Preamp Tubes? - Who, What, When, Where, Why, and How? - Page 15

MartyStrat54 · 06-05-2009, 11:22 PM

Quote:

Originally Posted by RiverRatt

Is this the 80's one with the autobot logo? I bought one of those and it didn't do anything for me.

Marty, did you see my tube question above?

I'm sorry, I got all caught up in that DEAN ad that Josh posted.

I can answer part of your question. It is a Tungsram. If you have four out of a guitar amp, I would say they are 12AX7. If so, and if they are good, these tubes go for between 40 and 70 dollars each. They are also considered by audiophiles (who roll tubes everyday) to be one of the sweetest 12AX7's around.

Go here for a little more info:

Tungsram 12AX7/ECC83.

Now as far as the metal tag? Not all Tungsram have them. I think they were limited to the AU7, the AT7 and the AX7 (ECC81, 82, 83). What do the other tags say? I doubt if they are 1963 tubes, "But they could be!" If I remember, the tags were lot or production ID numbers. I'll look a little harder. The main thing is you have four of them babies. Good for you.

Marty

solarburnDSL50 · 06-06-2009, 12:17 AM

Quote:

Originally Posted by RiverRatt

Is this the 80's one with the autobot logo? I bought one of those and it didn't do anything for me.

Marty, did you see my tube question above?

Well mine made sweet love to me. Just got to flip her switch.

Lots of players rave about the CV4024 that's why I tried it. I like it fine but I also thought the Jan sounded pretty much the same. I like At7's in certain apps.

solarburnDSL50 · 06-06-2009, 05:24 AM

Quote:

Originally Posted by jrm

made a mistake, not a at7 its a 12au7a RCA, it currently sits in the v4. The ge's are used and tested good (according to seller) I forgot the specs as i bought them about 6 months ago. I might be to cheap to spend $40 on 1 tube but let me know what you reccomend new and old.

The speakers are G12-85 celestion (I believe only produced for these cabs) I've owned these for 20 years and played many amps through them, they are good cabs.

what do you think of the mullard reissue el34's? I heard good things about them and what do you bias at?

Yeah I love their tones, glad you do makes it easier to shoot for that nice tone.

Why don't you try 1 Mullard RI 12AX7 and then finish the preamp off with the GE's. See how that sounds with what you already have.

As far as my bias goes I run mine about 70%. So with the Ruby's I have in there now my plate voltage was 470. After running the formula I get 37 for my bias.

joshuaaewallen · 06-06-2009, 08:17 AM

Quote:

Originally Posted by RiverRatt

... How's your quest for TVs and stuff going? I also found a Sylvania 6BQ5 in an old TV recently...

I am still looking whenever I drive by a garage sale or a thrift store, but so far no dice. I think I will concentrate on Stereos and Record Players... From what I'm told, and what I am seeing, most of the tubes in TV's just don't do it for guitar amps...

Quote:

Originally Posted by RiverRatt

... My latest find was a 1960's GE phonograph in STEREO! It had one amp and pair of speakers built into the phonograph case, AND it had an extension cabinet that was roughly guitar amp head sized which also had an amp and two speakers built into it, with an On/Volume knob and a tone knob. Both amps used miniatures, so no goldmine, but I put a 1/4 inch jack on the extension cabinet and it makes the ultimate low watt guitar amp. It has the tone of an old Fender Champ, but at a volume you could have a conversation or watch TV over. It even sounds good with pedals as long as you don't push it too hard...

That is a great find! Very cool.

I am jealous of that one. Hey... Marty is possibly looking for a low watt, "boutique", amp... Maybe you two could make a deal?

But seriously, that is a cool find and something that a person could have lots of fun with. I am hoping to find something like that myself.

Quote:

Originally Posted by RiverRatt

... Unfortunately, the amp in the turntable cabinet was fried. A big capacitor that looked like a stick of dynamite had leaked all over it. If you (or anyone else) want it to play around with, I'll take it out of the box and send it to you for the cost of shipping. Did I mention that I only paid $13 for it?

