Outboard Reverb and Loop schemo question

[wjdunham]

I'm currently building the combined reverb/Dumbleator schematic posted by Henry in the reference below in one of the Hammond 19" 1RU rack boxes. It's a tight fit with a full-size 3-spring Acutronics/fender style reverb tank, but I think I have a layout that fits. I'll post some pics and thoughts when I'm done. I was planning on putting the verb in series before the loop, is it worth playing with other configurations such as in parallel or after the loop?

One question on that schematic, it shows B+2 connected to the reverb driver transformer, should that be B+1 (317V vs. 296V)? I'm using the Fender standalone PT and the dropping string shown in the schemo.

https://tubeamparchive.com/viewtopic.ph ... verb+power

thanks,
Bill

[angelodp]

Very interested in seeing this projects as it progresses. I can imagine that it will be a great tool.

[M Fowler]

I believe the reverb driver transformer should be connected to the B+2 after the main filtering caps, at least that is how I have built my tube reverb amps.

Magnetic coupling causing a buzz/hum can be an issue with your 1 unit rack space.

[boldaslove6789]

I've built a unit similar to the 6g15 in a 1u rack and also had hum issues, tube reverb is very sensitive. I've opted for a digi rack verb, simple and quite as can be.

I am still trouble shooting the unit although ( only been building stuff for short while and I'll try to post some updates when I get the time. right now its getting serviced by Jon Mernyk.

I put a 100K Mf resistor on a dpdt switch ( in case I might want to use it for other applications ) in series with the input wire of the 12at7 for it to work with a d-lator.


Its not finished in these pics but I ended up using sheilded cable and isolation jacks on the I/O.

I also regret not using toroidal Xfrmr's and I should of mounted the tubes horizontally in the case so that nothing would have protruded out of the bottom of the case.

I know Henry's unit is his own spinoff w/ d-lator but, hope this helps.

[wjdunham]

Here are the photos of work in progress, the loop is up and running minus the bright caps. Some of the wiring is temporary, heaters and power connections and will be cleaned up. Very quiet even as is though. I haven't taken voltage readings in the tubes yet, I'll post those with my final dropping string once I get it all put together.

I am now more strongly considering building Gary's version, it's a little simpler than the more fender inspired version posted by Henry. I also like the idea of having the reverb contained within the loop driver/receiver. Can either of you guys (or anyone else too) talk about the trade-offs with the receiver circuits, Henry's has the two stage recovery circuit, Gary's has a single stage with both sides of the tube in parallel. I never understood why the fender amps had two recovery stages.

Gary's reverb-a-loop thread...
https://tubeamparchive.com/viewtopic.ph ... verb+power

More to come.
Bill