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Post by myles on Jun 26, 2005 16:22:35 GMT -7
Many folks that have been to my place know that I have more than a few amps of all sorts ... not just Dr. Z amps. With everything considered, the amp I love over all the others for everything really .... live, and the studio, is my Carmen Ghia. My quote of "if I could have only one amp for the rest of my playing days it would be a Carmen Ghia" is as true today as it was back in 2003 when I bought the amp. In any case, a number of folks have played the amp and later went out and procurred one of their own. A number of folks have asked what tubes I have in the amp. V1 is the Ghia really makes a big change. This is the entire gain and tone stage in the amp. V2 is the phase inverter, and how this tube breaks down when overdriven has a lot to do with touch and sustain (you want a balanced phase inverter from my point of view). V1 in my amp is a Telefunken 12AX7. I generally do not prefer Telefunken 12AX7s in V1 of any amp. This is just my personal taste. Many folks swear by them. I find their high end response too bright in most amps, especially Fender black face amps and Marshalls. But again, this is personal taste. But ... in the Ghia, it is magic. This may be due to the tone filter rather than conventional tone controls. It may be due to something else. The Doc would have a good take on it. The Telefunkens are "all over the place" on specs just as any 12AX7. RCA book 12AX7 spec at 250 plate volts and a 2 volt bias want the spec on a spec tube to be: Transconductance = 1600 Current output = 1.2mA Most 12AX7s today as a side note, fall far short of "spec". TC can be 1100-1300 and even fall below 1000 quite often. Current output over .8mA is not all that easily found. The current at 0.8mA is already down 30% on expected spec. My tube on one side specs out at 1510 / 1.3mA. On the other side of the tube it spec out at 1420 / 1.2mA. On a VTV tester (Mike at www.kcanostubes.com has one of these) the tube reads 104/103. Below 80 on this scale the tube should be rejected. On teh VTV tester this tube was also very closely balanaced on the A and B sides. The needle on the balance scale was not within the balance window but very very close. I went through a number of these and a number of new tubes. Other NOS tubes tried were RCA, Raytheon (really nice), Tung Sol, GE, Mullard, Japanese gold pin Telefunken copy, and a lot more. My V2 tube is a 1987 (8728 date code) GE 5751. I also collected all sorts of specs on these but since most folks do not have things like RCA WT100 testers or Tektronix 570 curve tracers I will say the VTV test numbers were 90/92. (< 62 is the reject point). This tube is an MPI .... Matched phase inverter. It falls right in the center of the VTV arc for match. Some folks think MPIs are smoke and mirrors or voodoo. Some swear by them such as many audiophiles. In any case, if you are close to LA and want to see and hear what happens when the MPI is removed and the same type/make of tubes with the same general specs in unmatched form do to the sustain on your guitar in certain spots on your fretboard feel free to give me a call to play this game. My output tubes are stock GT-EL84S (JJ) in a #6 rating. This is the stock Dr. Z selected tube. I have tried many other tubes and came back to these. If you want to try NOS test at 250 plate volts and 250 screen volts with a -7.3 bias volts. You need to see 48 milliamps of output. This is what you will see if you test a GT #6 +/- a few mA. I have seen a lot of JJ EL84S tubes with an average of 30 mA at this setting. (Ask Dan Boul at 65 Amps ... I went though a ton of his that were not pre tested). Down in the 30s will drop your headroom and your max output. The output set needs to be dynamically matched. Static match at idle means nothing. They tubes need to be matched over the entire operating range. Don't think it matters? Listen to a Ghia that is set up with a matched output section and compare to one that has any old tubes tossed in there in the output section. Happy Playing!
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Post by Lefty on Jun 26, 2005 17:30:40 GMT -7
I would like to try a Tele 12ax7 wanna send me one? What are your findings with the Tele vs. the JJ/Sovtek LPS etc?
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Post by scr on Jun 26, 2005 20:30:34 GMT -7
Good Stuff, Myles!