Eh... Ya win some, ya lose some. Overall I think you came out a winner with this one. No real money tubes, but when you love to play the $$$ isn't the main focus anyway.

Anyhoo... Far out RiverRatt. Rock on.

jrm · 06-06-2009, 09:00 AM

Thank You to everyone for the advice, with 12au7 in there it isn't bad sounding but I'll pull it and throw in another tube till I order the RI mullard and give it a try. I'm also gonna give the RI mullard el34 a try when I can. I'll post my results.

joshuaaewallen · 06-06-2009, 09:05 AM

Quote:

Originally Posted by jrm

Thank You to everyone for the advice, with 12au7 in there it isn't bad sounding but I'll pull it and throw in another tube till I order the RI mullard and give it a try. I'm also gonna give the RI mullard el34 a try when I can. I'll post my results.

You have been assimilated. You are now one with the collective.

RiverRatt · 06-06-2009, 12:37 PM

Quote:

Originally Posted by joshuaaewallen

I am still looking whenever I drive by a garage sale or a thrift store, but so far no dice. I think I will concentrate on Stereos and Record Players... From what I'm told, and what I am seeing, most of the tubes in TV's just don't do it for guitar amps...

Check out antique malls and flea markets. That's where I've come up with my best finds. Old film projectors with built-in audio can be good, too. I know where a couple of those are, but the owner won't part with them.

Marty, thanks for the Tungsram info. Sounds like they are pretty rare. I think at least a couple of them are microphonic, and I have no way to test them. I have several tubes I'd like to part with, but I don't want to sell them without knowing if they are good or not.

MartyStrat54 · 06-06-2009, 03:59 PM

RATT

Sorry to hear that not all of the tubes are good. Without a tester, about all you can do is play them and see if they work. The only problem with an AX7 is that it can be pretty run down and still sound good. I've discussed this before where I said a worn out AX7 can work solidly as a 12AT7. So sometimes it is tough to say whether an AX7 is still putting out a gain factor of 85 to 100.

Even if only two of them are good, you've come out ahead.

Marty

MartyStrat54 · 06-06-2009, 04:03 PM

Quote:

Originally Posted by jrm

Thank You to everyone for the advice, with 12au7 in there it isn't bad sounding but I'll pull it and throw in another tube till I order the RI mullard and give it a try. I'm also gonna give the RI mullard el34 a try when I can. I'll post my results.

Well if you throw in a 12AX7 let me know where to send the toilet paper, because there's gonna be an accident.

Marty

solarburnDSL50 · 06-06-2009, 04:33 PM

Marty

I put a new line up in the preamp and I felt the clean get better/richer. So now I'm pretty stoked on the line up as is. Sounding better with the new entry RFT. I'm going to keep cook'n it though to make sure I'm getting some nice flavor... besides robust.

Anyways see sig for line up.

RiverRatt · 06-06-2009, 07:06 PM

Quote:

Originally Posted by solarburnDSL50

Well mine made sweet love to me. Just got to flip her switch.

Lots of players rave about the CV4024 that's why I tried it. I like it fine but I also thought the Jan sounded pretty much the same. I like At7's in certain apps.

OK, I need to apologize. I tried the CV4024 with my current line-up and it was pretty sweet. I think I'm getting close to perfection. For some reason, my old RCAs just aren't doing it in V1 anymore. I'm happy with the hi-gain channel on the DSL, but the crunch channel is a little thin. I've need to find that magic 12AX7, and I don't think it's in my current arsenal.

