Hello
i have need of photos of the one beard p35mkII
photos of the inside transformers (power and output)
because my p35 have one hum noise and i think
that the power transformers was changed ... see the picture
help me...
i have need of photos of the one beard p35mkII
photos of the inside transformers (power and output)
because my p35 have one hum noise and i think
that the power transformers was changed ... see the picture
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
help me...
I would not advise turning the amp on without speakers connected.
It is difficult (and dangerous) to repair if you lack knowledge but it is also difficult to advise if you have no information. I would first measure voltages/current on strategic places (left and right). Something in the amp could be wrong resulting in excessive current draw. At first sight the powertransformer looks big enough for the job.
Check if your el84's do have glowing/red plates. If so change tubes first.
Measure voltages on the cathode of the el84's, perhaps a voltageregulator is dead or sick.
It is difficult (and dangerous) to repair if you lack knowledge but it is also difficult to advise if you have no information. I would first measure voltages/current on strategic places (left and right). Something in the amp could be wrong resulting in excessive current draw. At first sight the powertransformer looks big enough for the job.
Check if your el84's do have glowing/red plates. If so change tubes first.
Measure voltages on the cathode of the el84's, perhaps a voltageregulator is dead or sick.
I wish you a Happy New Year,
Sorry, I live in France and my English is not good.
I have a preamp BEARD P500 and I should like to get the schematic.
Please, I would be very happy if somedy can help me to get this schematic.
It is necessary for me to repear this preamp Beard P500.
Thank you
Best regards,
Yann44
Sorry, I live in France and my English is not good.
I have a preamp BEARD P500 and I should like to get the schematic.
Please, I would be very happy if somedy can help me to get this schematic.
It is necessary for me to repear this preamp Beard P500.
Thank you
Best regards,
Yann44
try to tighten up the bolts on the power traffo...if that does not help...you will need to dismantle that traffo from the amp and put a wooden wedge(popsicle stick types) between the core and the coil...then dipping into a bath of insulating varnish will kill that noise once and for all...
See a few posts back 270V AC secondary on the power tranny to give a VCC of +330V. 6 off EL84 will want 150mA DC minimum for each channel.
EL84 draw 0.76 Amps heater current each => 4.6 Amps + 0.3 Amps for the input/phase splitter, 6.3V @ 5 Amps (min.) for the Heater winding for each channel Double these currents if building a single power supply stereo amp.
A pair of Ultralinear EL84 needs a 8K Raa Output Tranny. 3 pairs will want approx. 8K/3 = 2700 Ohms Raa and a power rating of 55 to 60 watts. Raa=3K3 Output Trannies are reasonably common and would be fine. 43% Ultralinear taps.
Cheers,
Ian
Hammond 1650K Output Transformer.
50 W
3,400 ct
318 ma.
4-8-16
One Electron BFT-1B Power transformer.
These may work I had them on my list of possibilities.
I have been thinking along similar lines but fixed bias. I admit that power wise one is probably better off at this stage with something like EL34 PP but I like EL84's and all those tubes sure would look pretty
Of course I don't need another amplifier but that never stopped me before.
Andrew
50 W
3,400 ct
318 ma.
4-8-16
One Electron BFT-1B Power transformer.
These may work I had them on my list of possibilities.
I have been thinking along similar lines but fixed bias. I admit that power wise one is probably better off at this stage with something like EL34 PP but I like EL84's and all those tubes sure would look pretty
Of course I don't need another amplifier but that never stopped me before.
Andrew
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