Hi all, new here. This seemed like a good spot for some amp questions.
So i inherited this amp, it has no type indication, serial number or anything like that. I also can't find any Elk model with these knobs on the front. Is this some prehistoric model or an imitation Elk perhaps? Reason i'm asking is because there's a tube missing. The amp works but i can only assume it would work better with that missing tube. Does anyone know which type of tube ought to be used in that missing spot?
Perhaps it began life as an EB202-S 50 or 60 watt that had been modified. The 5th and 6th knobs were previously where inputs for the normal channel resided. Is V5 a 6AQ8 (ECC85)?
That schematic seems to have 4 inputs and a 4 Ohm speaker output. The one i got only has 2 inputs and (according to what's written on it) has an 8 Ohm speaker output. But maybe it can point us in the right direction as to which tube is missing.
E: How come that schematic has 2 tubes with a V2 indication and 2 with a V5 indication? Or is that normal for tube amp schematics?
Many preamp tubes, including ECC83/12AX7, have two triodes in each envelope. Schematics will sometimes label them "V1A" and "V1B" for example, but not always. Have you looked inside to see what is connected to that socket? It may be out of use, or if it is connected the surrounding components and connections may provide clues.
Yes that reverb thingy is on one side connected to the small transformer, the other side goes to the PCB somewhere.
From what i've seen thusfar the only 2 things that aren't connected are one of the DIN connectors and the voltage switch.
So what i've got on the tubes (small to big, possibly from V1-V7):
1,2,3: ECC-83
4: gap/empty
5: unknown (nothing readable on the tube anymore except 'D71' on the top)
6,7: EL-34
Does the reverb work? I'd guess not if the transformer and tank are connected to an empty socket. Chances are that takes a 12AX7 or 12AT7. Can you get back inside and see what is connected to the pins?
If you're interested, I have a set of plates for one of these. I converted mine to a Rockster years ago and have no need for the plates. In good condition.
"Education is what you're left with after you have forgotten what you have learned" - Enzo
martin manning wrote: ↑Mon Nov 20, 2023 4:47 pm
Does the reverb work? I'd guess not if the transformer and tank are connected to an empty socket. Chances are that takes a 12AX7 or 12AT7. Can you get back inside and see what is connected to the pins?
I don't think the reverb works but i haven't tried connecting a pedal (who has anything DIN nowadays )
So here you see the 2 wires coming from the reverb box:
And here you see wires that come from that left spot leading to that smaller PCB which also has some wires coming from the pedal DIN input.
dorrisant wrote: ↑Mon Nov 20, 2023 5:35 pm
If you're interested, I have a set of plates for one of these. I converted mine to a Rockster years ago and have no need for the plates. In good condition.
Did you convert the exact same model i got? If so, do you happen to know which tubes are used in your amp? Maybe even some pics of the inner works so we can compare surrounding components.
(Plates would be cool if they're for this model, maybe you can share some pics)
You are going to have to trace out the modification to see what that's about, and find some way to activate the functions controlled by the footswitch. Looks like there are two relays on that piece of perf board that are controlled by it. My best guess is that missing tube is a 12AX7/ECC83.
Can you post some pics?
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