Marty, do you have any suggestions as to how I can get the Tungsrams tested? I don't mind shipping them, and I really don't have any use for them.

jrm · 06-06-2009, 07:59 PM

well when i was digging around for a 12 ax7 to put in I remembered I have a old ampeg v4 that's waiting for service and it has one 12ax7 in it. Turned out to be a old GE so currently running 4 old GE 12ax7 and it sounds real nice very rich and punchy. Amp still has alot of high end. I'm running my treble on 2 and presence on 4. Wondering how a new set of power tubes will help? But this is closer then when I had the JJ's in the preamp. Sounding better even the red channel warmed up I run that with the gain on 4 and the master way up, gives a nice punchy dirty clean. Wish my 2203 was working so i could compare the amps side by side.

MartyStrat54 · 06-06-2009, 08:09 PM

Quote:

Originally Posted by RiverRatt

OK, I need to apologize. I tried the CV4024 with my current line-up and it was pretty sweet. I think I'm getting close to perfection. For some reason, my old RCAs just aren't doing it in V1 anymore. I'm happy with the hi-gain channel on the DSL, but the crunch channel is a little thin. I've need to find that magic 12AX7, and I don't think it's in my current arsenal.

Marty, do you have any suggestions as to how I can get the Tungsrams tested? I don't mind shipping them, and I really don't have any use for them.

I sent you a PM and you can go from there. Marty

MartyStrat54 · 06-06-2009, 09:20 PM

Quote:

Originally Posted by jrm

well when i was digging around for a 12 ax7 to put in I remembered I have a old ampeg v4 that's waiting for service and it has one 12ax7 in it. Turned out to be a old GE so currently running 4 old GE 12ax7 and it sounds real nice very rich and punchy. Amp still has alot of high end. I'm running my treble on 2 and presence on 4. Wondering how a new set of power tubes will help? But this is closer then when I had the JJ's in the preamp. Sounding better even the red channel warmed up I run that with the gain on 4 and the master way up, gives a nice punchy dirty clean. Wish my 2203 was working so i could compare the amps side by side.

Well I thought that you would have noticed a greater change than that. Of course there is no way to tell how much gain is left in them old GE AX7's. To me it would seem like the AU7 was like a choke on the gain of the amp. Putting an old GE 12AX7 in the PI slot should have made a very noticeable change in the way the amp sounded, unless the old GE is well, old.

If it were me, I would be looking at a complete tube make-over. I think it's due. I think some new preamp and power tubes would really make your amp come alive.

Marty

MartyStrat54 · 06-06-2009, 10:05 PM

Quote:

Originally Posted by RiverRatt

Thanks. I didn't think the spacers were a big deal, but I wanted to make sure.

I think the BZ7 is going to be a keeper. I did buy two, so yes, I will try it out in the Blackheart head. I was having too much fun with the Marshall last night to mess with it. You have to remove a ridiculous number of screws to get the back off that head.

While I have your ear, what can you tell me about this tube? I've been told it's a Tungsram. It has a little metal tag in it with the number "63" embossed. I have four of these that I pulled from an old Laney Pro Tube head. There are different numbers on the tags (year of manufacture?).

Well my memory is still intact. I found out on another forum what the little metal tag and number means. Here it is:

I live in Hungary, and I have a lot of Tungsram valves. Tungsram use Yellow logo on the valves, and of course the little metal tab, which contains a number. This number gives information about which machine line made this valve.

So as I had said prior, it was a lot or production number and that's what it is a production number.

Marty

jrm · 06-07-2009, 08:34 AM

Quote:

Originally Posted by MartyStrat54

Well I thought that you would have noticed a greater change than that. Of course there is no way to tell how much gain is left in them old GE AX7's. To me it would seem like the AU7 was like a choke on the gain of the amp. Putting an old GE 12AX7 in the PI slot should have made a very noticeable change in the way the amp sounded, unless the old GE is well, old.

If it were me, I would be looking at a complete tube make-over. I think it's due. I think some new preamp and power tubes would really make your amp come alive.

Marty

Oh its sounding great, I'm very happy so far but I agree it should get a retube, I'm not a gigging player anymore so there is no rush, I'm enjoying playing with the different tones of this amp. Now i need to get my 2203 working and I'll be in heaven.

