Herbert and Preamp Tubes : New Questions!!!

[ttosh]

I am going to experiment with complimenting my EL34's with 6550's and KT88's over the next few weeks. The amp was delivered to Salwendar in 2008 and has the same preamp tubes in it. Doug at Dougstubes recommended the following preamps. What do you guys think, just leave alone the originals, or try these. Any other recommendations for certain positions?

Do preamp tubes affect the Herbert much?

V1 Used by all channels : Ruby 12AX7AC5 HG+
V2 Used by channel 3 : Ruby 12AX7AC5 HG
V3 Used by all channels : Ruby 12AX7AC7
V4 Mixer & Loop Driver : Ruby AC5 select
V Return Driver : Ruby AC5 select
V6 Phase Inverter : Sovtek LPS

Thanks for the input.

 

[MARK2C]

You had me until the Sovtek. It's a terrible sounding tube.

I've tried everything from RFT, Ei and Telefunken in the Herbert. What is your objective in changing tubes ?

 

[ttosh]

You had me until the Sovtek. It's a terrible sounding tube.

I've tried everything from RFT, Ei and Telefunken in the Herbert. What is your objective in changing tubes ?

The tubes above were a recommendation from Doug. I am not real experienced with tubes and all I want is to get a bit warmer of a tone overall. My last Herbert sounded a little more 3D like than this one and I am going to be experimenting with Power tubes and was curious how much the preamp tubes affected the Herbert.

 

[MARK2C]

You can spend a lifetime trying new preamp tubes and you will be either delighted or miserable.
I don't see Doug's "cocktail" as anything special. The Ruby 12AX7C5 HG or HG+ could be used from V1-V6.
I don't get using all that high gain Chinese goodness topped off with a sub-par Sovtek. If your Herbert has the
stock pre's, it may have two JJ ECC83's in there. I like the JJ, but only in the V2, the rest are good with HG or HG+
Ruby's.

Didn't your last Herbert have 6550's ?

 

[ttosh]

You can spend a lifetime trying new preamp tubes and you will be either delighted or miserable.
I don't see Doug's "cocktail" as anything special. The Ruby 12AX7C5 HG or HG+ could be used from V1-V6.
I don't get using all that high gain Chinese goodness topped off with a sub-par Sovtek. If your Herbert has the
stock pre's, it may have two JJ ECC83's in there. I like the JJ, but only in the V2, the rest are good with HG or HG+
Ruby's.

Didn't your last Herbert have 6550's ?

My last Herbert had 2 6550's and 4 6L6's in it. I have 6550's coming and I was thinking of trying some KT88's as well. Currently I have 2 SED EL34's, 3 TAD EL34B - STR and 1 Ruby EL34B - STR in the power section. So it is all EL34 and I am thinking the 6550's may be what gave my last one the extra dimension or depth I am missing with this one. I do like the mid texture of the EL34's and I am thinking of going with 4 6550's and 2 SED EL34's. Since I have the external bias I did want to experiment a bit, but I know a lot of you guys have already done this and have great ears. I wanted to learn from your experiences as well.

So the Sovtek is out then, not sure what Doug had in mind, and will take your recommendation any day. I will make sure to keep the JJ only in V2 and do the HG or HG+ for the others.

Any other input is greatly appreciated as well.

Thanks again!!

 

[MARK2C]

There may not be anything physically or tonally with the pre's you have in now. The biggest changes will come
when experimenting with a different V1 and V2, plus whatever you decide to put in the power section. I think
you will like a mix of EL34 and 6550's. It should be big, wide, 3D and have a little mid bump from the EL34's.

 

[ttosh]

For a mix what would you recommend 4-6550s and 2-EL34's or the reverse and have 4-EL34's with 2-6550's?

 

[MARK2C]

You can try both, but after a year of running six 6550's I am now using six EL34. I suppose four EL34 and two 6550's
would give you a nice midrange and a wallop in the bottom end.

I just checked out what I am using in the preamp and it's an Ei ECC83 in the V2.

 

[King Crimson]

I'm not into mixing the power amp tubes. Even though you may with Herbert.

IMO - the Ruby EL34B-STR are the bomb, hands down. Tone tone tone...

I've tried everyting elese, KT88, KT100, 5881, 6550, JJ-E34L, EL34, 6CA7, 6L6GC, 2675, 1234-E, XYRW-OOO et cetera. Mr. Diezel knows what the deal is.

The Ruby EL34B-STR are in the house.

