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View Full Version : What's your favorite phase inverter 12AX7 tube and why?


clay49
12-31-2011, 12:42 PM
List the amp and power section of the amp, and tell us what PI you use, and what effect that tube gives to your sound....

Joe Porto
12-31-2011, 12:53 PM
One with matched triodes. Much more important than brand IMO. Gain factor is important too. Find a dealer that matches and rates gain level of each triode.

clay49
12-31-2011, 02:07 PM
next....

Norjef
12-31-2011, 03:26 PM
I keep hearing that long plates make the best PIs.
Anyone use JJ803, Yugo, LPS, current schtuff?

Oh yeah, Happy New Year too !!!

PS - MANY self-appointed and real tube-gurus "say" matched PIs are "snake-oil" as too much of related circuits and components are not matched anywhoooo.
me ? - "I Know Nutting !!" (Schultz)

falconer
12-31-2011, 03:37 PM
I'm not saying this article is the end-all in content, but it may answer some of your questions:

http://www.guitaramplifierblueprinting.com/files/Phaseinverter.pdf

HandOfTheHost
12-31-2011, 03:41 PM
I've tried 12ax7's in the pi position and ended up going back to a lower gain 12au7, less noise and tighter sounding overall.

clay49
12-31-2011, 04:14 PM
I've tried 12ax7's in the pi position and ended up going back to a lower gain 12au7, less noise and tighter sounding overall.

Really...12AU7...that's a lot lower. I've got an old 50's Sylvania 12AU7 that I'll have to chunk into my Soldano and see what it does....

sublimeaudio
12-31-2011, 04:22 PM
I've had excellent results with the Sovtek 12AX7LPS. I'm not usually a big fan of Sovtek tubes, but this one is great.

AD_
12-31-2011, 04:33 PM
I recently went through all my tubes trying to find which combination of gain stage and phase inverter tubes sounded the best to me. I have a tone king metropolitan, and the guitars I have make me try to find something that goes well with their tone. I don't want to say I need a 'subdued' top end, maybe not as detailed. I like the sound of a Mullard in v1, but it is very detailed. If I have a very detailed tube in the phase inverter, it tends to be way too bright and ice-picky. I have a RCA long/black plate 12ax7 in the PI slot now, and it seems to be a happy medium between too detailed and too dark. The phase inverter tube plays a huge part in how this tone king sounds. Another mullard in the PI is the worst, to me. Tungsrams, which are very detailed, are also bad sounding with a detailed v1. Raytheon long/black plates sound very punchy and strong, but not quite what I was looking for. A Raytheon/Amperex 12ax7 in the phase inverter sounds a bit dark, but could work if I didn't like the RCA better.

elsicodelico
12-31-2011, 04:46 PM
I have a, Laney gh-50, JJ kt77 power tubes with a sovtek 12ax7 lps in the p.i.
Works for me

Onioner
12-31-2011, 05:06 PM
Depends on the amp, but one thing i've learned is that matched triodes not only isn't necessary, it may be outright undesirable.

neville5000
12-31-2011, 05:10 PM
I've had excellent results with the Sovtek 12AX7LPS. I'm not usually a big fan of Sovtek tubes, but this one is great.

After listening to multiple NOS and new production tubes this is the one I settled on. The Tung Sol RI is good in the PI slot also. FWIW I run NOS in every other position, but my ears can't detect a big enough change to cause me to switch.

riffmeister
12-31-2011, 05:25 PM
whatever sounds good with the rest of the amp. :)

usually a Philips 12AT7......

Coldacre
12-31-2011, 05:45 PM
I like GE for NOS or Gold Lion current for PI

Joegalaxy
12-31-2011, 06:17 PM
I spent some time trying out different ones in my Roccaforte C30 and ended up with a smooth long plate Telefunken in the PI. That's with Bugle Boys in the V1 and V2. It's all about trial and error with your particular amp.