MartyStrat54 · 06-07-2009, 02:50 PM

Quote:

Originally Posted by jrm

Oh its sounding great, I'm very happy so far but I agree it should get a retube, I'm not a gigging player anymore so there is no rush, I'm enjoying playing with the different tones of this amp. Now i need to get my 2203 working and I'll be in heaven.

Same here, my hard core gigging days are over with. I'm just trying to pass on a little knowledge for those who wish to accept it.

Marty

MartyStrat54 · 06-07-2009, 02:55 PM

I was doing some research to help out a friend and came across this and thought I would post it.

12AX7 Vacuum Tube-

12AX7 is a vacuum tube of high gain. It is believed to have been originally developed in 1946 by RCA. The 12AX7 vacuum tube was originally intended as miniature form-factor follow-on to the 6SN7 vacuum tube family of dual-triode low-cost amplifier tubes for audio and computer applications. Its wide use as a vacuum tube in tube based guitar amplifiers has caused it to be one of the very few small-signal type of vacuum tube to continue in production since it was introduced. The 12AX7 is the most common member of a huge family of miniature twin-triode type of vacuum tube types.

The vacuum tube has a center tapped filament so it can be used in either 6.3V 300ma or 12.6V 150ma heater circuits.

Presently the 12AX7 vacuum tube is made in various versions in Russia, China, and Slovokia and one in Serbia, for a total annual production figure of 2 million units (estimated). The vast majority of these types of vacuum tube are used in new-production guitar amplifiers or for replacement purposes in guitar or audio equipment.

However, in our opinion, these new production types of 12AX7 vacuum tube do not even come close to the tonal qualitites of NOS (New Old Stock) type of vacuum tube produced in the USA, Great Britian, Holland, and Germany. If you would like to check out the NOS 12AX7 vacuum tube offerings we have then please Click Here! Vacuum tube and electron vacuum tube and audio vacuum tube 12AX7 at LOW Prices!

Marty

cooljuk · 06-09-2009, 01:08 PM

Hey Marty -

Thanks for the link. I had not found that site yet.
You seem to be a pretty knowledgeable guy concerning glass. What are your thoughts on these:

NOS Mullard EL34- Matched pair (approx 7 mA apart) of Mullard made XF3. Slightly further apart than we like for Hifi, but should be fine in most guitar amp applications. Put them in that old guitar amp and hear the magic! Specially reduced price $199.99! Save $40.00!

I know the XF3 is less desirable than the 1 or 2. I've not used the XF3s, myself. A 7mA difference won't be a problem other than one tube wearing out a bit quicker if anything, I think. Would you agree?

MartyStrat54 · 06-09-2009, 02:16 PM

Quote:

Originally Posted by cooljuk

Hey Marty -

Thanks for the link. I had not found that site yet.
You seem to be a pretty knowledgeable guy concerning glass. What are your thoughts on these:

NOS Mullard EL34- Matched pair (approx 7 mA apart) of Mullard made XF3. Slightly further apart than we like for Hifi, but should be fine in most guitar amp applications. Put them in that old guitar amp and hear the magic! Specially reduced price $199.99! Save $40.00!

I know the XF3 is less desirable than the 1 or 2. I've not used the XF3s, myself. A 7mA difference won't be a problem other than one tube wearing out a bit quicker if anything, I think. Would you agree?

Well I just bought a super strong matched pair of xf4's for $99 and I have them loaded in a TSL602. Yes, the overall sound is amazing. Are you selling these tubes, or did you find someone selling them? 7 mils apart would not be a problem. One tube would however be passing more current and voltage. I personally feel the price is too high. Did they state how much life was left in the tubes? What did they test at? As I said, I do not know if you are selling or attempting to buy these tubes. In closing, I will always recommend Mullard EL34's. They are one of the best sounding 34's out there and hardly any of what is known as 34 rattle. Very solid construction.

