Tube Rolling among the Great's 12AX7

[Gary Mattis]

I decided to take the day and roll some 12AX7 pre amp tubes to try to decide what is my best sounding tube and I can't really say that only one brand of tubes would be my choice in every amplifier. I did decide on Amperex Holland in the end over Telefunken East Germany and Mullard Blackburn UK. I was not able to test Brimar UK or Smooth plate Telefunken East Germany because I only had one of each type. I did test Ei Yugoslavia smooth plates. I also tested RCA long black plate tubes being the best USA 12AX7s made here. Though I like GE long plate tubes I did not think that they were up to the task of sound quality against Vintage Mullards and Telefunken tubes. I used two Bogen CBH 100 mono blocks for the test and a cassette tape deck plugged into aux 1 on both amplifiers. 8 ohm full range 12 inch 30 watt speaker's. Nothing fancy at all just power amps into single 8 ohm speaker's. I wanted to hear the tubes without any additional speaker coloration. By using the aux inputs instead of Mag I was able to run a single 12AX7 into the splitter on each amplifier. The splitters are pretty cheap tubes a Triad Japan and RCA . Waiting for two Mullard 6C4 to get here. The outputs are 7868 RCA and two either Sylvania or Westinghouse with square plate holes. I'm not sure if the tape would sound better on the Mag inputs but I was trying to test single 12AX7 tubes. They all sounded good in the amplifiers and with speaker network's and input coloration you could use any of those tested and be pretty happy with the results. I just liked the Amperex Holland tubes the best. The overall sound and balance just seemed better with the Amperex tubes and the mids seemed to hold up much better in the mix. On certain songs the Mullard and Telefunken tubes really shined but it seemed like the Telefunken tubes were a little dry sometimes and The Mullard Blackburn were just a little bit dirty. The Ei tubes were not bad at all but we're kinda inbetween the Telefunken East Germany and Mullard Blackburn UK tubes. The RCA black long plate tubes were not bad just not in the same league. I only wish that I had another Brimar to compare with the other tubes. Brimer are good tubes also. The Amperex Holland Bugle Boy wins my vote for The best sounding 12AX7 tube. Also do consider the early Mullard long box plate tubes and the smooth plate Telefunken tubes. I did not have two of those or Brimar to compare. The Amperex tubes were quieter at idle also. There's a lot of factors in audio that color the sound and some of those things may actually pick your tubes for you , your amp and speaker's may only like one or two tube types. My amplifiers both seem to be pretty friendly with just about any tube that I installed in them , The long grey plate RCA did not sound very good when you compared it to the other tubes I tested. I honestly expected for the Telefunken or Mullard to win hands down and I didn't really see The Amperex as being a big threat to either one. So much for my expectations.

 

[chuckworkb]

I also admire Amperex 12AX7's. Great sounding tube. Believe it or not ive also tried and like the Sylvania 12 AX7's.

 

[Dswankey]

I decided to take the day and roll some 12AX7 pre amp tubes to try to decide what is my best sounding tube.... I did decide on Amperex Holland in the end over Telefunken East Germany and Mullard Blackburn UK. I was not able to test Brimar UK or Smooth plate Telefunken East Germany because I only had one of each type. ........On certain songs the Mullard and Telefunken tubes really shined but it seemed like the Telefunken tubes were a little dry sometimes and The Mullard Blackburn were just a little bit dirty. .... the Telefunken East Germany and Mullard Blackburn UK tubes.

East Germany?

 

[apachef1]

Amperex over the RCA 12AX7 Black plates?? Thats a first. Amperex is a nice sounding tube but a little congested in the highs with difficult classical chamber music. RCA are silky smooth topend with tight deep bass to rival all the Euro tubes.

On a side note - I see you mentioned Mullard 6C4 tubes? did you mean Mullard M8080 with the big box plates? Fantastic tube over the US 6C4

 

[GuyNoir]

Amperex over the RCA 12AX7 Black plates?? Thats a first. Amperex is a nice sounding tube but a little congested in the highs with difficult classical chamber music. RCA are silky smooth topend with tight deep bass to rival all the Euro tubes.

I dearly love RCA BP. Bonzo's (Led Zep) drumming and high hats just sound so perfect with this particular tube; like no other I've tried. A very lively tube.

 

[onepixel]

My favorites are the Amperex Bugle Boys too.

