Which preamp tubes for my Bogner XTC 101B? Need suggestions

[eco2112]

Hi:

I haven't posted here in years, hi guys!
I would like to know which tubes do you guys recommend for a Bogner Ecstasy.

If you are going to recommend the damn POS tubes that Bogner puts in the preamp, please don't!
I have had 3 going microphonic in the last 3 months. I want something that will work for a while (like the next 30 years probably, lol)

TY in advance!

 

[eco2112]

anyone?

 

[fusedbrain]

I think the stock Chinese 12ax7b's sound the best in an xtc, but you have to buy them screened and tested from a good tube vendor.

 

[Ventura]

Clean Chinese 12AX7 seem to be great, and I always like an LPS in the PI slot of pretty much every amp I own. I've used a Tung Sol with some success in the loop to brighten them up; just in case you have a slight tone shift with your FX loop.

My 20thA XTC is loaded with GL-ECC83 preamps, pricey buggers, but they sound great. Great enough to make the difference of that much kaching?? Hmmmmmm, jury's still out

Svetlena is also make some really nice 12AX7s now too - but they're very smooth and this sometimes translates to "darker" even though that's not the term I'd opt to use.

In short, HQ Chinese 12AX7 with a Sovtek LPS in the Phase Inverter slot and you're good to go.

Peace

 

[Rdodson]

I love the old Yugo EI in V1. Getting harder to find. They sound great, though. LPS in PI works as stated above. I like the "Mullard" labelled stuff, but it can be "smooth" and some folks want "grainy". If so, go with the "Tung Sol" RIs.

I'm a long-plate guy. I'd rather give up gain and get harmonics.

The loop became the issue for me in the 101b. Finding a tube that will lesson the compression and slight "dulling of the shine" helps. Just got to roll those tubes.

Listen to Ventura, he's got good ears and great taste.

 

[trappguitars]

What ever you do don't put a LPS 12ax7 in the cathode follower circuit (hi-gain) - it will fry your amp.
I've been having good luck with Ruby's HG for the gain Channel's. Also JJ's seem to be cleaner but a bit less gain.
The Chinese Ruby's seem to have a little more highs too.

 

[Troy Baer]

What ever you do don't put a LPS 12ax7 in the cathode follower circuit (hi-gain) - it will fry your amp.

Yeah, most of the Russian made 12AX7s with spiral heater filaments are only rated for ~100V between heater and cathode, and a Marshall-style cathode follower has more like ~160V between them. (Technically, this is valid -- the 12AX7 spec says Vhkmax=100V, while the ECC83 spec says Vhkmax=180V -- but in practice, every one assumes that 12AX7 and ECC83 are interchangeable. In this particular case, they're not.)

 

[Setneck]

It is true that You should avoid russian tubes with spiral filaments (Sovtek LP, LPS, EHX, TungSol RI, Mullard RI) in CF which means that it shouldn't be put in V3 position in XTC. You may put there old russian tubes such as Sovteks WA, WB or WC, but as they were constructed for military purposes they don't sound too good, being rugged as hell though .

It may also depend on the tube, as I used to gig for a some time with EHX's in V2 & V3, with no problems.

But to be fully sure about reliability (if it is possible at all with tube amps ) use chinese in V3. I would always recommend LPS in V1 & PI though, great tones, with less "cloggy" sound.

 

[Emg77]

I’ve a Tungsol in V3 of my 20th XTC. Are you saying it shouldn’t be there? I’m just read the spec sheet and I believe, if I’m reading it correctly it’s rated at 180v but correct me if I’m wrong.

 

[Setneck]

That's correct but the spiral fillament may cause a malfunction there. May but not necessarily should - like I said, I've used EHX in V3 (for a few months if I remember correctly) with no problems.

 

[Ventura]

I’ve a Tungsol in V3 of my 20th XTC. Are you saying it shouldn’t be there? I’m just read the spec sheet and I believe, if I’m reading it correctly it’s rated at 180v but correct me if I’m wrong.

Just pull the data-sheets for whatever tubes you're looking at and check the heater-to-cathode value. There are some Russian tubes out now (Svetlana 12AX7) that are rated at +/-200V which is more than adequate. And they aren't spiral filament to the best of my knowledge, nor are they long legged, but they do sound really smooth and nice and have a gain value of [I think] no less than 85 and upwards of 115, so they're right in the zone for a proper 12AX7.
High-Quality Chinese for the loop or a Tung-Sol (IME) has helped with putting the sparkle back into the loop.

 

[jamme61]

Im running these in my 101b - long plate love em
Genalex Gold Lion 12AX7/ECC83 Gold Pin Preamp Tube

 

[Ventura]

Im running these in my 101b - long plate love em
Genalex Gold Lion 12AX7/ECC83 Gold Pin Preamp Tube

I've ran these flush across the board of my 20thXTC with an LPS and now an Ei Yugo in the PI slot. AND I crank my amp. Never had an issue with the V3 although I've heard of concerns due to CF positioning. Worst case scenario is a blown preamp, but thus far, I've had a swath of different pres in my 20th and they've all worked well. I like the new production Svets in there now, GL-ECC83 in V1, Ei Yugo PI.

YMMV.