Marty

cooljuk · 06-09-2009, 02:51 PM

Oh, sorry if I wasn't clear. Those tubes are listed for sale on the site of the link you posted, Vacuum tube and electron vacuum tube and audio vacuum tube 12AX7 at LOW Prices!

No other information was there than what I posted above. I assume if they are listed as NOS they should have "full" life left, if that answers your previous question. He didn't post any other measurements, but I could always call.

I've had XF1s and normally prefer Siemens these days because I can find them for far less that Mullards.

If you think they are overpriced, would you please share a fair priced source for original Mullard NOS EL34s? PM me if you prefer. If I can score some Mullards for that price, I'll switch back to them from my Siemens.

Thanks, btw! I haven't posted in this thread much, but I follow it.

MartyStrat54 · 06-09-2009, 07:53 PM

Quote:

Originally Posted by cooljuk

Oh, sorry if I wasn't clear. Those tubes are listed for sale on the site of the link you posted, Vacuum tube and electron vacuum tube and audio vacuum tube 12AX7 at LOW Prices!

No other information was there than what I posted above. I assume if they are listed as NOS they should have "full" life left, if that answers your previous question. He didn't post any other measurements, but I could always call.

I've had XF1s and normally prefer Siemens these days because I can find them for far less that Mullards.

If you think they are overpriced, would you please share a fair priced source for original Mullard NOS EL34s? PM me if you prefer. If I can score some Mullards for that price, I'll switch back to them from my Siemens.

Thanks, btw! I haven't posted in this thread much, but I follow it.

Well I can tell you are a knowledgeable glass person yourself. I too use Siemens and have two 100 watt amps glassed with them. Siemens are a hell of a good deal if you want "real" EL34's. I guess right now I have twelve of them and eight are being used. Old, original TESLA's are a good buy for 34's.

That link I posted was to show another member some info on some tubes he had. I think once you get away from EBAY, the prices get freaky. I usually just bid on tubes from buyers I can trust and I never buy from overseas sellers. (Too much hassle if there is a problem with the tube(s). So far, I haven't had to pay a set price for tubes.

You are right about the NOS tube. If they stated it was NOS, then it should test on a tube tester in the mid to high 90's or better. I hate it when someone sells me NOS tubes and they read 85. They may have come in factory boxes, but you can buy those as well. 85 means the tube has been used for a while.

To me, I think the Mullards you are looking at are over-priced by about 40 to 50 dollars. I'd go $149 for them, but not $199. That is my opinion. I have a glut of preamp tubes, but I'm really short on good power tubes right now. I have several sets of current production EL34's that I keep just in case I need tubes. The best thing to do is get busy on EBAY. Search all EL34's, select "To Watch" option on those you are interested in and then you can get a feel for what the tubes are going for. I used this same technique for a month shopping for a TSL head and I ended up getting one that was like brand new for $700. The seller lost money, because he held a no reserve auction and I got up at 2 AM to finish bidding on it.

Marty

RiverRatt · 06-10-2009, 12:21 AM

I've been meaning to ask you guys about the 12AZ7 that you were talking about a few pages back. I can't find much info about them, except that they are pretty rare and are similar to a 12AT7. Are these worth seeking out, and is there a particular one to look for?

cooljuk · 06-10-2009, 12:13 PM

Thanks, Marty. I haven't been been actively seeking 34s in a year or two. I spent much time recently obsessing over 6922 and 12AX7 types. After recently scoring a few JCM 800s, I'm back to my old ways again.
My homepage on eBay is still full of saved favorite searches for NOS Teles, Mullards, Valvos, Amperex and such. I'm worried that ebay sellers will sell used as NOS and I have no tester at the moment to verify. I had a not-so-great Heathkit one, but sold it in hopes of getting a nice Hickok from a co-worker who had two, but the deal fell through. I should probably just spend more time reading seller's feedback.

Nothing like the trill of the hunt ...for quality tubes!

