Blown preamp tube on einstein 100W head, but wich one?

[blackslide]

Hi guys, I've been playing for quite a time now with 2x 6550's in the power amp and it's perfect for playing at home. My korean made Hamer Std. with DiMarzio pickups is a total killer with this amp and a cheap 2x12" V30 cab. Just recently I noticed this harsh noise that just appeared out of nowhere. It sounds like wind blowing hard into a microphone, etc. and I've looked all the pre-amp tubes through but they all seem okay. So if someone could give me a hint on what to try to determine the broken tube, would be great!

The noise is very apparent on CH1 Modes 1, 2 & 3 and On CH2 Mode 1.
CH2 is noiseless on Modes 2 and 3 (except for some white noise)
When the gain pot and channel volume pots are turned up and down, the noise sometimes abruptly disappears, and starts to build up static again quite fast, weird, but then again I'm a tube-o-newbie.

So.. V1, V2 or V3?

For the record, it's an Einstein 100W head S/N 003/437 and it has Ruby 12AX7AC5 HG+ in V1 and V2, the rest are TAD 12AX7A-C Selected.

I love the CH2 Sound, what should I put in to get CH1 mode 3 to sound more like CH2, or if I want even more gain in CH1 mode 3, witch tube makes the most difference?

I was also wondering if the jack for V7 is soldered into the head's PCB also, and how hard would it be to actually make a tube reverb happen?

Best regards,
Kristjan

P.S. Lots of thanks and I hope you all have as much fun playing with your Diezels as I do. Diezel amps kick ass (G.A.S. is building up in my head again.. might need a diezel cab soon)

 

[flownomis]

sry i didnt read your post just the header.


take a brush , remove the pretube covers and slightly touch the tubes with the brush while the amp is on . if you hear sounds and rattle the tube is busted.

 

[blackslide]

Thanks I tried your tip, didn't hear a thing at first, but when the tubes had heated up for about 10 minutes. V3 was microphonic on CH1 Mode 1, V1 and V2 were clearly microphonic on CH2 Mode 2 and 3, they're all busted? Very strange. I could hear the brush going against the glass envelope clearly through the speakers, no rattling, popping or anything else of that sort.

I'm again in the middle of moving, etc. So I'll have to look into this more closely once I get to settle down and get the money to finally buy the two KT88's and some pre-amp tubes, I was thinking of trying out some S's and T's in the place of those rubys.

Again, thanks! And if someone got anything up their sleeves, to just be able to play, I'd appreciate it. This noise is killing the sound totally

 

[blackslide]

Yeah! Finally had the time to open up my travelling combo.. yes it's scary, a Behringer AC108. But it gave me the opportunity to try a pre-amp tube that has been working. The faulty tube appears to be the HG+ ruby in V1. I'm using the Behringer 12AX7-A in V2 now, until I get some new ones.

Anyone know where to get the original rubys, or some NOS/Mullard's in the nordics? I've only checked thomann and they seem to be supplying JJ, Sovtek, TAD and GT (MesaBoogie and Engl also). I like the amp most in CH2 with the gain cranked up to 11:00-12:00. CH1 Mode 3 is great for some 'Up to eleven' blasting with my 7-string LTD

So if anyone got any advice what to use in V1-V3 to get best of both worlds, I would appreciate it. Though, I'm not sure if you can get better, sound-wise. And also, if there's a mod to add a reverb function to the amp, without the need for an external pedal, would be well appreciated.

I'm quoting MARK2C because this helped in pinpointing the faulty tube, and knowing what tube does what. This post (Einstein Head makes a strange noise - solved) was quite hard to find using the search engine. Solved threads get a lower ranking or?

Einstein:

V1 Used by both channels
V2 Used by channel 2
V3 Used by both channels
V4 Mixer & Loop Driver
V5 Return Driver
V6 Phase Inverter
V7 (just combo) Reverb (12AT7)

My best guess is V2.

Thanks for flownomis for the quick reply and getting me to actually try something, thanks for MARK2C for the nice info!


Regards,
Kristjan

 

[blackslide]

So I swapped the behringer crap in V2 with the original ruby tube. And put a groove tubes 12AT7 in V1. Sounds good.

Also put in a pair of electro harmonics EL34 in the power stage. Sounds awesome with the 6550's...

Still looking for the original ruby set...

 

[RJF]

If you have not replaced any tubes recently, I would suggest replacing all of them, and putting the stock diezel recommended tubes back in, including all 4 tubes in the power section.