Express build questions...

[ThomasV]

I've been eyeballin' some of those Dynaco a 470 output trannies on ebay and I guess the question would be as follows...

Would it be better to use one of these for an express build over a new Heyboer? What differences can I expect between the two?

Also, Would it be beneficial to use carbon comps in the tone stack vs carbon film? Or would I be just be introducing more noise in the circuit?

Any input would be much appreciated. Thanks guys.

[selloutrr]

I've been eyeballin' some of those Dynaco a 470 output trannies on ebay and I guess the question would be as follows...

Would it be better to use one of these for an express build over a new Heyboer? What differences can I expect between the two?

Also, Would it be beneficial to use carbon comps in the tone stack vs carbon film? Or would I be just be introducing more noise in the circuit?

Any input would be much appreciated. Thanks guys.

1.) THe dynaco A-470 was used in the ROCKET (EL84) not the Express (EL34) the Express used the Stancor A-3801 followed by the Pacific based on the stancor. heyboer would be best. The impedance is different between the two transformers. they were intended to run different tubes.

2.) carbon comp are more prone to drift and induce noise. the TW's are unstable by nature the more you can do to quiet them down the better.

[RJ Guitars]

I would tend to agree with sellout.

My 2 cents = The Dynaco is a great transformer and might sound cool in an Express, but you might not get Express behavior out of it. There are numerous builds in the archives here that can attest to the great results with both Heyboer and Pacific trannies created specifically for the Express circuit.

rj

[RJ Guitars]

Duplicate post...

[M Fowler]

While the A470 is a great transformer it is rated for use in 30w through 60W circuits but at 4k3.

I would not think that you will get the noted Express dynamics in the power section using this transformer. I would go with either Pacific or Heyboer 6k6 unless you find a Stancor of course. I like the Edcor transformer as well.

Mark

[My-Co]

Use Film, Thats all I can say.

[LeftyStrat]

Regarding Carbon Comp vs other resistors, this might be of interest:

http://www.geofex.com/article_folders/c ... oncomp.htm

[ThomasV]

Thank you very much for the info guys.