MartyStrat54 · 06-10-2009, 02:50 PM

Quote:

Originally Posted by RiverRatt

I've been meaning to ask you guys about the 12AZ7 that you were talking about a few pages back. I can't find much info about them, except that they are pretty rare and are similar to a 12AT7. Are these worth seeking out, and is there a particular one to look for?

Well the AZ7 has the same gain as a AT7. However the plate resistance and other electrical characteristics are different. What does this mean? It means that both tubes would sound and perform different in the same circuit.

It is a rare tube, but since it is close to a 12AT7, I'm not inclined to look in the bushes for an AZ7.

If you are bored and want to read up on tubes, here is a "long" link, but very fitting to this thread. It was upgraded on 12/31/2007.

12ax7

This link really gets down and dirty on on the subject of 12AX7's. Ratings on various tubes, including tone. (I may have posted this a long time ago on a different thread. If so, I'm sorry.)

Marty

MartyStrat54 · 06-10-2009, 02:59 PM

Quote:

Originally Posted by cooljuk

Thanks, Marty. I haven't been been actively seeking 34s in a year or two. I spent much time recently obsessing over 6922 and 12AX7 types. After recently scoring a few JCM 800s, I'm back to my old ways again.
My homepage on eBay is still full of saved favorite searches for NOS Teles, Mullards, Valvos, Amperex and such. I'm worried that ebay sellers will sell used as NOS and I have no tester at the moment to verify. I had a not-so-great Heathkit one, but sold it in hopes of getting a nice Hickok from a co-worker who had two, but the deal fell through. I should probably just spend more time reading seller's feedback.

Nothing like the trill of the hunt ...for quality tubes!

Here, here to that. You got the EBAY thing down. The main thing is I only buy from those who state their test results. I look at their feedback and whether or not they are a Power Sellers. Once I get a tube, I test it on my B and K 707 and if the tube does not test correctly, I either get the tube for less money, or I return it...and I have returned quite a few tubes for a refund.

The thing is, you can still get super buys on EBAY, but you have to follow certain rules.

Marty

solarburnDSL50 · 06-12-2009, 01:25 AM

I'm liking the JAN Philips 12AX7WA in both my amps. Its the last of the 80's military production. So far in the Marshall I've tried it in V1 & V2 and prefer it in V1. Its strong in the mids and has plenty of gain for me. It shows more of its personality in V1.

Seems to have a wide range of frequency. Lows , mids and highs come through nicely. Guitar roll off is natural with this one. Cleans sound nice, clear with neat little overtones especially when in V3 of the NT.

I feel its good for rock tones. Blues too. Well I got more to report about but I'm more tired than I thought so I'm off for sleep. I'll put more down later on another tube I've been using as well...

joshuaaewallen · 06-12-2009, 08:45 AM

Quote:

Originally Posted by joshuaaewallen

Quote:

Originally Posted by MartyStrat54

Quote from JOSH:

The Crunch channel has AC/DC written all over it. Lotsa great 70's era classic rock "crunch" kinda tones. Not too bright, but plenty of definition even with my stale strings.

Do you think it is a wise choice to perform the test will "stale" strings. This will disguise the top end performance of the tube... ... You have to keep your variable in a small window. I don't want you to go, "Wow! That sounds killer." Then you change strings and go, "Wow!!! That is friggin' bright!"

know, I know...

But the little kid in me just couldn't wait! I have barely touched my axe in near two weeks and the craving took over. But... Since you are correct as usual King Friday, I do plan to repeat the test of those tubes with fresh strings. It's just the "when" part that I'm unsure of.

... Boy, I'm sure glad your not in a hurry!

...

Well... I had just enough time in between running around like a chicken with it's head cut off to throw on a new set of strings. Now I just need a wee bit-o-time to play them through this tube set up...

While Restringing:

V1:

V2:

solarburnDSL50 · 06-12-2009, 08:58 AM

Josh

I want to hear about the EI. What slot you going to run that in first?

