Search found 479 matches

by Alexo
Thu Mar 08, 2012 3:17 pm
Forum: Technical Discussion
Topic: Ready to go SMPS for 15W tube amps!
Replies: 70
Views: 21311

Re: Ready to go SMPS for 15W tube amps!

Claims to be 300 ma on the HV, more than enough for a quad (or sextet!) of 6V6's or EL84's... although the listing suggests 6V6 SE (?)
by Alexo
Tue Mar 06, 2012 5:32 pm
Forum: Technical Discussion
Topic: 65 Fender Champ problems
Replies: 5
Views: 1259

Re: 65 Fender Champ problems

I would take a guess that the cathode resistor on pin 8 is not doing its job. Test for continuity there.. could be a bad connection or possibly the socket just needs tightening.
by Alexo
Mon Feb 13, 2012 6:54 pm
Forum: Technical Discussion
Topic: PT Failing under Load?
Replies: 14
Views: 2797

Re: PT Failing under Load?

What do you mean it is "delivering 300+ VAC?"

You mean it is a 300-0-300 center-tapped pt?
by Alexo
Fri Feb 10, 2012 10:00 pm
Forum: Technical Discussion
Topic: Tremolo troubles in a non-tremolo amp
Replies: 16
Views: 3390

Re: Tremolo troubles in a non-tremolo amp

I just watched the vid - holy crap - definitely not ghost noting.
by Alexo
Fri Feb 10, 2012 9:38 pm
Forum: Technical Discussion
Topic: Tremolo troubles in a non-tremolo amp
Replies: 16
Views: 3390

Re: Tremolo troubles in a non-tremolo amp

Few months ago I was working on my 100W bass amp build... I added a gain stage and forgot that it would change that negative feedback to positive feedback - flipped it on and it was like the gates of Mordor had been opened. Motorboating often comes on as some sort of oscillation at the resonant freq...
by Alexo
Thu Feb 09, 2012 6:42 pm
Forum: Technical Discussion
Topic: I dissected a dead tube. Pix.
Replies: 3
Views: 1027

Re: I dissected a dead tube. Pix.

Very interesting... what make and model?
by Alexo
Thu Feb 09, 2012 4:10 pm
Forum: Technical Discussion
Topic: 5E3 Modifacations
Replies: 6
Views: 1696

Re: 5E3 Modifacations

Is that a PIO death cap with a 2-prong cord??
by Alexo
Wed Feb 08, 2012 6:25 am
Forum: Technical Discussion
Topic: Tube Bass Preamp reco.
Replies: 6
Views: 1433

Re: Tube Bass Preamp reco.

The Ampeg B15 preamp has a nice, classic sound.
by Alexo
Mon Feb 06, 2012 9:26 pm
Forum: Technical Discussion
Topic: Half of a dual triode.....
Replies: 13
Views: 2581

Re: Half of a dual triode.....

You should ground the plate, grid and cathode in the unused triode if the filament is on, otherwise, it can wear them out over time.
by Alexo
Fri Feb 03, 2012 4:54 pm
Forum: Technical Discussion
Topic: Stand Alone Reverb
Replies: 3
Views: 1035

Re: Stand Alone Reverb

It just depends on the tube you are using and the impedance of the tank, it's the same as designing any output stage, except instead of a speaker, you're using the tank (but the tubes and transformers don't know that!) So with a 12AT7 or a 12AU7, the 50K load is pretty good (25K into two triodes equ...
by Alexo
Fri Jan 27, 2012 4:18 pm
Forum: Technical Discussion
Topic: Repeated arcing on pins 2 and 3 - JTM45 content
Replies: 6
Views: 2243

Re: Repeated arcing on pins 2 and 3 - JTM45 content

Maybe try this? Seems like a band-aid fix, but may be telling if it helps...
by Alexo
Tue Jan 24, 2012 6:48 pm
Forum: Technical Discussion
Topic: Jupiter Cap Quesiton
Replies: 20
Views: 13074

Re: Jupiter Cap Quesiton

Ordered a batch of Sozo standards for an AC30-ish build last week, all shipped out right away. I know they have had fulfillment issues, but they seem on top of it right now.
by Alexo
Fri Jan 20, 2012 7:05 pm
Forum: Technical Discussion
Topic: 5G9 Tremolux PTP Build
Replies: 16
Views: 3478

Re: 5G9 Tremolux PTP Build

The proof of the pudding is in the eating!

Looks like a fine PTP to me... bet that IEC socket was fun to cut out from that old plated steel, or whatever super-metal they used on some of those old chassiseses.
by Alexo
Fri Jan 20, 2012 5:12 pm
Forum: Technical Discussion
Topic: B+ reduction strategies
Replies: 7
Views: 1427

Re: B+ reduction strategies

I recently did this on my office stereo to adapt it to a cheaper tube than the EL34's I was burning through. Works just as the electronic theory books say - went from 375 VDC to something more like 250 or 225, but you need to have a choke rated for a lot of current, and you will get a very stiffly r...