Stand Alone Reverb

[stingray_65]

With the finish of my Princeton 5F2A (well I still have to finish the cabinet) I'm now looking at my next project.

I would like to make a stand alone reverb unit and am looking at the Weber Add A Verb circuit.

I've got a vintage Gibbs reverb pan but it has a 1475 ohm input

In the Add A Verb schematic it has a matching transformer coming off the plate and grid of the 6K6 and goes to the reverb with a 25K:8 spec

to use my pan i would need a 25K:1.5k tranformer

I'm hoping I can substite a small power transformer

math is being my nemisis at this point

am I correct thinking that the 1.5k seconday would need a 4:1 winding to reflect about a 25K to the tubes?

would a small 120vprimary 30V secondary transformer work?

or have I done my math wrong and I woould need a 16:1 winding

that would equate to about a 7.5V secondary




Thanks Ray

[Enzo]

SInce proper reverb pans are about $20 at AES - www.tubesandmore.com - it seems like a lot of effort just to massage that old pan into the project.

If you just MUST use the old high impedance input pan, look at some old Ampeg circuits that drive the pan through a cap off the plate of the drive tube. NO transformer at all.