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Do you understand tube amps? (help needed please)


melx

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ok, I'm loving my new valve amp, but I keep reading that the stock tubes aren't that great and a tube change can really improve the sound. what I need to know is what the 3 pre-amp tubes do, so I can select the right tubes for the sound i'm after. here's the info from the manual.

 

Project1.jpg

 

I know which are the 4 power amp tubes, but unsure what the 3 pre-amp tubes do, I hear people put different ones in different places, presumably because they are doing different things?? can anyone tell me what V1, V2, V3 are doing in my amp?

 

I hope i'm making sense (valve No0b) :)

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I can't read schematics very well, but it looks like V1 is your clean, V2 is the dirty, and V3 is effects loop/reverb.

Having said that, everyone seems to agree that switching your V1 will cause the biggest single tonal change to your amp, while switching all three will go even further. Aside from changing out your speaker(s) that is.

You don't need to rebias to swap preamp tubes, so you can buy some replacements and give it a shot. The new Mullard Reissue 12ax7's are really quite good, I'd recommend them to anyone.

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yeah, right that's what I was hoping.....so if I wanted the clean channel to break up earlier, I could put a tube that distorts earlier in V1, and if I wanted cleaner headroom in the drive channel I would put a tube which breaks up later in V2.

and V3 is probably just the FX loop/verb? so I don't have to worry about that one too much...sweet.

I can ask hotrox (excellent UK valve dealer) about the tubes properties so I can get the right tubes, I was just unsure of which ones to put where...thanks for that.

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If you haven't already you may try contacting the amp manufacturer and just asking them. I've done that in the past and had great success. Saved me a lot of time and wondering.



yeah, that's not a bad idea...the guys at Hotrox would probably know too, I just thought i'd ask here so I could educate myself a bit about my amp!! :)

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yeah, that's not a bad idea...the guys at Hotrox would probably know too, I just thought i'd ask here so I could educate myself a bit about my amp!!
:)



Understandable :thu: Nothing worse than needing help with something semi-technical (music gear or anything else in life) and coming across as clueless with people who deal with it all the time.

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Understandable
:thu:
Nothing worse than needing help with something semi-technical (music gear or anything else in life) and coming across as clueless with people who deal with it all the time.



lol, yeah exactly!! so when they go 'well this blah blah tube is really good to put in the drive section of your amp, because they have a really smooth break up" I'll know what the drive section of my pre amp is!! :)

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I'm far from an expert but V3 is usually the phase inverter. It's a preamp tube but it actually has a big part in driving the power section of your amp and its distortion. Changing a used or crummy phase inverter can have a big impact on "livening" up an amp. Just make sure you get a balanced one.

 

And yeah, it looks like V1 (first gain stage) is clean and V2 (second gain stage) is more for the dirty channel but remember that everything is still going to go through V1 no matter what. Even on multiple channel amps V1 is still going to feed the other tubes (and channels) behind it. Changing it will still effect the tone and gain of the dirty channel (possibly more so then changing V2).

 

If you want to really change the tone I'd try swapping out V1 or V3 or both.

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There isn't really a definitive answer to give about which is the best tube. It's likely to be pretty subjective, depending on your amp and your ears.

I'd agree that V1 is the one to change if you're only going to change one, but you might as well change all three, as they'll all have an effect on tone. If you've got money to spare, why not buy a few different branded 12ax7s and see which you like best? FWIW, I'm quite happy with the EH valves I put in my Cornell.

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There isn't really a definitive answer to give about which is the best tube. It's likely to be pretty subjective, depending on your amp and your ears.


I'd agree that V1 is the one to change if you're only going to change one, but you might as well change all three, as they'll all have an effect on tone. If you've got money to spare, why not buy a few different branded 12ax7s and see which you like best? FWIW, I'm quite happy with the EH valves I put in my Cornell.



yeah, thanks bob...I'm gonna be changing all 3, that's why I wanted to know which did what..if you see what I mean? I have a good Idea of what valves i'm going to use, but need to know which valve did what in the amp...

