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.
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.
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Latest test results with MELF SMT board looks pretty good.
4Vpp into 7kohms (45v Vcc):
20Vpp into 7kohms (45v Vcc):
Now, for the thread title namesake, 40Vpp into 7kohms (50v Vcc):
And if one raises Vcc to 59v, just before clipping this preamp can drive 51Vpp into 7kohms with 0.013% THD:
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.
4Vpp into 7kohms (45v Vcc):
20Vpp into 7kohms (45v Vcc):
Now, for the thread title namesake, 40Vpp into 7kohms (50v Vcc):
And if one raises Vcc to 59v, just before clipping this preamp can drive 51Vpp into 7kohms with 0.013% THD:
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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Hi X
Very good work.
For the +48V power supply would this be ok ?
Same as the one in Millett starving student HA;
CISCO 48V 0.38A AC/DC Adapter Desktop Power Supply PSU 34-2477-01 EADP-18FB B | eBay
Thanks
Eric
Very good work.
For the +48V power supply would this be ok ?
Same as the one in Millett starving student HA;
CISCO 48V 0.38A AC/DC Adapter Desktop Power Supply PSU 34-2477-01 EADP-18FB B | eBay
Thanks
Eric
I have not tried this but it may work fine. I personally like variable DC step up so you can set your Vcc precisely. With this you will be limited to 44v Vcc after cap Mx.
Took a chance on the $2.66 rca connectors. They can be converted if you are careful. The plastic part of the connector is fairly brittle. Don't ask me how I know. 🙁 Even so I think I'll go with these for my build. They are really good quality for the money.
Yes Sir! The large pins pull out of the body with a needle nose pliers and the signal wires bend relatively easy. The trick is putting the large pins back in on the bottom without cracking the plastic body.
C1
What are your thoughts in using one of these caps (Bipolar, 50V, Dia=10mm) from Mouser for C1?
647-UVP1H101MPD
667-ECE-A1HN101U
What are your thoughts in using one of these caps (Bipolar, 50V, Dia=10mm) from Mouser for C1?
647-UVP1H101MPD
667-ECE-A1HN101U
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.
Hi X,
I am referring to the capacitor that is in series with a 1K (R11) resistor on the daughter board.
I think you are referring to the input cap C132 on the mother board.
The information that you sent is good.
regards
Harry
I am referring to the capacitor that is in series with a 1K (R11) resistor on the daughter board.
I think you are referring to the input cap C132 on the mother board.
The information that you sent is good.
regards
Harry
Unfortunately a film cap will not fit on the daughter board.
I will try a bipolar cap in that position.
I will try a bipolar cap in that position.
.
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.
Tried fitting the eBay PCB RCA jacks on the board tonight. Unfortunately the holes don't align very well. I'll be using separate panel jacks and hook up wire for the RCA connectors on this project after all. 🙁
I’ve started to assemble the boards but I am unsure of the diode polarity on the TH daughter boards?
I assume you have the TH boards. The cathode (stripe or bar) end goes into the hole labeled with the “C”.
