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View Full Version : 12AY7 vs 12AU7


Cheebatone
05-02-2008, 07:49 AM
It looks like I'm getting a Fender Prosonic and (thanks to this place) I've been made aware of it's gain issues, so I'm looking to calm it down a bit. However, I've never had the need (or the inclination) to use anything other than a 12AX7 before, so I'm a bit lost. How do the AY and AU measure-up to each other? I'm leaning towards the AU because I've got my overdrive sounds sorted (thanks to an Ethos TLE and a Zendrive 2! :bow:AOK) but the KCA site's appraisal only says the 12AU7 is good, "...in pedals". Anybody ever use one in a pre-amp stage?

Cheers!

Charly

Cheebatone
05-02-2008, 08:10 AM
Also, can I swap the rectifier (a 5AR4) for something a bit more 'saggy'?

alltone
05-02-2008, 09:25 AM
http://www.thegearpage.net/board/archive/index.php/t-84518.html

Blue Strat
05-02-2008, 02:19 PM
Unless it's a VERY high gain stage, a 12AU7 will likely have too little gain. A 12AY7 is a more likely contender.

Using a 5R4 rectifier will definitely add sag at lower volumes. They're cheap too.

Cheebatone
05-03-2008, 03:15 AM
Thanks for that link Doug.

And your advice, as always, is invaluable Mike.

Cheers.

groovy daddy
05-03-2008, 02:15 PM
The 12AY7 sounds great for clean or jazz but tames it a little too much IMO. 12AU7 even more so. No extra kick if you need it. The 5751 works good for me.

Blue Strat
05-04-2008, 06:33 AM
The 12AY7 sounds great for clean or jazz but tames it a little too much IMO. 12AU7 even more so. No extra kick if you need it. The 5751 works good for me.

It's always best to avoid generalizations and be specific about what amp you're using. What works great in one amp for one person doesn't work at all in another amp for the same person.

Wakarusa
05-04-2008, 08:28 AM
Mike surely has a greater breadth of experience, but I've always had issues with microphonics in 12AY7 (both new and NOS) -- certainly more so than, say, a 12AU7. The best solution I would think would be to buy one of each and try 'em. NOS RCA 12AU7 are cheap and plentiful, and 12AY7 aren't that expensive (whether you get new EH or find a nice NOS GE). $20-$30 to know for sure seems a modest price to pay.

Cheebatone
05-05-2008, 02:57 AM
Just to be clear, I've got my overdrive sounds covered with pedals. I'm trying to calm down a notoriously OTT pre-amp stage to give myself a bit more room to breathe.

Thanks for all the advice so far, btw.

JimiStiff
05-05-2008, 03:31 AM
i swapped a ax7 for a ay7 in my bassbreaker (bassman circuit) and i'm extremely happy with the results...i even believe i get distortion at smaller volume...and the tone is amazing!

rockon1
05-05-2008, 03:40 AM
Using a 12AU7 in the clean channel of my Supersonic. The only tube that allows me to turn the volume knob past 2 before its insanely loud and starts to break up big time. Hate the way it sounds when it does. Generally Ive given up usings subs in my amps but in this case Im fighting probably the wrong type pot in the clean channel. Bob

johnnyguitar
05-05-2008, 05:59 AM
ay7

telemoxy
05-05-2008, 08:39 PM
It looks like I'm getting a Fender Prosonic and (thanks to this place) I've been made aware of it's gain issues, so I'm looking to calm it down a bit. However, I've never had the need (or the inclination) to use anything other than a 12AX7 before, so I'm a bit lost. How do the AY and AU measure-up to each other? I'm leaning towards the AU because I've got my overdrive sounds sorted (thanks to an Ethos TLE and a Zendrive 2! :bow:AOK) but the KCA site's appraisal only says the 12AU7 is good, "...in pedals". Anybody ever use one in a pre-amp stage?

Cheers!

Charly

The Tube Store (www.thetubestore.com (http://www.thetubestore.com)) has an interesting page on this topic. The Page is called Guitar Amp Gain Factor Tweak.

The 5751 seems to be the tube used for the purpose you describe. My friend used one in his Traynor 50Blue and it worked great. I too took their advice and used one in my H & K Cream Machine (yes it a real tube amp) and it made a big difference. It took the edge off. Gain is good but not too much. It becomes uncontrollable if not unmusical to my ear.

It does wonders for the clean sounds which sounds like your concern.

To each his own.

Neer
05-05-2008, 09:10 PM
Don't overlook the 12AV7--slightly less gain than the 12AY7, but more than the 12AU7.

Blue Strat
05-05-2008, 09:11 PM
The Tube Store (www.thetubestore.com (http://www.thetubestore.com)) has an interesting page on this topic. The Page is called Guitar Amp Gain Factor Tweak.



Sorta like this one http://www.kcanostubes.com/content/newsletter_details.asp?ArticleID=4 which came years earlier ;)

Cheebatone
05-09-2008, 01:47 AM
Don't overlook the 12AV7--slightly less gain than the 12AY7, but more than the 12AU7.

Are 12AV7's widely available? I've not heard of them before. How musical are they?

rockon1
05-09-2008, 03:18 AM
Are 12AV7's widely available? I've not heard of them before. How musical are they?


The difference in gain between the 12AY7 and 12AV7 is slight. They are not as popular as 12AY7's and can be had cheaply. How musical they are is very subjective. I find them a bit thinner/brighter sounding in place of a 12AX7 much like a 12AT7. They are cheap enough NOS to try on a whim though.Bob

Ohzoso
05-10-2008, 01:16 PM
some more interesting reading:
http://www.guitaramplifierblueprinting.com/files/Phaseinverter.pdf

rockon1
05-10-2008, 02:34 PM
some more interesting reading:
http://www.guitaramplifierblueprinting.com/files/Phaseinverter.pdf


I though he was off to a good start. Then he went into "channel switchers" with a an air of disdain. I use old stock tubes in all my channel switchers and can hear quite a bit of difference -some more than others.
Ive also noted a good bit of diffence between PI tubes in some of my amps also. Bob