aynirar27
01-01-2012, 07:03 AM
I recently went through all my tubes trying to find which combination of gain stage and phase inverter tubes sounded the best to me. I have a tone king metropolitan, and the guitars I have make me try to find something that goes well with their tone. I don't want to say I need a 'subdued' top end, maybe not as detailed. I like the sound of a Mullard in v1, but it is very detailed. If I have a very detailed tube in the phase inverter, it tends to be way too bright and ice-picky. I have a RCA long/black plate 12ax7 in the PI slot now, and it seems to be a happy medium between too detailed and too dark. The phase inverter tube plays a huge part in how this tone king sounds. Another mullard in the PI is the worst, to me. Tungsrams, which are very detailed, are also bad sounding with a detailed v1. Raytheon long/black plates sound very punchy and strong, but not quite what I was looking for. A Raytheon/Amperex 12ax7 in the phase inverter sounds a bit dark, but could work if I didn't like the RCA better.

any luck with a EH in the phase inverter? full sounding tubes and IMO the very opposite of detailed. They do seem to go bad awful quickly though. I had a good sound going in a Roccaforte 50 watt I had. It had a real ripping top end and a mullard in V1 and EH in the PI smoothed it out a bit.

ChorusCrackpot
01-01-2012, 08:06 AM
What phase inverter valves would you recommend for older Marshall JCM 800s, particularly the single channel 50 watt versions?

riff1006
01-01-2012, 12:55 PM
Mullard CV4024 in both my SF Fenders.

HandOfTheHost
01-01-2012, 01:57 PM
Really...12AU7...that's a lot lower. I've got an old 50's Sylvania 12AU7 that I'll have to chunk into my Soldano and see what it does....

Actually I misspoke, I'd tried a few different tubes in the pi slot and went back to the original 12at7.

clay49
01-01-2012, 02:15 PM
Guys, this is turning into a very informative and helpful thread...thanks for the varied responses...keep 'em coming!

aynirar27
01-01-2012, 04:14 PM
I had an 83 JCM 800 4104 vertical inputs. When it was stock I used a tung sol 12ax7 in the PI. Clear and punchy. After I had it modded at Voodoo amps for some more gain, it left the shop with ARS branded Balanced 12ax7. A gainy chinese tube that I found lost some of the punch but added some fluidity.

psychodave
01-01-2012, 04:39 PM
Tungsram 12AX7

aynirar27
01-02-2012, 08:28 AM
nice, i'll have to try a tungsram in the PI. One came in an 18watt clone I got a little while ago. came in the V2 though. smooth sound i'm guessing.

Hand of Doom
01-02-2012, 04:19 PM
Tungsram 12AX7

+ old Tesla.

Depends on the amp also. I absolutely loved a Siemens long plate in a Germino C45. Alas, I broke it by accident, but that gave me a chance to settle on other tubes. In the end the Tesla was the best fit, I use long plate Mullards in V1 and V2. Now the C40 likes Tungsram!

I like GE 12At7s in my BF Fender amps, couldn't bond with Mullards, to harsh for me.

In my JC20H head the China 12AX7 was actually a good fit. A short plate RCA was the winner out of several AX7 in that amp, although I never tried a LPS.

I do like the LPS in the 6505+ but a long plate GE is the best in that amp.

Tomo
01-02-2012, 05:48 PM
Guys, this is turning into a very informative and helpful thread...thanks for the varied responses...keep 'em coming!

Thanks so much and I really appreciate everyone's imput.

Tomo

t***9
01-02-2012, 07:17 PM
I'm not saying this article is the end-all in content, but it may answer some of your questions:

http://www.guitaramplifierblueprinting.com/files/Phaseinverter.pdf

This was a very good article, learned a lot - thanks for posting

t***9
01-02-2012, 07:41 PM
Depends on the amp, but one thing i've learned is that matched triodes not only isn't necessary, it may be outright undesirable.

A major tube dealer (I forget which one) did a blind tube test in an amp's PI position using tubes with matched and unmatched triodes. The subjects doing the test were guitar players, professional and other wise. And the tubes that were preferred, for all the commonly admired tone qualities, were those with unmatched triodes.

daveg62
01-02-2012, 08:35 PM
Depends on the amp. I do like 12at7's in the PI slot. They definitely sound better in most amps. I like a nos Sylvania 12at7 in my mesa Mark III. I use Sovtek 12ax7LPS in my Fryette SigX as that amp specifically specs a 12ax7 and the amp also doesn't seem to change much with various tubes as much as my mesa.

clay49
01-02-2012, 09:10 PM
I'm trying to find a Fryette SigX myself. I actually just bought one from a guy who calls himself pulverizer here on TGP, but he changed his mind and decided to keep it after I paid him, although I did get a refund (with no explanation...not good).

