Herbert Mark II - Tube Choice / Placement / Bias Question

[Moose]

Hi everyone,

I sold my Herbert about a month ago and alomost ended up sick after trying to go with a more scaled down setup so I immediately purcahsed a new Herbert and I now feel like I am reunited with a love that almost got away!!! I will never make that mistake again thats for sure.

Anyway - the Herbert I sold was the original and the Herbert I just got is the Mark II and from what I understand, it is only the 1st channel that has been impacted by the changes in the Mark II.

Unfortunately, a few of the pre-amp tubes seemed to fail when the amp was delivered to the dealer (Axe Palace in Walpole MA). The owner was nice enough to pull a few of the preamp tubes to find out which ones were bad and replace them with various Engl and JJ tubes he had lying around his shop. (The initial problem was that Channel 1 had no volume)

Obviously for the amount of money I paid for the amp and give the fact that this is my 4th Diezel Head (also had an Einstein and VH4), I would have liked to get one with the original tubes actually working.

The tubes that the amp came with are Ruby tubes (AX7s for preamp and EL34's for power). I really do like the sound of those tubes but because the dealer threw in a couple of random tubes to hold me over and to get Channel 1 working again, I was concerned and went to guitar center to by 6 new AX7 preamp tubes.

Since I have put those in the amp, I am not liking the sound as much as I did before. It is probably the tubes so what I need to know is:

1) What pre-amp tubes do you recommend?
2) Does the amp need to be re-baised if I just throw in new preamp tubes?
3) If I replace the power tubes with the same type (i.e. EL34's) but not necessaryily by the same manufacturer, do I have to have the amp rebaised?
4) Does one of the pre-amp tubes need to be a different power rating that the rest and be placed in one of the the first preamp slot and if so, what do I need to get and which slot is that slot? In other words, if I have the back grill open and I am looking into the amp from the back, is it the slot to the far left or the one to the far right?

Any advice you can give would be very much appreciated.

Sincerely,
Dana

 

[duesentrieb]

1) What pre-amp tubes do you recommend?
Ruby 12AX7 High Grade

2) Does the amp need to be re-baised if I just throw in new preamp tubes?
no

3) If I replace the power tubes with the same type (i.e. EL34's) but not necessaryily by the same manufacturer, do I have to have the amp rebaised?
Yes. I'd buy a bias adaptor from weber or something . . .

4) Does one of the pre-amp tubes need to be a different power rating that the rest and be placed in one of the the first preamp slot
no

and if so, what do I need to get and which slot is that slot? In other words, if I have the back grill open and I am looking into the amp from the back, is it the slot to the far left or the one to the far right?
Looking from the back of the amp - from right to left

Herbert:

V1 Used by all channels

V2 Used by channel 3

V3 Used by all channels

V4 Mixer & Loop Driver

V5 Return Driver

V6 Phase Inverter

 

[Moose]

Thanks Olaf!

If I replace the EL34s with Ruby EL34's (i.e. same as the ones in the amp now), do I have to rebias it then?

Let me know -

Thanks again!
Dana

 

[Moose]

One more thing Olaf - I just went looking for the Ruby Tubes on line and I am finding the following choices:

Ruby 12AX7 AC5 High Grade
Ruby 12AX7 ACZ High Grade
Ruby 12AX7 AC7 High Grade

Which would be best or closest to what ships from the Deizel Factory?

Thanks again!
Dana

 

[duesentrieb]

Thanks Olaf!

If I replace the EL34s with Ruby EL34's (i.e. same as the ones in the amp now), do I have to rebias it then?

Let me know -

Thanks again!
Dana

Yes, Dana. Powertubes always need rebias when replaced.

 

[duesentrieb]

One more thing Olaf - I just went looking for the Ruby Tubes on line and I am finding the following choices:

Ruby 12AX7 AC5 High Grade
Ruby 12AX7 ACZ High Grade
Ruby 12AX7 AC7 High Grade

Which would be best or closest to what ships from the Deizel Factory?

Thanks again!
Dana

We need to ask Peter, Dana. Could be 5 or 7, but I'm not sure.

But as long as they are well selected for lowest microphonics and hum, I'd personally use either.

 

[RedB4Black]

I got a brand new one last month. The C5 HGs are what came in mine. V one was TAD labeled the rest were Ruby labeled.

Get the C5+ from Ruby.
The C7s are the same....just cryo-frozen I believe. Don't buy the snake oil.

 

[King Crimson]

One more thing Olaf - I just went looking for the Ruby Tubes on line and I am finding the following choices:

Ruby 12AX7 AC5 High Grade
Ruby 12AX7 ACZ High Grade
Ruby 12AX7 AC7 High Grade

Which would be best or closest to what ships from the Deizel Factory?

Thanks again!
Dana

Diezel Stock Tubes 28.07.2010

V1/V2 - and/or V3:
Ruby Tubes 12AX7AC5 HG+ Diezel selection B-side
alternative
TAD 7025 Highgrade Pit Special

V2, V3, V4, V5, V6, (V7, V8, V9)
Ruby Tubes 12AX7AC5 HG
alternative
TAD 12AX7-C Selected

Reverb tube
12AT7-C

Power Tubes
Ruby Tubes EL34BHT
alternative
EL34SED (Winged C)

 

[CaptainBob]

Get the C5+ from Ruby.
The C7s are the same....just cryo-frozen I believe. Don't buy the snake oil.

... the Ruby AC5 (HG and HG+) and AC7 (HG) are made by Shuguang (China) but NOT the same Tube!
The AC5 are the "normal" Chinese Tube u can also buy from TAD, GT and any other ordinary Tuberelabeler.
The AC7 is a other Tube, with other design* and other Sound:
less screamin highs, but fatter mids and nicer overdrivesound (less saturated, more grrrrrrr )

greets

*
Ruby 12AX7 AC7:

Ruby 12AX7 AC5: