AKSA's Lender Preamp with 40Vpp Output

Hi Nico,
Thanks, but all the credit for layout goes to JPS64. He does this for a living - so these are perhaps, some of the most professional looking layouts that I have ever seen. The ground planes on the MB are insanely good.

For example, the multiple ground planes follow a star topology with the hub at the main input/output connector. The left and right are separate. The CRC and Cap mx ground planes are separate, etc.

649950d1512644395-aksas-lender-preamp-40vpp-ouput-gb-aksa-lender-pcb-delivered-04-jpg
 
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Latest test results with MELF SMT board looks pretty good.

4Vpp into 7kohms (45v Vcc):
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20Vpp into 7kohms (45v Vcc):
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Now, for the thread title namesake, 40Vpp into 7kohms (50v Vcc):
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And if one raises Vcc to 59v, just before clipping this preamp can drive 51Vpp into 7kohms with 0.013% THD:
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That's good for about 41Wrms into 8ohms if the power amp can handle it.

With Vcc at 59v, the SMT board is a bit hotter - but not excessive. I will let it burn in overnight to see if it can take it long term.
 
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That’s probably fine Harry3. But there may be a thing as too much capacitance. I installed my favorite 10uF Elna Silmic II there bypassed with 2.2uF 250v film. The FFT had elevated 20dB above -130dB noise floor of infrasonic (sub 40Hz to DC) content. I removed 10uF and infrasonic noise went away. Although +20dB above -130dB is pretty inaudible, it probably means home theater content would be fully represented through this preamp. The F3 with 2.2uF C1 is about 2Hz so even 2 octaves above is 8Hz should be plenty of bass extension. I recommend using at least a film cap there and skip the electrolytic if given a choice.
 
I have been buying the blue ones but they seem to only put out 45v. I just ordered these which can do a true 50v (reportedly). They are a bit more compact too. Will have to see what noise performance is once I get it.

Here are the blue ones:
DC/DC Boost Converters 8-32V 12V Step-up to 24v 9-46V 150W 8A 36V Driver Parts | eBay

Here are the newer metal PCB ones that go to 50v:
DC DC boost converter Constant Current Mobile Power supply 250W 10A LED Driver | eBay

250W CV/CC Car Notebook Power Supply LED Boost Driver Step-Up Module DC 8.5V-48V | eBay
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Hello X
I received your shipment intimation, thank You!
Of the three DC boosters you have tested, which one would you recommend?
Regards - MM
 
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Hello X
I received your shipment intimation, thank You!
Of the three DC boosters you have tested, which one would you recommend?
Regards - MM

The last two let you go to about 50v but you will have 4v drop in cap multiplier for 46v max. Which is good for most things. However, if you ever want to experiment with 50vpp, get this one as it goes up to 63v output.

All are low noise if fed with a decent 12v or 19v SMPS.

400W DC DC Step up Boost Converter Constant Current Power Supply Module LED Driver Step Up Voltage Module-in Inverters & Converters from Home Improvement on Aliexpress.com | Alibaba Group

The white ones are the most compact. The one I linked above is the most powerful voltage wise.

The white ones if heatsinked can provide 10amps so could be used as main step up on a Class A power amp for speakers.