nar - That is a very good observation! I didn't think of that! The inrush with those big caps will be pretty big, on top of the the 30,000uf on each board...
Rich - give that a try. Use a one amp slow and see if it stays on. Measure your voltages at the RIAA board power inputs as well as the regulator outputs.
Rich - give that a try. Use a one amp slow and see if it stays on. Measure your voltages at the RIAA board power inputs as well as the regulator outputs.
The RIAA board input is just where the PSU board hooks up to the Pearl circuit boards. RIAA board = the two green ones. (But you know that) 
I'm curious what the voltage is at the input to the Pearl boards, I.E., before the regulators, but under load.
And just to confirm, you have both boards hooked up, and the 1A fuse is holding?
I'm curious what the voltage is at the input to the Pearl boards, I.E., before the regulators, but under load.
And just to confirm, you have both boards hooked up, and the 1A fuse is holding?
So it works ? What type and size (VA rating) of xformer are U using ? I couldn't see it on the pics you previously posted.
Basically, I would recommend using 2 thermistors CL-60 in series with primary winding (mains 230V) so maybe after that you could try to lower the fuse value, and see if it powers up still without blowing @ 500mA
Next step ? rewiring ground scheme if you have audible hum ?
Each Board must have its own Ground wire from output Ground of PS. Then, if noise still, it can be reduced; 100nF can be put between floating RCA GND input socket and case ( which should be directly connected to Earth pole from Mains).
This often does the trick to achieve quiet operation.
Wasn't needed on the UGS pre, nor on Pearl II but on my new freshly mounted Aleph_J it worked wonders and totally cured the hum. I thought it was residue from CRC, was wrong; now the bloc is dead silent, only music out, no more noise
Best,
nAr
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Nar,
I will add another ground wire as you suggest
Transformer is 24-0-24 50va ... from farnell
All fets test good as new .
Is there a similar test for 450 and 3310 ?
Could you draw a little sketch of the CL60 on the mains you suggest please ?
Things sink home for me visually
Best , Rich
I will add another ground wire as you suggest
Transformer is 24-0-24 50va ... from farnell
All fets test good as new .
Is there a similar test for 450 and 3310 ?
Could you draw a little sketch of the CL60 on the mains you suggest please ?
Things sink home for me visually
Best , Rich
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Bags ,
AC + before fuse .... then on the + of both secondaries before diodes ? Same as my amps basically ?
Rich
Seems you have a 50VA xformer.
50/230= 0,217A more or less
This is the max current your xformer is intended to draw from the wall more or less
So, try adding another CL60 to the queue And pop in the 250mA slow blow fuse, be brave. If it stays still after 10 power on, then it's probably fine.
Pearl would never consume that amount of power anyway; you have high voltage film caps at the output, so even your DC coupled preamp wouldn't be destroyed in case of malfunction. I guess 250 mA slow is a pretty safe value.
If you can plug multimeter on Mains series with your circuit, (caution when doing this !!! Mains voltages can be hazardous) you can visualize the AC current draw on the line. Theroritically you could even go down to a 100mA fuse for a 50 mA continuous draw. After that all needed to know if the circuit has a biggest current draw at turn on ...
Circuit Ground can also be wired to Earth (Chassis) through a diode bridge. Or even diode bridge and cap paralleled I guess if noise issues.
Best,
nAr
50/230= 0,217A more or less
This is the max current your xformer is intended to draw from the wall more or less
So, try adding another CL60 to the queue
And pop in the 250mA slow blow fuse, be brave. If it stays still after 10 power on, then it's probably fine.Pearl would never consume that amount of power anyway; you have high voltage film caps at the output, so even your DC coupled preamp wouldn't be destroyed in case of malfunction. I guess 250 mA slow is a pretty safe value.
If you can plug multimeter on Mains series with your circuit, (caution when doing this !!! Mains voltages can be hazardous) you can visualize the AC current draw on the line. Theroritically you could even go down to a 100mA fuse for a 50 mA continuous draw. After that all needed to know if the circuit has a biggest current draw at turn on ...
Circuit Ground can also be wired to Earth (Chassis) through a diode bridge. Or even diode bridge and cap paralleled I guess if noise issues.
Best,
nAr
Thanks Guys .... it appears to working fine with 2 x CL60 in series with 250mA fuse .
Next step Please ?
what did I learn today .... AC divided by VA = A of fuse needed ?
Rich
Nope atoll
. VA Rating VA / AC line V = I A draw @ max. xformer current
It is the equivalent in AC to the Ohm law I = P / U
Next step ? Have you done the I/Os, and maybe ... listen to it ???
Glad to hear for the 2 CL60 working together
Best,
nAr
I have been checking voltages against Schematic .... ?
I have a flickering LED on one board .Measuring is nigh on impossible ? I have tried tracing it back ,but I'm at the edge of my knowledge .
On the other board I have a drop on Q3 ... I should be reading 10 VDC and I'm getting 1.3 VDC
Also , setting P1 ? I have + on pin and - on PAD ground is this correct , If so, why is my meter all over the place ?
HELP PLEASE ?
Rich
I have a flickering LED on one board .Measuring is nigh on impossible ? I have tried tracing it back ,but I'm at the edge of my knowledge .
On the other board I have a drop on Q3 ... I should be reading 10 VDC and I'm getting 1.3 VDC
Also , setting P1 ? I have + on pin and - on PAD ground is this correct , If so, why is my meter all over the place ?
HELP PLEASE ?
Rich