|
Post by gaetadog on Mar 12, 2006 20:12:43 GMT -7
Anyone out there using the Groove Tube 12AX7-M's in their amps and having trouble with them. I've got them in my Mazerati and I just re-tubed my AC30 and Cub II with them. Out of the dozen or so tubes I ordered at least five of them were micro phonic or bad. One of the good tubes I put in my Bad Cat went funky on me after one gig. I really dig the sound of these tubes, but they seem very inconsistent and unreliable. I thought GT was suppose to have really good quality control on their tube products.
Has anyone come across a 12ax7 that is similar in tone, but is more reliable?
|
|
|
Post by johnnyl on Mar 12, 2006 22:43:09 GMT -7
I'm sure myles will chime in here wih some good advice gaetadog.
|
|
|
Post by myles on Mar 13, 2006 9:38:13 GMT -7
Just call Rick Benson at 1-800-459-5687 and they will be replaced under warranty.
Where were these purchased and how long ago? There have been a series of tooling changes and they may not have come from the latest batch.
|
|
|
Post by gaetadog on Mar 13, 2006 10:07:54 GMT -7
One of my techs actually gets them for me through his wholesaler. He ordered them for me about two weeks ago. Who knows when the wholesaler ordered them. I was kind of wondering if maybe there was a bad batch floating around.
My tech has been in regular communication with one of the top Marshall guru's in the country (he's been using this tube) and this guy said he's been having similar problems with the GT-12ax7M. He's since stopped using the tube.
I really love the sound of this tube. I just can't afford to have them going down on a gig or during a session. Myles, I know you're the known "expert" in this area. Do you have any suggestions as to a replacement for the 12ax7-M? I hear the Tung Sol's are supposed to be really great (low microphonics and reliable). Any thoughts?
|
|
|
Post by billyguitar on Mar 13, 2006 11:28:06 GMT -7
Off thread a bit, but yesterday I bought a GT 12AX7C from Guitar Center. Plugged it in my amp. Hums like crazy. I've never had a tube do that over 35 years of owning and using tube amps. I'll return it. The only other AX7s they have are either the silver, and I don't want that, or the 12AX7M. I might just credit the card and get my tubes elsewhere.
|
|
|
Post by hdahs143 on Mar 13, 2006 15:51:39 GMT -7
I know it's been said enough on this forum, but I would recommend getting tubes from either: kcanostubes.com/content/Default.aspor www.dougstubes.com/Both have quality products, test their products, and most importantly are real human beings that you can talk to on the phone, and stand behind what they sell! And back to the thread, I have a couple of the 12AX7M's and have had no problems with them. That being said, I'm more of a 5751 guy. I love the sound of those tubes!
|
|
|
Post by terryg on Mar 13, 2006 17:59:10 GMT -7
I'm digging the latest batch of 12AX7Ms immensely. Pry them from my cold dead hands, I dare you
|
|
|
Post by myles on Mar 13, 2006 19:54:21 GMT -7
One of my techs actually gets them for me through his wholesaler. He ordered them for me about two weeks ago. Who knows when the wholesaler ordered them. I was kind of wondering if maybe there was a bad batch floating around. My tech has been in regular communication with one of the top Marshall guru's in the country (he's been using this tube) and this guy said he's been having similar problems with the GT-12ax7M. He's since stopped using the tube. I really love the sound of this tube. I just can't afford to have them going down on a gig or during a session. Myles, I know you're the known "expert" in this area. Do you have any suggestions as to a replacement for the 12ax7-M? I hear the Tung Sol's are supposed to be really great (low microphonics and reliable). Any thoughts? The Tung Sol is very similar to the 12AX7EH. It is a tube that varies widely on spec and is on the low side current wise. I prefer the 12AX7R2 (Sovtek 12AX7LPS). The Svetlanas that the Doc put in my SRZ-65 as stock were all really nice. I have to look into these more. The RFT's from Mike at www.kcanostubes.com are a tube I like a lot as are the Brimars he has.
