New Mesa TT-800 hiss

[moderatelyfunky]

Last night's rehearsal at the drummer's house was the maiden voyage for my new tt-800 amp. My Mesa 1-12 cabinet is on backorder so I used my Euphonic Audio 1-15.

I was surprised at the loud hissing and light humming when I turned it on - like white noise with subtle 60 Hz underneath. I turned the horn down to zero to minimize it, tried a different mains circuit with no luck. Our keyboardist's solid-state combo amp wasn't hissing. After rehearsal, I turned the amp off after we spent a few minutes talking and the sudden lack of noise in the room was remarkable - it's significant.

This morning I have it running at home with the same loud hiss and subtle hum.

I unplugged the bass, (Tried Stingray and Jazz with Nordstrand HBs), unplugged the speaker and still hear the hiss and hum through headphones.

The mute switch quiets the hiss, but it doesn't eliminate it.

The issue is more noticeable with the gain and volume up.

Both channels have the same noise.

Is this normal?

 

[agedhorse]

No, this isn’t normal.

A couple of possibilities external to the amp should be eliminated though, the first being that the power source needs to be grounded. Can you try the amp in a different location to eliminate this as a possible cause?

Are you using any pedals? Some pedals are quite noisy.

You can always PM me and I will help you get this resolved.

 

[moderatelyfunky]

Thanks for the confirmation.

The hiss happens with nothing at all connected.

I tried it at two different physical addresses on different 20A grounded circuits in each.

 

[agedhorse]

Ok, how do you have the controls set?

 

[moderatelyfunky]

I have tried the "presets" described in the back of the manual and various combinations.

The hiss gets worse as gain and volume are turned up. It disappears completely if the volume is at 0. It does not disappear, but it improves if the gain is at 0.

Are there any videos available that have the amp at idle while the gain and volume are up? It would be good to see if my expectations are realistic. I'm coming from an Acoustic Image Focus 1 which is very quiet.

 

[Le beau JP]

I own a D800+ that hissed a lot and got worse with time. With crakling noises too.
Had it fixed under warranty, turned out it was a bad capacitor. If it helps!

 

[Jim C]

As a point of reference, my TT800 has no noises issues with P, J, or SR even with the volume up.

 

[Le beau JP]

As a point of reference, my TT800 has no noises issues with P, J, or SR even with the volume up.

How is the TT compared to d800+?

a friend of mine wants my D800+ and ive got my eyes on a TT. Is it worth it?? Les mids shaping possibilities but tubes and 2 channels….

 

[jeff7bass]

How is the TT compared to d800+?

a friend of mine wants my D800+ and ive got my eyes on a TT. Is it worth it?? Les mids shaping possibilities but tubes and 2 channels….

Sounds like you know the differences already. Checkout the huge TT thread. TONS of info there.

 

[Le beau JP]

Sounds like you know the differences already. Checkout the huge TT thread. TONS of info there.

Didnt find it!!
Yeah I know the differences on paper but cant find any demo video that shows it well

 

[FunkHead]

Didnt find it!!
Yeah I know the differences on paper but cant find any demo video that shows it well

NEW MESA TT 800 AMP. OH. MY. GOD.

 

[moderatelyfunky]

I own a D800+ that hissed a lot and got worse with time. With crakling noises too.
Had it fixed under warranty, turned out it was a bad capacitor. If it helps!

Thanks for your reply.

Aged Horse really went out of his way and very generously offered to make the repairs happen painlessly, but I bought it through Sweetwater and they’d rather have it returned to them which I did.

Unfortunately the replacement wasn’t a keeper. The 400 channel was awesome - nearly perfectly quiet with all boosts on and gain and volume at 10. It confirmed for me that the first amp was defective.

Surprisingly, the Subway channel had a loud hum in it though - nothing like white noise.

The other thing that jumped out at me was that the I’m pretty sure the fan wasn’t running in the first amp I got, because the replacement was making a nice breeze that would have been difficult not to take note of.

I really hated to give up on it, but I returned it for a refund.

 

[jeff7bass]

NEW MESA TT 800 AMP. OH. MY. GOD.

There it is! I couldn't find it either. It was on the front page so long I thought it was a sticky thread! LOL