I'll have to get a Tele 12AX7 from Mike @ KCA. ;D
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Post by scr on Jun 27, 2005 17:46:02 GMT -7
damn, those Telefunken 12AX7's are hard to come by. I couldn't find any NOS. Only used from Doug's Vacuum Tubes for $49. Is buying a used tube for fifty bucks worth the risk?
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Post by scr on Jun 27, 2005 17:55:25 GMT -7
I finally found somebody that has some NOS Telefunken 12AX7's for sale. Vacuum Tube Valley has a few... but they are selling them for $215!!! Are they worth it??? from their website... Telefunken ECC83/12AX7 NOS 1960s Now a few back in stock!! I just got a limited quantity of these in. The best of the best 12AX7 types. In original Telefunken boxes. 100,000 hour rated for longest life and best sound. NOS/NIB. This is considered to be the pinnacle of 12AX7 technology. Getting very rare and hard to find. $215 and not getting any cheaper!! $75 each used, test great with low microphonics. $45 each driver grade
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Post by scr on Jun 27, 2005 17:57:15 GMT -7
The $49 used tube is starting to look like a pretty good deal.
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Post by myles on Jun 28, 2005 7:32:56 GMT -7
I would like to try a Tele 12ax7 wanna send me one? What are your findings with the Tele vs. the JJ/Sovtek LPS etc? On the Tele .... you are going to have to find one the same way I did On the other tubes ..... The JJ ECC83S is the most midrangey. The LPS did not have decent current drive.
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Post by myles on Jun 28, 2005 7:35:09 GMT -7
d**n, those Telefunken 12AX7's are hard to come by. I couldn't find any NOS. Only used from Doug's Vacuum Tubes for $49. Is buying a used tube for fifty bucks worth the risk? Yes, they are pricy and you also have to watch out as there are fakes on the market. A long grey smooth plate Ei 7025 is made on the same tooling (but is not of the same materials) but will look so close that when silkscreened with the a pirated logo are sold as NOS. Fortunately, the real ones have a diamond imbossed in the glass of the base.
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Post by myles on Jun 28, 2005 7:40:31 GMT -7
I finally found somebody that has some NOS Telefunken 12AX7's for sale. Vacuum Tube Valley has a few... but they are selling them for $215!!! Are they worth it??? from their website... Telefunken ECC83/12AX7 NOS 1960s Now a few back in stock!! I just got a limited quantity of these in. The best of the best 12AX7 types. In original Telefunken boxes. 100,000 hour rated for longest life and best sound. NOS/NIB. This is considered to be the pinnacle of 12AX7 technology. Getting very rare and hard to find. $215 and not getting any cheaper!! $75 each used, test great with low microphonics. $45 each driver grade $215 is really excessive to my thinking. I mean to pay about 1/4 of what the entire amp costs for a tube? Well, I would not do that. "driver grade" is a really nice way of saying: "this tube is so microphonic that it cannot be used in a tone or gain stage and can only be used in a current drive stage". Unfortunately, where we want to use this tube IS in the tone and gain stage. I have gotten a few off ebay from time to time and with luck sometimes you can find them for $50. At other times they go for over $100 and more. Mike at KCA had a few stated as ANOS (almost new old stock). I would trust Mike quite a bit as he uses a test unit from Vacuum Tube Valley and that little box is one of the best small vacuum tube testers ever developed. If it reads above "80" on that box and is not microphonic on the box it will be a great tube. Actually, mine was not fresh new, it had been used.