Depends on the amp. I do like 12at7's in the PI slot. They definitely sound better in most amps. I like a nos Sylvania 12at7 in my mesa Mark III. I use Sovtek 12ax7LPS in my Fryette SigX as that amp specifically specs a 12ax7 and the amp also doesn't seem to change much with various tubes as much as my mesa.

Ramblin390
01-02-2012, 09:42 PM
I've had excellent results with the Sovtek 12AX7LPS. I'm not usually a big fan of Sovtek tubes, but this one is great.
that

Tele Wacker
01-02-2012, 09:52 PM
I recently bought an old tube organ and it had 28 RCA 12AX7's and all were dated 1955. I tested them and they were all good. They sound great in my old Fender amps. I don't have a new tube in any of my Fender amps. The old ones never fail me and they sound so good.

Timbre Wolf
01-02-2012, 10:15 PM
I recently bought an old tube organ and it had 28 RCA 12AX7's and all were dated 1955. I tested them and they were all good. They sound great in my old Fender amps. I don't have a new tube in any of my Fender amps. The old ones never fail me and they sound so good.

:omg

That's a mighty impressive organ you've got there!

:rimshot

Super 100
01-02-2012, 10:27 PM
I tried a lot of tubes out and I really like Brimar CV4004s in both my Marshalls (Super100 and 77 Superbass).
Tighter bass and rich harmonics.

In the AC30 I like Bugle Boy 12ax7s. Chimey. :cool:

teleman55
01-02-2012, 11:49 PM
Can't say about 12ax7s. My amps use 12at7s in that slot. I like Jan Philips 12at7s. They're available, they work good, and they're affordable.

Purplexi
01-03-2012, 03:47 AM
There's a lot of hype about JJ's 12AX7 PI being the ticket, or NOS stuff like EI. A great sounding, Phase Inverter position tube, like the Tung Sol 12AX7 ECC83, is only $17+ and easily re-stocked.

Tomo
01-03-2012, 09:26 AM
thanks guys! I really enjoy reading this thread. Please keep coming...

Tomo

Tele Wacker
01-03-2012, 09:40 AM
I received a question about what type tube organs I salvaged the 12AX7's. I'm not sure how to reply to the individual who sent the question. Well, it's several different ones. Old Hammonds, Baldwins and Wurlitzer. The Baldwins seem to have more tube than any of the old organs. If the organ doesn't work and is really beyond repair, I will salvage it out for the amp, tubes, speakers and lots of beautiful old wood. I don't think I've paid over $50 for any organ I've bought. I have a tube tester and I test every tube I salvage. But, the best test is to put them in an old Fender amp and see how they sound. I have an old Hammond M2 now but it works great and is in great shape.

freaksho
01-03-2012, 09:46 AM
Depends on the amp, but one thing i've learned is that matched triodes not only isn't necessary, it may be outright undesirable.

A major tube dealer (I forget which one) did a blind tube test in an amp's PI position using tubes with matched and unmatched triodes. The subjects doing the test were guitar players, professional and other wise. And the tubes that were preferred, for all the commonly admired tone qualities, were those with unmatched triodes.

at the risk of turning this very informative and interesting thread into a shouting match, can someone who has done balanced vs unbalanced testing describe the differences they hear?

clay49
01-03-2012, 09:50 AM
at the risk of turning this very informative and interesting thread into a shouting match, can someone who has done balanced vs unbalanced testing describe the differences they hear?

I think that's well within the parameters of my OP...good question!

macmax77
01-03-2012, 10:58 AM
after trying a few tubes (now included) the Sovtek 12ax7lps gets my vote

freaksho
01-03-2012, 11:16 AM
after trying a few tubes (now included) the Sovtek 12ax7lps gets my vote

did you try it based on that article's recommdation?

i currently use a balanced triode EH 12AX7 based on Doug's recommendation but thinking of throwing in another one just for the helluvit. not even sure exactly what's in my tube drawer but pretty there's a 12AY7 and a 12AU7 to try.

