New Rebel preamp tubes

  • Thread starter Thread starter jwdubois
  • Start date Start date
Ok,i finally opened the Rebel yesterday.As i expected,the new JJ12AX7 was the culprit,but the bottle was blown up (all white inside) :confused: ,and the top was cut !Weird! Anyway,i swapped V1 & V2 with 2 new Tung Sol's and let the GT in V3.I'll write a review tomorrow.Right now,i have mixed feelings about the results..
 
Currently I have a TS and a 5751 in V1 & V2. This is not particularly because that sounds the best, but it's just where I was last time I quit changing tubes. I've tried multiple combinations of V1, V2, and V3 with Tung Sols, Mullards, Sovteks, and 5751's.

Honestly guys, the differences are so subtle that I've convinced myself that there is a lot of placebo involved in this tube swap stuff. Most of the differences from tube to tube can be made up with slight adjustments of tone and gain.

Granted I'm not running fully cranked, and I know my ears aren't what they used to be, so maybe that's why I don't hear all that much of a difference, but there was no "magic transformation" of the amp by changing the preamp tubes. If I can say anything, the Sovteks might sound a little harsher.

JWW
 
jwdubois":6egduhml said:
Currently I have a TS and a 5751 in V1 & V2. This is not particularly because that sounds the best, but it's just where I was last time I quit changing tubes. I've tried multiple combinations of V1, V2, and V3 with Tung Sols, Mullards, Sovteks, and 5751's.

Honestly guys, the differences are so subtle that I've convinced myself that there is a lot of placebo involved in this tube swap stuff. Most of the differences from tube to tube can be made up with slight adjustments of tone and gain.

Granted I'm not running fully cranked, and I know my ears aren't what they used to be, so maybe that's why I don't hear all that much of a difference, but there was no "magic transformation" of the amp by changing the preamp tubes. If I can say anything, the Sovteks might sound a little harsher.

JWW
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The two tubes that definitely affect the tone the most for me is the Chinese 12ax7a and the JP 5751. The JP 5751 really does help a lot in the lower - mid gain modules (I know this is a rebel thread...but it still holds weight) as it lowers the gain some...and has a natural compression I love. More than tonally, it really effects the feel and headroom for me. Same with the Chinese. It really affects the feel moreso than the actual "tone" of the amp. The Chinese has a smooth feel, and adds a bit more gain to the modules I use them in.
 
aeroic":ckcqkz13 said:
The two tubes that definitely affect the tone the most for me is the Chinese 12ax7a and the JP 5751. The JP 5751 really does help a lot in the lower - mid gain modules (I know this is a rebel thread...but it still holds weight) as it lowers the gain some...and has a natural compression I love. More than tonally, it really effects the feel and headroom for me. Same with the Chinese. It really affects the feel moreso than the actual "tone" of the amp. The Chinese has a smooth feel, and adds a bit more gain to the modules I use them in.
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Yeah, that says it better than I did. More about feel than "tone".

JWW
 
The JJ preamp tubes have the GT ECC83 label and, boy were those trouble. The first Sovtek 12AX7WAs were tested and labeled by GT, which also turned out to be a waste if time and money. We have since built our own tube testing equipment that is used at the factory. In house testing has turned out to be the best for us as we test for more parameters than most other companies and have full control over the QC. We are no longer at the mercy of people who just want to sell us tubes but really didn't care about the consequences of not doing a good job for us. We have tested hundreds of different tubes and found that the Sovtek is by far the most reliable and consistent brand out there. Be forewarned, just because a tube is brand new is not an assurance that it is good or that it meets it's specs. If you get a new tube and it sounds bad, weird or weak, it is most likely defective. I believe some of the differing opinions about the sound of certain brands of tubes possibly comes from the inconsistencies of the tubes themselves and not necessarily that one "brand" sounds better than another.
 
bruce egnater quote: If you get a new tube and it sounds bad, weird or weak, it is most likely defective. I believe some of the differing opinions about the sound of certain brands of tubes possibly comes from the inconsistencies of the tubes themselves and not necessarily that one "brand" sounds better than another.
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That's interesting.It would ,indeed,explain the wide diversity of opinions about some tubes.But,i would like to know if you have a "favourite"tube for the Rebel ,for ex.?Let's forget the commercial aspect and concentrate only on sound quality.Which tubes would you use for the Rebel?
 
I'm having a good experience with a set of NOS JAN/Phillips 5751s.

For a while, I ran them in both V1 and V2, but just recently replaced V1 with the original 12ax7 that came with the amp (keeping in mind that in the Rebel, V2 is the first gain stage). This is really the hot set-up, at least with my guitar and clean boost... smoother than the stock tubes (at the cost of some gain, natch), but it will still really start to sing when you crank the Gain control.
 
jwdubois quote :Honestly guys, the differences are so subtle that I've convinced myself that there is a lot of placebo involved in this tube swap stuff. Most of the differences from tube to tube can be made up with slight adjustments of tone and gain.
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It's funny because my experience is almost the opposite :confused: As soon as i swap tubes,it changes the sound & feel drastically!(But it doesn't mean there is a magic formula to get the sound i/you want.)For example,if i had to run my Nomad with TS12AX7's,i would have to sell it right away!There is something in the "attack",the 1° impact of the sound,i can't stand when i'm using TS's.It took me quite some time,by trial & error,to find the right tubes for that amp.The Power Tubes (6L6,EL34,KT77,EL84 etc.)change the sound even more (but differently).
 
Back to the Rebel :) I was disappointed,once again,by the TS's (V1 & V2)..It was not as bad as it was with the Nomad but...still,not my cup of tea !I was ready to give up and go back stock (nice cleans..) when i remembered i still had some Chinese's :D So,i decided to use a Chinese 12AX7A in V1 and keep the stock GT's in V2 & V3.Bingo :yes: !I like it :lol: :LOL: It's only the 1° day,but it sounds really nice!Had a lot of fun :rock: Time will tell if it's a keeper..
 
viking22":nz0zkcn8 said:
jwdubois quote :Honestly guys, the differences are so subtle that I've convinced myself that there is a lot of placebo involved in this tube swap stuff. Most of the differences from tube to tube can be made up with slight adjustments of tone and gain.
Click to expand...
It's funny because my experience is almost the opposite :confused: As soon as i swap tubes,it changes the sound & feel drastically!(But it doesn't mean there is a magic formula to get the sound i/you want.)For example,if i had to run my Nomad with TS12AX7's,i would have to sell it right away!There is something in the "attack",the 1° impact of the sound,i can't stand when i'm using TS's.It took me quite some time,by trial & error,to find the right tubes for that amp.The Power Tubes (6L6,EL34,KT77,EL84 etc.)change the sound even more (but differently).
Click to expand...

I'm not saying they don't sound or feel a little different. The main difference, especially with the 5751's, was an obvious loss of high end gain, but that was to be expected. When cranking the Rebel preamp to about 75%, I liked the feel of the 5751's, and while swapping tubes I could tell myself things like "this is smoother in the midrange", or "this is not as harsh", or "this is a punchier clean", but the overall sound of the amp didn't change. I think what you are saying is that there are some definite perceptable differences in tone and feel, which I agree with, but "drastic"? I'll have to stick with "subtle".

JWW
 
Exactly. You're not changing the circuit by swapping tubes.... you're just getting a different feel, i.e. response to pick attack, etc.

The difference between the 12ax7 and a 5751 in V2 may not be "dramatic," but it's stronger than subtle.
 
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