Thread: Preamp Tubes? - Who, What, When, Where, Why, and How?
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Old 04-04-2009, 01:05 AM   #70 (permalink)
solarburnDSL50
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Re: Preamp Tubes? - Who, What, When, Where, Why, and How? - RCA 12AX7A
Quote:
Originally Posted by joshuaaewallen View Post
How's this for rambling on...

Well, the wife is out scrap-booking w/ her friends, so I have the house to myself. Well, myself and our four dogs. Sucks that I have a cold and everytime I take a breath I hack up a lung, . But... At least I can play a bit...

Tonight I have been playing around with that RCA 12AX7A.

First, since I have had such success with the 1961 GE 12AX7 and the Westinghouse 12BZ7 in slots V1 & V2 (respectively), I figured I'd pull the GT out of V3 and try the RCA tube in there. With this arrangement there is a wee bit of hum... Not the microphonic feed back I got before w/ that other bad tube, but hum coming from the speakers. There were some very interesting warm and round kinda over tones coming into my chords that were pretty cool, and with the neck pickup it was a pretty sweet dirty bluse kind of sound, but... Muddy. Actually it was too muddy for my taste on either pickup. Too bad, because overall for the sheer uniqueness of the sound, this was the spot I liked the RCA in best. It was just too noisy and too muddy.

So... I proceeded to try it out in all the other spots too. I next put the Westinghouse 12BZ7in V3 and the the RCA 12AX7A in V2. Better, less muddy, but the high strings were too brassy. Not my thing, as I hoped more for a brighter version of what it sounded like in the V3 slot.

Next up... I put the 1961 GE 12AX7 in V3, the Westinghouse 12BZ7 in V1, and the RCA 12AX7A in V1. Still no go. I think the tube has potential, but I'm not sure if it's right for this amp... But...

Undeterred, I figure, well... I know I like the sound w/ the 1961 GE 12AX7 in V1, the Westinghouse 12BZ7 in V2, and the Groove Tubes ECC83/7025 12AX7R in V3, so... Now I pulled out JJ ECC83S 12AX7S out of V4 and popped the RCA 12AX7A in. Better. Much better. Especially when I actually can turn it up past 1! Suffice to say any higher than 3 and being in the same room becomes pretty uncomfortable. I guess now I'll try a direct comparison in V4 between the JJ & the RCA... But not tonight. I need to get some rest. I have to get my hide up in the morning.

Cheers!
Great posts and I'm soaking it all in. I love to hear how these tubes work in other's amp circuits cause it may be just what I'm looking for or interested in.

I tried the JJ ECC83S in my circuit and they were dull and flat and EQ adjustments didn't help. I tried one in my HT Dual pedal as well and got the same result. I don't like them with my ears and in my amp. I know quite a few Marshall guys that do. What can ya do but decide for your self. Here are some other preamp tubes I liked in my circuit:

V1- Tung Sol, new Mullard, LPS, Electro Harmonix.
V2- Tung Sol, JAN Philips 12AX7WA
V3- Penta 12AX7 which is a version of the 9th gen Shuguang 12AX7.
PI- I really haven't experimented here yet except I did try the JAN GE 5751. I didn't like it.

All of those are 12AX7's except the 5751. Out of the preamp tubes I've tried so far I only have 2 I didn't want to use at all:
1. JJ ECC83S
2.JAN GE 5751

I also like the new Mullards. I will prolly replace the AC5's in V2/3 with Mullards down the road and see what I get.
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DSL50 - FJA modded
Loaded with a Martimus Maximus Preamp Tube Stack
Power tubes 6CA7EH's

Strat HSS & Tele HH

Avatar 412 loaded with Greenbacks

Vox Night Train
RFT 84's
JP 12AX7WA & RFT ECC83

Quote:
Originally Posted by steelhorse View Post
I couldn't handle it after a few minutes. I got whiplash during the cleans (from almost nodding off) and then thought the dog was howling during the first part of the distortion.

He pretty much lost me with the tongue thing right off the bat though to be honest.
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