Tomo
01-03-2012, 11:24 AM
I received a question about what type tube organs I salvaged the 12AX7's. I'm not sure how to reply to the individual who sent the question. Well, it's several different ones. Old Hammonds, Baldwins and Wurlitzer. The Baldwins seem to have more tube than any of the old organs. If the organ doesn't work and is really beyond repair, I will salvage it out for the amp, tubes, speakers and lots of beautiful old wood. I don't think I've paid over $50 for any organ I've bought. I have a tube tester and I test every tube I salvage. But, the best test is to put them in an old Fender amp and see how they sound. I have an old Hammond M2 now but it works great and is in great shape.

Thanks for writing! Several my students are keep buying these old organs for tubes and parts. That's fun project. Yes, tester first and test on vinatge Fender. That's I am doing right now. So many 12AX7s to go through...but it's great to reuse these tubes.

Tomo

Laplacian
01-03-2012, 11:46 AM
Lots of good info here and opinions.

I have to side on the strong side with "It really depends on #1 the amp, #2 the power tube type and #3 what in V1 ..... then followed by V2, etc.....

Some amps do not care which as long as it's the right value of tube (12AX7, AT7, etc..)

.. but In general, I always seem to like Mullard or Amperex in V1 and then depending on power tube type, in the PI position, I like Telefunken 12AX7's for El34's, Mullard 12AT7(whatever the CV4*** something is) with KT-66's and 6L6GC's and often a Mullard 12AU7 with 6550's or KT-88's, something to do with the current they supply, I've been told.

Old tesla's sound like a poor man's telefunken IMO, and I have a bunch of them, but you have to work through a handful to find the right ones in each amp. I also agree the triodes do not need to be balanced after enough experimentation, although the Dr. Z Delta 88 I have really likes a balanced PI and it is noticable, so ..... it all depends, as usual.

5751's work great on fine tuning in various slots too.

Taking the time and patience to really go through a bunch of different combinations of tubes and brands can really change the character of an amp, from too bright to too thin, to ultra-phat, to high headroom to low headroom, etc.. and like I said, some amps don't seem to care at all.

I would have written this stuff off years ago as malarky, but it's quite noticable in sensitive amps. P.S. A balanced Sovtek LPS has often sounded quite nice in the PI.

Timbre Wolf
01-03-2012, 01:46 PM
There are some assumptions here that I hope to unearth:


one's particular amp has a phase inverter that was designed for a 12AX7
one's particular amp has a phase inverter of the long-tailed pair type
one's particular amp has a phase inverter at all

Most BF Fender amps, for instance, were designed with a 12AT7 phase inverter. One exception is the BF Princeton or Princeton Reverb, which had a 12AX7 PI - and that was a split load style PI (no discussions of "balanced PI" are applicable). '50s Fender tweeds mostly used this cathodyne/split-load PI, or even paraphase style for the earliest Fenders. Single-ended amps, such as Fender's Champ, do not have a phase inverter at all.

That said, you can change the tone and feel of the amp with swaps. I encourage each player to experiment, as you wouldn't otherwise know what you like the best. I can't emphasize enough how much the feel and response of the amp is changed with PI swaps, as well as tonal emphasis.

For 12AX7 PI, consider a 5751 for a lower gain sub - this will give a tighter, cleaner character. Likewise, for a 12AT7-designed PI, a swap to E180CC will give analogous gain drop (an E180CC is to a 12AT7 like a 5751 is to a 12AX7). Using a 12AX7 in place of a 12AT7 in the PI will give a looser feel, and earlier breakup that may feel more lively.

This thread is about using a 12AX7 in a PI, so I'll make this point: if you have an otherwise wonderful, but microphonic vintage 12AX7 (long-plate is most likely), you should try it in your PI where the microphony is not problematic - you may love it there. I find those old long-plate 12AX7 to have greater clarity in their sonic character, and that comes through in the PI position.

As for personal favorites, mine are very specific, after literally hundreds of swaps to fit my taste. Here are a few examples:

Carr Slant 6V (BF Deluxe style design, with LTP 12AT7 PI): Mullard Mitcham 1960 square-getter 12AT7 TK1 type. That's the clearest, smoothest 12AT7 I have.

Richter 5E7+ (tweed Bandmaster style design, with cathodyne 12AX7 PI): Mullard Whyteleafe CV4004 (box-plate 12AX7); bright and clear, but microphonic in earlier preamp stages.

