Dumble Reverb?

[Structo]

I was browsing through schematics and came across this Supro Reverb print.

Signed by guess who?

[David Root]

I don't know what HAD's signature looks like, but the only thing in that drawing that otherwise looks possibly Dumble-esque to me is the precision of some of the numbers, eg cathode volts 1.18, B+ 315.4V.

His freestyle layout dwgs that I've seen are a lot looser than that.

[Structo]

I thought it curious none the less.

[FUCHSAUDIO]

Been floating around for years. Nobody knows whether he designed it, or just drew it up and someone posted it....interesting circuit.

[talbany]

Looks a bit like his signature, although it would take me about 10 min in PS to copy/process and layer it to the schematic..I agree w/ Dave a bit too neat and don't buy it....BTW..Has anyone here seen a computer generated schematic/layout image from him?..

Tony

[ampdork]

It was published in one of Aspens books.....seems to me it was at a time when no one was trying to clone his stuff....so I highly doubt it is a fake or forge...Have also seen similar drawing is his just as neatly done and with the same HAD sig...
Do not think he designed it though....think he just enjoyed drawing it out... but this is all my own opinion of course.

[David Root]

"interesting circuit" indeed! The 12DR7 is a new one on me. One triode is more or less "normal", ie like a 12AX7, or maybe a 12AY7. The other one seems more like a 12AU7.

Which is similar to the 12DW7 I guess, except the 12DR7 is a TV tube. I guess that's why the high current triode grid has two pins connected to it, not one?

[ampdoc1]

I found that years ago on Free Information Society (I believe), and looked and looked for it again a year ago. Thanks for sharing.

a'doc1

[renshen1957]

"interesting circuit" indeed! The 12DR7 is a new one on me. One triode is more or less "normal", ie like a 12AX7, or maybe a 12AY7. The other one seems more like a 12AU7.

Which is similar to the 12DW7 I guess, except the 12DR7 is a TV tube. I guess that's why the high current triode grid has two pins connected to it, not one?

I couldn't find 12dr7 at Frank's electron tube data website:

http://frank.pocnet.net/sheets11.html

Could be a misprint, or an intentional "error."

I went to look up Supro schematics at schematic heaven but www.schematicheaven.com is no more; some parasite has the url now and its just a fraud website (multiple popups for ripoff offers for stuff you don't want or won't get after jumping through hoops).

I look at other Supro Schematics that had been archived from another website, don't see this tube on any of them.
http://www.valcopages.com/Schematics/Supro_6650.pdf

The Supro typeface looks exactly very similar.

Best Regards,

Steve

[Structo]

Yeah, I don't know why it is stuck in the Supro files.

Schematic Heaven had some troubles a while back and they changed servers.

http://www.webphix.com/schematic%20heav ... _HTML.html