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

[MartyStrat54]

Well it has the seam top, but no cut-outs on the plates. This could be an original tube that came with the amp. Marshall was using Ei's until 2002.

Looks like and Ei copy of a Tele Smooth Plate.

Alan?

 

[Procter2812]

Hey guys.

I got some pics of the tube I can't identify. Can some one please identify this tube?

Looks a lot like a Telefunken. I have one and it looks pretty much the same as that.

has it got a diamond on the bottom?

And are there four seams? they will be in an X pattern

 

[wegman]

Well it has the seam top, but no cut-outs on the plates. This could be an original tube that came with the amp. Marshall was using Ei's until 2002.

Looks like and Ei copy of a Tele Smooth Plate.

Alan?

That tube is out of the organ. I have no clue what it is. You were able to see the seems on the top. Those are seems right?

 

[wegman]

Looks a lot like a Telefunken. I have one and it looks pretty much the same as that.

has it got a diamond on the bottom?

And are there four seams? they will be in an X pattern

Yes there are four seams at the top in an X pattern. One seam is not as pronounced as the others but it is there.

No diamond on the bottom that I can see.

 

[Procter2812]

Well its more like a square inside the circle which is formed into the bottom of the valve.

The seams sound about right. all the one on mine are not perfect.

Does it sound good? thats the main thing

 

[wegman]

Well its more like a square inside the circle which is formed into the bottom of the valve.

The seams sound about right. all the one on mine are not perfect.

Does it sound good? thats the main thing

Yes it has a sound all it's own compared to any other tube I have. Very unique sounding.

 

[MartyStrat54]

The owner of Twister has already contacted me twice. Apparently my first email got lost in Cyberspace. Anyway, he gave me all the info on the amp. Good thing I have my generic Bias Rite because this baby doesn't bias up like a Marshall. I'll have to plug in the sockets, put the tubes in Bias Rite sockets and then take the meter to the leads off of the Bias Rite.

Man, the B+ on this is 475. I was thinking it would be around 425.

And the preamp tubes? They're like Weggie's amp.

Here's the function of all three preamp tubes.

V1A Gain stage
V1B Cathode Follower

V2A Gain Stage
V2B Gain Stage

V3 A&B Phase inverter

Plate voltage on the power tubes with the preamp switch in the up position should be around 475 give or take depending on your wall voltage.

Three gain stages in this amp. That should be enough. Now I know how to tube it.

 

[Procter2812]

Man thats quite high for a B+ voltage both my Marshalls are lower than that..

you gonna go with NOS or CP power tubes... Obviously its gonna be NOS... but you gonna try out the 6CA7's or Gold Lion KT66's?

 

[MartyStrat54]

Yes, now I know what tubes I am going to use. Since V1A is gain, I will probably go 26-24 in V1. In V2 I will go 29-29. If that is too hot, I will change to taste, but it will probably be something like that. The nice thing is I can still stick a Tele in V1 and a Black Plate in V2. Yeah!

Since I haven't biased with the Bias Rite in a while, I will start out with a set of NOS 6CA7's that tested at 77-77. If I fug them up, I won't be too pissed off. Once I get the hang of the sensitivity of the bias control, then I will be using some rare Sylvania Triple O Getters in this amp.

Eventually, I will be getting rid of my 100 watt amps. I like the 50's and they are cheaper to operate.

 

[Procter2812]

Yes, now I know what tubes I am going to use. Since V1A is gain, I will probably go 26-24 in V1. In V2 I will go 29-29. If that is too hot, I will change to taste, but it will probably be something like that. The nice thing is I can still stick a Tele in V1 and a Black Plate in V2. Yeah!

Since I haven't biased with the Bias Rite in a while, I will start out with a set of NOS 6CA7's that tested at 77-77. If I fug them up, I won't be too pissed off. Once I get the hang of the sensitivity of the bias control, then I will be using some rare Sylvania Triple O Getters in this amp.

Eventually, I will be getting rid of my 100 watt amps. I like the 50's and they are cheaper to operate.

Sweet sounds good Marty!

I was reading one of your posts about you thinking about getting rid of you 100 watters, when you were talking to Joe. And it made me think.. Do I really need a 100 watt amp?

More expensive to run-yes... do i ever use 100 watts... no!

I like my 800 too much to let go of it!

 

[RiverRatt]

Well it has the seam top, but no cut-outs on the plates. This could be an original tube that came with the amp. Marshall was using Ei's until 2002.

Looks like and Ei copy of a Tele Smooth Plate.

Alan?

