FORTIN EVIL PUMPKIN OWNER HELP?

[adrianher]

Hi there, I got a Fortin E.P 100w new. It’s still in guarantee, so I wanna ask about it.

I got the amp a week ago and has no time until today.

First of all I noticed EL34 pair (2 & 3) were glowing a lot also measuring 200mV while 1 & 4 were 25mV. Fortunately the amp has external adjustment.

I loaded a cab and turn it on. When I crank it up (no guitar plugged in) I get a terrible feedback in high frequencies in ch2 and 3 (not in clean ch.)
Also the amp itself its microphonic, the chasis.

It’s hissing a lot in both channels.

I thought it was a preamp tube… but tried different brands and is the same hiss, feedback at high vol lvl and microphonic.

Any idea what could be the issue?
Thx a lot

 

[adrianher]

The preamps tubes are hot as I’ve never seen. Its hot enough when I try to handle it.

 

[FourT6and2]

First, make sure the amp is set to the correct wall/mains voltage for your country. There's a switch on the back for that...

Bias should be 72mV per PAIR of tubes. That means each bias test point should measure 72mV. That's 36mV per tube.

Hiss on the high gain channels is normal.

What tubes did your amp come with? All EL34? Two EL34 and two 6CA7? Or two EL34 and two other EL34 that are just labeled 6CA7?

 

[japetus]

@novosibir

 

[adrianher]

First, make sure the amp is set to the correct wall/mains voltage for your country. There's a switch on the back for that...

Bias should be 72mV per PAIR of tubes. That means each bias test point should measure 72mV. That's 36mV per tube.

Hiss on the high gain channels is normal.

What tubes did your amp come with? All EL34? Two EL34 and two 6CA7? Or two EL34 and two other EL34 that are just labeled 6CA7?

Hi, the amp is set to 220vAC, right for my country.

The amp came with 2x EL34 (1 & 4) and 2x 6CA7 (2 & 4)

What do u mean with “EL34 labeled as 6CA7”?

 

[FourT6and2]

Hi, the amp is set to 220vAC, right for my country.

The amp came with 2x EL34 (1 & 4) and 2x 6CA7 (2 & 4)

What do u mean with “EL34 labeled as 6CA7”?

The tubes labeled as 6CA7 are most likely just EL34, even if it says 6CA7 on the glass. BUT... that doesn't matter regarding your problem.

The easy thing to do is adjust the bias until all four tubes are set properly... then see what happens. But if one of the pairs was set to 200mV (100mV per tube), that means they were operating at 192% of their maximum rated plate dissipation. That's not good lol...

Chances are those tubes are cooked.

If you bought the amp new and it's still under warranty, then you might be able to get a new quad of replacement tubes. Maybe reach out to the store or to Fortin.