|
|
|
Post by gaetadog on Mar 13, 2006 20:17:58 GMT -7
Thanks for the info myles. I had the EH's in my amps before I put the M's in. Overall, they sounded pretty good, but not even close to the M's. I've used the LPSs in a 65 twin reverb I used to own, but that's when they first came out and everyone they sent me was horribly micro phonic. You barely touched the amp and it sounded like a church bell. We ended up sending them all back. I think they must have improved since my initial purchase. I just slapped a pair of LPS in one of my mic pre's here at the studio and the sound fantastic. Anywhoose, I'll have to look into some of the tubes you suggested. Thanks again.
|
|
|
Post by myles on Mar 13, 2006 20:54:01 GMT -7
Thanks for the info myles. I had the EH's in my amps before I put the M's in. Overall, they sounded pretty good, but not even close to the M's. I've used the LPSs in a 65 twin reverb I used to own, but that's when they first came out and everyone they sent me was horribly micro phonic. You barely touched the amp and it sounded like a church bell. We ended up sending them all back. I think they must have improved since my initial purchase. I just slapped a pair of LPS in one of my mic pre's here at the studio and the sound fantastic. Anywhoose, I'll have to look into some of the tubes you suggested. Thanks again. Right now the Tung Sols are getting a bit of bad press. When the LPS came out the same thing happened. Making a new tube from the get go is more difficult that you can possibly imagine. There are hundreds of interactive ingredients in the recipe and THEN you have the tooling setup and stabilization. Change one little thing and it all goes down the toilet. The M's initially were amazing. Then the plate stamping dies settled in, and/or the plate alloy changed ever so slightly, or something maybe got contaminated or, .... who knows. Then the M got it's share of bad press too. But we were still looking at a low percentage that was tolerable as testing would weed out the bad ones. Or would it? Not if something is contaminated and having a tube run for weeks or months just to go south later was not good at all. Making these things is hard! My personal hat is off to folks like Mike Matthews (Sovtek / EH) and Aspen Pittman for forking out the big bucks to keep bringing new tubes into the fold for players. I don't even care if the reissue is or is not exactly like the original if it has the same characteristics. Just having more choices for the players is the cool aspect. On the M .... I will use nothing else in V1, V2, V4, and V5 of a Fender Black or Silver face amp. All the MPIs for phase inverter use I use are also now M's due to their current drive. On a side note on GT stuff, they have a six month warranty on preamp tubes so if you ever have problems let me know and I will get it taken care of.
|
|
|
Post by foxx on Mar 13, 2006 21:45:01 GMT -7
Your the man Myles!!! +1 I'm getting all my tubes from you from now on.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 13, 2006 23:35:40 GMT -7
Hey Myles, I see your 45 posts away from a thousand. Will the administrators get a cool new ranking? Perhaps 'High Priest of the Temple of Z'. ;D
|
|
|
Post by zane on Mar 14, 2006 20:17:39 GMT -7
I've had about 5 "M's"...haven't had problems with any of them yep...dig the way they sound... myles 3 of them went into a "Super" Reverb my brother has ...sounds good!
|
|
|
Post by myles on Mar 15, 2006 10:53:00 GMT -7
Your the man Myles!!! +1 I'm getting all my tubes from you from now on. Don't be too hasty! If things are right from me then that's great but if there are better ideas I will be happy to work with you and get you to the right folks. Working with individuals on their own amps gives us a lot more options than working with an OEM or amp maker that has to ship a lot of product and buy a lot of the same tubes that make economic sense in high production. For a single player we can do a lot more that at times is even more cost effective due to the longer life of some tubes (such as EF86's). It is always a case of using the right tool for the job.
|
|
|
Post by myles on Mar 15, 2006 10:53:47 GMT -7
Hey Myles, I see your 45 posts away from a thousand. Will the administrators get a cool new ranking? Perhaps 'High Priest of the Temple of Z'. ;D I have no idea what will happen but it would be nice if those ugly brown stars changed to another color!