Mesa/Boogie 20/20 Power Amp (fixed-bias EL84 power, with LTP 12AX7 PI): Mullard Mitcham early-'80s CV4024/12AT7WA; drop from 12AX7 to 12AT7 type tightened up the response, and tonally-fat/viscous 12AT7 retained thick feel that other 12AT7 types would not.

Mark Kane Trainwreck Liverpool style head (LTP 12AX7 PI): Brimar '50s long black-plate 12AX7: thick tone and extreme clarity.

Greer Thunderchief (6V6-powered AC30 Top Boost style head, with LTP 12AX7 PI): Mullard 1959 long-plate ECC83 f92 type): thick barking lows, airy clarity.

Victoria Regal II and Lexicon Signature 284 no PI in these single-ended amps - though Darin of Tonic Amps (http://www.tonicamps.com) assures me that single-ended amps can be made with a phase-inverter!


Lastly, FWIW, I disagree with a certain oft-referenced PI treatise that tells you to change your PI every time you change power tubes. Instead of that, I urge you to experiment with your own amp/ears/taste, find out your preferences, obtain a few back up tubes that sound the same, and take a listen, swapping with your reference tubes, to find out if any change is necessary. Likewise for the balanced/un-balanced PI argument: use your own ears.

- Thom

Onioner
01-03-2012, 02:53 PM
at the risk of turning this very informative and interesting thread into a shouting match, can someone who has done balanced vs unbalanced testing describe the differences they hear?

Well, I have a very small sample size, which is why I won't draw any hard conclusions, but I can share my one experience.

It's a 25W, push/pull 6v6 Blackface style amp. I had nine different preamp tubes to chose from, seven of which were AXs, two of which were balanced. I swapped, and swapped, and swapped, and swapped, and at the end of the day, I felt the balanced tubes sounded sort of flat, and lacked the deep depth and swirlyness of the other tubes. I just got a second amp w/ a PI and it'll be interesting to see if I reach the same conclusion.

Note that there are many things here that keep this from being any kind of valid experiment. This is one amp, and nine tubes aint much to go on, two even less so. Still, I had similar issues with both the balanced tubes I had (a RCA greyplate, and an Amparex): flat, unlively, sort of boring. Confirms what I've read in the past. But, proof it definitely is not.

For the record, I ended up w/ a Matsushita 12AX7 in the PI of that amp. I loved it as a V1, but this one went all microphonic on me, so I was happy to find that I liked it in the PI.

AD_
01-03-2012, 06:04 PM
any luck with a EH in the phase inverter? full sounding tubes and IMO the very opposite of detailed. They do seem to go bad awful quickly though. I had a good sound going in a Roccaforte 50 watt I had. It had a real ripping top end and a mullard in V1 and EH in the PI smoothed it out a bit.
You know, I didn't think to try an EH tube for phase inverter. I like the RCA I have in there now, but I'll remember to try one. Good call.

clay49
01-12-2012, 09:00 PM
Still trollin' for more input...thanks!

EADGBE
01-12-2012, 09:20 PM
Sovtek 12AX7LPS. Just like the rest of my other preamp tubes. More output, crunch, and sustain.

clay49
01-12-2012, 09:23 PM
Sovtek 12AX7LPS. Just like the rest of my other preamp tubes. More output, crunch, and sustain.

So you run a straight flush of the 12AX7LPS?

silverrocket2006
01-13-2013, 12:25 AM
I love the way my Telefunken "polishes" up my sound...12AT7 in the PI position in my Rockitt Retro JMP 50 clone. Gives depth, lowers the gain a little, really fills out the sound. A good PI tube... I think is my secret weapon. Not so secret now. I've tried the Mullard CV4024, too bassy and muddled. Just kinda mushed it all up. Others too...just don't hold a candle to the Tele AT7. Mullard 161 in V1, 163 in V2. Just freaking sweet....oh....Gold Lion KT77's replaced the EL34's too. I wish I were playing right now.

Timbre Wolf
01-13-2013, 12:36 AM
I love the way my Telefunken "polishes" up my sound...12AT7 in the PI position in my Rockitt Retro JMP 50 clone. Gives depth, lowers the gain a little, really fills out the sound. A good PI tube... I think is my secret weapon. Not so secret now. I've tried the Mullard CV4024, too bassy and muddled. Just kinda mushed it all up. Others too...just don't hold a candle to the Tele AT7. Mullard 161 in V1, 163 in V2. Just freaking sweet....oh....Gold Lion KT77's replaced the EL34's too. I wish I were playing right now.
Try a Mullard Tk1 12AT7/ECC81, if you get the chance; they're my favorite 12AT7 for blackface Fenderesque PIs. You'd have a small-bottle Mullard full house if you used one of those, and I think you'd appreciate the stellar clarity the Tk1 provides.

