Belton "Brick" Digital Reverb In My Octal Fatness, Round #2

[Paul Marossy]

Here is my Octal Fatness that I built way back in 2004. I was working on it over the weeked, had to pull the chassis several times and was annoyed by my satellite digital reverb arrangement. So I decided to actually add it to the chassis somehow, although I was not looking forward to it as it's not a big chassis and it's packed full of stuff.


5 watts of greasy single ended 6V6 crunch. This has one of the only amp produced distortions that I have ever really liked a lot. Very touch sensitive and does clean well as a nice bluesy tone to a mild crunch. Sounds great through a 15 watt alnico speaker. The digital reverb I added a while ago is in a Hammond 1590B style enclosure inside the cabinet, but I was never really too happy with this arrangement.


Hard to believe it's already been 8 years since I scratch-built built this into a chassis from a cheap junked amp (Ross "Fame" 15 watt amp I think). I made everything else from scratch.


Digital reverb is now relocated to the chassis (made integral with chassis instead of a seperate entity inside the cabinet). It was a pain in the neck, but I made it work. I now have a reverb bypass switch and a front panel reverb control.


Reverb unit is all rewired. Last thing to do now is make a shield for the reverb unit and pop my trio of NOS tubes back in it (GE 6V6, and RCA 6SJ7 and 12AX7). I also have an NOS Tung-Sol 6V6 I could use.


I sure have a lot of stuff packed into a very small chassis for a tube amp. This is star grounded, too. Yeah, I know I'm a heretic for using ceramic caps in the tone stack... but I like how they sound. They're rated for 1.5kV, so they're not too non-linear.


Reworked quite a bit of the preamp section this weekend. There was a bunch of changes to the circuit that I never picked up, so I brought it up to date. Sounds much better and the tone controls all work much better, too.


Aerial view of chassis


Shielding for reverb all done, made out of some thin aluminum sheet metal obtained at Lowes, same stuff I use to shield the upper part of the cabinet in my DIY amps. (I'm a skilled metal worker LOL). Lovin' how touch sensitive this little amp is.

[head_spaz]

Attaboy! Nicely done Paul.
Would you mind sharing your reverb schematic and perhaps a schematic showing how and where you installed the reverb into your circuit?
I bought a Belton reverb module last year with the intent to add it to my AX84 October Studio Amp (my favorite amp of all time!) But lately the fever kicked in, hankerin' me to build Doug's Rocktal Fatness with reverb since my October already has a working effects loop.

BTW, Is your 6JS7 noisey?

Best Regards,
David

[Paul Marossy]

It's just the GGG reverb unit right at the input of the amp. It's powered by a voltage regulator set at 9.5V, which is typically what a brand new 9V battery will measure.

Yes, my 6SJ7 is noisey when I have the gain all the way up. It's not really noticeable until the master volume is more than half way, and at max it's very noticeable. I'm still trying to figure out why this is and if I can do anything about it. Every single thing I have tried has resulted in failure. I'm beginning to think that there just isn't anything that can be done about it as I have done every trick in the book and the problem still persists.

[boogietone]

Nice! The custom octal fatness label on the back, what is that made from: paper label, etched steel?

[Paul Marossy]

Nice! The custom octal fatness label on the back, what is that made from: paper label, etched steel?

I created the graphics on AutoCAD and printed it out on "sticky back", a clear self-adhesive plastic applique. I placed that on top of a piece of self-adhesive aluminum foil, known as "metal repair tape" at places like Home Depot. Looks like a for real label when it's done.

[gritz]

Nice! The custom octal fatness label on the back, what is that made from: paper label, etched steel?

I created the graphics on AutoCAD and printed it out on "sticky back", a clear self-adhesive plastic applique. I placed that on top of a piece of self-adhesive aluminum foil, known as "metal repair tape" at places like Home Depot. Looks like a for real label when it's done.

The label really caught my eye too - as did those ceramics. I love a bit of heresy! Good stuff. 

[nelson]

Nice! The custom octal fatness label on the back, what is that made from: paper label, etched steel?

I created the graphics on AutoCAD and printed it out on "sticky back", a clear self-adhesive plastic applique. I placed that on top of a piece of self-adhesive aluminum foil, known as "metal repair tape" at places like Home Depot. Looks like a for real label when it's done.

That's DIY genius.

[Paul Marossy]

Necessity is the mother of invention. 

[RedHouse]

Is that the same Octal Fatness from the AX84.com threads?

[Paul Marossy]

Is that the same Octal Fatness from the AX84.com threads?

Yes, but I built it way before it became an AX84 project. I haven't been to the AX84 forum in years. I'm sure it's had some tweaks since I built it in 2004.

[RedHouse]

...I haven't been to the AX84 forum in years...

Me neither, but just went over and looked, jeez-o Chris sure needs to update that old forum software, it's painful to navigate the old threads anymore, but it was a cool place to hang for a while.

[Paul Marossy]

Yeah, I never liked that forum software too much.

[Paul Marossy]

BTW, Is your 6JS7 noisey?

Just thought I'd point you to this post where I figured out my noise source. Four inches of shielded cable on the input fixed the whole problem I was having - http://www.diystompboxes.com/smfforum/index.php?topic=97779.0

[Paul Marossy]

I felt that the amp looked a little bland, so I did a few things to it to make it look a little more snazzy.