Doug Self Preamp from Linear Audio #5

Basic question on gain structure. With the default gain of 10 db, how does this translate to input sensitivity? What is the max input signal that leaves enough headroom to avoid clipping with the 17v power supply? Is this dependent on the crest factor of the source signal?

If the source is unbalanced 2Vrms / 5db, the default 10db gain structure would increase this to unbalanced 6Vrms / 16db at the output. Do I have the math correct?


The op amps can handle max 10V. 10dB means gain of ~3. If you need 1V for your power amp, al least 333mV at input is required.
 
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Ordered boards about a half year ago and am now getting to them I noticed my power supply is v1.0 on my earlier build the power supply was v1.0b they are certainly not the same. Can you still order boards?

Rock12,

I've already sent you a private message that gives you an URL for the DOCs. I also wanted to let you know that I have power supply PCBs on hand should you want for use in other projects.

Of late I have been shipping a very nice 'old school' series regulated supply PCB as described back on post #1231. This one has the advantage of being easily configurable for 120v or 230v systems.
 
I have this power supply and I am looking for a BOM?
 

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What is needed to change the original power supply from 115V to 230V? I've moved from the USA to Australia and need to make the change. Thanks, Rene

Hello all,

Just so you don't all get the wrong impression and think that I am ignoring him, Rene and I have been exchanging private messages. And I think he now has a happy resolution to his problem. I invite anyone with a problem to message me and I will do my best to help.
 
Assuming the only difference between the my version of the PCB (1.1) and later ones (such as this 1.2 version) to be in the placement of parts, and later on the pot meter placement, I simply used Hicoco's version of the back panel (quoting him doesn't seem to work). A quick measure of my PCB seemed to indicate that it would fit, but this turned out not to be the case.

Does anyone have any back panel sizes for v1.1, or is there any way of obtaining a later version of the back panel?
 
Assuming the only difference between the my version of the PCB (1.1) and later ones (such as this 1.2 version) to be in the placement of parts, and later on the pot meter placement, I simply used Hicoco's version of the back panel (quoting him doesn't seem to work). A quick measure of my PCB seemed to indicate that it would fit, but this turned out not to be the case.

Does anyone have any back panel sizes for v1.1, or is there any way of obtaining a later version of the back panel?

I also first attempted using Hicoco's version of the back panel, and found that it didn't fit (a few millimeters off on many parts).

I'll measure myself and will order a new back panel from Schaeffer when my measurements are done. If the new panel fits the board, I'll post the Schaeffer / Frontpanel Express file in this thread.
 
I also first attempted using Hicoco's version of the back panel, and found that it didn't fit (a few millimeters off on many parts).

I'll measure myself and will order a new back panel from Schaeffer when my measurements are done. If the new panel fits the board, I'll post the Schaeffer / Frontpanel Express file in this thread.


Thanks in advance! :)