DIY Spring Reverb Unit

[repoman]

I built a 6G15 from a mojotone kit, I had it working for a couple days but then it stopped and I don't know how to fix it. Sounded amazing when it was working though.

[BetterOffShred]

Looks good, along the same lines as Cloudscape's design. I was in an abandoned factory with a screwdriver on my person the other day and happened to find a very nice old 24v transformer so I'm gonna go big and build the Carlsbro.

Are the Rutheniums available to buy anywhere?

Sick! Nah I don't think so. It's just a couple 5088s a 74 and a 1054.. I used the long time accutronics tank . The whole thing fits in an XX size box too.

[Dr Satan]

I built a 6G15 from a mojotone kit, I had it working for a couple days but then it stopped and I don't know how to fix it. Sounded amazing when it was working though.

Start from the easiest and most obvious then work out from there. Check your solder connections. Reflow anything even remotely suspicious. Look for signs of arcing and burnt components, that will give you an idea of what could be the culprit. But before any of that, swap the tubes out one at a time with known good ones. Make sure it isn't redplating anything. Make sure it has the right fuse in it. Make sure the outlet you're plugging into works, lol. Oh man, the frustration I've caused myself over not turning on the power strip I was plugged into...

[repoman]

I built a 6G15 from a mojotone kit, I had it working for a couple days but then it stopped and I don't know how to fix it. Sounded amazing when it was working though.

Start from the easiest and most obvious then work out from there. Check your solder connections. Reflow anything even remotely suspicious. Look for signs of arcing and burnt components, that will give you an idea of what could be the culprit. But before any of that, swap the tubes out one at a time with known good ones. Make sure it isn't redplating anything. Make sure it has the right fuse in it. Make sure the outlet you're plugging into works, lol. Oh man, the frustration I've caused myself over not turning on the power strip I was plugged into...

Yeah I think I need to completely redo it, I suspect I burnt out one of the transformers. When I initially built it, I wired the heater wires incorrectly, which completely fried one of the tubes. Then I redid that wiring, replaced the tube and it worked and sounded amazing. Used it for a couple days then it just stopped working, I rebuilt it a couple times after and replaced the filter caps and it still doesn't work, tubes light up, very little sound comes through it though. I'm not savy enough to know the procedure to see if the transformers are functioning properly and I haven't been keen on dropping another $100 into those as trouble shooting...although I probably should the thing has been sitting under a chair in my room for a couple years. My state doesn't have any competent amp techs either...theres only one and he is terrible, I've had him work on 3 amps and he fucked up every one...including stealing all the mustard caps out of a 1974 JMP I had. (I had no idea about amps back then)

[crochambeau]

Yeah I think I need to completely redo it, I suspect I burnt out one of the transformers.

Are you able to safely measure live circuits?

[repoman]

Nope

[repoman]

The surf thread motivated me to dig this out again and start working on it
I realized the wiring supplied in the mojotone kit was single strand, and figured there was probably a broken connection somewhere, so I redid all the wiring and it works! ...Kinda...the controls are acting funky, where if I reduce the DWELL to zero there is no volume, and the TONE knob is *sort* of acting like a volume too (it seems like theres a bit more volume with it all the way up, and the MIX knob doesn't go completely dry at zero. I've spent a couple hours just tracing the connections and can't find anything wrong...the mojotone layout diagram is kind of shitty, the eyelet board doesn't match up to the one supplied, theres incorrectly displayed resistors, caps, poor/unclear marking on a lot of connections, needless use of some eyelets.
But with the dwell dimed and the other knobs up a good ways it sounds so freaking good. The reverb in my PRRI sounds like nothing compared to this.
I'm wondering if its a grounding issue...theres a ground that goes off the 3 lug on the DWELL that I have connected to the back of the potentiometer, wondering if thats not doing its thing?

[crochambeau]

Caveat: I've built a 6G15 off of the official schematic, and am not aware of any differences between that and the kit you built (meaning if there are my conclusions may be in error).

Dwell at zero should just give you no reverb, the fact that it's giving you no volume indicates the ground connection there is fine. That said, I avoid completing grounds through the mechanical connection of the pot like the plague. If it's pulling down your dry feed too then I'd suspect you've got a wiring error in which your dry channel is branching out after the first tube stage as opposed to before it.

The mix control is just the wiper position between the two feeds (dry & wet), so in full wet you've got a 250K trickle of dry & vice versa. If you swapped pots here with a lower value you'll wind up with more bleed, a proper crossfade could resolve this if the bleed bums you out, but I've never run an outboard reverb full dry - that's what the tank muting footswitch is for.

Tone shouldn't act as a volume, unless you're just listening to the high frequency. Are the capacitors oriented correctly? You want the smaller one referencing ground on that pot.

[repoman]

I yanked all the wires out, I did remember I bootlegged something on the board which was attaching the resistors to the capacitors instead of putting them into the eyelets, do you think this is maybe whats causing the issue? I did this because the supplied resistors legs are not long enough to reach the eyelets.

[crochambeau]

I don't think those wire jumpers would give you much grief, do you have a multimeter to test continuity?

Nothing jumped out at me as being wrong on the board, aside from the obvious wiring that's missing.

[repoman]

Redid the wiring again and now it works 100%, I think the issue was there was a resistor jumper I initially made that attached to the leg of a capacitor that should have gone to the eyelet, its the one in the above picture that has the bit of copper strand extending the leg of the resistor, previously it had been attached to that capacitor next to it, I was kind of guessing it was dealing with what you were saying with the issue of the signal being screwed up somewhere with the dry channel.
I need to figure out what to do with the front panel now, I was thinking about putting a piece of plexiglass over it so I could put some kind of graphic/art behind it, but dunno what to do.