Show posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Show posts Menu

Messages - Psabin8951

I have a DSL401 combo which sounds great on clean channel but both OD channels give a loud nasty buzz drowning out the guitar signal. This only exists with an input signal and is not there when signal is put in the fx return so must be something in pre amp section any ideas?
Having resolved rectifier issue on this amp and having replaced all tubes the amp now works BUT when I plug a guitar lead in, what is a barely audible tick becomes loud and clear. Turning the cut control down makes it worse. It is there where tremelo circuit is on or off.
The tick pattern is constant changing to a harder tick every few seconds.
Can anyone assist? Is it a filtering cap gone awol?
Tubes and Hybrids / Re: Vox AC30 Jimi era
March 20, 2023, 10:47:51 AM
Yes all 1k5 and 100R grid resistors charred and destroyed.
I've seen 100Rs before but not both.
Tubes and Hybrids / Vox AC30 Jimi era
March 19, 2023, 07:40:38 AM
Hi all,
I have Vox AC30 jimi era Combo come to me with all of its 100R 1W grid resistors and associated 1W 1k5 resistors totally fried.
Obviously these will all need replacing and I will most likely uprate at the same time but would be the likely cause of the damage?
Tubes and Hybrids / Re: Vox vt120+ combo schematic needed
September 30, 2020, 07:13:32 AM
Yes spot on. They are the same.
Do we think a blown valve would be likely to make C184 "explode"?
Tubes and Hybrids / Vox vt120+ combo schematic needed
September 29, 2020, 12:17:14 PM
Does anyone have a schematic for a vox vt120+ valvetronic combo please.
Or even be able to tell me values for C184 and C185 as both are burnt out erasing markings.
Many thanks
Tubes and Hybrids / Blackstar HT5 noisy Clean channel
August 15, 2020, 09:51:48 AM
I have an early (non reverb) Blackstar HT5 here which has a noisy clean channel which occasionally has volume drop but mainly has a crackle and hiss that appears after about 10 mins of being on.
Both valves have been replaced with new matched ones and all connections have been cleaned, checked and resoldered to eliminate them.
Any thoughts what it could be?
At initial switch on it sounds great.
Ok standby switch was causing an issue.
I'm now getting sound but quiet and distorted on all channels.
I've changed all the tubes and no difference.
Ideas please?
Ok DC voltages with ref to dc gnd are:-
P1 0v
P2 0.1v
P3 0.46v
P4 0.46v
P5 -42v
P6 0v
P7 0v
P8 0v

P1 0v
P2 0.1v
P3 0.39v
P4 0.39v
P5 -42v
P6 0v
P7 0v
P8 0v
Resistantance across tip and sleeve with tubes in is 138k
+15 & -15v supply rails are present
Hi all,
Ok so I got a new transformer from Marshall all fitted ok.
I now get a less bright limiter bulb and no smoking diodes, channel switching works but no sound at all. No sound plugging in to fix return either.
Where do I look next?
With wires from W104 and W105 the limiter bulb still glows brightly and yes standby switch does go to W103 and W106. F102 is ok.
So sounds like I need a new transformer right?
If so can anyone suggest best place to obtain them in the UK?
Sorry, having double checked it glows bright with or without tubes and on standby
Limiter bulb glows even on standby so surely that's not tubes is it?

Limiter already being used and bulb glowing brightly until tubes removed.