M Fowler wrote:OT is a EM0720 but with white common. 35w 5k2 with screen taps. Took the amp apart to make sure what I have.
I like the wiring label on top not the bottom of transformers I don't care what hifi guys say.
What is worst about it that I think these have always been that way... just looked at some old photos and they all have the white wire common on the secondary... I'll get the web site updated so I can avoid future confusion.
I agree totally, put that label where we can see it. I even try to put the caps in so you can read the values from a photo view. It's not like these are atomic weapons and we need to hide the secret formula... and history kinda shows that most atomic programs are not all that successful at hiding stuff anyway. I hope I can go to my grave believing I gave away ever amp secret I ever knew! Maybe somebody somewhere will sound just a little better using one of my ideas?
Edit note - They have also labeled the 4.3K taps as UL taps... I suppose you could use them that way but it does give you some insight into their HiFi state of mind. When they first wound these trannies for me I had to really press them to label them above 25 watts... the engineer told me something like "you might get some distortion if you go above that level." It really seemed to confuse him when I said yes I hope so!
Finished up rj's Rockster Reverb combo amp and it is a great sounding amp rj
Had a little issue with reverb circuit had dc on the reverb pot, changed out two caps .047 on PI, also where the OD .005 cap is on the board and still had dc.
Then I studied many variations of rj's schematics and layouts and decided 22uf cap should not be there and switched to .005 OD and presto issue resolved.
Tomorrow I'll put the chassis in the combo cab.
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Nice!! I have high hopes of doing one of these for myself. Seems like it would be an awesome grab and go amp and already has reverb plus takes pedals. Very cool! what speaker did you use?
BTW - I think I found a couple black tolex panels for the back of that - I'll send them out to you.
M Fowler wrote:... had a little issue with reverb circuit had dc on the reverb pot, changed out two caps .047 on PI, also where the OD .005 cap is on the board and still had dc.
Then I studied many variations of rj's schematics and layouts and decided 22uf cap should not be there and switched to .005 OD and presto issue resolved...
Sorry, it has been on my mind to look into this since you first mentioned it but I was waiting for a quiet moment to look it over. We had a slight dusting of snow and my plans for the rototiller have been set aside for now... Yeah, take that the "prototype" warning label seriously in this case, it definitely needs tweaked. I'll be working on it...
Reverb tanks are designed to be mounted in a certain orientation so that the transducers are centered under the influence of gravity. Most tanks are meant to be mounted horizontally with the open side down (Fender), but many tanks that went into organs are meant to be mounted vertically on the side of a cabinet.
Bottom line: if you use a tank that's meant to be mounted at the bottom of a cab (open side down) but mount it at the top of a cab (open side up) there's a chance that the moving parts will rub while in use. You could mount it at the top of a cab with spacers so that it's open side down. It'll be less convenient to mount, and be a little funny looking, but is more likely to work without trouble.
I've been searching all over my work area for those back panels, I couldn't remember if I had them or not. Please send. 