 

[apachef1]

My favorites are the Amperex Bugle Boys too.

View attachment 1618780

BB have the sweet holographic sound. I went one step further and grabbed a pair of Amperex labeled Electronics for Medicine 12AX7 & 12AU7. A really beautiful sounding tube and very clean on the top end but rare and expensive.

 

[Yamariv]

East Germany?

Thought the same when I read this.... The only Tube that I know of that says East Germany on it is an RFT. OP, does it have the square Telefunken stamp on the bottom?

 

[yuman]

BB have the sweet holographic sound. I went one step further and grabbed a pair of Amperex labeled Electronics for Medicine 12AX7 & 12AU7. A really beautiful sounding tube and very clean on the top end but rare and expensive.

Take the final step and try some Amperex 12AX7 long plates with D getter. The Bugle boys are awesome...the long plates are other worldly.

 

[Gary Mattis]

Amperex over the RCA 12AX7 Black plates?? Thats a first. Amperex is a nice sounding tube but a little congested in the highs with difficult classical chamber music. RCA are silky smooth topend with tight deep bass to rival all the Euro tubes.

On a side note - I see you mentioned Mullard 6C4 tubes? did you mean Mullard M8080 with the big box plates? Fantastic tube over the US 6C4

I don't listen to much classical chamber music to be honest, that is pretty funny to me ! , I got one of the NOS 6C4 Mullard England box plate tubes labeled Amperex in today , GHO/R8C code, EC 90 number but no real time to listen to it. I'm going to re do the same tube test again with the Mullard 6C4 box plates installed after the other tube arrives and after they break in for a few days. I'm probably going to get another Brimer and a smooth plate Telefunken for the next test also. It takes a while to break in new tubes about 75 hours. That will give me some time to find the other two 12AX7 tubes for the test. As far as RCA long blackplates go, to me they are not as good as the vintage foreign tubes. I like RCA long blackplates but I don't consider them as good as the better 12AX7 foreign tubes. The RCA are a dirty tube with a bit of American distortion. A gritty tube with a slight attitude. I do like them and GEs in guitar amps. But just about any USA long black plate tubes work good in guitar amps. I just don't see the clarity In audio applications from any American 12AX7 tubes. I use American long plate tubes in my lower power amplifiers and they sound OK in them. I'm just looking for something a little bit better this time. I'm not trying to throw away my money for nothing, I'm trying to get the best sounding tubes even if it costs me a little bit of money. The vintage 7868 are pretty expensive tubes and the vintage 12AX7 pre amp tubes are also. Even the 6C4 Mullard England cost a good bit. It is not a real cheap project that I am doing , I knew that the tubes and speaker's were going to cost me some money before I was done. I could come in at around 500 dollar's for both amplifiers rebuilt if I wanted to use RCA tubes in the pre amp section and I do have them , but I have other choices and wanted to explore them. I have not even decided on speaker's yet. I may change my mind later on the tubes I use. I'm just testing the higher dollar 12AX7 tubes on 1 way speaker's. I just threw The RCA long black plate tubes into the mix of tubes, I already knew how they sounded in comparison. I'm just as Red White and Blue as any American but I am not tone death. And I don't drive a ford either ! , My standards are a lot higher than driving a ford . I am not able to afford two Vintage Macintosh's or a 1960 Ferrari or I would not even be doing this project. But I can buy and rebuild a few reasonably priced tube amplifiers and buy a few foreign vintage pre amp tubes. I don't have to justify USA tubes as being the greatest thing ever made. If they were no one would buy foreign tubes would they ? . Even USA amp maker's used foreign tubes in their more expensive amplifiers. Nothing wrong with USA or even Chinese and Russian tubes as long as you understand their limits. I have them all and I use them all also. Some amplifiers sound better with cheaper tubes in them. It all comes down to finding a good combination in the end . My Fisher ambassador likes a Mullard England in stage 1 of the tuner and likes cheap Chinese tubes in the phase inverter stage. It was terrible sounding and noisy with Telefunken tubes in the phase inverter stage. Every tube amplifier has it's own personality and it likes what it likes. Your rebuild makes a difference also with the capacitors and resistors that you use. I used two different part's suppliers on these two amplifiers and I may end up using different brand of tubes in each one before I am done with it but I am trying to use the same tubes in both. I bought the amplifiers at two different times and one of the part's suppliers went out of business after I rebuilt the first one. I have no choice sometimes on the part's available only on the values that I order. Even the values of the part's are a compromise sometimes. You can only buy what is available. On the 6C4 phase inverter it seems like everyone says Vintage Mullard England are the best, the Vintage 6C4 RCA was not great sounding so I am trying the Mullards instead. I will most likely tweek the capacitors some down the road after I get some good speaker's. The basic idea here is get the best sounding tubes in it to start with and then pick my speaker's out, then tweek the capacitors and tone controls to sound best to my ears. Sometimes a little bit of luck doesn't hurt any especially when picking speaker's. My 3 other tube amplifiers sound pretty good with the combinations that I put together on each one. I like each one the way they are and I don't want to change them in any way. You can make make them worse sometimes and you need to know when to stop changing them. A full and balanced sound at any volume is what I try to accomplish with each one. If my combination gets really close to being that , I stop right there. A very slight adjustment to recordings once in awhile I can live with.

