JTM45 / 50 Build

Help Support GroupDIY:

john12ax7

Well-known member
Joined
Oct 14, 2010
Messages
1,851
Location
California, US
Check your incoming wall voltage and also ask the transformer manufacturer what the tolerance is.

You can also check things with another volt meter to make sure that's not the issue.
 

juan86

Member
Joined
Jul 22, 2008
Messages
17
Location
NL
Hi,

With the new Power Tx are you still using the full wave rectidier for B+?

if so what did you do with the B+ center tap?

And are the 100 Ohm resistors for the heaters still in place?


Regards Juan
 

Spencerleehorton

Well-known member
Joined
May 12, 2012
Messages
3,251
Location
Felixstowe, Suffolk, UK
Someone else tested the power txf 6.3vac winding and they tested it at 5.9vac unloaded as well.
I have msg'd demeter about this as obviously something was off when it was wound.
The tubes all conduct from 5.5vac so I should be fine, cant think that 0.4vac will make a great deal of difference? I might be wrong, I have been many times before!!
 

Spencerleehorton

Well-known member
Joined
May 12, 2012
Messages
3,251
Location
Felixstowe, Suffolk, UK
Have a bit of an issue which I'm puzzled about.

If I plugin a guitar to top left input, hi input channel 1, and link low ch1 to hi ch2, I can hear a sort of phasing sound and when turning up volume I get squeals.
If I use the link to ch1 to ch2 from low ch1 to low ch1 I dont get squeals and I dont hear the phasing?

Could anyone explain this please and what I need to do to fix this please?
 
Top