that look really nice I'm glad you like the layout
can you post more images of the complete board sir ?
Regards
Juan
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A friend from Venezuela is making the AX-14 too
Hello Juan, Soldering is too good!.
temporary senior moments happen
Hallo xrk, sonal and prasi.
Thank you for punting me to my failure- oh it's so bad!!!
Forget to check the pin orientation.........aaarrrrgggggg!!! any blind moments
in soldering fever .
I only have BD139 in my box and the Tech DIY part lying unused around.
Anyone wrote here about MPSA18 for better offset and lower noises???
I have checked now resistor value- nothing wrong there.
Now i will desolder Transistors and place in right orientation and hopefully
give a reply about success later here.
Cheers Bangla.
Hallo xrk, sonal and prasi.
Thank you for punting me to my failure- oh it's so bad!!!
Forget to check the pin orientation.........aaarrrrgggggg!!! any blind moments
in soldering fever
.I only have BD139 in my box and the Tech DIY part lying unused around.
Anyone wrote here about MPSA18 for better offset and lower noises???
I have checked now resistor value- nothing wrong there.
Now i will desolder Transistors and place in right orientation and hopefully
give a reply about success later here.
Cheers Bangla.
You can share pcb files and layout? I searched the forum but not found the pcb and layout. Please share in pdf file format .
THANK YOU VERY VERY MUCH
Hallo xrk, sonal and prasi.
Thank you for punting me to my failure- oh it's so bad!!!
Forget to check the pin orientation.........aaarrrrgggggg!!! any blind moments
in soldering fever
I only have BD139 in my box and the Tech DIY part lying unused around.
Anyone wrote here about MPSA18 for better offset and lower noises???
I have checked now resistor value- nothing wrong there.
Now i will desolder Transistors and place in right orientation and hopefully
give a reply about success later here.
Cheers Bangla.
What are you using for the input LTP and CSS?
Can you tell us exactly which components you replaced with something else and where?
I don't recall anyone lately saying anything about MPSA18 for the LTP. 2SC1845 were chosen by Bimo for lower noise.
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FH9 HV cranks out the watts
I switched back to BC546's after having some trouble getting the amp to work with the 2n5551's. The KSC3503 and KSA1381's are still there instead of the BD139/140's though. Bias current set at 175mA as measured through the pair of 0.47R source resistors. 52v rails provided by Abletec SMPS and CRC filter.
I mounted the FH9HV onto an old Pentium solid copper heatsink and connected a 100w dummy load comprised of four 8R 25w aluminum shell power resistors in series parallel. They measure 10ohms when hot though.
Amp connected to 52v SMPS and CRC PSU filter, small noiseless fan used to augment cooling:
Closeup of amp connected and playing music:
Stress test using 1kHz sine wave at max input before clipping gives 34.5v rms. For a 10R load that is about 120 watts. It was steady from 30Hz to 10kHz (tested at 20, 30, 100, 1000, 2000, 10kHz). At 20Hz it drooped to 34.1v, otherwise rock steady output rms voltage output vs frequency. The amp was able to sustain this level of output no problem. I ran the test for 15 minutes. The resistors were giving off a smell, and the heatsink was outgassing some of the leftover grease/cutting fluid used for the tapping operation. But heatsink could be touched for 10 seconds or so when fan is on.
How does it sound? Excellent - still one of the best sounding amps I have. With 52v rails, I have to say, the bass is very powerful and crisp. Clean, undistorted bass with a deep reach. Very nice. Mids and highs still clear and no sibillance or fatigue.
I think this HV version is a pretty compact 120w class amp. The Chinese hexFETs held their own - which leads me to believe they are real. No mini-die fake can hold up to that kind of test.
I highly recommend this build - easy amp to make and swapping out the drivers and using 63v rated electrolytic caps gives it some much needed power reserve.
I guess Jay was right - this amp and hexFET shouldn't have any problems running at these voltages.
I switched back to BC546's after having some trouble getting the amp to work with the 2n5551's. The KSC3503 and KSA1381's are still there instead of the BD139/140's though. Bias current set at 175mA as measured through the pair of 0.47R source resistors. 52v rails provided by Abletec SMPS and CRC filter.
I mounted the FH9HV onto an old Pentium solid copper heatsink and connected a 100w dummy load comprised of four 8R 25w aluminum shell power resistors in series parallel. They measure 10ohms when hot though.
Amp connected to 52v SMPS and CRC PSU filter, small noiseless fan used to augment cooling:
Closeup of amp connected and playing music:
Stress test using 1kHz sine wave at max input before clipping gives 34.5v rms. For a 10R load that is about 120 watts. It was steady from 30Hz to 10kHz (tested at 20, 30, 100, 1000, 2000, 10kHz). At 20Hz it drooped to 34.1v, otherwise rock steady output rms voltage output vs frequency. The amp was able to sustain this level of output no problem. I ran the test for 15 minutes. The resistors were giving off a smell, and the heatsink was outgassing some of the leftover grease/cutting fluid used for the tapping operation. But heatsink could be touched for 10 seconds or so when fan is on.
How does it sound? Excellent - still one of the best sounding amps I have. With 52v rails, I have to say, the bass is very powerful and crisp. Clean, undistorted bass with a deep reach. Very nice. Mids and highs still clear and no sibillance or fatigue.
I think this HV version is a pretty compact 120w class amp. The Chinese hexFETs held their own - which leads me to believe they are real. No mini-die fake can hold up to that kind of test.
I highly recommend this build - easy amp to make and swapping out the drivers and using 63v rated electrolytic caps gives it some much needed power reserve.
I guess Jay was right - this amp and hexFET shouldn't have any problems running at these voltages.
Attachments
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The one by Sonal Kunal found here:
http://www.diyaudio.com/forums/soli...imate-fidelity-amplifier-746.html#post4718255
I ordered my boards from Seeedstudio with the Gerber file.
The "HV" version simply uses KSA/KSC vs BD's for the drivers. Also make sure your electrolytics can handle the higher voltage rails. The BC546's for the LTP and CCS work fine with 52v rails.
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Have you checked the Directory (Index) thread?
http://www.diyaudio.com/forums/solid-state/292226-directory-apex-audio-amplifiers.html