Any way to reduce noise floor on an F-50 combo?

Just picked up a nice used F-50 and retubed it from Eurotubes.
Sounds great when playing, but the noise floor is up with the full new JJ tubes set.
Hiss in background is more noticeable now. There is slight hum also (transformer?).
Have tried swapping the VI tube with the V2 and then another spare 12ax7 I had here.
No change.

What do people do in this case? I have read a few other posts on forums about the F-50.
Some say this is just the way it is, others say their F-50 is quiet.

Any info is welcome. Do noisegates work?

Thanks.

Every JJ tube I've ever had was pretty noisy. I could see it being a problem in something as high gain as an F-50. A gate in the FX loop might help.

That's strange because I had an F-30 that was hissy in the clean channel and buzzy in the distortion. I retubed it with JJs and the hiss in the clean channel completely went away. The distortion was just barely noisy. As a whole, the JJs made the amp quieter, cleaner, crunchier, and tighter. I thought they sounded AWESOME.

Did you order the standard retube set or the high gain set? I opted for the standard set for my F-30.

I have all JJs in my DC-3 head and they sound great. It's quiet as a mouse. I've not tried the high gain set, but I've heard they sound great in some amps. Might try them for giggles when I get some spare cash...

nemesys said:

Every JJ tube I've ever had was pretty noisy. I could see it being a problem in something as high gain as an F-50. A gate in the FX loop might help.

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I have not had a tube amp since an older hybrid Musicman about 10-12 years ago. Was a bit surprised as to the noisefloor hiss. The 60 Hz hum is likely not the amp or circuit fault though-probably comes with the territory.
I do have an all tube preamp for my home stereo which is quiet as a mouse with NOS small tubes.

I did swap power cords with a heavier duty power cord that I use for hifi stereo applications and that did help a bit overall.

Can lower gain tubes be safely used in the VI slot such as a 12AU7 or 12AT7??

Any reasonably priced noisegates that do not suck tone?

Anything people suggest to deal with the 60hz/transformer hum?

Any simple mods on the circuit that people do to make this amp quieter? Somebody on a thread here I searched claimed their tech did something to tame it down. They did not specify

Eurotubes told me to clean the tube sockets so will do that later today and see if that does anything.
I also will try using the noisegate in the POD XT I have in the effects loop and see if that is usable.


Sorry for all of the questions. Still learning about this amp. I like it very much-just would like a bit lower noise floor.

MusicManJP6 said:

That's strange because I had an F-30 that was hissy in the clean channel and buzzy in the distortion. I retubed it with JJs and the hiss in the clean channel completely went away. The distortion was just barely noisy. As a whole, the JJs made the amp quieter, cleaner, crunchier, and tighter. I thought they sounded AWESOME.

Did you order the standard retube set or the high gain set? I opted for the standard set for my F-30.

I have all JJs in my DC-3 head and they sound great. It's quiet as a mouse. I've not tried the high gain set, but I've heard they sound great in some amps. Might try them for giggles when I get some spare cash...

Click to expand...

I got the standard set.

Noisegate on PODXT in the effects loop works decently with some tweaking of levels.
Looks like I will not need a dedicated noisegate, but noisegates are always a balancing act.
Prefer not having to use them at all, or at a minimum level.

Using the PODXT in the Return input in front of the amp only and bypassing the Mesa preamp really seems to illustrate the noise is primarily coming from the preamp circuit/tubes.

Getting there.

I just re-tubed my f-50 with all JJ tubes and its quiet and sounds better than ever, The f-50 rocks.

MusicManJP6 said:

That's strange because I had an F-30 that was hissy in the clean channel and buzzy in the distortion. I retubed it with JJs and the hiss in the clean channel completely went away. The distortion was just barely noisy. As a whole, the JJs made the amp quieter, cleaner, crunchier, and tighter. I thought they sounded AWESOME.

Did you order the standard retube set or the high gain set? I opted for the standard set for my F-30.

I have all JJs in my DC-3 head and they sound great. It's quiet as a mouse. I've not tried the high gain set, but I've heard they sound great in some amps. Might try them for giggles when I get some spare cash...

Click to expand...

I've sold hundreds of JJ's over the last 5 years. Very little failure, and very few returns.

I did find one batch that was horribly noisy and crappy sounding, but other than that, they are great tubes.

Here is what I would do in your case. Put all of the old tubes back in.
Then, I would swap each JJ 1 at a time with V2. Find the quietest one, and this is the one that should stay here.
Then, I would swap each remaining JJ for V2. Find the quietest one and leave it here.
Then, I would move on to V3, and finally V4.

If one of the tubes is incredibly noisy, mark it with a sharpie or piece of tape. Then, send it back to Eurotubes.
I would be willing to bet that you have a noisy one and it is early on in the signal chain. The earlier in the signal chain a noisy tube is, the more noise you will have. This is why you can use noisy tubes later in the chain, because the noises are not getting amplified as much as the noises in the beginning.

Hope this makes sense.

Oh yeah! I forgot....

I have the High Gain set from Eurotubes in my DC-10 and it sounds mean!!!!!!
Plus, it's dead silent! :lol: The only unwanted noises coming out of it is my crappy playing! :lol:

I had an F50 which I sold because of the white noise much, I ONLY used the clean channel and the noise was TOO much, the other people in the band told me it was unacceptable.
I borrowd another F50, which was a little bit quieter but still noisy.