Arkless Electronics
Trade: Amp design and repairs.
It's been disconnected yes and there are some non standard resistors around the area. Lots of dodgy soldering throughout where it's been "serviced" before...
Leak TL/12+ Stereo 60 shed find
- Thread starter Budney
- Start date
It's been disconnected yes and there are some non standard resistors around the area. Lots of dodgy soldering throughout where it's been "serviced" before...
John_73
pfm Member
Much as I’d enjoy the challenge of restoring the Stereo 60 if it was my own, I’d agree about getting the TL12s sorted first. I guess the first port of call is testing all the transformers to ensure money isn’t wasted on a rebuild. They look quite rusty in places, touch wood it hasn’t gotten into the transformers.
Arkless Electronics
Trade: Amp design and repairs.
Agreed. I'd be bothered about the transformers having been overloaded etc rather than "rust" but yeah best to make sure they work correctly before proceeding.
Arkless Electronics
Trade: Amp design and repairs.
It's advisable yes. Properly testing them out of circuit is rather involved though...
I am tempted to agree with you, if what everyone is saying, the 60 isn't the best sounding amp, plus its collectable value is all but gone and it needs to be completely rebuilt anyway, is there a way I can 'supercharge' this amp with the parts I have? If I have to get a new mains transformer anyway would it make more sense to try and have it built more like a 20? Or another more desirable design.
Whats the best way of testing them? I did a quick resistance/continuity check between some pins, and none of them are open or short circuit, they show some kind of low resistance reading so I thought I was okay.
I will start with the TL12+ to get up and running first, and I can temporarily use these on the KEFs while I figure out what to do with the 60.
Perhaps if explain the system I want to use these in, we can decide if its worth keeping the 60 as stock or changing it somehow.
I have a pair of purple velvet Seeburg DWS2 'Discotheque' speakers. Apparently they came from an RAF base! Common in the US but you don't tend to see them over here, especially since they have a velvet cover, normally they were just brown wood.
They consist of an Altec 806A 1 inch compression driver mounted on a gold 806A horn and a JBL 2202A 12 inch driver. I then plan to stick a JBL 2403 'Cats eye' tweeter on the top, and then a JBL LE15A 15 inch underneath. I have a thing for American made alnico legacy loudspeakers
, I have never heard anything quite like them and don't think I ever will do!I had planned on running these on my BGW power amps (again US made) and a Bozak CMA 2DL (US), with a Urei 525 (US) active crossover. This was going to be my 'All American' living room system, with the KEFs on some Quad 303s in the dining room for the 'British' system. Also got some AR3as in the bedroom, Bolivars (rebadged JBL) in the workshop, and some JBL 4320 and BBC Rogers LS5/9s in the studio running on BGW and Quad amps respectively, so I'm big into well made pro audio from Britain and the US alike. These Leak amps throw a spanner in the works in the sense that it buggers up my 'All American' system, but I think its worth it!
I basically can't decide whether to go 2 way active (biamp) or 3 way active (triamp).
2 way would be
TL12+ monoblocks - Seeburgs (2403, 806A, 2202 with a passive crossover)
Stereo 60 - LE15A
3 way would be
TL12+ monoblocks - highs (2403,806A with passive crossover)
Stereo 60 - mids (2202)
BGW 250a - lows (LE15A)
I am tempted to go with 2 way to keep it simple, but not sure if the TL12+ would be able to handle a 12 inch woofer plus 2 compression drivers. Also I have read that the Stereo 60 is not the best for low end, so perhaps it would make sense to keep the low end solid state and go 3 way. If I were to go 3 way, then perhaps the Stereo 60 kept as stock would work well? Since it would not be full range, and thus its shortcomings would not be as noticeable. If I were to go 2 way, then a 'supercharge' of it might make sense to make it perform best for that low end application?
Pic of the beautiful Seeburg DWS2 'Discotheque' speakers
Tony L
Administrator
No problem with high-efficiency stuff like that. I’ve got a pair of 15” Tannoy Monitor Golds in Lockwood studio cabs and the Leak Stereo 20 (basically a stereo pair of TL12+) drives them amazingly well. Ten good valve watts goes a very, very long way into horns.
