Tube Amp Archive

One standard type of 50s-60s two prong is called a "cheater cord" Have a look here: http://www.ceitron.com/passive/acords.html If you have a pic, maybe I can be more specific. If you want to run two prong, make sure you remove the "death cap" or replace it with one rated for across the line service....

That's wrong ain't it? Oh oh. More study coming up... That is actually correct. It might help to think of a power supply as an electron sucker, with B+ terminal as the nozzle of the vacuum. Ground is a huge pile of electrons that get sucked through the circuit by this force of attraction. For some ...

I'm wiring one up right now, matter of fact.

What layout problems did you notice with the board. I'm sorta checking it as I go along and haven't noticed any freakyness.

Most of the 7-pin triode/duodiode datasheets mention that the diodes cannot be used to bias the triode.

How about using the diodes from different tubes to bias each other?


EDIT: Never mind...the cathode would have to be grounded. Duh.

Amp appears to use a 6SN7 input stage and a 5687 SRPP driver stage, according to the website. I'd say it is well thought out in terms of good basic engineering. Of course you can build an equivalent or better amp yourself for less than the cost of the kit, but it wouldn't look like a commercial prod...

Thanks, Structo! Damn, no wonder H.A. Dumble is so famous...the man draws up a nice schematic! Here's another which like the Supro mentioned above uses a 6DR7 for input and reverb driver. The second section of this tube is a low mu triode which is a good choice to slam electro mechanical transducers...

Well I have a stash of NOS, so I am not bound to new production...but I suspect that even the old ones were often microphonic. EF86 had that reputation before they were reintroduced. At the risk of an oxymoron, I think the reasons you don't see RV-1s around often is that they were low production ver...

Anybody have a line on an RV-1 schematic? Thinking about constructing a stand-alone reverb and surveying prior art. Going by general description, this one seems to be off the usual well-beaten Fender track, with EF86 preamp and 6AL5 type tube used to some mysterious end. Any other interesting reverb...

"Leave it alone" ... p*ssies. Cool

Since you are such a player, try a miniature shaped charge. Plastique.

Dude, I tolds ya to leave it alone! :P I'd epoxy in the sheared off ends, rig them up as best possible--having the nut side intact will at least work as a spacer, and get on with the amp! Three bolts should hold the iron. If you drop it hard enough to shear off three bolts, even metal cheese bolts, ...

I'd just rely on the remaining three bolts and get on with it. There won't be much force on that sheared bolt with the other three tightened down. You can glue the head back on with some Goop for cosmetics. "Steel" is a bit of a reach for some hardware these days, much of which is made out of some k...

did anyone else notice the difference between the two channels?

You may or may not be smart, but your eyesight is unquestionable!

the plot thickens!!

Dissipation is on the order of 0.25 W...don't need WW. Something like 1 mA bleeder current and what 2 mA cathode current? I have measured the inductance of WW resistors before and it is quite low for something like a 470 ohm. Definitely talking high RF range effects in a cathode circuit like that. P...

Can't see inductance playing much role... in a cathode circuit that would give a very slight peak way up in the VHF RF range...well beyond any frequency Estey's wiring techniques would support :P Only reason to use WW would be dissipation (or low noise)...but its a dang 12AX7 and this is an Estey am...

Well, scratch the NFB suggestion since the 220k is on the filter cap side of the plate resistor. Why do you think that 470R is WW? Very little current flows through that resistor. All I can see is a voltage divider that puts 0.3V fixed bias on the cathode, in addition to the voltage developed across...