 

[Gary Mattis]

East Germany?

May be West Germany ? But it is Germany, I'm sure of that.

 

[Gary Mattis]

Thought the same when I read this.... The only Tube that I know of that says East Germany on it is an RFT. OP, does it have the square Telefunken stamp on the bottom?

Real Telefunken tubes, not any RFTs. I Never used any RFT 12AX7 tubes on anything but I could get a few for the test also. I forgot RFT even made 12AX7 tubes, you don't see them very often. The RFT Siemens/Telefunken labeled EL 34 are not bad sounding tubes. I think that the RFT 12AX7s actually should be included in this tube test. I will see if I can get some for my retest with the Mullard 6C4s. I'm not trying to make any tube win out over the other tubes, I would rather let each tube speak for themselves in my amplifiers and if RFT makes a good 12AX7 it will be known after the testing is finished. It is a pre amp and phase inverter test that I am doing, and I didn't plan on doing a phase inverter test in the beginning. I just was not impressed with the Vintage RCA 6C4 in the phase inverter stage. To be honest the NOS Japanese Triad 6C4 sounds much better than the NOS Vintage RCA 6C4. The phase inverter stage certainly makes a big sound difference in these amplifiers. I'm really starting to pay a lot more attention to the sound of the phase inverter tubes. I used to put any good tube into the phase inverter stage and never considered its sound very much. I was told that they don't have much effect on the sound. I don't agree with that false teaching anymore. I always wondered why people would pay 100 dollar's for a Mullard 5AR4 rectifier tube if rectifier tubes and phase inverter tubes did not really effect the sound much . It was always the same people who said both things. If electrons flow through any tube in the chain it has to effect the sound. Even a simple switch makes a sound of it's own.

 

[Dswankey]

May be West Germany ? But it is Germany, I'm sure of that.

I assumed it was a typo when I initially replied. To my knowledge original real Tele's were made in Western Germany not maybe.

http://www.tube-classics.de/TC/Tubes/AudioTubes.htm

http://www.tube-classics.de/TC/Tubes/SieTel/SieTelIntro.htm

http://www.audiotubes.com/teledate.htm

http://tctubes.com/telefunken-date-codes.aspx

 

[Gary Mattis]

Take the final step and try some Amperex 12AX7 long plates with D getter. The Bugle boys are awesome...the long plates are other worldly.

I had some of the first long plate Amperex 12AX7s made, some very early ones that tested NOS and I sold them off not really knowing what I had at the time. I remember the guy asking me if I had anymore of them. Of course I didn't but I did try them out and I remember that they sounded good. I have not seen any sence.

 

[Gary Mattis]

I assumed it was a typo when I initially replied. To my knowledge original real Tele's were made in Western Germany not maybe.

http://www.tube-classics.de/TC/Tubes/AudioTubes.htm

http://www.tube-classics.de/TC/Tubes/SieTel/SieTelIntro.htm

http://www.audiotubes.com/teledate.htm

http://tctubes.com/telefunken-date-codes.aspx


View attachment 1620305

Definitely West Germany, 1958 to 1962 tubes and the smooth plate is 1966 I think 22 1 06 code.

 

[Gary Mattis]

Take the final step and try some Amperex 12AX7 long plates with D getter. The Bugle boys are awesome...the long plates are other worldly.

