Sorta OT - Octal Fatness, I've Been Bitten.... (update)

[Paul Marossy]

by the amp building bug.  :oops:

I've had my Matchless Spitfire clone done for a couple of weeks now, and I love it! Now I'm itchin' to build Doug Hammond's version of the Octal Fatness. UGH!

Since I'm talking about the Octal Fatness... Doug, if you read this, I have a question for you. This 1K/12W(!?) bias pot, what is that exactly? A trimpot, a regular pot, or? Could you accomplish the same thing with a rotary switch and several resistors for different power tubes? I suppose that's not as good as a pot wired as a variable resistor, though... Hmm... that would be cool if you could wire a rotary switch somehow to use a 6AR6 and then switch to a 6L6GC or a 6V6. I'm also wondering what an EL34 would sound like... I dunno if B+ is high enough, though.

[RDV]

If you have trouble storing them I'd gladly give one a nice home.

:wink:

RDV

[Paul Marossy]

I bet you would!  

[petemoore]

We're already in area marked OT...edit: sorry, this turned out to be OT from the first OT...turns out it's really about sticking with tubes, and half drooling about the Behringers clean sound for low bux.
 Still happy I started learning with tube amps, still recommend it [especially for effects builders, but the cmu's are enticing, usable, great sounding amps....wormbag of opinions...too late, I won't delete.
 If you're into working up efkts circuits, have a tube amp, you'll have the chance to encounter the same can of worms I did, [A/Bing to Emu amp], my opinion is that a tube amp is more variable, more dynamic, more trouble, more fun.
 IMO it's kind of an either/or. Factory presets can be plenty nuff' fun, but my personal take is that tube amps give more, and in a different way [that I prefer]...I can take 'X' effect tone, that is very close to what I'm looking for, then tweek it to the point it surpasses my expectations, to the point that most of the 'tone zones' I want access to, can *totally be had.
 That's my take on sorting that can of worms.
 That said:  
My buddy bought a Behringer amp, 2 X12 jensen combo.
 The clean sound is so good it could probably be called 'best', at the very least 'amazing' for 250$.
 The distortion side, according to early reports from him over the phone...these distortion tones were dubbed 'weak'.
 After trying the amp, I agreed they are 'weak' and 'thin' sounding...usable, but weak and thin, or not able to get fat and full.
 2 things they'll never have a subsitute for:
 1. Sleep
 2. Tube amps
 If I needed a great sounding amp, And had 500$-800$ I'd go with the Behringer [for purposes of OT, since this is one I've really tried out}, this would take care of amp And speakers and leave 250-550$ left over for...gas.
 As far as distortion, any of my Tube jobs [MkII 50w, Heathkit, Dynakit, or even little RCA Victor] could Smoke/Dust the 'B.' amp, in this A/B test.
 Have to say the clean sounds and phase was lushchious, reverb's nice too.  The Behringer purchase is A heck of a 250$ package IMO.
 WOuldn't mind at all using one for clean, but I'm still sticking to my Tube 'heritage'...pricing criticism aside, tube amps A/B test consistantly well [well if they're working 'right]..that's my story, and I'm still sticking to it.
 I guess the jist of all that is: "They're getting better at it", 'it' being tube emulation amps. I seriously doubt I could Blind A/B test and sort the clean tones out according to tube/tube emu. ...but very certain I could on the DIST/OD Side.
 I haven't had a chance to try the reportedly 'works great' TS in the efkts loop.

[Hal]

Paul (et al) - what do you finish your amps with?  Do you use Tolex, stain/polyurathaine, paint, or something else ?

I just finished up an extention cab, and was wondering what other options I have...The "pure plywood" look is a little _too_ ghetto for me :-D

[Paul Marossy]

Hal-

Take a look at my website (linked below) under "Guitar Amps", specifically the Firefly and the Spitfire. That will give you an idea of how I finish my amps. I did my Firefly with this cool looking upholstery fabric and the Spitfire with some recycled Tolex from an amp I cannibalized to make my Firefly. For my Octal Fatness, I have this cool looking fabric that I am going to cover the cabinet with.

[Paul Marossy]

One quick question for Doug:

B+ voltages are not indicated on the schematic. What should they be, approximately? I'm just trying to determine if my transformer is OK as is, or if I have to use the power MOSFET on the center tap trick...

[nightingale]

paul~
IMO this would be a great page for your site.. that is if doug didn't mind..

i have just been bitten by the same bug.. i have all of parts for a minimalist 18watter.. the chassis is nearly completely drilled.. and i just finished my eyelet board.. i have just been putting a few minutes into it each day.. taking it really slow..

i kind of planned on building the real mctube next.. but  dougs design looks pretty hot too.. i'm exited to see how yours works out.!

[Paul Marossy]

I've got a page going for this project as well.  
I'm about 40% complete with building the circuitry so far. I have to round up the filter caps and an output transformer before I can fire it up. And get some 6SJ7s...

BTW, the Real McTube looks like a cool circuit. If you build it, let us know how you like it, and of course, some sound clips would be good.

[Travis]

The McTube was my first high(er) voltage project.  It's just the front end of an early Fender Champ/Princeton.  People give it a bad rap, but it's sound is highly dependent on the tube used.  Good quality=good sound, etc.  

Lower quality tubes produced fizzy, solid-state type tones.  Good tubes make it sound amazing.  I preferred an old Lowery Organ 12AU7 in mine.

[Paul Marossy]

So, it's more like a medium gain tube overdrive?

[Paul Marossy]

Well, I'm real close to being done. All of the wiring is complete, save the O.T., which I have to order. It was a challenge fitting all of the circuitry into my recycled 12.5"x6"x1.75" amp chassis, and trying to re-use existing holes, etc., but I've got it figured out. (whoever that was from here who donated the chassis to me, thanks! Was that you JD?)

I'll post some pics later today for anyone who is interested in seeing how to fit 10 lbs of crap into a 5 lb bag, so to speak.  :wink:
I was able to stuff all the parts into the chassis, use a star ground scheme and still maintain good lead dress. The real test will be when I fire it up, though...

[Cecil]

I read over in AX84 that he used an adjustable power resistor. They have it at mouser the number is 588-D12k-value. hope that helps. When you get it done give us some clips I have kicking around building one of those myself, or the California Dreamer.

[Paul Marossy]

Thanks Cecil, Doug told me where to get one of those 12 watt jobs. I have something else that I am going to use that I think will work just as well (I hope). I will try to make some soundclips of the Octal Fatness when I get it done. I also need to get some soundclips of my Matchless Spitfire clone. I know some of the guys at AX84 want to hear how mine sounds.

BTW, I was looking at the California Dreamer schematic the other day. It looks like it would be a great sounding amp, from what I can tell. Heck, I might even build it! Darn tube amps, they're addicticting, mutter mutter grumble grumble...  :wink:

EDIT: OK, here's some pics: (sorry for the quality, they look better viewed at a smaller size)

http://www.diyguitarist.com/Images/OF-ChassisAngle.JPG
http://www.diyguitarist.com/Images/OF-ChassisRear1.JPG
http://www.diyguitarist.com/Images/OF-ChassisFilterCaps.JPG
http://www.diyguitarist.com/Images/OF-ChassisSockets1.JPG
http://www.diyguitarist.com/Images/OF-ChassisSwitches.JPG
http://www.diyguitarist.com/Images/OF-ChassisFront1.JPG
http://www.diyguitarist.com/Images/OF-ChassisBottom1.JPG

It's sort of a Frankenstein, I used a bunch of parts I had lying around that needed a home and some odd value resistors in series and stuff like that. It should sound OK, though. All I have to do now is get an OT....