|
|
|
Post by myles on Mar 15, 2006 11:06:48 GMT -7
I've had about 5 "M's"...haven't had problems with any of them yep...dig the way they sound... myles 3 of them went into a "Super" Reverb my brother has ...sounds good! I have M's in V1,2,4,5 of all my Fender black face amps. I did have one go bad in my Pierson amp. On an earlier run (run 3), I had one in a Fender Deluxe Reverb that would tick-tick-tick for about 5 seconds and then stop and be fine. The time grew over time to maybe 20 seconds. Now it stays at about 20 seconds so I have just left it in there as I love the specs on the tube: BFDR #3 - V2 TC 1690 1.3 iK GP 0.016 A side GAIN 105.6 Gain TC 1740 1.4 iK GP 0.015 B side GAIN 116.0 Gain These are the specs on the tube in V2 of one of my deluxe reverbs. This was a "find". The first side of the tube has a lot more gain and current than you will generally find in most any current 12AX7/ECC83. The second side in these Fender amps is tone recovery, and it is even nicer than the first side! So .... I will keep it. Below is an average run 12AX7R3. This is what used to be called the 12AX7EH and now is the Tung Sol reissue. 12AX7R3 (EH) effects loop DJ JCM900 TC 1410 1.0 iK GP 0.016 A side GAIN 88.1 Gain TC 1360 0.9 iK GP 0.016 B side GAIN 85.0 Gain 12AX7 book spec looks for a gain of 100 (but this can change in amps depending on the circuit) but the figures above are off industry standard machines. The gain is actually not as important as the GP which effects gain. But the TC should be 1600 (most new tubes are way below this) and the expected current should be 1.2 millamps. In this R3 we see a pretty typical example where the current is down 20-33% from spec. In a Z amp it is not as critical but in a complex front end amp like a Mesa, Bogner, or multi channel amp it really makes a HUGE difference to ANY ears. In a Marshall DSL or TSL this low current number is the kiss of death!
|
|
|
Post by prowler on Mar 15, 2006 17:18:17 GMT -7
I've never had good luck with M's & lord knows I've tried and tried. My last batch had 3 out of 3 go bad within 30 mins of installation.
|
|
|
Post by myles on Mar 15, 2006 18:25:38 GMT -7
I've never had good luck with M's & lord knows I've tried and tried. My last batch had 3 out of 3 go bad within 30 mins of installation. Well .... GT would be happy to replace them. That is about all they can do. But .... each batch is getting better and better. I'd really like to see three out of three bad ones personally to measure them and analyze them.
|
|
|
Post by JASON (aka jgleaton) on Mar 16, 2006 1:47:53 GMT -7
I've had about 5 "M's"...haven't had problems with any of them yep...dig the way they sound... myles 3 of them went into a "Super" Reverb my brother has ...sounds good! Same here, but i filled up one of my tweeds with the GT12AX7M's... It woke it right up... that amp NEVER sounded that good before and I never have had any problems with those tubes... but the batch thing explains something... cause I bought these right after they 1st came out and then I heard a guy I know sayin he got some bad ones and he also didn't like them very much, which I didn't understand cause I loved mine in a fender style amp... was probably a later batch that guy got... mine was maybe the early batch... they're still going strong... I really like em in certain amps... Jason
|
|
|
Post by myles on Mar 16, 2006 10:40:57 GMT -7
I've had about 5 "M's"...haven't had problems with any of them yep...dig the way they sound... myles 3 of them went into a "Super" Reverb my brother has ...sounds good! Same here, but i filled up one of my tweeds with the GT12AX7M's... It woke it right up... that amp NEVER sounded that good before and I never have had any problems with those tubes... but the batch thing explains something... cause I bought these right after they 1st came out and then I heard a guy I know sayin he got some bad ones and he also didn't like them very much, which I didn't understand cause I loved mine in a fender style amp... was probably a later batch that guy got... mine was maybe the early batch... they're still going strong... I really like em in certain amps... Jason Jason, There have been continual changes and we have another run that will be going through tests in the next two weeks. I had a test run of 100 two weeks ago that I rejected totally. It is a matter of continual dialing in until things get stable. I just did some tests this morning and was not happy with the results. The tubes have all the proper specs and numbers but have inconsistancies that should not be there. I am having the