PS Loving the funky ‘70s purple & gold disco look!
fegs
pfm Member
I am tempted to agree with you, if what everyone is saying, the 60 isn't the best sounding amp, plus its collectable value is all but gone and it needs to be completely rebuilt anyway, is there a way I can 'supercharge' this amp with the parts I have? If I have to get a new mains transformer anyway would it make more sense to try and have it built more like a 20? Or another more desirable design.
Whats the best way of testing them? I did a quick resistance/continuity check between some pins, and none of them are open or short circuit, they show some kind of low resistance reading so I thought I was okay.
I will start with the TL12+ to get up and running first, and I can temporarily use these on the KEFs while I figure out what to do with the 60.
Perhaps if explain the system I want to use these in, we can decide if its worth keeping the 60 as stock or changing it somehow.
I have a pair of purple velvet Seeburg DWS2 'Discotheque' speakers. Apparently they came from an RAF base! Common in the US but you don't tend to see them over here, especially since they have a velvet cover, normally they were just brown wood.
They consist of an Altec 806A 1 inch compression driver mounted on a gold 806A horn and a JBL 2202A 12 inch driver. I then plan to stick a JBL 2403 'Cats eye' tweeter on the top, and then a JBL LE15A 15 inch underneath. I have a thing for American made alnico legacy loudspeakers
I had planned on running these on my BGW power amps (again US made) and a Bozak CMA 2DL (US), with a Urei 525 (US) active crossover. This was going to be my 'All American' living room system, with the KEFs on some Quad 303s in the dining room for the 'British' system. Also got some AR3as in the bedroom, Bolivars (rebadged JBL) in the workshop, and some JBL 4320 and BBC Rogers LS5/9s in the studio running on BGW and Quad amps respectively, so I'm big into well made pro audio from Britain and the US alike. These Leak amps throw a spanner in the works in the sense that it buggers up my 'All American' system, but I think its worth it!
I basically can't decide whether to go 2 way active (biamp) or 3 way active (triamp).
2 way would be
TL12+ monoblocks - Seeburgs (2403, 806A, 2202 with a passive crossover)
Stereo 60 - LE15A
3 way would be
TL12+ monoblocks - highs (2403,806A with passive crossover)
Stereo 60 - mids (2202)
BGW 250a - lows (LE15A)
I am tempted to go with 2 way to keep it simple, but not sure if the TL12+ would be able to handle a 12 inch woofer plus 2 compression drivers. Also I have read that the Stereo 60 is not the best for low end, so perhaps it would make sense to keep the low end solid state and go 3 way. If I were to go 3 way, then perhaps the Stereo 60 kept as stock would work well? Since it would not be full range, and thus its shortcomings would not be as noticeable. If I were to go 2 way, then a 'supercharge' of it might make sense to make it perform best for that low end application?
Pic of the beautiful Seeburg DWS2 'Discotheque' speakers
They look great !!!!!!
I know
the moment I saw them I snapped them up immediately! They’ve been sat for over a year, I haven’t had the space to set them up properly but currently renovating a new house so soon they will have a home.Good news on that front, then the problem will be if the Stereo 60 will be up to snuff running the LE15 on the low end. LE15s are pretty efficient so I think they will be fine power wise, but will it sound as good as the BGW transistors?
Arkless Electronics
Trade: Amp design and repairs.
I am tempted to agree with you, if what everyone is saying, the 60 isn't the best sounding amp, plus its collectable value is all but gone and it needs to be completely rebuilt anyway, is there a way I can 'supercharge' this amp with the parts I have? If I have to get a new mains transformer anyway would it make more sense to try and have it built more like a 20? Or another more desirable design.
Whats the best way of testing them? I did a quick resistance/continuity check between some pins, and none of them are open or short circuit, they show some kind of low resistance reading so I thought I was okay.
I will start with the TL12+ to get up and running first, and I can temporarily use these on the KEFs while I figure out what to do with the 60.
Perhaps if explain the system I want to use these in, we can decide if its worth keeping the 60 as stock or changing it somehow.