I may have to hit Marty up for a couple of RCA-A's. I like em'.

solarburnDSL50 · 06-12-2009, 10:54 AM

I've been demoing a RFT 12AX7 in V1 in my DSL for a solid week now. I have had the chance to play it at volume with a couple of different line ups in the preamp. In my first line up I felt it was a bit too gainful and hurt the cleans and guitar roll off a little. Still was great but I like my touch and feel intact.

I changed the other slots and ended up with the RCA 12AX7A in V2, RCA V3 and then Magnavox in the PI. That fixed it. Clean was awesome and guitar roll off back.

So with my current line up and the RFT sitting in V1 I'm hearing my Marshall get ballzier in the gain department. Its a darker tube with pronounced lows including lower mids where the ballzee gain comes from. The highs are present though so it doesn't dull up or sound flat.

I noticed this tube right away which is not always the case when rolling tubes. The low volume gain was crazy but what really caught me off guard was when I opened her up to the power section it just smoothed out and crunched up with those low mids and was so meaty sounding. It is harmonically gifted and has nice feedback to held notes.

I was bitch slapped by this tube! The difference was easy to hear from previous combination's because the tone really warmed up and punched hard from what I had been getting from the other tubes in V1 and as a group. The RFT really has a hard rock flavor to it. It smokes. I have tried milder tones with it and it has done well there too but it really shines in the hard rock category me thinks.

With the Night Train and its EL84's it didn't react the same. With that circuit it was too warm and dark in V3. In the PI slot it was good paired with the JP 12AX7WA in V3.

I mixed the Mullard RI in in both spots and found the JP in V3 and the RFT in the PI was best. I don't know that I will leave the RFT in the PI, seems a waste there. Going to try a couple more I have in the PI. It will stay if it turns out better though.

The RFT has good reviews in Marshall's, Boogie Mark 3's, Dr. Z Maz, Diesel Herbert's and Carmen Ghias just to name a few.

I love how it sounds. Its a great setup as is now. I consider it right up there with a couple of my best NOS line ups since Marty sent me a group to roll.

So in summary this tube sucks and don't waste your money. They are getting hard to come by any more.

06-06-2009, 09:00 AM	#425 (permalink)
jrm Junior Member Join Date: Oct 2008 Posts: 21	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Thank You to everyone for the advice, with 12au7 in there it isn't bad sounding but I'll pull it and throw in another tube till I order the RI mullard and give it a try. I'm also gonna give the RI mullard el34 a try when I can. I'll post my results. __________________ 1979 JMP 2203 1998 DSL50

06-06-2009, 03:59 PM	#428 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,583	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? RATT Sorry to hear that not all of the tubes are good. Without a tester, about all you can do is play them and see if they work. The only problem with an AX7 is that it can be pretty run down and still sound good. I've discussed this before where I said a worn out AX7 can work solidly as a 12AT7. So sometimes it is tough to say whether an AX7 is still putting out a gain factor of 85 to 100. Even if only two of them are good, you've come out ahead. Marty

06-06-2009, 07:59 PM	#432 (permalink)
jrm Junior Member Join Date: Oct 2008 Posts: 21	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? well when i was digging around for a 12 ax7 to put in I remembered I have a old ampeg v4 that's waiting for service and it has one 12ax7 in it. Turned out to be a old GE so currently running 4 old GE 12ax7 and it sounds real nice very rich and punchy. Amp still has alot of high end. I'm running my treble on 2 and presence on 4. Wondering how a new set of power tubes will help? But this is closer then when I had the JJ's in the preamp. Sounding better even the red channel warmed up I run that with the gain on 4 and the master way up, gives a nice punchy dirty clean. Wish my 2203 was working so i could compare the amps side by side. __________________ 1979 JMP 2203 1998 DSL50

