DIYstompboxes.com

DIY Stompboxes => Building your own stompbox => Topic started by: petemoore on June 03, 2004, 11:20:15 PM

Title: Higher tube circuit voltage
Post by: petemoore on June 03, 2004, 11:20:15 PM
I've built the Shaka Tube minus the OA part. It works quite great.
 I've assembled another Shaka tube minus the OA part, and contemplated the idea of running the signal circuit parts of the tube on higher voltage.
 Will the circuit bias and operate the same for the most part at a higher voltage...[I know to use caps rated for the supply]?
 I have a 30V adapter, is there a circuit that I can use to raise the voltage supply using this adapter?
Title: Higher tube circuit voltage
Post by: Paul Marossy on June 04, 2004, 09:40:03 PM
In theory, you could use a voltage tripler of quadrupler circuit to boost the voltage. I'm not sure how practical that would be, though. I imagine it would also pummel your amp's input running at a higher voltage like that.  :wink:
Although, I'm sure you could scale down the output a little bit by using a voltage divider. (like on Joe Davisson's Blackfire)
Title: Higher tube circuit voltage
Post by: toneman on June 04, 2004, 10:27:15 PM
Geez Stompers,
tube amps?
voltage triplers?
how come no one's mentioned PAIA?
Oh Kay, i am.....  :-)
why not check out PAIA's Stack in a Box?
here:
www.paia.com

PAIA has been producing this kit for almost 20yrs.
voltage trippler.
opamp input preamp.
1 12ax7, 2 stages of gain.
balanced/unbalanced outs.
FrankeClarke in Canada has got a web page on the SIAB.

AFN
tone
Title: Higher tube circuit voltage
Post by: R.G. on June 04, 2004, 10:49:33 PM
Any AC-output wall wart can be doubled/tripled/quitupled/xxxxtupled. Do a web search on voltage multiplers.

As a practical matter, it's hard to beat two 120:12Vac transformers run back to back. The 12V secondaries provide the filament voltage and the free primary provides 160Vdc to run the plates. It's cheap - Mouser sells a 120:12Vac transformer for about $3.00.

You can do CMOS-driven multipliers as well, which is what the SIAB does.
Title: Well Dagnabbit
Post by: petemoore on June 04, 2004, 11:21:56 PM
That sounds great !!!
 So basically I could use an inexpensive transformer to build a small tube amp !
 At any rate Mouser is getting the call in for some Iron shipment !!!
 Not that have any real problems with my present tube amps, except portability.
 Trying some DIY Tube amps is just too enticing !!!
 As much as I love working with transistors and using tube amps, I Know I'm going to like starting to working with tubes in amps!!  
 BTW, I just boxxed up a two stage clean booster [Mos]. Superb !!!
 AND...I got lucky with a phone call about PS's, and scored a 30VDC [34VDC measured] and 6VDC [9.34VDC measured] wall warts, and a 12VDC to boot!
 Connected a 9VDC [measured 11.2] to the Shaka Tube 'only' 12ax7 heater, and the 30VDC to the plate/cathode circuit...
 This sounds superb, the Dual mosBOOst into the 12ax7 into the RCA Victor...also will sound superb in my other tube amps  :!:
 Very soft round ever so slight OD tone, super true highs but no harshness even when attack strummed ...beautiful, true sounding, ringing tones, well defined lows. Really quite amazing what these tubes do. Just loving the 'clean side' today.
  OT
 I didn't get a chance to try this in my buddy's Fender Frontman  15, I was hoping to get a chance to do this, he'd set the amp up outside and it was making a horrible 'glach geg g g glach] when plugged in, he found the 5 YEAR Warranty stuff for it [amazing], he wants to turn it into the local Akron Music [a fender dealer] to have it fixed. I left a Little Gem with Mcintosh Power Pro speakers there / where I got the wall warts.
Title: Higher tube circuit voltage
Post by: Paul Marossy on June 05, 2004, 01:32:54 AM
Welcome to the clean side!  boo-wha-ha-ha-ha.  :lol:
Sounds like you are discovering the world of tubes. Careful, it can be addictive.  :wink:
Title: Higher tube circuit voltage
Post by: puretube on June 05, 2004, 08:12:11 AM
...it is addictive!

but be ye all aware of the hum-issues that can arise
when using transformers near tubes!
Title: Higher tube circuit voltage
Post by: Paul Marossy on June 05, 2004, 09:48:44 AM
Yep, that's a good point puretube. Hum can be a real PITA to get rid of. The key to that is keeping any transformers and AC wiring as far as possible from anything that is carrying an audio signal, including the tube itself, which can pickup a hum.  :evil:
Title: Yes
Post by: petemoore on June 05, 2004, 10:56:00 AM
Growing my own as a sseasoned tube sound addict is getting to be a 'powerful potion producer'.
 I have 4 tube amps, three have pre's, the Dynakit having two 7199 pentodes and 4 EL34's...this one tells me it needs or at least really likes having a 12ax7 [or two] help drive it.
 I wired and tested my second 12ax7 circuit...[Shaka tube -OA section].
 Wiring up the circuit section of a tube is really not much different than an OA or transistor, the V supplies tho, being new to transformer PS's...[studying them, but havent actually wired Iron yet], they present the 'new' [to me] challenge...be that as it may, this will change in the near future.