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Post by scr on Jun 28, 2005 19:03:17 GMT -7
I finally found somebody that has some NOS Telefunken 12AX7's for sale. Vacuum Tube Valley has a few... but they are selling them for $215!!! Are they worth it??? from their website... Telefunken ECC83/12AX7 NOS 1960s Now a few back in stock!! I just got a limited quantity of these in. The best of the best 12AX7 types. In original Telefunken boxes. 100,000 hour rated for longest life and best sound. NOS/NIB. This is considered to be the pinnacle of 12AX7 technology. Getting very rare and hard to find. $215 and not getting any cheaper!! $75 each used, test great with low microphonics. $45 each driver grade $215 is really excessive to my thinking. I mean to pay about 1/4 of what the entire amp costs for a tube? Well, I would not do that. "driver grade" is a really nice way of saying: "this tube is so microphonic that it cannot be used in a tone or gain stage and can only be used in a current drive stage". Unfortunately, where we want to use this tube IS in the tone and gain stage. I have gotten a few off ebay from time to time and with luck sometimes you can find them for $50. At other times they go for over $100 and more. Mike at KCA had a few stated as ANOS (almost new old stock). I would trust Mike quite a bit as he uses a test unit from Vacuum Tube Valley and that little box is one of the best small vacuum tube testers ever developed. If it reads above "80" on that box and is not microphonic on the box it will be a great tube. Actually, mine was not fresh new, it had been used. The KCA website says he has two in stock... but it also states they are out of stock. I'm guessing they're out of stock as there isn't a "Buy Now" button. I emailed Mike to make sure and will pick one up if available. from his website... ANOS Telefunken ECC83/12AX7 ANOS (used but tests as new) Telefunken ECC83/12AX7 'Smooth Plates' Only 2 in stock. These test very strong and may actually be unused. Stamped "Computer Grade" and have <> markings on the bottom. Out of stock $60.00
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Post by scr on Jun 28, 2005 19:30:14 GMT -7
Yes. KCA is out of the ANOS Tele 12AX7's. Mike recommended this tube for the Ghia... NOS Philips ECC83/12AX7 1970s version. Made in Holland by Philips (parent company of Mullard, Amperex, etc). Same tube as sold/labeled by Amperex from the late '60s early '70s. Solid disk getter with the same plate structure as Mullard/Amperex ECC83s. I66 (delta) production codes. Great in guitar and audio applications. "Hi Mike, I'd like to order two more of those Dutch Phillips ECC83s. It's amazing what that tube does for both my Vox AC30 and brown Deluxe. David" $65.00 kcanostubes.com/content/estore_details.asp?product=30Anybody have experience with this tube in the Ghia?
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Post by myles on Jun 29, 2005 9:39:27 GMT -7
$215 is really excessive to my thinking. I mean to pay about 1/4 of what the entire amp costs for a tube? Well, I would not do that. "driver grade" is a really nice way of saying: "this tube is so microphonic that it cannot be used in a tone or gain stage and can only be used in a current drive stage". Unfortunately, where we want to use this tube IS in the tone and gain stage. I have gotten a few off ebay from time to time and with luck sometimes you can find them for $50. At other times they go for over $100 and more. Mike at KCA had a few stated as ANOS (almost new old stock). I would trust Mike quite a bit as he uses a test unit from Vacuum Tube Valley and that little box is one of the best small vacuum tube testers ever developed. If it reads above "80" on that box and is not microphonic on the box it will be a great tube. Actually, mine was not fresh new, it had been used. The KCA website says he has two in stock... but it also states they are out of stock. I'm guessing they're out of stock as there isn't a "Buy Now" button. I emailed Mike to make sure and will pick one up if available. from his website... ANOS Telefunken ECC83/12AX7 ANOS (used but tests as new) Telefunken ECC83/12AX7 'Smooth Plates' Only 2 in stock. These test very strong and may actually be unused. Stamped "Computer Grade" and have <> markings on the bottom. Out of stock $60.00 The smooth plate is what I like best in the Telefunkens.
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Post by myles on Jun 29, 2005 9:42:08 GMT -7
Yes. KCA is out of the ANOS Tele 12AX7's. Mike recommended this tube for the Ghia... NOS Philips ECC83/12AX7 1970s version. Made in Holland by Philips (parent company of Mullard, Amperex, etc). Same tube as sold/labeled by Amperex from the late '60s early '70s. Solid disk getter with the same plate structure as Mullard/Amperex ECC83s. I66 (delta) production codes. Great in guitar and audio applications. "Hi Mike, I'd like to order two more of those Dutch Phillips ECC83s. It's amazing what that tube does for both my Vox AC30 and brown Deluxe. David" $65.00 kcanostubes.com/content/estore_details.asp?product=30Anybody have experience with this tube in the Ghia? I have used these and Mullards. They are nice and all, and it all boils down to personal taste in the end, but I found the Phillips and Mullards not as articulate and did not have the sparkle of the Telefunken. I normally don't like those characteristics in other amps though and it only seems to be the Ghia (and not even a Mazerati) that I like the Telefunken in.