I have a pair of purple velvet Seeburg DWS2 'Discotheque' speakers. Apparently they came from an RAF base! Common in the US but you don't tend to see them over here, especially since they have a velvet cover, normally they were just brown wood.
They consist of an Altec 806A 1 inch compression driver mounted on a gold 806A horn and a JBL 2202A 12 inch driver. I then plan to stick a JBL 2403 'Cats eye' tweeter on the top, and then a JBL LE15A 15 inch underneath. I have a thing for American made alnico legacy loudspeakers
I had planned on running these on my BGW power amps (again US made) and a Bozak CMA 2DL (US), with a Urei 525 (US) active crossover. This was going to be my 'All American' living room system, with the KEFs on some Quad 303s in the dining room for the 'British' system. Also got some AR3as in the bedroom, Bolivars (rebadged JBL) in the workshop, and some JBL 4320 and BBC Rogers LS5/9s in the studio running on BGW and Quad amps respectively, so I'm big into well made pro audio from Britain and the US alike. These Leak amps throw a spanner in the works in the sense that it buggers up my 'All American' system, but I think its worth it!
I basically can't decide whether to go 2 way active (biamp) or 3 way active (triamp).
2 way would be
TL12+ monoblocks - Seeburgs (2403, 806A, 2202 with a passive crossover)
Stereo 60 - LE15A
3 way would be
TL12+ monoblocks - highs (2403,806A with passive crossover)
Stereo 60 - mids (2202)
BGW 250a - lows (LE15A)
I am tempted to go with 2 way to keep it simple, but not sure if the TL12+ would be able to handle a 12 inch woofer plus 2 compression drivers. Also I have read that the Stereo 60 is not the best for low end, so perhaps it would make sense to keep the low end solid state and go 3 way. If I were to go 3 way, then perhaps the Stereo 60 kept as stock would work well? Since it would not be full range, and thus its shortcomings would not be as noticeable. If I were to go 2 way, then a 'supercharge' of it might make sense to make it perform best for that low end application?
Pic of the beautiful Seeburg DWS2 'Discotheque' speakers
Personally I'd be tempted to ditch all but the output transformers from the 60 and build a new amplifier on a new chassis using a different circuit. The chassis is butchered, the original mains TX missing and all the resistors and capacitors shagged out anyway leaving just the output TX's as useful salvage. The choke looks too puny to bother reusing really.
I'd prob go for something very similar to the Radford STA25 circuit but mods would be required for the Leak transformers. I'd modernise things beyond the STA25 never mind the Leak. Obviously the question remains of how good the transformers are... is the allegedly not as good as St20 etc sound due to a poorer TX design or limitations elsewhere?
It goes without saying that this would need to be a labour of love and require electronics knowledge...
Easier would be to keep it as basically "a Leak St 60 and but who cares about originality" and get whatever mains transformer you can of the correct voltages and make it fit. As originality has already gone out the window you could modernise and improve the beast to get better sound and greater reliability.
If you can get a new exact replacement for the mains TX (£300 maybe if one must be built to order and look the same) I guess there will be specialist metalwork shops who could weld in a new section around the TX, smooth out the weld and re-spray in original colours.... then there's new decals.. It could be a very expensive way of getting a not quite original St60!
As to testing the TX's there is sure to be plenty of how to guides on the interweb thingy that include how to test for shorted turns etc etc and so spare my typing fingers!
Tony L
Administrator
I agree with a lot of what Jez says (i.e. even having a ‘restorer/conservationist’ mindset myself I’d have absolutely no issue hacking kit in this already hacked condition), though if was all mine I’d just cash-in the Stereo 60 as-is as it potentially has surprisingly good value. I’d test all the valves and sell as following separate lots:
Quad II mains transformer.
Leak Stereo 60 restoration project.
Quad of Mullard EL34s.
Mullard GZ37.
I’d also sell the Troughline and preamp.
I suspect, assuming the transformers and valves can be verified good, that would easily pay for everything and leave a now ‘free’ pair of TL12+ to restore and re-valve as well as possible.
Quad II mains transformer.
Leak Stereo 60 restoration project.
