diytube.com

This is probably the wrong category but I couldn't find another that was better suited. My setup is an ST70 and a DYNA preamp. The preamp has 11 rows of RCA jacks in the back (L and R). Physically, they are 2 pieces hardware that have 6 RCA female, and then 2 pieces of hardware that have 5 RCA female. I'm having a lot of signal breakup and I think I need to replace these jacks. Since this isn't just a typical 1-piece 1-RCA jack replacement, is there an option for replacement parts that others have used, or do you actually put in 22 individual RCA female jacks after taking out the 4 old pieces of hardware that contain the 22 jacks?

There are a few guys selling a pricey ($ 60 or so) replacement
for the messy RCA jacks and a selector switch also. google
curcio audio and dynaco rca jacks and you'll find some. I was
on curcio's site but didn't find any pictures of the RCA assembly,
but I've seen them before - I think they require some metalwork.
Back in the days when Dynaco stuff was new, RCA plugs were
usually hand soldered on the end of a piece of thin wire, and the
plugs were no bigger around than the metal ... no giant handles
like they have today ... so jacks could be spaced very very closely.

The preamp has 11 rows of RCA jacks in the back (L and R). Physically, they are 2 pieces hardware that have 6 RCA female, and then 2 pieces of hardware that have 5 RCA female.

That sounds like too many rows for a PAS-2 or 3 preamp but if it is, then Tubes4hifi sells an updated RCA input board for PAS-2,3.

http://www.tubes4hifi.com/PAS3.htm[/url][/quote]

I've been moving over to the superior BNC connector as $ allow.

In the meantime, this is a pretty good bang for the buck:
http://www.parts-express.com/pe/showdet ... er=090-278


Cheers!

Geek wrote:In the meantime, this is a pretty good bang for the buck:
http://www.parts-express.com/pe/showdet ... er=090-278

Will this really fit in the preamp if I wrench the RCA's loose from the 5-across / 2-down RCA jack's fiberboard? Somehow I don't expect it to work.

The thing is, you need to space the jacks apart more than they
are now so modern cable will fit ... the jacks from Parts Express will
work, mounted on some fiberglass circuit board.

Those parts-express RCA’s work well. I replaced all the RCA’s on my PAT-4 . I used a single sided copper clad board and drilled some holes maximizing the spacing in between like Tom said. Here are a few pictures highlighting the end result.

http://diytube.com/phpBB2/album_pic.php?pic_id=64
http://diytube.com/phpBB2/album_pic.php?pic_id=65

Brad

Nice job Brad !

I'm torn between restoring my PAS to original, or ripping it
up and making a nice preamp out of it.

... tom

The thing is with restoring a PAS is you basically replace everything in it except maybe the power transformer.

So why not sell it on ebay for $200 - $300, get a new Antek 12x12x4 chassis and a toroid transformer and build a NEW PAS. This way you will have a lot more room to play with, better jack placement, etc.

What about replacing those 2000uF 18V electrolytic capacitors? I can't find a place that carries those.

A modern equivalent would be 2200 at 25 or 35 volts.
You may even find them at Shadio Rack ...

... tom

Thanks Tom.
I too thought about tearing apart the PAT4 and using the chassis for an Aikido or tubes4hifi sp-6, but I couldn’t find the courage to do it. So I did a complete restore on the PAT4 using the VanAlstine modifications (new PS, tone control deletes, replacing all electrolytics with film and tantalum capacitors, etc..). The project put some life back in the old preamp. The output seems a little on the high side to me but I will continue using it for a few weeks to see if things start to stabilize during the burn in period. I was surprised to see that every original resistor in the preamp had drifted by a fair amount. I replaced all of those with some metal films.

Brad

I took out the complete old junk, cut and routed a one piece board to replace the old one. I left out 2 of the useless connectors and have enough space between the connections.