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Packard Bell amp

blhagstrom

blhagstrom

Mad Scientist, fixer.
Subscriber
Swung into an out-of-the way thrift store that usually doesn't come up with much interesting.

Found a Packard Bell console full of tubes.

Pulled the works and cleaned it up and tested the tubes. ALL Packard Bell tubes, I assume all originals! Most tested pretty strong. Brought it up on the variac as she was singing away.

The amp and tuner/preamp are separate units.

I uncoupled the amp. a 5U4 rectifier, a pair of 7025 (one hidden behind the multi-cap) that tested iffy so I rolled in some 12AX7s. A quad of EL84. Seems pretty strong. I was guessing about 10wpc. I hooked up a pilot lamp to the old connection and jumped the power switch connections and taped into the audio. 10ga fits the pin holes pretty well. Should be pretty easy to rig up some decent connections without modifying it.

Model tag says DPA30-4.

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I have one of these. It was one of my early tube experiences. It got modified quite a few times before I put it on the shelf. As I remember it sounded quite good but it wasn't anywhere near the original circuit by the time I finished. Great learning experience. It was in a large console which included a 25" B&W television that was marked free at an estate sale. I guess they just wanted someone to haul it away and when I saw the tubes in the back I couldn't resist. It should be good fun for you.

John
 
DPA30-1 is covered in Sams folder 595-8, DPA30-3 in 669-11. I should have the former one, MAYBE the latter too.
 
Model tag says DPA30-4.

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blhagstrom I am close to a finished product just waiting on the stained wood, you have tons of potential there :banana:
 
Schematic and parts list of DPA-30-1 (don't have the later one).
 

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Congrats on a nice rebuild!

The C89 .002 uF as the other channel coupling caps are .022 and the parts list shows C89 as that value also? With that type of circuit (Concertina or simplified Williamson split phase) it has to be a typo.
 
Thanks Tom,

The coupling caps are all .022, I'll replace those.

I need to trace down the multi-cap leads to see what is amp and what is pre-amp/tuner. I think some of the caps are not needed if I lose the pre/tuner. I may not "lose" it and will keep the connection intact since the tuner works so well.

I went through the resistors on the amp and they are all in spec.
I'm tempted to upgrade them though.

Metal film? Metal oxide? Carbon doesn't seem like an improvement except to do some matching and tighten the specs.
 
I usually use carbon film to replace carbon comp. I don't claim to be able to hear resistors, but I figure the sonics of a CF ought to be similar to CC. I've heard people say metal film and metal oxide can sound harsh. If they're in spec though, I'd probably let them be.
 
Just dawned on me that I didn't check the drivers to get an idea on the speaker load.

Anyone know if this is an 8 or 16 ohm load tap amp?
 
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