Express 5:25-Fizz at high volume

[espresso]

Hi,

When playing my 5:25 loud I hear a fizz, it's not a tube or speaker problem. I think it's inherent in the amp, either that or it's my ears. Turning down the treble removes a good deal of it but then I told have as much of the clarity I like on the low end. This happens mostly in the 25W setting with the gain at 12 or higher and the volume at 10:00 or higher. Can lower gain preamp tubes remove some of the fizz?

Dan

 

[dr_iggi]

I changed the preamp V1 tube for a EHX 12AT7 and that reduced the hizz considerably. Also a bit less gain though. You can change the tubes in V1 and V2 for even less hiss. Lastly, I have to admit that I did not bond with the 5:25 and got rid of it. I am using a solid-state until my Zinky Blue Velvet gets home next week.

 

[espresso]

I changed the preamp V1 tube for a EHX 12AT7 and that reduced the hizz considerably. Also a bit less gain though. You can change the tubes in V1 and V2 for even less hiss. Lastly, I have to admit that I did not bond with the 5:25 and got rid of it. I am using a solid-state until my Zinky Blue Velvet gets home next week.

Thanks for replying. My problem isn't hiss, it's a fizz that I hear when playing at high volume. I can only get rid of it by reducing the treble below 12:00. I otherwise like the amp.

 

[vatoben]

I think it might be the combination of a 10" speaker, rear mounting, and EL84's cranked up. I find that front mounted speakers have more full range spread and rear mounts tend to be fizzy and directional. And 10" drivers and high gain don't normally work for me. Add the 84's chime and it's a recipe for sizzles. This is from my experience. Others might and will disagree. For higher gain I love a front mounted 12" (like a Thiele) and some 6550s. But I have a 5:25 that I love and I run it through other cabs when I can. Tube swapping can definitely change your top end. You may like a 5814 or something similar in the input socket. I use one in another amp (a THD Univalve) and it makes butter come out my speakers. It does cut your gain in half though.
My two cents.
Good luck with whatever you try.
-Ben

 

[22+]

I have to agree with that. The subway rocket with a rear mounted 10" speaker sounds alot different-better run into a cab.

 

[espresso]

For higher gain I love a front mounted 12" (like a Thiele) and some 6550s. But I have a 5:25 that I love and I run it through other cabs when I can. Tube swapping can definitely change your top end. You may like a 5814 or something similar in the input socket. I use one in another amp (a THD Univalve) and it makes butter come out my speakers. It does cut your gain in half though.
My two cents.
Good luck with whatever you try.
-Ben

Some time in the near future I'll be renting some different speaker cabs to try out. This is something my brother and I have been planning for a while. I'm not a high gain player, playing mostly blues and some late 60s/early 70s rock so a loss in gain for "better" tube might be OK with this type of amp. Thanks for your reply.

Dan