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Post by newangel on Oct 20, 2005 12:49:43 GMT -7
Hmmm......no mention of the GT12AX7M ?
I read all the hubbub over at the gear forum, but I noticed there weren't any complaints from anyone who was using it with a lower wattage amp like our Ghia. All I know is that it sounds much better than the JJ that it came with.
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Post by myles on Oct 20, 2005 14:31:57 GMT -7
I use the M's as phase inverters in most of my amps that use the 12AX7 as a PI.
I use the M in V1 of my MAZ.
I also use it in the Mini-Z.
In V1/V2 of all my Fender BF amps resides an M.
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Post by steveinnashville on Oct 30, 2005 12:12:36 GMT -7
If somebody could please help me out... I just dug out a box of a bunch of tubes I got YEARS ago for my 99 (?) Carmen Ghia... (back then I got the head and 1x12 cab for $750, shipped (!). I love the amp, but hardly have time to play much because of work and school. I graduate soon, so I'm getting the itch to make noise again really bad.
So I found this box, I think some of the tubes are for my 1980 Fender/Rivera Champ II... Please help me sort out these tubes! I think I got most or all of them from Lord Valve...
-5AR4, weird symbol/logo, "Electron Tube MADE IN CHINA", rectifier, right? -matched pair of JJ EL84s -pair of Fender power tubes (6v6) old, probably originally in my Champ II... no way they sound as good as the ones in there now... at least I'm not using the original speaker (the Champ drives its amp stand, which is a '63 Leslie 120 cabinet) -small Fender-branded USA 12AX7s, probably the same situation as the previously listed Fender tubes... -pair of Sovtek 12AX7s -GE (USA) 5751
I just checked the Champ, it's got two Sovtek 6V6s in the power section and two Sovtek 7025/12AX7WAs in the preamp.
The Carmen Ghia, from right to Left, is running an Ei 12AX7, an unreadable 5751 that used to have a green script now faded to nothing, a matched pair of JJ EL84s and then the large (rectifier?) tube has no readable label at all... it does bear a lot of resemblance to the 5AR4, but it doesn't appear to be of identical manufacture, the base and components look a "little" off from the 5AR4, so I have no idea.
When I was messing with all of these (probably in 1999), Dr. Z advised me some and I think I took his recommendation of using a 5751 and 12AX7 in the preamp, the JJ EL84s sound really good. The rectifier that is unreadable is likely to be the original Ghia rectifier, so I wonder what Mike was using as stock for that run (I faintly recall searching out the 5AR4).
Are there any things I should try here? I play a PRS McCarty Rosewood with zero to a lot of effects into the front end... Currently, I'm very excited about placing the order for a custom switching system from WOBO guitar electronics in Poland, will add buffered outs and parallel mixing of clean, dirty, Memory Man echo output and Loop Station output to each amp, each of the 4 channels having 2 mute switches (one for each amplifier). Tuner out, custom designed routing plan to swap between clean and dirty signals being sent to loop station, their individual output being automatically muted while recording loops (stomp for loopstation input engage and one for swapping between the clean/dirty inputs going to the loopstation). 12 stomps/LEDs, big box, tuner out, effects loop for amplifier B (for Polyphonic Octave Generator and weird Walco Chord & Note Sustainer in front of Champ->Leslie for organ emulation).
Do I already have the optimal tube arrangement in the Ghia? The Champ II? I think the mixed preamp pair in the Ghia, as per Mike's recommendation, is supposed to yield a blend between the breakup of one type and the headroom of the other.
Any thoughts? This is a cool forum, I just found it. Dr. Z is incredible. Thankfully, Rock Block guitars here in Nashville has a few of them in the shop to try out...
Thanks,
-Steve
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