- Thom

lang.murphy
01-13-2013, 12:40 AM
I love the way my Telefunken "polishes" up my sound...12AT7 in the PI position in my Rockitt Retro JMP 50 clone. Gives depth, lowers the gain a little, really fills out the sound. A good PI tube... I think is my secret weapon. Not so secret now. I've tried the Mullard CV4024, too bassy and muddled. Just kinda mushed it all up. Others too...just don't hold a candle to the Tele AT7. Mullard 161 in V1, 163 in V2. Just freaking sweet....oh....Gold Lion KT77's replaced the EL34's too. I wish I were playing right now.

Dude! I wish I'd read this post before I ordered two CV4024's t'other day! Day-um!

I'm running a Gold Lion AT7 in the PI position in my RR and I love it. Agree that it lowers the gain a tad and fills out the sound. Also, maybe... just a tad more clean headroom on the same pot settings, but not claiming "true" higher headroom. Don't have any way to measure that...

lang.murphy
01-13-2013, 12:42 AM
at the risk of turning this very informative and interesting thread into a shouting match, can someone who has done balanced vs unbalanced testing describe the differences they hear?

I know this is like a necro bump on this thread... I mean, I didn't bump it, but since "It's ALIVE!" I'll jump in... just ordered two CV4024's, one balanced, one not. I will be testing and reporting back my experience.

Guinness Lad
01-13-2013, 05:31 AM
Sovtek LPS for me, pretty sure I was doing this well before many of you if you read through the history in this forum. I personally think the LPS is just as good as any NOS tube I have (phillips, tesla, telefunken, rft, rca, sylvania). The LPS usually ends up in V1 and the PI slots in any amp of any type.

twangbanger
01-13-2013, 07:35 AM
Those mullard ec81's . I think they're CV4024? for Fender amps using 12at7's. Have had good luck w/ the sovtek 12ax7lps tubes in the past . But right now using a telefunken smoothplate in that amp (Allen Encore).

Jon Silberman
01-13-2013, 08:02 AM
Someone may have already posted this but in case not, a worthwhile read:

http://www.guitaramplifierblueprinting.com/files/Phaseinverter.pdf

riffmeister
01-13-2013, 08:06 AM
What do I use? I use good ones.

Why? Because.

sublimeaudio
01-13-2013, 08:30 AM
Sovtek 12AX7LPS. Cheap, and a very good sounding tube for the phase inverter.

Blue Strat
01-13-2013, 08:41 AM
Really...12AU7...that's a lot lower. I've got an old 50's Sylvania 12AU7 that I'll have to chunk into my Soldano and see what it does....


PI circuits have very low gain, much lower than a 12AX7 can provide. The circuit determines the gain of the circuit, not the tube.

mjtripper
01-13-2013, 08:46 AM
12ax7lp in almost all my amps, just sounds right I guess.

tapehead
01-13-2013, 09:06 AM
In a '74 100W SF TR/QR I like old stock Mullard or Tung-Sol 12at7...but the Sylvania JHS 12AT7WA is also stellar.

The Mullard emphasizes bottom end and lower mids, even with the open back cab.
The Tung Sol seems to really make the midrange harmonics shine more like a British, EL34-powered amp.
The Sylvania seems to give the 6L6GC power tubes that musical, top-end sparkle familiar to EL84s.

Various grey plate GE & RCA glass v1-v5, but I also like the Tung-Sol 12at7 driving the reverb...


In a '67 Selmer TNB 50 MK II, Telefunken ecc83, smooth or ribbed plate but I've been sticking with smooth lately.

Amperex ecc83 v1, Mullard ecc83 v2, Telefunken ecc83 v3 PI, Mullard EL34 in v4 and v5, Mullard gz34 v6.


In a '69 Oliver PA100 bass head; the tube types are a bit unorthodox: 6eu7 in v1 and v2, 6an8a PI, 7027a v4&v5, gz34 v6. Mullard everything aside for the 7027a, those are RCA.



