Dyna Pas...

[LPD]

Here's a couple shots of a Dyna Pas modded that I picked up recently. It has a bizarre outboard power supply with the stock transformer, another transformer and a choke. In the unit it has all switches bypassed and a new volume switch and smoe mods on the power supply filter capacitors with diodes ect. The boards are original and I might replace them with upgraded capacitors, and the rca's on the back are stock which I will replace as well. Haven't listened yet but I will post a review at a later date. Right now I'm going to clean it up and check all voltages...anyone seen a power supply like this?

 

[tubino]

More info please?

So the builder used the same leetle original power transformer, but added a filament transformer and tube rectifier? And maybe the black one is a filter choke, and another filter choke is in the main chassis?

I'm just guessing from the photo. What is the octal tube? Is the DC filament supply in the main chassis still in use? Wonder why not use a beefier PT...

Anyway, the builder was probably trying to keep down noise by isolating the PS, which is perfectly reasonable.

 

[LPD]

The rectifier is a 6X5. A question if I may...the coupling caps on the line stage are as follows:
-(2) Sprague Black Beauties .2@400vdc
-(2)Aerovox metal foil? .22@400vdc
-(2)Astron metal foil? .047@400vdc

It seems a couple were left out on the line stage...any ideas why? Should I replace the couplings and if so what would you recommend?

Thanks

Peter

 

[Russellc]

So the builder used the same leetle original power transformer, but added a filament transformer and tube rectifier? And maybe the black one is a filter choke, and another filter choke is in the main chassis?

I'm just guessing from the photo. What is the octal tube? Is the DC filament supply in the main chassis still in use? Wonder why not use a beefier PT...

Anyway, the builder was probably trying to keep down noise by isolating the PS, which is perfectly reasonable.

Hello,
As to the use of the original power transformer, It works much better w/o the load of the filaments. In was in this particular area where the original transformer was weakest. Relieved of the filament load, the original will do a much better job on the B+, now that its load is simplified by having a seperate tranformer for the filaments. The original portion of the transformer that powers the filments is lacking big time and is the major liability of this transformer. Now it will run much cooler as well.




Russellc

 

[Ed in SoDak]

Certain old Zenith tube radios used a 6X5, those sets had a bad reputation since the 6X5 would arc, fail and take out the transformer. Modding the unit to use a 5Y3 and replacing the filament transformer to suit that tube was the fix.

-Ed