 

[philbag]

I can't agree more with Mark2C on how horrible Sovtek 12ax7's are - my GOD, I'm just astounded that such a horrible sounding tube can be on the market. Noisy, thin and unpleasing in the high end as per my experience. Perhaps the 3 individual tubes I had experienced at different times were all bad ones? I'm an open minded guy but damn, thats a bad run of luck if it's true - so I tend to lean in the other direction

 

[RG955TT]

Sovtek LPS's are known to be good in the phase inverter, used in that one spot on many amps. You do not "hear" the tone of the phase inverter tube, it is there as part of phase inversion (hence the PI spot) for the power amp. I've tried several of these in other spots including V1 and my thoughts were it was a decent sounding very balanced tube w/not too much high end and fairly fat in the mids, but it wasn't my first choice for that spot untimatley. Again, this is the LPS only, spiral filiment tube known to be an excellent PI tube. Your mileage may vary...

 

[ttosh]

I'm not into mixing the power amp tubes. Even though you may with Herbert.

IMO - the Ruby EL34B-STR are the bomb, hands down. Tone tone tone...

I've tried everyting elese, KT88, KT100, 5881, 6550, JJ-E34L, EL34, 6CA7, 6L6GC, 2675, 1234-E, XYRW-OOO et cetera. Mr. Diezel knows what the deal is.

The Ruby EL34B-STR are in the house.

I am looking at these to match with the 6550's, I have an option of early, average or late distortion. I would think late distortion would give the most note clarity, etc... What is the consensus on this with the Herbert?

Also the preamp tubes in the Herbert currently are as follows:

V1: TAD 7025 HG
V2: blank preamp tube
V3: TAD 12AX7A-C Select
V4: TAD 12AX7A-C Select
V5: TAD 12AX7A-C Select
V6: TAD 12AX7A-C Select

Are these goo preamp tubes for the Herbert??

 

[MARK2C]

The TAD 7025 HG is supposed to be a Chinese Mullard copy good for low noise. I don't see any issue with
the rest of the TAD 12AX7-C's either. As long as they are quiet they should be fine. I know that is what I have in V3-V6.

The major issue with preamp tubes is they are supposed to have a gain factor of 100. The manufacturers and retailers today
don't really care to inform the consumer of this. If a vendor does inform us of the actual measured gain factor they charge $3.00
a tube extra. In truth, you never know when you are buying a preamp tube with a gain factor of 80 or 110 so it's extremely difficult to
know whether you are increasing possible gain from a position or reducing it. Simply re-tubing the preamp is a total gamble.
I personally don't have the money to buy a VTV preamp tube tester so I do what I call a poor mans blueprint. I label each tubes V position on the bottom
with a sharpie. From there, I try the tubes in different V positions and listen for noticeable differences, either good or bad. If I find a combination
that suits my purpose, like more gain or less gain etc, I leave them in. If after a few tries I get nowhere I then start to think about bringing in fresh, or
different brands of preamp tube.

When you get the new power tubes in you will know whether or not you like the tone, of course. If you don't consider the poor mans blueprint.
You may be surprised how a buffer or PI reacts with different gain availability. I also like a V2 tube that brings channel 3's gain down a bit. I know when
it's lower because it breathes better and there is not as much sizzle past 1:00 on the gain knob.

Happy tone chasing....

 

[ttosh]

The TAD 7025 HG is supposed to be a Chinese Mullard copy good for low noise. I don't see any issue with
the rest of the TAD 12AX7-C's either. As long as they are quiet they should be fine. I know that is what I have in V3-V6.

The major issue with preamp tubes is they are supposed to have a gain factor of 100. The manufacturers and retailers today
don't really care to inform the consumer of this. If a vendor does inform us of the actual measured gain factor they charge $3.00
a tube extra. In truth, you never know when you are buying a preamp tube with a gain factor of 80 or 110 so it's extremely difficult to
know whether you are increasing possible gain from a position or reducing it. Simply re-tubing the preamp is a total gamble.
I personally don't have the money to buy a VTV preamp tube tester so I do what I call a poor mans blueprint. I label each tubes V position on the bottom
with a sharpie. From there, I try the tubes in different V positions and listen for noticeable differences, either good or bad. If I find a combination
that suits my purpose, like more gain or less gain etc, I leave them in. If after a few tries I get nowhere I then start to think about bringing in fresh, or
different brands of preamp tube.

When you get the new power tubes in you will know whether or not you like the tone, of course. If you don't consider the poor mans blueprint.
You may be surprised how a buffer or PI reacts with different gain availability. I also like a V2 tube that brings channel 3's gain down a bit. I know when
it's lower because it breathes better and there is not as much sizzle past 1:00 on the gain knob.

Happy tone chasing....

Thanks for your input, and I hope it ends up as Happy tone chasing and not frustrating.

I will say having an amp I can bias with external bias is very nice for me as I never wanted to take one out of the headshell before. I already dig the tone, but like stated above would like to get a more 3D sound or more depth like my last Herbert. So off I go to figure out what alters her and how... Kind of like dating at first