Rack-mount 6G15 standalone reverb build NOW WITH AUDIO

Ossyrocks

You are quite inspiring! 

Keefy

mikem8634 said:

I love this thread, even though I might as well be looking through a wizard's window.

Ossyrocks said:

You are quite inspiring! 

Thank you both! No guarantee it will actually work though...

Keefy

It works!

I completed the heater wiring this morning, then buzzed out all the connections to ground and to the valves - all good. I powered up the unit via a Variac and dim bulb tester. No magic smoke, no blazing bulb, HT and filament voltages ok. Then I repeated with the valves fitted, still no drama.

Now I connected the unit between guitar and amp. There is reverb but it’s very quiet, and there’s no dry signal at all. Hmmm.... The 7025 mixes the wet and dry signals so I tested it first - it’s ok. So is the 12AT7. (I have no way to test the 6K6.)

I decided to check all the voltages shown on the Fender schematic. Some of them are way over spec, especially around the 6K6, which is biased to 100% of its rated 8.5W dissipation. I ended up with a 470R dropping resistor (not shown in first photo)before the first node, which brought all the voltages into range except the plate of the 6K6. Dissipation of the 6K6 is now a healthy 4.8W. According to the schematic there is supposed to be 70V drop across the OT primary, whereas I’m dropping only 11V.

Anyway I tried the unit again into an amp and yay, we now have a working reverb unit. All the controls operate as they should and it sounds phenomenal.

This build is nearly complete. The blue knobs are temporary until I source some nice chicken heads.

Winny_Pooh

Very cool, nice big tank too!

Keefy

Winny_Pooh said:

Very cool, nice big tank too!

Yes that's a nice old 3-spring Accutronics, from when they were still good!

I did the labelling and phono leads last night and final drilling and assembly today. The tank sits on a foam pad on some cross-bars. It's not secured, but if this becomes an issue I can add some cable ties.

I can feel an audio demo coming on soon...

mikem8634

Just excellent. Looking forward to hearing it.

Ossyrocks

Nice one!

Keefy

mikem8634 said:

Just excellent. Looking forward to hearing it.

Ossyrocks said:

Nice one!

Thanks. Here ya go with an audio demo, it had to be surf didn't it! I recorded this with the reverb first, as the original users would have connected it in front of their non-reverb amps, so signal chain is:

Strat > 6G15 Reverb > Revival Drive (emulating tweed Fender amp) > Torpedo CAB

Walk Don't Run

I had my doubts about doing this build because I had already made a 1U IC-driven spring reverb, but tbh this one pisses all over it from a great height!

mikem8634

That sounds wonderful, a big, bright, authentic sheen (for want of a better word). And really well played too btw.

NPP

mikem8634 said:

That sounds wonderful, a big, bright, authentic sheen (for want of a better word). And really well played too btw.

couldn't have said it better!

Keefy

NPP said:

mikem8634 said:

That sounds wonderful, a big, bright, authentic sheen (for want of a better word). And really well played too btw.

couldn't have said it better!

Thanks chaps! Colour me chuffed.

Keefy

Couldn't post these last night because Imgur was having a paddy, but this is where the 6G15 sits above the Rack Drawer of Wonder (TM), and its place in the patchbay. God those pedals are dusty! The SPRING REVERB label in the patchbay pic is the older IC-driven build.

PeteC

nice set up - lovely job ! What valve based project next ?    

If you fancy a very good mic then I'd highly recommend the Gyraf G7 build project  - or a G-PULTEC from the same website , or dual LA2A for the studio set up    ...Its a very deep rabbit hole !!!
 

Keefy

PeteC said:

nice set up - lovely job ! What valve based project next ?    

...
 

I have a couple of pedal things to do, but after that I’m thinking of (in no particular order):
(1) Ampeg B15 head - I have downloaded a Ceriatone ‘Aunt Peg’ layout but I think I would build it valves-upwards, albeit not in the exact same form factor as the original!
(2) 6L6-powered Champ eg Weber Maggie. I had a Swart Space Tone which was Champ-based and to me sounded much more open and lively running a 6L6 than a 6V6.
(3) Princeton Reverb rebuild. I bought a used 68 Custom model on here a couple of years ago with the intention of gutting and hand wiring it but I liked it so much as-is that I left it. I have since done the mains voltage mod, increased the NFB to original spec, and tamed the bass in the tone stack. At some point I will get round to a full rebuild.