same issues with the new Tung Sol 12AX7 reissue. This is a new tube also and needs to stabilize. I have even updated the GT website stating that these will not be available until the 1st or 2nd week in April at this point. I have a bunch of amps with these in there that have been running great and these tubes came from all batches. But then again .... if I have 20 tubes, and 50,000 have been shipped (if not even more) and there have been 500 complaints, those are still great numbers for the most part. The Internet is actually cool in this respect for folks that want to help and be honest (there are folks on some forums that make statments like .... "I bought 20 and they all failed". You tell them you will replace them and find out they did not ever have them at all, just making noise on a forum). But ... folks that do have issues have the tubes replaced and we then look at what went wrong and try to move forward. For me, tube QA for all the vendors is a big part of my day to day activity. I do tests on Magic Parts, JJ, Reflector, Sovtek, EH, SED, Svetlana, Ei, and provide full and detailed reports. If you look at the NAMM Ruby catalog from 2003 I believe, you find one of my reports and writeups right in their catalog. That was a bit sticky at the time as Ruby and GT had booths across from each other and folks would come to the GT booth and ask about the Ruby tube that showed such great results! Part of my agreement when I came to GT was that I would only be there about 20 hours per week and would need to be able to say what I felt and learned no matter whose product it was ... GT or otherwise. For almost 5 years now Aspen at GT has lived up to his agreement in regard to letting me be independant.
|
|
|
Post by JASON (aka jgleaton) on Mar 16, 2006 12:11:51 GMT -7
Myles, as ALWAYS... great info... I didn't realize how MUCH goes into making CONSISTANTLY GOOD tubes... I also have 3 brand new 12AX7 M's I bought a couple of months ago to put in my OLD RX head but I havn't used them yet.. was maybe gonna play with them in a couple of other amps first when I got around to it ( but since then I got my Ghia and the Stingray I have never had the time... ).... If I have any problems I'll let you know cause thats probably my favorite 12AX7 for "making" my tweed sound so good... I was thinkin they'll be great in the old RX too... love the NOS stuff for the ghia i'm gonna try a NOS 5751 in the PI of the Stingray... Just out of curiosity.. with the 12AX7M's that you've had that were good... Which Z amp's do they work in well that YOU liked? and of those amps... Which positions have YOU really liked them in??Thanks Myles, Jason
|
|
|
Post by myles on Mar 16, 2006 21:08:50 GMT -7
Myles, as ALWAYS... great info... I didn't realize how MUCH goes into making CONSISTANTLY GOOD tubes... I also have 3 brand new 12AX7 M's I bought a couple of months ago to put in my OLD RX head but I havn't used them yet.. was maybe gonna play with them in a couple of other amps first when I got around to it ( but since then I got my Ghia and the Stingray I have never had the time... ).... If I have any problems I'll let you know cause thats probably my favorite 12AX7 for "making" my tweed sound so good... I was thinkin they'll be great in the old RX too... love the NOS stuff for the ghia i'm gonna try a NOS 5751 in the PI of the Stingray... Just out of curiosity.. with the 12AX7M's that you've had that were good... Which Z amp's do they work in well that YOU liked? and of those amps... Which positions have YOU really liked them in??Thanks Myles, Jason Jason, I like them as phase inverters in any Z amp that has a 12AX7 phase inverter. I like them in V2 of a MAZ Sr (5751 in V1) V1 in the Mazerati but also like an RFT in there for some things. Not in my Carmen Ghia - Telefunken in there and it is the only amp I like Telefunkens in. Not a Z amp but in V1, V2, V4, V5 of all Fender black face amps. V1 in the RxES but also like Mazda NOS 12AX7 in there for some things. I also like NOS Brimars in there. I disliked them intensely in the SRZ-65 in any position. The Svetlana 12AX7s that the Doc had in there were better. .... much better. Now I am taking those three Svetlanas and trying them in other amps to see how I like them. Of the three that came in the amp all three measured within a few percent points of perfect RCA book spec. I originally HATED the shiny plate version of this tube a year or so back but they have been done differently and the plate material is different, and maybe a lot more. Z-28 phase inverter when I am not using a 5751 which I prefer.
