct, all the red GEC caps measure perfectly as do the Lenco and LCR ones. In fact only the cathode bypass caps are u/s. And the only carbon resistor (1k on the phase splitter) has drifted.

@ John 73, yes this one has lost a few tags too. Like you I have a recovery method using ring tags. Thanks for the socket offer, I am using modern under chassis Belton types as I have them to hand.
 
snowman_al said:
Jez,
That is more than coincidence, what a story, thanks! Some history the old girl has.
I am sure some one else has been in there since you. The transformers have been off (one shell is a different colour to the rest) and old copper Marantz screws used in a couple of places.
Another obvious fault is that one of the HT+ red wires is very brittle and failed in two places. One here and again next to the OPT.



You are correct, all the red GEC caps measure perfectly as do the Lenco and LCR ones. In fact only the cathode bypass caps are u/s. And the only carbon resistor (1k on the phase splitter) has drifted.

@ John 73, yes this one has lost a few tags too. Like you I have a recovery method using ring tags. Thanks for the socket offer, I am using modern under chassis Belton types as I have them to hand.
Click to expand...

I bought it for IIRC £20 or £30 from a manager at said GEC plant who was about to retire at the time. His names on the tip of my tongue... but no not quite remembering it... still know someone from GEC who would know it for sure.. academic really... ALL the film caps other than the ones with like LCR or Plessey on them are GEC. Not just the ones which say GEC on them. I still have bags of them left! The original smoothing caps were in a bad way and REALLY bulging so had to go. I would think I've used higher voltage ones to allow for the much higher voltage until the valves warm up and start to draw current. The wirewounds allow for the much lower series resistance of the SS rectifiers compared to the GZ34 and for the "dual mono-ing" (ish) I did. I sold it to Bob Surgeoner of NEAT loudspeakers who sold it on to a customer at his second hand hi fi shop he was running before he became a speaker manufacturer. The £60-80 I got was on the low side even then but I needed cash like NOW and he was taking a punt on a highly non standard one. I've no idea of its history between then and now but I'll guess this is the one that was discussed a few weeks back in the classifieds.
 
snowman_al said:
Jez,
That is more than coincidence, what a story, thanks! Some history the old girl has.
I am sure some one else has been in there since you. The transformers have been off (one shell is a different colour to the rest) and old copper Marantz screws used in a couple of places.
Another obvious fault is that one of the HT+ red wires is very brittle and failed in two places. One here and again next to the OPT.



You are correct, all the red GEC caps measure perfectly as do the Lenco and LCR ones. In fact only the cathode bypass caps are u/s. And the only carbon resistor (1k on the phase splitter) has drifted.

@ John 73, yes this one has lost a few tags too. Like you I have a recovery method using ring tags. Thanks for the socket offer, I am using modern under chassis Belton types as I have them to hand.
Click to expand...

Come to think of it... the Marantz copper screws (or could have been Sony) were me and one of the OPT's had a slightly different shade of paint when I had it so maybe an OPT had been changed way back or it was sold with slightly differing shades of paint on the covers.
 
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