Tom,
The power supply PCB that you will soon be receiving in your PCB kit is fully adjustable from +/-9 volts to +/-24 volts.
Details are here: Dropbox - SERIES_VREG_PWR_SUPPLY.zip
Have a look at the PSU schematic in the first post: it is lm317/337
in the schematic its only transistor in the new layout no regulators.
and the first layout i see in this tread was regulators lm7815andlm7915
thats why i asked....
but since all things are changed for the better i am happy about it.
thanks anyway
I never needed this. But I guess you could just use a standard summing amplifier. And you could use LM4562 here, as well. And you might want to read the chapters about mixers in Small Signal Audio Design.
Hello Jeff,
It's good to see you here. The 1.25 inch heat sinks work fine. In fact the heat sinks in the project BOM are 1 inch tall.
Thanks Carl, I didn't actually see a part number for the heat sinks in the BOM.
Voltage drop is dictated by the secondary voltage of the transformer, that's why I mentioned it. The target output voltage is +/- 18VDC. Likely this could be achieved from 15VAC secondaries in the transformer. If heat was going to be an issue I would switch to the later transformer.
I wouldn't go too close to the lower limit with the transformer as the input voltage typically is not very stable. As you go for 18V DC outputs, I assume you only want the best
The rather low power consumption of the preamp will help you - there has been a discussion about it within this thread.
Slo-blow on the inputs as the inrush current may be times higher than the nominal current, especially when using torroidal transformers.
I noticed this on mine recently too and have been meaning to post a comment. I found that the TL750L12 was failing to regulate because it is oscilating at around 20khz. It needs to be loaded with 10uf, I used a tantalum.
Rob
