A related observation is that my SuperMOS-I modules ran pretty much stone-cold at low listening levels (i.e. very efficient, that's the whole point of "Active class-A"). At full output, they ran very hot. My case had an 80mm fan per module, speed-controlled according to heat-sink temp. (Perhaps the fans were the reason that my modules lasted a relatively long time?)
Agreed, anyway, very little bias at low signal levels.
Have been following this thread for some time. I bought a couple of Supermos-2 modules from Les Sage in March 89. Was attending a course in Reading at that time so I had them delivered to my hotel and I brought them over to Norway myself. These modules performed absolutely fantastic. They were driving a couple of DIY Apogee Duetta copies for several years until one of them failed as so many others have experienced I understand now. These speakers are still playing but with another DIY class A amp with a regular class a bias, not a sliding bias. I have always hoped to come across one working Supermos-2 module as I have one working module. At least it was some years ago.I have now found the documentation that was sent to me by Les Sage. Hope these scanned images can be useful and shed some light on these modules. I also have a small (A5 format) user manual for the Superamp, Supermos and Supermos-1. The block diagram is from this manual. If it is interesting I could scan the whole manual.
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I've finally been out to my storage and found my old files...
Zero D – Unfortunately no sign of the letter from Les’s Lawyer, so I can’t help you with contact details sorry.
Recalling all the time I’ve spent re-engineering this thing is making me feel ill. (or foolish!). I will have one more go at the diagram but no promises on timeframes sorry. Those who have seen inside these things will sympathise!
Zero D – Unfortunately no sign of the letter from Les’s Lawyer, so I can’t help you with contact details sorry.
Recalling all the time I’ve spent re-engineering this thing is making me feel ill. (or foolish!). I will have one more go at the diagram but no promises on timeframes sorry. Those who have seen inside these things will sympathise!
Supermos 2
Here is a test done by the Danish High Fidelity in January 92. This is of course, and unfortunately, only in Danish. Leslie Sage had at this stage a Swedish distributor the article says. These monoblocks had one 1300 VA transformer in each box. They are giving it good marks, especially regarding the bass reproduction. This I can confirm. They had steel control and they ran only lukewarm. There was also a built in overload protection visible as a LED that went from green to red hidden between the wings of the heat sink.
Here is the scanned article:
https://picasaweb.google.com/tsundsd/February272012?authkey=Gv1sRgCMbD69mWnKLezAE
Here is a test done by the Danish High Fidelity in January 92. This is of course, and unfortunately, only in Danish. Leslie Sage had at this stage a Swedish distributor the article says. These monoblocks had one 1300 VA transformer in each box. They are giving it good marks, especially regarding the bass reproduction. This I can confirm. They had steel control and they ran only lukewarm. There was also a built in overload protection visible as a LED that went from green to red hidden between the wings of the heat sink.
Here is the scanned article:
https://picasaweb.google.com/tsundsd/February272012?authkey=Gv1sRgCMbD69mWnKLezAE
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If you click on one of the images a magnifying glass should appear on the line on top of the picture. Click on that one. When you have done that a zooming function should appear in the the low right hand corner. Let me know if there is a problem and I will certainly try to save them in PDF format
Just come across this thread. Brings back memories!
Like many I had some dealings with Les Sage. Originally I bought a
pair of his modules which I think were before the SuperMos ones.
They sounded good better than than what I was using at the time
but blew up literally. Les Sage was not very helpful accusing me
of using substandard power capacitors so I didnt use them again.
Subsequent to this I got into making my own amps for sale in a small
way and used his o/p mosfets which were matched for transconductance.
It was cheaper for me this way. I eventually found that they were by
Toshiba (I may still have some somewhere). I also used some later
ones of his (for SuperMos?) which were by IXYS I think.
I didnt have any more dealings until I heard of his unfortunate death
by an ad placed by his father to sell off some off his assets. I bought
such things as heat sinks etc and his father wanted to sell his
intellectual property but this was apparently locked in his computer.
I wasnt interested at the time.
Anyway his father gave me several finished and unfinished circuit boards
one of which was for an amplifer marked SuperMos 150. I built a copy of this
and got it to work after a fashion but its bias drifted too much I seemed to
remember. I lost interest after this.
I probably still have the original board somewhere
Like many I had some dealings with Les Sage. Originally I bought a
pair of his modules which I think were before the SuperMos ones.
They sounded good better than than what I was using at the time
but blew up literally. Les Sage was not very helpful accusing me
of using substandard power capacitors so I didnt use them again.
Subsequent to this I got into making my own amps for sale in a small
way and used his o/p mosfets which were matched for transconductance.
It was cheaper for me this way. I eventually found that they were by
Toshiba (I may still have some somewhere). I also used some later
ones of his (for SuperMos?) which were by IXYS I think.
I didnt have any more dealings until I heard of his unfortunate death
by an ad placed by his father to sell off some off his assets. I bought
such things as heat sinks etc and his father wanted to sell his
intellectual property but this was apparently locked in his computer.
I wasnt interested at the time.
Anyway his father gave me several finished and unfinished circuit boards
one of which was for an amplifer marked SuperMos 150. I built a copy of this
and got it to work after a fashion but its bias drifted too much I seemed to
remember. I lost interest after this.
I probably still have the original board somewhere
@ triplej
Thank you Very much for trying to find the info
Looking forward to your diagrams etc.
@ dacen
Thanks for the Danish High Fidelity scans & info Pity there isn't an English translation though.
