Valves for Vox AC30 cc1

Jacquesg4j

Tried Google, browsed GFSA, but I am considering a valve change in my Vox since I have no idea what it has at the moment.

Basically 4 x El84s, 3 x 12AX7s and 1 x GZ34...

What would be a good combination and also who can open her up and do it for me in the Gauteng area?

ezietsman

I believe the ac30 is cathode biased so its just plug and play.

Jacquesg4j

ezietsman wrote: I believe the ac30 is cathode biased so its just plug and play.

... meaning...

HAHA dude... What does it mean?

ezietsman

it means you can swop the valves yourself, you don't need to adjust the bias for the new valves. Just don't touch the circuit board when you take the bits out (I think you have to do that on an AC30)

Jacquesg4j

Awesome that would save me some! No issues of current and hair raising experiences?

ezietsman

Jacquesg4j wrote: Awesome that would save me some! No issues of current and hair raising experiences?

Well, there acn't be any if you don't touch the circuitry. Most modern amps have the so-called 'bleeder' resistors for every power supply capacitor (Those big ones that kill), so when you switch the amp off the capacitors discharge through these. On my amp it takes about 30 seconds for them to bleed out completely. BUT better not to assume they will discharge (you only know that they have if you measured them), so if you need to take the chassis out to get to the valves, you must avoid touching the circuitry. On most amps you can replace valves without having to remove the chassis but in your case maybe not.

AlanRatcliffe

Stock valves are usually a combo of EH and Sovtek. I like the TAD EL84s, but many guys are happy with the JJs. I also like NOS 12AX7s (Telefunkens, RCA, GE, etc.), but the Tung-Sol are pretty good for new production. NOS rectifiers are best (fit and forget for the next 20 years) and only the JJs are worth considering from the modern production valves.

Jacquesg4j

Can't seem to find teslas or TADs at tube depot! Will consider ebay!

Would you not suggest JJs in the pre? Like the High Performance Gold tipped ones?

http://tubedepot.com/jj-ecc803g.html

They seem reasonable and at least cheaper than the NOS ones? The cheapest one there being a JAN GE?

http://tubedepot.com/nos-12ax7-jange-lp.html

Jacquesg4j

ezietsman wrote:
Jacquesg4j wrote: Awesome that would save me some! No issues of current and hair raising experiences?
Well, there acn't be any if you don't touch the circuitry. Most modern amps have the so-called 'bleeder' resistors for every power supply capacitor (Those big ones that kill), so when you switch the amp off the capacitors discharge through these. On my amp it takes about 30 seconds for them to bleed out completely. BUT better not to assume they will discharge (you only know that they have if you measured them), so if you need to take the chassis out to get to the valves, you must avoid touching the circuitry. On most amps you can replace valves without having to remove the chassis but in your case maybe not.

It appears that I must remove the board and all! But also apparently you can just leave your standby and on/off switch on and this will drain the current?

makepeace

JJ's are tesla's (its JJ Tesla ?)

NOS or the best new productions (JJ/Gold Lions for 12AX7's) will be largely up to your individual discretion.. ie whether you're prepared to pay to get the BEST tubes (and you will pay..)

TAD's can be found here: http://www.turretboards.com/guitar_amplifier_parts_vacuum_tubes_tad.html

For the recto, check what you have in there first. Another GZ34 isn't going to do much for your tone other than maybe changing your B+ somewhat (you'll have to find out if thats a good thing or a bad thing for your specific amp). Its the kind of thing that you HAVE to have in there to make everything work ?. But if its old and getting ready to go, you might as well replace it.

edit: have a look here for reviews of the new production EL84's and 12AX7's
http://thetubestore.com/el84review.html#review
http://thetubestore.com/12ax7review.html

AlanRatcliffe

Jacquesg4j wrote: Can't seem to find teslas

Sorry Tung-Sol. Senior moment. :-[ JJ are basically the new production Teslas.

or TADs at tube depot!

Should be available from Watford Valves or KCA NOS. I was very impressed with them in my Heritage Handwired AC15.

Would you not suggest JJs in the pre? Like the High Performance Gold tipped ones?

The ECC803? I've heard some good things about them but haven't tried them myself yet. The general consensus is they are a good match for brighter amps, helping to smooth them out.

Jacquesg4j

Stop making fun of the iPod generation please!!!! haha