I think I've got it figured that out now though.:thu:

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What amp have you got then ? Does the builder have their own forum ? TGP have a very good amp forum, inclides a lot of people who build their own amps / boutique makers - some good advice over there. May be worth signing up for help.

V1 is your pre amp valve and does clean, changing this will give you the that "cleaner brighter clarity" if you know what I mean.

V2 is where the dirt comes from, this is probably the valve to change the most to get the dirty sound you want, then you are into a world of pain of 12AX7 vs EC83s and all the associated crap - talking with someone like Hotrox can be quite rewarding here. From my experience with them (and Watford Valves) they can really help you out.

V3 is important for the phase of the +/- arms into the speaker.

Try googling this forum for your amp and see what other tubes people have changed to.

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What amp have you got then ? Does the builder have their own forum ? TGP have a very good amp forum, inclides a lot of people who build their own amps / boutique makers - some good advice over there. May be worth signing up for help.


V1 is your pre amp valve and does clean, changing this will give you the that "cleaner brighter clarity" if you know what I mean.


V2 is where the dirt comes from, this is probably the valve to change the most to get the dirty sound you want, then you are into a world of pain of 12AX7 vs EC83s and all the associated crap - talking with someone like Hotrox can be quite rewarding here. From my experience with them (and Watford Valves) they can really help you out.


V3 is important for the phase of the +/- arms into the speaker.


Try googling this forum for your amp and see what other tubes people have changed to.



cheers that's all helped. :thu:

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A higher gain tube will push the later stages harder and earlier with the same relative input. Some new 12ax7 can vary significantly in the amount of gain. A lot of people spend a lot of money on NOS tubes. Some can be brighter than others. Lower gain preamp tubes like a 12AY7 or 12AT7 will not push the later stages as hard with the same input as the ax7. This appears to give you more clean head room as you have to turn the amp volume up higer to get the same signal to later stages.

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thanks everyone...right, I know a fair bit about different tubes and thier properties from reading about them on sites like watford valves and Hotrox.

my amp is a laney Vc30, the stock valves are 'TAD' made in china.

right...phew complicated stuff!!! :)

What I want to do is put a valve in V1 to give me the maximum clean, bright headroom, because I use fuzz alot and I prefer to run that into a clean bright channel. (no worries there, I can just ask the specialists which valve will give me that)

V2 is my dirt, if what i'm understanding is right so far? so in V2 position, I want to put a valve that will give me a nice smooth early break up..correct? (no problems there either, I can ask the specialist which valve will give me that)

V3 is the phase inverter..correct? so I guess all I need to know know is what kind of tube I need in there? what does that tube do?

the power amp tubes I'm just gonna ask the specialist which are the loudest cleanest ones.

so really now the only thing I don't know is what V3 does and what type of tube I need in there, ie the same as v1, v2 or a tube with some other property that will help me get the best from the amp?

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yeah, right that's what I was hoping.....so if I wanted the clean channel to break up earlier, I could put a tube that distorts earlier in V1, and if I wanted cleaner headroom in the drive channel I would put a tube which breaks up later in V2.


and V3 is probably just the FX loop/verb? so I don't have to worry about that one too much...sweet.


I can ask hotrox (excellent UK valve dealer) about the tubes properties so I can get the right tubes, I was just unsure of which ones to put where...thanks for that.

 

 

V3 is the phase inverter actually

 

http://www.eurotubes.com/euro-i.htm#10.

 

From what I understand, phase inverters effect your tone the most, If you have a 12au7, ay7, at7, or ax7, it will make a big difference.

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Essentially the phase inverter helps drive the power tubes. Changing them will actually change the amount of power tube distortion you're getting. You can use any preamp tube as a phase inverter. The classic choices are usually 12ax7's and 12at7's. 12ax7's have the most gain, then I believe it goes 12at7, 12ay7, 12au7 (I forget where the 5751's fall in that). As I said before just make sure it's a balanced tube.

 

(Oh and also as I said before, remember that changing V1 will still probably result in a change in the tone of your dirty channel as well because your dirty signal is still going through there before it hits V2).

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