In 6 tube, RCA/Bassman derived circuits I greatly prefer era-appropriate glass. Shortplates in v1 and v2, long in v3. These circuits tend to be highly sensitive to tube swaps FME, and variety is the spice of life:)

clay49
01-13-2013, 10:14 AM
Hey guys...thanks for reviving the thread! I'm taking notes and will try some of these options for sure! Keep 'em coming!!!

clay49
01-13-2013, 10:16 AM
Sovtek LPS for me, pretty sure I was doing this well before many of you if you read through the history in this forum. I personally think the LPS is just as good as any NOS tube I have (phillips, tesla, telefunken, rft, rca, sylvania). The LPS usually ends up in V1 and the PI slots in any amp of any type.


What does the Sovtek LPS give you that the others lack (that you have tried)??? I've seen that suggested in several threads (as well as several mentions here).

Tomo
01-13-2013, 10:21 AM
Mullard CV4024 in both my SF Fenders.

I used put those in my BF Fenders... now I prefer older RCA 12ATs or GE 12AT7s now. A bit more fuller and sexier tone???

Tomo

riff1006
01-13-2013, 10:29 AM
I used put those in my BF Fenders... now I prefer older RCA 12ATs or GE 12AT7s now. A bit more fuller and sexier tone???

Tomo

I've got a GE 12AT7 in a reverb driver slot. I'll have to try it in a PI. I know the GEs/RCAs certainly sound better in reverb circuits than the Mullards. I'm also possibly in the market for a new PI tube for my Vicky Golden Melody. It's got a 12AX7 in it but will try the GE in that spot before I buy anything.

Guinness Lad
01-13-2013, 10:55 AM
What does the Sovtek LPS give you that the others lack (that you have tried)??? I've seen that suggested in several threads (as well as several mentions here).

Just has richness, even sounding, chime, I just think it's a great tube regardless of being a new tube verses NOS stuff. Only thing I never heard was a real Mullard, those are supposed to be happening.

sricabla
01-13-2013, 11:31 AM
Telefunken ECC83

A well known tube among audiophiles and guitarists, some people regard the Telefunken ECC83 as the ultimate pre-amp tube. It is used more commonly by audiophiles. The Telefunken is considered a wide-band 'neutral' or 'clear' tube. It does not really impart any color to the sound. Therefore, if you have an overly warm stereo or guitar amp, you may want to consider this tube. There are two main types of Telefunkens: smooth plates and ribbed plates. The smooth plates are usually more desirable and expensive for audiophiles, probably because people consider this type to be more 'neutral'. Telefunkens are not used in guitar amps as much as other ECC83 types. I have found that the smooth plate Telefunken lacks personality in a guitar amp and does not really overdrive well. The ribbed plates are a little better in this regard. However, there is a good place to put a Telefunken smooth plate in a guitar amp... in the phase-inverter slot (usually the last slot closest to the power amp tubes.) I have found that this can add some 'clarity' and '3-D' effect to your overall sound

Timbre Wolf
01-13-2013, 11:51 AM
I beg to differ on the "neutral" smooth-plate Telefunken ECC83. It certainly has its own character, and, as with all tubes, imparts that character to the signal path.

In my experience, smooth-plate Telefunken ECC83 are tonally slender in the lows, relative to most 12AX7, and have a unique upper-mid band emphasis, without imparting piercing highs. The ribbed-plate Telefunken ECC83 have a wider range of tones (deeper lows, higher highs), don't have that upper-mid emphasis, and can have harsher treble emphasis.

As for clarity - most '50s US 12AX7 are noticeably more clear than the smooth-plate Telefunken ECC83. Those '50s US 12AX7 mostly tend to break up more easily than the Telefunken. Quality can vary, even amongst only Telefunken choices, and I find that the ribbed-plate version is more clear and open than most smooth-plate samples.

One of the Telefunken's greatest qualities is its durability, and that alone can be impetus to use one for a PI.

- Thom

'58Bassman
01-13-2013, 12:28 PM
at the risk of turning this very informative and interesting thread into a shouting match, can someone who has done balanced vs unbalanced testing describe the differences they hear?