The painted , medical and scientific tubes are very select tubes. You don't see them very often. I got lucky a few year's ago with two select RCA 6L6GCs and I found two more that matched with them. It appears that I actually have one of the early Amperex 12AX7 long plates in one of my amplifiers , I didn't even notice it until just now !

 

[Dswankey]

The painted , medical and scientific tubes are very select tubes. It appears that I actually have one of the early Amperex 12AX7 long plates in one of my amplifiers , I didn't even notice it until just now !

I have some Amperex 12AX7's that have the following green paint on them. I also have a few with yellow paint too.

I found the tubes as they were in an Ampex RtR player. The funny thing is I had someone try to tell me they were useless because it was obvious someone had spilled paint on them. When I explained there was no way that any paint had ever been spilled on the console let alone into the bottom of the RtR player he proceeded to tell me that it must of been an accident at the Amperex plant. The guy was clueless but what annoyed me was he was so adamant that he was correct.



As for Amperex long plates this is a good resource for identification purposes

http://www.tube-classics.de/TC/Tubes/Valvo ECC83/ECC83.htm

For example, the etchings towards the bottom of the glass should look like this when ID'ing Amperex

 

[Gary Mattis]

I have a little bit of time on my hands today and I have found that the Amperex tube I likes code is a triangle 3J marked tube. Today I used the Amperex long plate D foil getter 3J into a Triad 6C4 splitter to the 7868 outputs on the left amp and a Amperex short plate triangle 1A2 into a Mullard box plate 6C4 to the 7868 outputs. Somehow it all balanced out pretty well and the Two amps had a sweet sound together. What I was going to try next was putting a Telefunken smooth long plate and a Mullard long plate in the right amp with the Mullard 6C4 so both amplifiers have long plate tubes in them. On the previous test I had mixed up the Amperex and Mullard short and long plates with each other by accident because I don't have two of each of them in long plates. The Telefunken ribbed , RCA and Ei were all 3 longplates in both amplifiers. Sence I don't have another long Bugle Boy I thought I would try to substitute a Telefunken smooth or Mullard ribbed until I can get one. Plus I still have another Mullard boxplate 6C4 coming in the mail. Right now I have great results with the tubes that are in them and I was thinking that another longplate like the Telefunken or Mullard put in place of the short bugleboy may sound even better than what I have now. I'm just trying to buy a little bit of time before I go buy another long plate Amperex. But if it likes one of the two tubes and sounds good I might just leave it in.

 

[AlTinkster92]

Love that "flash" my BB 12ax7's make when first turned on.........

 

[Gary Mattis]

I have some Amperex 12AX7's that have the following green paint on them. I also have a few with yellow paint too.

I found the tubes as they were in an Ampex RtR player. The funny thing is I had someone try to tell me they were useless because it was obvious someone had spilled paint on them. When I explained there was no way that any paint had ever been spilled on the console let alone into the bottom of the RtR player he proceeded to tell me that it must of been an accident at the Amperex plant. The guy was clueless but what annoyed me was he was so adamant that he was correct.

View attachment 1620592

As for Amperex long plates this is a good resource for identification purposes

http://www.tube-classics.de/TC/Tubes/Valvo ECC83/ECC83.htm

For example, the etchings towards the bottom of the glass should look like this when ID'ing Amperex


View attachment 1620610

I have some Amperex 12AX7's that have the following green paint on them. I also have a few with yellow paint too.

I found the tubes as they were in an Ampex RtR player. The funny thing is I had someone try to tell me they were useless because it was obvious someone had spilled paint on them. When I explained there was no way that any paint had ever been spilled on the console let alone into the bottom of the RtR player he proceeded to tell me that it must of been an accident at the Amperex plant. The guy was clueless but what annoyed me was he was so adamant that he was correct.

View attachment 1620592

As for Amperex long plates this is a good resource for identification purposes

http://www.tube-classics.de/TC/Tubes/Valvo ECC83/ECC83.htm

For example, the etchings towards the bottom of the glass should look like this when ID'ing Amperex


View attachment 1620610

Not exactly accurate information on the Amperex long plates at that website, My tube is a 8J but it also has a flat getter on top of the D getter from a 9 number tube. Both are Heerlem made tubes 1958-ish. Apparently they also made a inbetween tube with both a D getter and Foil getter and the stapled plates. I don't think that the plates are welded looking at them. Your tubes are selected tubes nomatter what the guy thinks.