Here's one of my Marshall-branded Ei ECC83s. This one came out of an amp made in 2000. I'd guess that John's tube is an Ei, too. Does it flash when you first power it up? Ei's will flash, but Teles won't.

 

[wegman]

Here's one of my Marshall-branded Ei ECC83s. This one came out of an amp made in 2000. I'd guess that John's tube is an Ei, too. Does it flash when you first power it up? Ei's will flash, but Teles won't.

Hey Ratt.

No it doesn't flash when it starts up. This tube did not come out of my amp, it came out of the organ I found.

 

[MartyStrat54]

Thanks for the pictures Alan. I believe the pictures show that it is indeed an Ei 12AX7. These are good tubes, especially the older one's. Very close to a Tele in sound. They aren't as sweet sounding as the Tele, but close.

 

[MartyStrat54]

Sweet sounds good Marty!

I was reading one of your posts about you thinking about getting rid of you 100 watters, when you were talking to Joe. And it made me think.. Do I really need a 100 watt amp?

More expensive to run-yes... do i ever use 100 watts... no!

I like my 800 too much to let go of it!

Well it's easy to see, but hard to explain. 100 watt amps have been the standard for so long. If you are in a Hard Rock or Heavy Metal band that is getting famous, you are going to have 100 watt heads and full stacks. However, the average musician that gigs does not need a 100 watt amp. I mean I see pro's playing with 20 watt amps. A microphone does wonders through a PA system. I am getting to the point where it is tough for me to move some of my equipment and so lately I've been asking myself. "Why?"

My new 50 watt Twister head weighs 30 pounds. I can handle that. I'm going to build a custom 212 cab and that won't be too bad. I can handle that. I'm through taking the TSL122 out of my house. It weighs a ton. My 602's weigh almost as much. Then you have to look at 412 cabs. Just a pain in the ass to load in anything but a van or pickup. I'm really seeing myself with 50 watt heads and 212 cabs.

Don't worry, my Strat is lighter than a Les Paul. I can handle it.

 

[RiverRatt]

Hey Ratt.

No it doesn't flash when it starts up. This tube did not come out of my amp, it came out of the organ I found.

Curious. All my Ei's flash. A real Telefunken wouldn't. I've never heard of a Tele with a pinched top, either. Both Ei and Telefunken are listed in the Philips factory codes. I don't know if this means that Philips owned them, or that they bought from them and re-labeled.

I'll bet that tube ended up in the organ when it was serviced. Ei has been making tubes for a long time. Maybe these earlier ones didn't flash? Look at these photos - Tubemonger has some Ei's in their library from the 1960's.

Ei ECC83 12AX7 - Late 1960s Smooth Plate Philips or Edicron Labels - Nish Yugoslavia

 

[wegman]

Curious. All my Ei's flash. A real Telefunken wouldn't. I've never heard of a Tele with a pinched top, either. Both Ei and Telefunken are listed in the Philips factory codes. I don't know if this means that Philips owned them, or that they bought from them and re-labeled.

I'll bet that tube ended up in the organ when it was serviced. Ei has been making tubes for a long time. Maybe these earlier ones didn't flash? Look at these photos - Tubemonger has some Ei's in their library from the 1960's.

Ei ECC83 12AX7 - Late 1960s Smooth Plate Philips or Edicron Labels - Nish Yugoslavia

I agree I believe it to be an Ei as well but it does not flash. I powered up the amp in pitch darkness and there was no flash. The tube just lit up gradually like the rest of them do.

It's a pretty sweet sounding tube by the way.

 

[MartyStrat54]

If you look at the bottom of the tube, in between the pins, does it have a impressed circle? It could be an RFT Tele clone.

 

[wegman]

If you look at the bottom of the tube, in between the pins, does it have a impressed circle? It could be an RFT Tele clone.

Hey Marty. Congrats on forum member of the year.

Yes, it appears to have a circle in the center of the pins that is impressed some what.

 

[MartyStrat54]

Hey Marty. Congrats on forum member of the year.

Yes, it appears to have a circle in the center of the pins that is impressed some what.

Well like I said, it could be a smooth plate RFT/Tele clone.

Yeah, I responded to the "Member of the Year" thing. I'm honored, but it was based on just a handful of votes. Basically, all the nominee's are winners.

 

[wegman]

Well like I said, it could be a smooth plate RFT/Tele clone.

Yeah, I responded to the "Member of the Year" thing. I'm honored, but it was based on just a handful of votes. Basically, all the nominee's are winners.

I read your response. I think it was excellent and showed a tremendous amount of class.

This tube sounds excellent. Very smooth and defined. It is great in V1. It bumped the black plate out of V1. The Electrohome sounds great in V3 I find, it bumped out a GE.