New tubes for Bugera 1960 "Plexi"

JulianLM

Member
Messages
44
Hi there !

I got a Bugera 1960 Infinium for Christmas, I swap the stock EL34 for Yougoslavian EL34, and some Sovteks 12AX7. (Tubes I had in stock)
The amp is based on a Marshall Plexi Super Lead, schematic is reaaally close if not the same.

I feel that I can find something better.

Don't want and can't spend hundreds of $$ on NOS stuff, but I'm pretty sure there's some very good and inexpensive new production tubes.

I'm searching for something vintage and organic sounding. (Think Black Keys for exemple. And God almighty Hendrix of course...)
Huge lows, wide mids, and smooth highs, dynamic as possible, don't care about high gain.

So... What power tubes and preamp tubes would fit my needs ?
I was thinking about using some 12AT7 or 5751 to tame the preamp a bit.
The fact is the Channel 1 alone sounds REALLY harsh if you push it too much (I got to lower the volume knob on pedals), so maybe a good choice of preamp tubes can fix this ?
I'd like to keep the British sound as much as possible. (I already got a Fender tube amp)

I heard about Shuguang, Ruby... I love TAD too.

What do you think ? I'd like to try some KT66 ! What would you suggest ?
I'm totally LOST !

Thanks a lot ! ;)

PS : I live in France so, better avoid US shops because of shipping fees and taxes...
 
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Rod

Vibrato & String Bender on Overdrive
Gold Supporting Member
Messages
25,156
I don't think you can run KT66's in it... EL34 is not the same tube....new production Mullards are fine tubes. I like both their EL34's and their 12AX7's...they're actually made in Russia.. probably reasonably priced in France
 
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JulianLM

Member
Messages
44
The amp is designed to run EL34 or 6L6GC so as KT66 are direct replacement for 6L6... Plus I read that some guys do this.

New Mullard as power or preamp ? I read many times that new Mullards 12AX7 are not really good. Have you tried them yourself ?

Thanks :)
 

Rod

Vibrato & String Bender on Overdrive
Gold Supporting Member
Messages
25,156
The amp is designed to run EL34 or 6L6GC so as KT66 are direct replacement for 6L6... Plus I read that some guys do this.

New Mullard as power or preamp ? I read many times that new Mullards 12AX7 are not really good. Have you tried them yourself ?

Thanks :)
Hi Julian...sorry.. didn't realize you could run those.... and yes, I've been using the Mullard reissues in most of my amps.... I usually mix them with JJ's for the pres..
 

Vanyu

Member
Messages
738
If I remember correctly, this amp will bias up with whatever you throw in it, so you could hypothetically buy 4 single RFT EL34's and make a "matched" quad. Transconductance will still be a little different, but that isn't necessarily a bad thing, depending on who you ask... Lots of harmonics can be had this way. Buying single tubes would probably put you out about $100, well worth the money. Also look into a Matsushita 12AX7 for V1 of your amp, leave whatever you already have in V2 and V3. The Matsushita's are about as close to an original Mullard ECC83 as you can get, but at a fraction of the price. (N)OS doesn't have to be expensive!

If you're hellbent on on current production, just draw straws, nearly all of the newer EL34's (except JJ and Chinese) are very closely related. Same goes for 12AX7's. I've heard fantastic things about both of the KT66's and KT77's offered by Genalex, though they're a little pricey. Even though your amp is 'designed' to run both EL34 and 6L6 tube types, I'm still not sure how the output transformer would like the impedance difference between the two, I'd stick with the EL34 family if I were you.
 

JulianLM

Member
Messages
44
Ok !

Matsushida are 30$, if that's just one, that's fine.
I think they say Mullard RIs are kinda weak...

You know that's weird because I tried to change the V3, but the stock one sounds better than some good reviewed Sovteks ! (WB, WC or LPS)
What's the role of the V3 ?
What about V2 ?

I follow your advice but they say in the manual that you can run 6L6 so as there's a 2 years warranty I guess they would not say that if there were any risk, but I'll keep my EL34 for a while, until I get the preamp section right.

Thanks ! :)
 
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Bandit127

Member
Messages
121
V2 is a gain stage.

V3 is the phase inverter. In electrical theory it should be balanced but views differ on sound quality with well balanced vs a bit of distortion induced by unbalanced. It is easy to buy a balanced one and try both. (I paid £10 for a balanced EH 12AX7 that had an hour on it for example. It was labelled balanced by EH but obviously I can't vouch for the use it had).
 

Vanyu

Member
Messages
738
V2 is a gain stage.
Allow me to add a little bit of info...

One half of V2 is a gainstage, while the other half of V2 is a cathode follower. This position will make a slight difference in tone, but nowhere near as drastic as V1, especially if you're linking the channels together. A Matsushida in this position would make a noticeable difference, but prioritize V1.

V3 is the phase invertor, as @Bandit127 was saying. This position should have very little impact on tone, and usually isn't picky as to what you stick in it. Unless you have a REALLY bad 12AX7 there, it really shouldn't matter if it's balanced or not, as in my experience, the two triodes of a 12AX7 are usually 'close enough' anyways. If your amp has a notceable hum at idle, this could be the culprit. Swap tubes around in this position and see what's the quietest and leave it.
 




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