06-07-2009, 02:55 PM	#438 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,583	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? I was doing some research to help out a friend and came across this and thought I would post it. 12AX7 Vacuum Tube- 12AX7 is a vacuum tube of high gain. It is believed to have been originally developed in 1946 by RCA. The 12AX7 vacuum tube was originally intended as miniature form-factor follow-on to the 6SN7 vacuum tube family of dual-triode low-cost amplifier tubes for audio and computer applications. Its wide use as a vacuum tube in tube based guitar amplifiers has caused it to be one of the very few small-signal type of vacuum tube to continue in production since it was introduced. The 12AX7 is the most common member of a huge family of miniature twin-triode type of vacuum tube types. The vacuum tube has a center tapped filament so it can be used in either 6.3V 300ma or 12.6V 150ma heater circuits. Presently the 12AX7 vacuum tube is made in various versions in Russia, China, and Slovokia and one in Serbia, for a total annual production figure of 2 million units (estimated). The vast majority of these types of vacuum tube are used in new-production guitar amplifiers or for replacement purposes in guitar or audio equipment. However, in our opinion, these new production types of 12AX7 vacuum tube do not even come close to the tonal qualitites of NOS (New Old Stock) type of vacuum tube produced in the USA, Great Britian, Holland, and Germany. If you would like to check out the NOS 12AX7 vacuum tube offerings we have then please Click Here! Vacuum tube and electron vacuum tube and audio vacuum tube 12AX7 at LOW Prices! Marty

06-09-2009, 01:08 PM	#439 (permalink)
cooljuk Senior Member Join Date: Mar 2009 Posts: 135	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Hey Marty - Thanks for the link. I had not found that site yet. You seem to be a pretty knowledgeable guy concerning glass. What are your thoughts on these: NOS Mullard EL34- Matched pair (approx 7 mA apart) of Mullard made XF3. Slightly further apart than we like for Hifi, but should be fine in most guitar amp applications. Put them in that old guitar amp and hear the magic! Specially reduced price $199.99! Save $40.00! I know the XF3 is less desirable than the 1 or 2. I've not used the XF3s, myself. A 7mA difference won't be a problem other than one tube wearing out a bit quicker if anything, I think. Would you agree?

06-09-2009, 02:51 PM	#441 (permalink)
cooljuk Senior Member Join Date: Mar 2009 Posts: 135	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Oh, sorry if I wasn't clear. Those tubes are listed for sale on the site of the link you posted, Vacuum tube and electron vacuum tube and audio vacuum tube 12AX7 at LOW Prices! No other information was there than what I posted above. I assume if they are listed as NOS they should have "full" life left, if that answers your previous question. He didn't post any other measurements, but I could always call. I've had XF1s and normally prefer Siemens these days because I can find them for far less that Mullards. If you think they are overpriced, would you please share a fair priced source for original Mullard NOS EL34s? PM me if you prefer. If I can score some Mullards for that price, I'll switch back to them from my Siemens. Thanks, btw! I haven't posted in this thread much, but I follow it.

06-10-2009, 12:21 AM	#443 (permalink)
RiverRatt Senior Member Join Date: May 2008 Location: Between Memphis and Nashville Posts: 517	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? I've been meaning to ask you guys about the 12AZ7 that you were talking about a few pages back. I can't find much info about them, except that they are pretty rare and are similar to a 12AT7. Are these worth seeking out, and is there a particular one to look for?

06-10-2009, 12:13 PM	#444 (permalink)
cooljuk Senior Member Join Date: Mar 2009 Posts: 135	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Thanks, Marty. I haven't been been actively seeking 34s in a year or two. I spent much time recently obsessing over 6922 and 12AX7 types. After recently scoring a few JCM 800s, I'm back to my old ways again. My homepage on eBay is still full of saved favorite searches for NOS Teles, Mullards, Valvos, Amperex and such. I'm worried that ebay sellers will sell used as NOS and I have no tester at the moment to verify. I had a not-so-great Heathkit one, but sold it in hopes of getting a nice Hickok from a co-worker who had two, but the deal fell through. I should probably just spend more time reading seller's feedback. Nothing like the trill of the hunt ...for quality tubes!

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