@ Zeta4
Hi & thanks for posting. Did Les sell you his o/p mosfets directly ? I can confirm he did use Toshiba !
In which publicatian did Les's father place the Ad & what year/month ? Do you still have his contact details etc. If you can help in Any way, please PM me with more info
You were Very fortunate to receive those several finished and unfinished circuit boards ! How were you able to complete them without a circuit diagram ?
If you could locate the original board & photo both sides & upload them here, that would help us tremendously
@ bear
Hi, you need to enhance the images, as i did. See my screenie for an example
Thank you Very much for trying to find the info
Looking forward to your diagrams etc.@ dacen
Thanks for the Danish High Fidelity scans & info
Pity there isn't an English translation though.@ Zeta4
Hi & thanks for posting. Did Les sell you his o/p mosfets directly ? I can confirm he did use Toshiba !
In which publicatian did Les's father place the Ad & what year/month ? Do you still have his contact details etc. If you can help in Any way, please PM me with more info
You were Very fortunate to receive those several finished and unfinished circuit boards ! How were you able to complete them without a circuit diagram ?
If you could locate the original board & photo both sides & upload them here, that would help us tremendously
@ bear
Hi, you need to enhance the images, as i did. See my screenie for an example
Attachments
Hi ZeroD
Yes he advertised matched pairs for sale. They were in his brochure that he advertised in Audio Conversions .They were not particularly cheap.
Sorry cant remember where I saw the ad or even the year/month. Only thing
I remember was that his father lived in Tottenham. His father said that Les
originally worked at the Thorn-EMI TV plant nearby. His death was announced
in Audio Conversions issue 17 (1993?).
A lot of the boards looked like prototypes for such things as a phono stage
or something like that. It was only the SuperMos 150 board that looked
interesting to me as it was completely populated. So I back engineered
the circuit onto another board as I didnt want to risk blowing up the original.
From memory it was some kind of sliding bias. I got it to work but the bias
would not stay stable so I lost interest. I see in the Audio Conversions that
Ive looked at that his range didnt include a SuperMos 150 so maybe this
was a prototype.
I will certainly have a look to see what I can find.
Yes he advertised matched pairs for sale. They were in his brochure that he advertised in Audio Conversions .They were not particularly cheap.
Sorry cant remember where I saw the ad or even the year/month. Only thing
I remember was that his father lived in Tottenham. His father said that Les
originally worked at the Thorn-EMI TV plant nearby. His death was announced
in Audio Conversions issue 17 (1993?).
A lot of the boards looked like prototypes for such things as a phono stage
or something like that. It was only the SuperMos 150 board that looked
interesting to me as it was completely populated. So I back engineered
the circuit onto another board as I didnt want to risk blowing up the original.
From memory it was some kind of sliding bias. I got it to work but the bias
would not stay stable so I lost interest. I see in the Audio Conversions that
Ive looked at that his range didnt include a SuperMos 150 so maybe this
was a prototype.
I will certainly have a look to see what I can find.
A schematic showing this sliding bias would be great as this is the only part I cant get to work properly, probably because of mistakes in the schematics so far shown.
Interesting about the fets, if toshibas they would probably be 2sj200/2sk1529 or 2sj201/2sk1530, it will be helpful if you could confirm from the populated board. Whats curious is that toshiba sells these as factory matched if you buy them by the pair.
Interesting about the fets, if toshibas they would probably be 2sj200/2sk1529 or 2sj201/2sk1530, it will be helpful if you could confirm from the populated board. Whats curious is that toshiba sells these as factory matched if you buy them by the pair.
Found the SuperMos 150 board and my copy. The Sage board has Toshiba 2SK115
and 2SK405s on it. These look like the ones I first used to get as matched pairs.
I used a pair of his matched ones on my copy.
Its a long time ago but I seem to remember though that I got some others which he told me were from IXYS.
Ill take some photos but cant post for a few days yet.
and 2SK405s on it. These look like the ones I first used to get as matched pairs.
I used a pair of his matched ones on my copy.
Its a long time ago but I seem to remember though that I got some others which he told me were from IXYS.
Ill take some photos but cant post for a few days yet.
@ Zeta4
I didn't see the later issues of Audio Conversions, so i expect that's why i missed them being advertised. Also the reason i only discovered his death until recently !
Thanks for info about his father living in Tottenham.
Yes Les originally worked at the Thorn-EMI TV plant down south, before relocating with them up north. When it closed down, he set up his Audio business.
Re the 2SK405 & 2SJ115. So they were soldered on the PCB's, Without the ID's removed ?
@ homemodder
Remember, the Mosfet's we are talking about are from 20-25 years ago. Les "presumably" thought he could make some extra £ by matching & selling to His specs !
That would be great
I didn't see the later issues of Audio Conversions, so i expect that's why i missed them being advertised. Also the reason i only discovered his death until recently !
Thanks for info about his father living in Tottenham.
Yes Les originally worked at the Thorn-EMI TV plant down south, before relocating with them up north. When it closed down, he set up his Audio business.
Re the 2SK405 & 2SJ115. So they were soldered on the PCB's, Without the ID's removed ?
Can't wait
@ homemodder
Remember, the Mosfet's we are talking about are from 20-25 years ago. Les "presumably" thought he could make some extra £ by matching & selling to His specs !
That would be great
These are the MOSFETs from my SuperMOS-I. They are screwed to the heatsink and then the PCB is lowered over them, soldered on, and finally potted.
An externally hosted image should be here but it was not working when we last tested it.
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