Quad of Mullard EL34s.
Mullard GZ37.
I’d also sell the Troughline and preamp.
I suspect, assuming the transformers and valves can be verified good, that would easily pay for everything and leave a now ‘free’ pair of TL12+ to restore and re-valve as well as possible.
That pretty much amounts to building a completely new amp...which I agree will be a big undertaking, perhaps a bit ambitious for my first tube project. It would just make more sense to get hold of some new OPTs and building up from there. Modernising and improving was more what I had in mind with regards to 'supercharging' it. Looking over the schems for the 20 and 60, they do look very similar apart from the EL84 vs EL34. Perhaps it could be rebuilt as a hybrid of the 20 and 60? or perhaps its not worth the trouble. Finding a 325 transformer seems to be easier than finding a 430...so that might be a cheaper route to take. I'm also not that fussed about the butchered chassis. If I get hold of a transformer thats similar size to the original, it will hopefully mostly cover the scars that the chassis has. I have quite a lot of gear with 'battle scars' and it doesn't really bother me, I like things a bit crusty! Also I've been looking into the standee resistors, I see that they were quite a strange custom part. I saw that someone got a batch remade a few years ago, I wonder if there are still any floating around? Some people have success rebuilding them or making things that look similar, which intrigues me.
I do not plan on selling the Stereo 60, even with its caveats. I don't think I'll ever find another one and I'm looking forward to restoring it and getting my hands dirty with some classic valve amps. I'm not that bothered about getting a free pair of TL12+, I'm much more interested in having a fully valve bi amp system. The Quad II transformer and the tuner/pre amp will go however, hopefully that can bring the overall cost back down slightly. There is also the option of mods on the 60 to make it perform better, which I think will be a fun project once its back up and running properly.
Arkless Electronics
Trade: Amp design and repairs.
The transformer you want is 380V (380 - 0 - 380). Ones near to that should be OK. Just 0 - 380V could be used with bridge rectifier using SS rectification if that's all you can get. It would work the same. I'd forget the Standee resistors.... they are just cathode resistors and all sorts of other things will work better.
Ah yes, taking a closer at the schematic, I see now that the transformer is 380VAC, which is rectified to 430VDC. Hopefully makes it a bit easier to find a replacement. Would 400ma be sufficient for this since its stereo? What would you recommend instead of the standees? any high wattage resistor?
Arkless Electronics
Trade: Amp design and repairs.
400mA will be more than enough yes. Any 5W or so wirewound resistors will do fine to replace the standees. 470R with half Watt 6k8 in parallel will give you the original 440R.
Just got off the phone with Majestic, new transformer comes to £178.50, exact same size and form factor as the original. Not as painful as I imagined. Only difference is the shrouds are pressed zinc, but I can just remove them and spray them black, then maybe give them a slight patina to match the others. So hopefully someone wants to buy the Quad transformer for around that price.
I've emailed Sowter so hopefully they get back to me with an even better price!
I've emailed Sowter so hopefully they get back to me with an even better price!
Arkless Electronics
Trade: Amp design and repairs.
That's cheaper than I expected. An obscure thing to have off the shelf.
John_73
pfm Member
That’s a very good price indeed. I’ve got a pair of Quad II transformers (for a future project) and they’re made by Majestic. Seem very well made and Keith Snook also seemed impressed with their quality on his Quad website. If it’s of any help, I’m currently looking into a company to do a paint match to my grey Stereo 20 as I need to paint all the transformer shrouds. I can give you the code if I go ahead with them (two companies have already let me down in terms of paint ‘matching’ so hopefully third time lucky!).
I was surprised too, considering this isn't on their shelf, they will make it up for me. He also said there were some different models of transformers for the 60, so makes sense to go with the latest one to match mine, I assume the grey models were later than the champagne.
That would be great! I hadn't thought about trying to get the colour matched. If you manage to get the paint produced, I would certainly be interested, thank you
That would be great! I hadn't thought about trying to get the colour matched. If you manage to get the paint produced, I would certainly be interested, thank you
Radfordman
pfm Member
The KEF's look interesting, KEF Kit 3? with added supertweeter.