I brought a broken SA20 with a bad output stage. I'm thinking about reusing the chasiss and transformer as a donor for another hybrid. Anybody know the secondary voltage of the power transformer ? I have 16 replacement MOSFET for a Hafler XL600, I'm thinking of using a an Aikido WCF driving the Hitachi Mosfet. Any other suggestion ?
BTW, I used to have a short chasis SA7 Preamp ... I found it to be kind of hard sounding. Very simple design , and if I can remember properly the phono stage was always connected to the line stage. You can play the line source and a LP at the some time.
BTW, I used to have a short chasis SA7 Preamp ... I found it to be kind of hard sounding. Very simple design , and if I can remember properly the phono stage was always connected to the line stage. You can play the line source and a LP at the some time.
The simpler Counterpoint designs were always the better ones. Michael seemed to lose control and did silly things as the price tag went up. That means a small Counterpoint preamp will very probably outlast the more expensive ones. If you get a chance to see the diagram for an SA-9, you'll understand. It's a house of cards. 
Hi Grey,
Hi stoolpigeon,
I'm trying to save it.
Hi quinnling,
I wouldn't just gut it out of hand. You can use the same PCB unless the areas near the PCB supply fuses are burned. I made a small outboard PCB for that situation (two actually).
The original circuit is a repair job waiting to happen. Sounds bad as well.
-Chris
Hi Grey,
Hmmmm, could it be ..... the design!
Hi stoolpigeon,
On many models, the buffer was factory. It was required for proper operation. The DA-10 uses a discrete version of the BUF03 - messed up. The power supply is a disaster! I have one here that is dead due to an "upgrade". They yanked all the plate through parts out with the old caps.
I'm trying to save it.Hi quinnling,
I think the old secondary DC was 45 V bipolar. The HT should run around 330 VDC. This is what I'm working on and it's not hard to make it sound better. Dropping the idle current will cool down the transformer a lot. No more transformer failures then.
I wouldn't just gut it out of hand. You can use the same PCB unless the areas near the PCB supply fuses are burned. I made a small outboard PCB for that situation (two actually).
The original circuit is a repair job waiting to happen. Sounds bad as well.
-Chris
Hi Kevin,
You can still get output sets from Michael. If you buy enough normal stock, you can match your own. From looking at what Michael sends, I found that I matched them tighter than the factory. It's an incredible pain in the **s to match them though. Takes a long time.
This was the major reason they failed as a company I bet. A very poor product design that should never have left the prototyping stage.
-Chris
You can still get output sets from Michael. If you buy enough normal stock, you can match your own. From looking at what Michael sends, I found that I matched them tighter than the factory. It's an incredible pain in the **s to match them though. Takes a long time.
This was the major reason they failed as a company I bet. A very poor product design that should never have left the prototyping stage.
-Chris
SA-7.1 Repair
Just thought I would add my two cents as I am just about finished restoring my old SA-7.1. I was never crazy about it but I figure I might add some control and "tube" sound to my Ipod d riven sencondary system.
As long as you have it open you should replace the volume and balance pots.Mine were quite scratchy. I found an exact match for tthe stock volume pot (100k) at radio shack. In mine half the electrolytics were leaking , probably due to excess heat as everything seems to look like its slightly crisped, so I replaced them all . I would look for a better way to heat sink the LM-358 regulator, I think it may be responsible for some of the heat problems.
Don't get me wrong, I seem to remember thinking it was well priced at the time I bought it and I really only have about $40 sunk into restoring it. I was also unable to find a schematic on web for my Rev 7.1 unit.
Just thought I would add my two cents as I am just about finished restoring my old SA-7.1. I was never crazy about it but I figure I might add some control and "tube" sound to my Ipod d riven sencondary system.
As long as you have it open you should replace the volume and balance pots.Mine were quite scratchy. I found an exact match for tthe stock volume pot (100k) at radio shack. In mine half the electrolytics were leaking , probably due to excess heat as everything seems to look like its slightly crisped, so I replaced them all . I would look for a better way to heat sink the LM-358 regulator, I think it may be responsible for some of the heat problems.
Don't get me wrong, I seem to remember thinking it was well priced at the time I bought it and I really only have about $40 sunk into restoring it. I was also unable to find a schematic on web for my Rev 7.1 unit.
Hi.
I bought my SA-7 at a car boot sale for £50 - bargain !!
The guy had just upgraded to Krells.
The only problem I had was the switching arrangement - SW1/2 - the phono stage is always in circuit.
I sourced a 3-way ON-ON-ON from RS Components and rewired it.
I sold the SA-7 for £275 when I went CD only. (almost my bestbuy at boot sales - the complete stereo quad 22/II/FM2/AM2 for £25 will take some beating)
For those interested, I have posted the circuit here :-
http://www.yourfilelink.com/get.php?fid=364086
Andy
I bought my SA-7 at a car boot sale for £50 - bargain !!
The guy had just upgraded to Krells.
The only problem I had was the switching arrangement - SW1/2 - the phono stage is always in circuit.
I sourced a 3-way ON-ON-ON from RS Components and rewired it.
I sold the SA-7 for £275 when I went CD only. (almost my bestbuy at boot sales - the complete stereo quad 22/II/FM2/AM2 for £25 will take some beating)
For those interested, I have posted the circuit here :-
http://www.yourfilelink.com/get.php?fid=364086
Andy
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