I haven't gotten to the end of this thread, so I apologize in advance if it ahs been answered- symmetrical tubes will distort more like an old Tube Screamer and asymmetrical is more like a Boss SD-1 because the overtone content is higher with asymmetrical.

http://archive.ampage.org/threads/0/fxdiy/004905/Asymmetrical_vs_symmetrical_distortion-1.html

conundrum
01-13-2013, 12:37 PM
I haven't gotten to the end of this thread, so I apologize in advance if it ahs been answered- symmetrical tubes will distort more like an old Tube Screamer and asymmetrical is more like a Boss SD-1 because the overtone content is higher with asymmetrical.

http://archive.ampage.org/threads/0/fxdiy/004905/Asymmetrical_vs_symmetrical_distortion-1.html



Ehhhhh, not really that simple. You have to remember that in a Long Tail Pair, one section is grid driven and one section is cathode driven, and each drive type distorts differently.

Tomo
01-13-2013, 12:52 PM
I beg to differ on the "neutral" smooth-plate Telefunken ECC83. It certainly has its own character, and, as with all tubes, imparts that character to the signal path.

In my experience, smooth-plate Telefunken ECC83 are tonally slender in the lows, relative to most 12AX7, and have a unique upper-mid band emphasis, without imparting piercing highs. The ribbed-plate Telefunken ECC83 have a wider range of tones (deeper lows, higher highs), don't have that upper-mid emphasis, and can have harsher treble emphasis.

As for clarity - most '50s US 12AX7 are noticeably more clear than the smooth-plate Telefunken ECC83. Those '50s US 12AX7 mostly tend to break up more easily than the Telefunken. Quality can vary, even amongst only Telefunken choices, and I find that the ribbed-plate version is more clear and open than most smooth-plate samples.

One of the Telefunken's greatest qualities is its durability, and that alone can be impetus to use one for a PI.

- Thom

Thom, thanks for your experiences with TONE.

Tomo

Timbre Wolf
01-13-2013, 02:38 PM
Thom, thanks for your experiences with TONE.

Tomo
Hi Tomo -

It is my pleasure to share what I know from my experiences. And I appreciate learning from the experiences from others who have much to offer on TGP, such as yourself.

By the way - I've not forgotten I've got something to send you... Wow - time has flown by :o

- Thom

Structo
01-13-2013, 02:53 PM
From what I have gathered reading and researching, a long plate tube that may be normally microphonic in V1 or V2 can work great in the long tailed pair phase inverter.

Having the triodes close in Gm (transconductance) seems to benefit the tone.
But you just have to roll through the tubes you have to hear what sounds best to you.

shapeshifter
01-16-2013, 05:28 PM
I tried a few of my tubes, and really like RCA 12Ax7 longplates in my Deluxe Reverb and Princeton Reverb......unfortunately they are a bit microphonic, because they also sound great in V1 or V2. They sounded the best of all the other 12AX7s I tried (GE, EI, Raytheon,...)

As already mentioned, it is a nice way of loosening up the feel of the amp....
12AT7 sound tighter to me...

t***9
01-16-2013, 06:08 PM
I tried a few of my tubes, and really like RCA 12Ax7 longplates in my Deluxe Reverb and Princeton Reverb......unfortunately they are a bit microphonic, because they also sound great in V1 or V2. They sounded the best of all the other 12AX7s I tried (GE, EI, Raytheon,...)

As already mentioned, it is a nice way of loosening up the feel of the amp....
12AT7 sound tighter to me...

Try some of those Tube Tamers (or ? - round polymer things) that reduce microphonics so you'll be able to use those fine tubes where you want. I prefer the clear over the red ones for some reason.

Tomo
01-16-2013, 06:13 PM
Hi Tomo -

It is my pleasure to share what I know from my experiences. And I appreciate learning from the experiences from others who have much to offer on TGP, such as yourself.

By the way - I've not forgotten I've got something to send you... Wow - time has flown by :o

- Thom

Hi Thom,

Thanks for your kind words. I enjoy tasting good tone! Life is only once, good tone, good food... I love both! I really enjoy reading your posts. Very informational and very rich knowledges from your own experiences. Nice to sharing with others.

That's very exciting to hear... please email me when you have a chance.

Tomo

Doc58
06-24-2014, 05:32 AM
Depends on the amp, but one thing i've learned is that matched triodes not only isn't necessary, it may be outright undesirable.
You're absolutely correct...Think Matchless!