Dynaco from scratch

[DigitalJunkie]

A friend has a Bell 6060,needs some work,but it still functions fine and sounds good.. Not a bad piece..

I've got the schematic at:
Part 1
Part 2

 

[seanzozo]

the triode/LTP does a lot for the amp. I have Ned's old board that did this (cascode 12au7 to 12bh7). Though I am thinking of trying shannon's board, for the CCS and the straight triode input tube.

I totally disagree with the bad tranny argument.

My MK-IV's measured on an audio Precision (with 10db less feedback than original circuit) still were flat to 10Hz and -1db to 20KHz with no response wrinkles at HF.

You can knock the supa cheap input stage and bias supply of the original dyna. The PS aint anything special either (though they did spring for a baby choke). The Trannys though are worth the hype (which is that they are a good sub 100 dollar output tranny)....no ones saying they are Tamura's or Manequest Cobalts.

Sean

 

[cogsncogs]

...no ones saying they are Tamura's or Manequest Cobalts.

Yeah, you shouldn't compare apples to oranges!

You've got thank the dyna's for turning some heads and ears from SS to toobs!
Thanks D-Junkie for the 6060 schems, I've downloaded them from an earlier thread plus I've got the circuit firmly imprinted in my brain from years of modd'ing and repairing my mistakes as a teen! The 6060 I had was a later revised run as some of the circuit values for the phono stage where changed (plate and cathode resistors) and plus it had bias adjustments for each 6CA7/EL34.

Wayne

 

[TubeMack]

Well I decided to procede foward after doing more research, but will be using a modernized ST-70 chassis. I'm also using Shannon's LTP CCS triode board as well as the SDS cap board. My research seems to indicate that the output Transformers are "Pretty good" as is the slightly better Power trans clone from Ned. I'm confused by all the negative comments regarding a ST-70 with redesigned topology. Some stated that the Dynaco could never sound good "no matter what".The only thing original would be the chassis and the transformers (which the consensus seems to be that they are not world class but, are not bad at all). This would would mean that you believe the chassis is somehow influencing the performance, or are just name bashing.

 

[warpedcorp]

Dynaco PAS Rebuild

I have two Ellas which are wonderful but....

I'm in the midst of rebuilding a dynaco PAS and have the following question:

The original circuit (Dynaco PAS Preamp) has a 250K volume control and a 750K balance control.

I'm thinking of replacing the original 250K volume control with the 250K alps I and then replacing the original 750K balance control with two individual 100K Alps pots to allow me to individually 'trim' each channel instead of a single balance control. Will this work or is the 750K value for balance a critical spec?

Thanks

 

[Gooch]

I use a Noble 50k volume and balance in my moded PAS for years with no problems.

Regards

Dave