|
|
|
Post by dei305 on Mar 22, 2006 12:39:51 GMT -7
Hi All, I have been using the GT12AX7M in all my Fenders and now my newly acquired MAZ Invasion. The Invasion is simply incredible (it's my first "Z" amp and I am still in total bliss). The "M" is in the V1 position followed by several JJ803 (sound very good). The M just has "something more". I have experienced a few bad ones, had them replaced, and life is great. In my opinion if the M doesn't work for you check out the JJ 803. Thanks!
|
|
|
Post by prowler on Apr 5, 2006 8:14:08 GMT -7
I wish that I had good experience with the M. Every one I tried went bad on me very quickly. Had I not been so angry I would have saved them and shipped them back to GT.
|
|
|
Post by myles on Apr 6, 2006 8:49:22 GMT -7
I wish that I had good experience with the M. Every one I tried went bad on me very quickly. Had I not been so angry I would have saved them and shipped them back to GT. You should have contacted GT. They cannot make things better if you do not send them back so things can be made better.
|
|
|
Post by prowler on Apr 7, 2006 5:51:38 GMT -7
Agreed. I *might* give them another try in the future.
|
|
|
Post by bustertheboy on Apr 8, 2006 18:37:00 GMT -7
I've used a GT 12AX7M in my ghia- maybe the best of the new stuff sounds fat and rich but nowhere as good as NOS stuff- see KCA or tubedepot- i'm using nos GE for 12AX7 and 5751- more detailed drive and clearer but not sharp top end all the best
|
|
|
Post by anacephalic on Apr 19, 2006 12:11:25 GMT -7
another good place for NOS is upscale audio. Pricey though. I'm planning on doing an A-B with the 12ax7ms and NOS Mullard ax7s. the NOS were $100 ea for matched triodes in the platinum grade. worth trying in a home rig with a life expectancy of 10,000 hrs +/_ but no way for my Z. A friend of mine just got some NOS 5751 that i might try as well.
|
|
|
Post by myles on Apr 19, 2006 12:52:43 GMT -7
I've used a GT 12AX7M in my ghia- maybe the best of the new stuff sounds fat and rich but nowhere as good as NOS stuff- see KCA or tubedepot- i'm using nos GE for 12AX7 and 5751- more detailed drive and clearer but not sharp top end all the best I find the 12AX7M way too dark in my Carmen Ghia. I actually prefer a Telefunken although they are very pricy. The Carmen Ghia is the only amp I do like Telefunken's in (V1) and considering their cost I suppose that only liking them in one amp is a blessing. If you don't want to go the pricy Telefunken route, my favorite 12AX7 for the V1 slot in the Ghia is the long smooth plate Ei 7052. www.groovetubes.com/product.cfm?Product_ID=1588It is a tube (as is the Telefunken) that is generally too bright for my personal tastes in most other amps in the first gain stage. They can go microphonic more easily than most 12AX7s but so can any long plate tube in a front end gain stage. These are actually made on the old Telefunken tooling from the days when Ei was the OEM for Telefunken for a number of tubes. The tooling is now a bit worn and sloppy so you get a higher percentage of microphonic tubes so they need to come from a vendor that tests and has a long warranty period.
|
|
|
Post by myles on Apr 19, 2006 12:54:46 GMT -7
another good place for NOS is upscale audio. Pricey though. I'm planning on doing an A-B with the 12ax7ms and NOS Mullard ax7s. the NOS were $100 ea for matched triodes in the platinum grade. worth trying in a home rig with a life expectancy of 10,000 hrs +/_ but no way for my Z. A friend of mine just got some NOS 5751 that i might try as well. You do not need matched triodes for the first gain stage of the Ghia ... the two sides of the tube have different functions and paying for matched triodes here is money not well spent. I do not like the NOS 12AX7 Mullard in the Ghia for the same reasons I do not like the GT 12AX7M in the Ghia.
|
|