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Post by pedro58 on Oct 23, 2007 20:55:42 GMT -7
Like the title says... there are 3 12AX7's in the Gal's preamp section. I'm wondering how different tubes will affect the sound. I see that V1 is used by both channels, but what about V2 & V3? I'm looking to tame the drive channel a bit. There's more gain there than I will ever use!
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Post by zimmer on Oct 25, 2007 18:20:59 GMT -7
I'm working on this puzzle at the moment. I'm not really shooting for less gain in channel two, however. Stock V1 was a JJ, but I'm using a Svetlana. It's more real maple syrup than the Mrs. Buttermilk JJ, which is a good thing. I haven't yet tried the V3 position, or the Ruby pair. There's a Sovtek 12AX7LPS for the V2 socket in a box, too.
It's cool how much difference small changes make. I'm moving slowly, however.
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Post by JD on Oct 26, 2007 6:31:18 GMT -7
Question - I would like to reduce the gain on channel 2, but will that decrease the overall volume of Ch 2? I found that I have my Ch 1 Volume around 1:30 and my Ch. 2 Vol at about 9:30 and Channel 2 is a bit louder than Ch 1 (going through an Airbrake as well) which is what I want for my lead tones. Not sure how Ch 2. changes in preamp tubes would affect gain and overall volume.
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Post by pedro58 on Oct 27, 2007 8:06:42 GMT -7
Okay, I fooled with it and e-mailed Z. Brent replied and confirmed my findings, which were: All pre-amps tubes have an effect on the overall tone, feel, volume of the Galaxie because there isn't a single tube dedicated to a single channel... V3 is the phase inverter and Brent said to leave a 12AX7 there... That's what I ended with after experimenting with various types. I tried a 12AU7 Mullard... it took too much away from the amp. The volume and punch were gone, though everything was really smooth at this point-- not a solution for a gigging amp. Maybe bedroom volume situations? I tried a 12AY7 and it was a little better, but still too far away from the 12AX7 in gain. The 12AT7 I don't remember... the 5751 was a viable option, but I found better subs, for me, in the other valve positions. V2 & V3-- I tried the 12AU7's here and, again, lost too much. The 5751 and the 12AY7 can be interchanged between these positions for a reduction in gain for the drive channel. I have mine as 5751 in the V1 spot and the 12AY7 in the V2. You could trade them, but I don't remember what difference it made. I just settled on this configuration b/c it sounded best to my ears. Keep in mind that this took days... after a few changes, my ears got tired and I couldn't discern differences as clearly. You could even go as far as taking notes from day to day, but I didn't go that far! Hope this helps!
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Post by GIBBYMYLESPAUL on Oct 27, 2007 22:14:57 GMT -7
Pedro58! Not trying to rain on your parade but it sounds to me like it wasn't really worth the time swapping the pre-amp tubes! You know that Doc put the tubes that would give the best performance based on the design goals of the Galaxie! I know everybody always wants to tweak and swap tubes but my experience over the last 10 years with the Z-Amps as well as other Z-Owners shows only slight tonal improvement in most cases. I am going to enjoy my GALAXIE 1X12 combo and use the exact tubes that Doc put in it cause it sounds mighty fine to my ears! Get an AIRBRAKE! You definitely need one to tame the GALAXIE!
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Post by zimmer on Oct 28, 2007 5:43:31 GMT -7
FWIW, it's perfectly enjoyable "as the Doc made it."
On the other hand, if you have a question about what they've tried at the shop, I found Brent to be helpful. He suggested I might like one of the Chinese tubes as well.
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Post by pedro58 on Oct 28, 2007 10:10:22 GMT -7
Gibby-- your point is well made and I agree. The amp sounded great when I got it. I appreciate the Dr. Z's design working with tubes that are readily available and reasonably priced. It's a good thing that there is something, a Z., with quality second to none, that doesn't need rare tubes to sound right. I can't afford them, anyway.
But I wasn't looking for a tonal improvement. I was looking to bring the gain of the drive channel down. I have heard some talk that the first Galaxies are gainier than later production models. I don't know whether that's true or not, but I just wanted a little more headroom before the thing started to drive. That was my ears. I'm confident that the Z can handle a tube change without any ill effects, and if the tone had suffered, and it did with some of the tube choices, I went back to a 12AX7.
I did, in fact, e-mail Brent and he suggested the 5751 as an alternative...
Aside from all of that, how would an Airbrake help? I would still be attenuating both channels. It wouldn't affect the gain, only the volume. And the Galaxie's volume is perfect for the small stages I will play on.
I would argue that needing an Airbrake to enjoy the amp is the same as needing a tube change.
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Post by Jim @94 Amps on Nov 22, 2007 20:10:37 GMT -7
"I have heard some talk that the first Galaxies are gainier than later production models. I don't know whether that's true or not"
Not true. No difference in the circuit of any of the Galaxies built so far.
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Post by zimmer on Nov 26, 2007 12:11:24 GMT -7
All right! Thanks for that.
I'm now using a Ruby in V1 for a few weeks. The Sovtek was pleasing, but the Ruby is less dark, and smoother to boot.
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Post by GIBBYMYLESPAUL on Nov 26, 2007 15:23:08 GMT -7
Zimmer,
What is the actual model/type of 12AX7 of the RUBY tube that you mentioned in your post?
Were your impressions of the Ruby more noticeable in Channel 1 than channel 2 or equally in both!
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Post by zimmer on Nov 29, 2007 18:27:11 GMT -7
The Ruby has 7025 SS Selected on the top of the box, and was purchased from KCA NOS, here: www.kcanostubes.com/categories/73/1/Chinese.htmI think the silver specials are newer than my tube. I noticed it more in channel one, but that's because I spent more time there, up until the arrival of the Airbrake. The Airbrake is the most useful hardware purchase I've had the good fortune to buy in the last two years, and changes my opinions of the strengths of the amps. Channel one in triode cranked, and then attenuated to a tolerable volume through the Airbrake, is pretty amazing. The Galaxie has more tones in it than I would have known without serious hearing loss in the long run. Short version: I've left the $10 Ruby in, and it shows no signs of deterioration or change in tone as yet.
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Post by GIBBYMYLESPAUL on Nov 30, 2007 0:50:34 GMT -7
Thanks for the lowdown on the RUBY 7025! I might snag one to try! I also found firsthand that the Z-AIRBRAKE is an awesome tool to have for the cranked tones that the LOUD MOFO - GALAXIE delivers in channel 2 as well as channel 1! It will "TAME THE BEAST" in the GALAXIE!
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Post by Jim @94 Amps on Dec 3, 2007 21:09:13 GMT -7
the tone of the grey plate chinese 12ax7 is a little less bright/harsh compared to the shiny silver plate ones, but we usually put the grey plate in the galaxie
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