el84 se amp layout

[wildmouse]

not to sure which way to layout components on the board
any ideas size is 30x30 cm or 12x12 in imperial
trying to keep input away from power supply
wildmouse

 

[ruffrecords]

I am building something similar. My layout is more like your right hand one but my chassis is rectangular. I have the three tubes in a row along the front.

Cheers

Ian

 

[Alkis]

There should be 90 degrees between the cores. Transformer covers will also help and aesthetically are better.

 

[wildmouse]

thanks

Seems like the rh layout might be the one. I he opt are 90degrees to the power tx' , if I have problems with that I will rotate them 45 degrees and put covers on them
Hope to get the plate drilled today, and the bus bar grond wire in the next few days
thanks
wild mouse

 

[jean michel]

Hello All ...

so possible build to 25 x 30 cm ...

look the 6V6 GT SE UL ...

 

[ruffrecords]

Hello All ...

so possible build to 25 x 30 cm ...

look the 6V6 GT SE UL ...

Mine is 20cm by 30cm and everything fits in easily.

I just finished wiring up the output stages and the power supply. After checking the heaters were OK and the the HT and then the cathode volts were OK I connected a speaker. When I turned on there is some mains hum right away, before the valves heat up. When the valves start to operate there is some buzz, most likely from the unconnected grid of the EL84.

The hum immediately at switch on concerns me. I have the power transformer at right angles to the output transformers. Initially I was connect to the ouptu transformer nearest the power transformer. Then I connected the speaker to the output transformer furthest away from the power transformer and the initial hum is no longer there. This convinces me it is induced from the power transformer.

Cheers

Ian

 

[jean michel]

hello all ...

the back to détail in build ...

no suspect noise , not "" huummm "" to low sound , and 1 run is so good .

just approximatly build to ten hours for easy build

 

[Alkis]

The power trafo could fit under the chassis and leave the OPTs stay along on top of it, so we have now a different axis. No EMI in any case, no worries.

 

[ruffrecords]

hello all ...

the back to détail in build ...

no suspect noise , not "" huummm "" to low sound , and 1 run is so good .

just approximatly build to ten hours for easy build

I suspect the toroid mains tranformer has a lot to do with the lack of hum. WHat make/model is it?

Cheers

Ian

 

[ruffrecords]

The power trafo could fit under the chassis and leave the OPTs stay along on top of it, so we have now a different axis. No EMI in any case, no worries.

Good idea. I might do it the other way round; mount the OP transformers under the chassis. I'll try that out tonight and report back.

Cheers

Ian

 

[pointy]

the "Leak ST 20" lay-out has it for me...........you could even have the speaker outs in the sides of the chassis which keeps things nice.

 

[ruffrecords]

the "Leak ST 20" lay-out has it for me...........you could even have the speaker outs in the sides of the chassis which keeps things nice.

I thinks the bobbin shields play a very important part in this layout. Without them the mains transformer would surely induce lots of hum in the output transformers.

Cheers

Ian

 

[wildmouse]

layout

mount the OP transformers under the chassis. I'll try that out tonight and report back.
h ow did it go
glen

 

[ruffrecords]

mount the OP transformers under the chassis. I'll try that out tonight and report back.
h ow did it go
glen

In the end I got a toroid mains transformer to replace the EI one. I mounted it under the chassis and now there is no hum

Cheers

Ian

 

[wildmouse]

el 84 SE amp finished

Finally finished ,been playing for 1 hour now.
power tranny a little hot, only rated at 69ma.
the build is based on shannons budgie using hammond iron, 369jx and 125cse opt
I have a switch for petode or triode mode ,but triode mode is way loud enough
n ot much bass, but bueatiful midrange
no noise at all
im happy
glen