[raindance]

You need to know what voltage your power supply puts out and determine if it is compatible with any of the ClassD boards.

The VA rating refers to the power capability of the transformer and is similar to watts. It does not give a clue as to what the output voltage is.

[SCM]

From what I`ve gathered...74.5 volts. Does that sound right ?
Thanks
Steve

[Barry_NJ]

It's just a bit high...

SDS-258 Specifications:
· Output: 250 X 2 - 8 Ohm, RMS
· THD+N, 1W - 1KHz: Better than .02%
· Dynamic Range: 101 db
· Efficiency: Over 90%
· Required Power Supply: +/- 60 Volts DC to +/- 70 Volts DC

But your best bet is to send an email to Tom.

[Feanor]

Greetings Gents...I`ve been reading along with great interest !
 
I`d like to use an Adcom 555 MK II that i`ve had for years as a platform for an SDS-258 build.
I know the 555 it has an 800va torodial for a power supply.

I have a question...What all can I reuse/salvage from the 555 while building this project ?

SCM, personally I'd sell the Adcom 555II and buy Tom's or a Connex power supply & transformer and the case Tom provide.

First, Adcom 555II's can be sold on eBay for $400+.  Secondly, that model Adcom is a classic vintage unit much valued by audiophiles and collectors and it would be shame to demolish a good copy.

[SCM]

Tom responded with this as to wether or not the Torodial in the 555 MK II would work... "You should be able to get a + voltage and a – voltage. The SDS-258 uses between +/- 60 and 70 volts "

Can anybody help me find what Tom needs ?

Thanks
Steve

[SCM]

SCM, personally I'd sell the Adcom 555II and buy Tom's or a Connex power supply & transformer and the case Tom provide.

First, Adcom 555II's can be sold on eBay for $400+.  Secondly, that model Adcom is a classic vintage unit much valued by audiophiles and collectors and it would be shame to demolish a good copy.

Thanks..I would agree BUT...this one had the speaker leads crossed by my daughter and never worked again ( 8 years ago). Blows fuses including the main incoming fuse.

I did a COMPLETED LISTINGS search and a good one averages about $250.00. So by the time I got hosed by a repair shop I`d probably get stuck with it.

If I can work with the good parts I`d be ahead..Right ?

[srb]

If I can work with the good parts I`d be ahead..Right ?

You can certainly make use of the case, power cord, (or IEC receptacle if present), power switch, rear panel fuse holder, speaker binding posts and RCA input jacks (if not PC board mounted).
 
But you will have to disconnect the transformer secondary leads and measure the output voltages with a voltmeter.  The voltage requirement of the SDS-258 is +/- 60-70V DC, which would mean you would need a transformer with  +/- 42V-50V AC secondaries to connect to the required DC power supply board.
 
Steve

[Barry_NJ]

Tom responded with this as to wether or not the Torodial in the 555 MK II would work... "You should be able to get a + voltage and a – voltage. The SDS-258 uses between +/- 60 and 70 volts "

Can anybody help me find what Tom needs ?

Thanks
Steve

Do you have any pictures of the inside of the amp? If the power-supply board isn't integrated into the amp board it should be pretty easy to tell where the voltage reading should be done. If the boards are integrated, you may be able to use just the transformer. if that's the case just get a read off the output leads of that and tell Tom what they are.

[SCM]

Here`s some pics...

[jtwrace]

If it were me, I'd take all the stuff inside and toss it.  Just save the IEC, fuse holder and input connectors (if you can).  Replacing the transformer that will cost you ~$40 is well worth the investment.  That amp is probably 20 yrs old anyway...

Use the case and be done!

[roymail]

I agree with Jason.  Gut it but save all the connectors you can.  Buy the SDS-258 kit, it's well worth the cost.  You should be very pleased with the outcome.

Why pay to get the 555 working again since you haven't used it in 8 years.  Besides, an SDS-258 would mop the floor with the Adcom.  No brainer to me. 

[Barry_NJ]

Well the consensus seems to feel you should scrap all but the case and connectors, but I believe the heavy Red and Yellow wires from the transformer can be measured to get the output voltage of the transformer.

[Feanor]

...
Why pay to get the 555 working again since you haven't used it in 8 years.  Besides, an SDS-258 would mop the floor with the Adcom.  No brainer to me. 

I've owned the 555II.  It was a powerful and pleasant sounding amp;  OK into 2 ohms and slightly "dark" in tone. But it is nowhere as good as the SDS-258.  The latter is far more transparent and is capable of more accurate intrument timbres.

[SCM]

Well the consensus seems to feel you should scrap all but the case and connectors, but I believe the heavy Red and Yellow wires from the transformer can be measured to get the output voltage of the transformer.

Barry, I know absolutely nothing and have no meters at all, although a kit doesn`t scare me off !.
 I was hoping that the info I needed would be readily available.
But too, as has been posted, maybe I`d be better off not using the old stuff after all.

Maybe the Adcom transfomer isn`t up to speed with what Tom sells anyway.

Feanor, I believe you on that !!! ....I`m looking forward to this build up (new territory for me).

Anybody have any suggestions for me on this project, upgraded parts and such ?

[Barry_NJ]

Well if that's the case, you probably are better off just getting the full kit and the assembly instructions, and just using the case, connectors and switch from the Adcom. From what I've seen here, Tom's kits are pretty easy to assemble and well documented.

Best, Barry

[Nick77]

Update: I upgraded my stock PS from 40k uf to 60k uf with 2 more Panasonics tsha's just for giggles, but i got a really nice bump in dynamics and mico details. Highly reccomend taking the supply to 60k.

SDS254 w/60k uf Panasonics tsha. 

[jtwrace]

Anybody have any suggestions for me on this project, upgraded parts and such ?

Get the kit installed and working first.  Once you learn about the whole circuit and listen to it you can then decide if you want to continue. 

[mjosef]

Barry, I know absolutely nothing and have no meters at all, although a kit doesn`t scare me off !.
 I was hoping that the info I needed would be readily available.
But too, as has been posted, maybe I`d be better off not using the old stuff after all.

Maybe the Adcom transfomer isn`t up to speed with what Tom sells anyway.

The Adcom transformer is pretty beefy, it would have been more than enough for any of  of the ClassDaudio amps, however the secondary voltage are too high, I measured about 85 to 90VDC after the 555II power supply. The Red-Black-Orange are the secondary leads, with black being the 0 point. The power caps in the Adcoms are 100VDC.
Afraid all you can use in there are what jtw posted

save the IEC, fuse holder and input connectors (if you can).

You can also reuse the power switch, speaker terminals. The heat sinks are useless, dead weight. The power supply you can maybe reuse (if its not damaged) but you will have to know how to reconfigure it...
Perhaps you can just sell it as/is for parts only.

[toxteth ogrady]

Update: I upgraded my stock PS from 40k uf to 60k uf with 2 more Panasonics tsha's just for giggles, but i got a really nice bump in dynamics and mico details. Highly reccomend taking the supply to 60k.

SDS254 w/60k uf Panasonics tsha. 

Are these the caps you're referring to? http://www.diycable.com/main/product_info.php?products_id=602&Cid=d267424e09d9ab5452567d828ec78634

[Nick77]

Are these the caps you're referring to? http://www.diycable.com/main/product_info.php?products_id=602&Cid=d267424e09d9ab5452567d828ec78634

Yes thats who i bought them from, i purchased only 4 to start with thinking the amp would not respond beyond 40k but the bump to 60k was very favorable.