How to: Pin/Blade SDA 1C running off Adcom GFA-565 monos

ratpin

I recently found a pair of one owner Adcom GFA-565 mono blocks that I would like to use to independently power a pair of SDA 1C with pin/blade interconnect. I've heard about combining the grounds via the negative output on the amps, but have also heard this can introduce noise or cause other problems.

What is the best way to do this with available parts for both pin/blade and blade/blade interconnect SDA's?

Thanks!

pitdogg2

FIRST contact Adcom to see if you can even do that. You could fry gear and/or speakers.

Your best bet is to make a dreadnought.

Get your read on:
https://forum.polkaudio.com/search?query=dreadnought&scope=site&source=community


Read this;
https://forum.polkaudio.com/discussion/172315/dreadnought-transformer

These are the people to order from
https://avellindberg.com/transformers/y23_range_specs.htm

This is the part number you want to buy.
800VA - Y236906

You could also start a want to buy ( WTB ) thread to see if there is anyone who has one to sell. You may get lucky and get one already built. YOU will need to convert to Speakon connections and move away from the P/B cable.

99.999999% of the Blade/blade inconnect generation of speakers are NOT compatible to do what you want to do.

BlueBirdMusic

@pitdogg2 good job! Reminds me of the old days.

ratpin

I cannot find the 800VA - Y236906 transformer available for purchase anywhere online. Anybody got a link?

audioluvr

https://www.avellindberg.com/transformers/toroidal_transformers_index.htm

F1nut

ratpin wrote: »

I cannot find the 800VA - Y236906 transformer available for purchase anywhere online. Anybody got a link?

Pitdogg2 gave you a direct link....geesh!!!

Last one at the bottom of the 800VA list.

pitdogg2

He got the last one they had in stock

ratpin

Nobody had them listed as available. I called direct and she went and checked inventory while I waited. She said it was the only one they had.

ratpin

On a side note, what are people using as a standoff to secure the transformer in the case? I see a few people that seem to have them strapped in with zip ties, but I can't see what/how they are secured down or what the zip ties are strapped too.

pitdogg2

ratpin wrote: »

On a side note, what are people using as a standoff to secure the transformer in the case? I see a few people that seem to have them strapped in with zip ties, but I can't see what/how they are secured down or what the zip ties are strapped too.

As I mentioned in the PM, one of the hammond cases is tight enough to keep it from moving around. If I had the part number I would give it to you, unfortunately I sold that yrs ago. The case one of our members made for the group buy we used a stainless steel bolt threw the middle of the torrid and threw the side of the case to hold the transformer in place. You do have to be careful not to tighten down so much as you can damage the windings on the side against the case.

@westmassguy @trav0810 could either of you guys help with the hammond cases?

westmassguy

Case:
https://www.mouser.com/ProductDetail/Hammond-Manufacturing/1550NBK?qs=/ha2pyFaduhYCDw4jx8xytTdtLC%2BU29/zFy2eLT0B4E=

A plain vanilla verticle Dreadnought I built:








And the Deluxe model:
https://forum.polkaudio.com/discussion/164550/800va-dreadnaught

pitdogg2

Thank you Dave!

westmassguy

pitdogg2 wrote: »

Thank you Dave!

Anytime Ivan

ratpin

Great info westmassguy, Thanks

westmassguy

ratpin wrote: »

Great info westmassguy, Thanks

You're welcome

ratpin

Do the transformers come with clamping plates?

I made up my transformer strapping disc while I wait for parts.

pitdogg2

No. My 1000va had the center filled with epoxy like material. I cannot remember if I drilled a hole or if it was drilled. I do know I put a 5/8" stainless steel bolt with a huge stainless steel fender washer outside the case and inside the case with a SS locking nut.

I do not remember the length of bolt I bought several lengths between 3"-5" and used the closest that I needed.

Not all SS is non magnetic so make sure what you buy is.

westmassguy

The last one I did came with a through-bolt, top plate, foam gasket, and a wing-nut as I recall. All were magnetic/ferrous metal, not stainless or aluminum. I used my own hold-down method.

pitdogg2

Interesting. I figured ferrous might muck with it somewhat. Back when we were doing these SS was favored. So I rolled with it.

Dammit man, I'm going to have to open mine up and see. First I must crawl behind stuff and heft it out...
Dammit Dave😜

chrispyfur

A lot of stainless hardware will be 18-8 (same as 304) stainless steel, which is non-magnetic. I'm not sure how common other grades of stainless are in hardware, but as a general rule 300 series is non-magnetic and 400 series is magnetic.

ratpin

All kinds of good info in here. That’s good to know crispyfur

audioluvr

You want to use an aluminum housing and either a brass or stainless hold down bolt. Somewhere on here is my drunken redneck mod using an old circuit breaker box. Worked great. I think Troy has it now.

F1nut

My 1000va had the center filled with epoxy like material. I cannot remember if I drilled a hole or if it was drilled.

It was already drilled.

ratpin

audioluvr wrote: »

You want to use an aluminum housing and either a brass or stainless hold down bolt. Somewhere on here is my drunken redneck mod using an old circuit breaker box. Worked great. I think Troy has it now.

Why aluminum exactly? I have ordered an 18g steel box.

audioluvr

It helps block RF.

F1nut

Steel is a no no.

Toolfan66

ratpin

F1nut wrote: »

Steel is a no no.

Even if shielded as pictured? I found a steel case that will work well, but if it will cause notable issues I'll do the aluminum case.

F1nut

ratpin wrote: »

F1nut wrote: »

Steel is a no no.

Even if shielded as pictured? I found a steel case that will work well, but if it will cause notable issues I'll do the aluminum case.

I retract my comment, was thinking of something else. Carry on.

ratpin

Is there a diagram of what wires (transformer) connect to what wires (speaker cabinet)? Im using speakOn connectors and canare 4S11

pitdogg2

ratpin wrote: »

Is there a diagram of what wires (transformer) connect to what wires (speaker cabinet)? Im using speakOn connectors and canare 4S11

Post a picture of YOUR 800va torrid. The pictures above are pretty clear, your wire colors are probably different. You should still be able to get a good idea.