Ashdown Peacemaker P60 valve combo, 2003

[N_Cook]

I discovered how to get into it, remove front knobs etc and remove the facia
panel first.
This amp runs very hot in the region of the EL34 output valves, almost to
the
point of charring the pcb, localised black rather than just brown
discolouration. The valves are inverted and no ventillation path
under or around the valve bases. There is plenty of space to mill holes in
the pcb around the periphery, and avoiding traces, to allow some ventilltion
through. Anyone done this before or aware if it actually reduces localised
heat build-up ?

 

[hr(bob) [email protected]]

I discovered how to get into it, remove front knobs etc and remove the facia
panel first.
This amp runs very hot in the region of the EL34 output valves, almost to
the
point of charring the pcb, localised black rather than just brown
discolouration. The valves are inverted and no ventillation path
under or around the valve bases. There is plenty of space to mill holes in
the pcb around the periphery, and avoiding traces, to allow some ventilltion
through. Anyone done this before or aware if it actually reduces localised
heat build-up ?

You have demonstrated a good practical diagnosis many times here, go
for it. Too many of those amps were designed by engineers who never
got to se the final product in operation and had little or no common
sense.

Bob Hofmann

 

[N_Cook]

I discovered how to get into it, remove front knobs etc and remove the facia
panel first.
This amp runs very hot in the region of the EL34 output valves, almost to
the
point of charring the pcb, localised black rather than just brown
discolouration. The valves are inverted and no ventillation path
under or around the valve bases. There is plenty of space to mill holes in
the pcb around the periphery, and avoiding traces, to allow some ventilltion
through. Anyone done this before or aware if it actually reduces localised
heat build-up ?

onhttp://home.graffiti.net/diverse:graffiti.net/

You have demonstrated a good practical diagnosis many times here, go
for it. Too many of those amps were designed by engineers who never
got to se the final product in operation and had little or no common
sense.

Bob Hofmann

Scraping back some of the pcb surface browning and into the bulk of the pcb
material , the browning extends the depth of the material. Also some brown
staining on the surface of nearby solder points, probably some vapour coming
off the polyester and settling on the solder. No ventillation grill in the
cabinet top either.

 

[Ancient_Hacker]

You might consider adding a small DC fan. A 12V fan running off a
diode and capacitor off the (supposed) 6.3VAC heaters will be running
relatively quietly at V.

 

[N_Cook]

You might consider adding a small DC fan. A 12V fan running off a
diode and capacitor off the (supposed) 6.3VAC heaters will be running
relatively quietly at V.

I'd half considered a fan but there is no obvious place to put it and
without cutting a hole in the steel chassis or the wood cabinet it would
just be circulating the air, unless mounted outside the chassis , directed
over the bottles. Good idea about the heater supply use.

 

[Sofa Slug]

I'd half considered a fan but there is no obvious place to put it and
without cutting a hole in the steel chassis or the wood cabinet it would
just be circulating the air, unless mounted outside the chassis , directed
over the bottles. Good idea about the heater supply use.

How about "tube coolers"? I've never used them, but if there's no room
for a fan... http://www.partsconnexion.com/audiogon_pix/WEBPAGES/PEARL.htm

 

[N_Cook]

http://www.partsconnexion.com/audiogon_pix/WEBPAGES/PEARL.htm

They could get the heat away from the tubes, but it'd still be in the
box. By themselves, they'd probably make little difference.

Isaac

Unfortunately I cannot contact the owner , no replies so far.
I intend cutting a 3 x 2 inch hole in the cab top , masked with grill.
Positioning it asymmetrically off-centre in both senses so above the big
bottles and clear of internal encumberances so a 2 inch fan could be fixed
under the grill , later, if required. And the pcb perforations pf course

 

[N_Cook]

If there is not a corresponding hole in the bottom, or the bottom of the
rear panel, you should do that too. Convection can do wonders.

Isaac

EL34 bases are 15mm diam and the metal chassis holes 45mm so plenty of
airgap there, but absolutely no holes through the valve bases or pcb.