Pre-amp tubes for Einstein

[Profound]

Just my two cents
I own an 100w Einstein for almost a year. My ears were complaining for some unwanted high frequencies when playing dirty sounds at high volumes through my V30 Diezel cab.Not to much highs but a rather brittle voicing. I replaced a set of 6550 with EL34 (fried outer 6550 ) but this change did not alter the pronunciation of the amp, concerning those particular frequencies ether in bad or good way. After a lot of internet reading I decided to get deeper. I replaced PI preamp with JJ 12AT7 and this was it.
I am wondering if is the change from 12AX7 to 12AT7 that did the trick, or that particular 12AX7 that was not working well in as a PI. I saw some (expensive) Groove Tubes that said to be designed for PI. Some day, when I will have money and time to spare, I will buy one of those, along with other 12AX7, 12AT7 and experiment. Until then I will just enjoy my Diezel as it is.

PS: I have to say that Diezel V30 cab has a very wide frequency spectrum.
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Kyriakos

 

[darkhorse]

Just my two cents
I own an 100w Einstein for almost a year. My ears were complaining for some unwanted high frequencies when playing dirty sounds at high volumes through my V30 Diezel cab.Not to much highs but a rather brittle voicing. I replaced a set of 6550 with EL34 (fried outer 6550 ) but this change did not alter the pronunciation of the amp, concerning those particular frequencies ether in bad or good way. After a lot of internet reading I decided to get deeper. I replaced PI preamp with JJ 12AT7 and this was it.
I am wondering if is the change from 12AX7 to 12AT7 that did the trick, or that particular 12AX7 that was not working well in as a PI. I saw some (expensive) Groove Tubes that said to be designed for PI. Some day, when I will have money and time to spare, I will buy one of those, along with other 12AX7, 12AT7 and experiment. Until then I will just enjoy my Diezel as it is.

PS: I have to say that Diezel V30 cab has a very wide frequency spectrum.

Kyriako, dont you find the 12AT7 ruins the texas mode on channel one?
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Kyriakos

 

[Profound]

Kyriako, dont you find the 12AT7 ruins the texas mode on channel one?
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Dont think so but I will tell for sure after I'll switch back to a 12AX7. If you find channel two a little bit brittle (or whatever), I suggest you to do the experiment. A hi-fi store at Acharnon & Stournari has jj's in stock. There are cheap tubes so you can just try by yourself.Dont forget to feedback to us all.

 

[MrNixon]

wow thanks for the info. i've always loved the tone of my Einstein with an AT7 in the V1, and it never occurred to me to bring the gain on V2 & 3 down as well.

now i can use the Einy the way i've been wanting to!!!

dont get me wrong, it sounds great with the V slots filled with AX7s but i love the way the mids sing with lower gained tubes a little more!!!

 

[darkhorse]

Kyriako, dont you find the 12AT7 ruins the texas mode on channel one?
_______________________________

Dont think so but I will tell for sure after I'll switch back to a 12AX7. If you find channel two a little bit brittle (or whatever), I suggest you to do the experiment. A hi-fi store at Acharnon & Stournari has jj's in stock. There are cheap tubes so you can just try by yourself.Dont forget to feedback to us all.

That s what i ment, for me it tamed chan.1 mode 2 more than I cared for (the gain was just not enough). So i put the 12AX7 back in there.

 

[Profound]

That s what i ment, for me it tamed chan.1 mode 2 more than I cared for (the gain was just not enough). So i put the 12AX7 back in there.

I put 12AT7 in V6 phase Inverter position. So it did not affect the gain of the amp nor the volume level.
But as I said before I have not already conclude if it was the change from 12AX7 to 12AT7 that did the job or it is just that the new tube is working better as a Phase Inverter. I will have to find more time (and tubes) to experiment.

 

[darkhorse]

That s what i ment, for me it tamed chan.1 mode 2 more than I cared for (the gain was just not enough). So i put the 12AX7 back in there.

I put 12AT7 in V6 phase Inverter position. So it did not affect the gain of the amp nor the volume level.
But as I said before I have not already conclude if it was the change from 12AX7 to 12AT7 that did the job or it is just that the new tube is working better as a Phase Inverter. I will have to find more time (and tubes) to experiment.

ok, sorry i just re-read your post. What is it the PI in v6 does? you think i might have a shot eliminating the feedback on channel 2? Or is it not related?

 

[slyvren]

That s what i ment, for me it tamed chan.1 mode 2 more than I cared for (the gain was just not enough). So i put the 12AX7 back in there.

I put 12AT7 in V6 phase Inverter position. So it did not affect the gain of the amp nor the volume level.
But as I said before I have not already conclude if it was the change from 12AX7 to 12AT7 that did the job or it is just that the new tube is working better as a Phase Inverter. I will have to find more time (and tubes) to experiment.

ok, sorry i just re-read your post. What is it the PI in v6 does? you think i might have a shot eliminating the feedback on channel 2? Or is it not related?

If you want to lower gain in channel 2 use v2. It is tied only to chan 2. So try 12at7 or 12au7 in v2. I tried 12at7 in mine and it did the trick. It does not effect Texas mode only chan 2.
Good luck

 

[Profound]

ok, sorry i just re-read your post. What is it the PI in v6 does? you think i might have a shot eliminating the feedback on channel 2? Or is it not related?

It's related with the function of push pull amplifiers. I will not try to explain it to you. Instead I am posting you a lick that you might find useful http://www.guitaramplifierblueprinting. ... verter.pdf
Keep in mind the words of an old Greek movie "I dont want to learn in, I just want to eat it". Just do the experiment.
Also I would like to mention that I always have feedback with my neck pickup, while there is no just a problem with the bridge, nor with the stock neck pickup. Now if you're having feedback with a decent guitar and a low output pickup while you're not facing the cab,,, just keep searching.

 

[darkhorse]

Thanks for the info guys. I ll let you know how it goes.

 

[nbarts]

less messing with tubes, more playing is the best

 

[soldanospwn]

Ive been having lots of feedback/squealing trouble with my newly acquired used Einstein 100w head. Tried many different cab/cable/guitar combos and get lots of squealing with the gain or volume anywhere past bdrm levels... Try to palm mute or play rest and get crazy squealing... on all channels modes except clean. no effects, straight into the amp. Could it be a bad preamp tube? fuck I just wanna rehearse with my new rig!!!