Testing AA9MD into 4 ohms. Latest version by Prasi. Board layout is excellent with some small improvements from last version including decoupling caps at output devices. Building 3 stereo amps for active speakers!
chermann, my board has keystone holders installed but no covers on at the moment
chermann, my board has keystone holders installed but no covers on at the moment
Attachments
Hy Hennady,
What are your suggestions to improve the operating modes of the driver stage?
Thanks in advance.
just starting with the BOM...i refer to the schematic attached...
caps: (partnumbers from digikey)
C1 any MKP 2,2µ or the bipolar nichcion UES are fine 10µ....or a Clarity cap...whatever..max LS 35mm
for the Supply caps ...C12, C15, C9, C16
is there a need for Audio caps? e.g. UKZ 470µF/50V...UKZ1H471MHM...about 2 euros
or is the pana EEU-FM1H471 okay?
C4 220µF/ polar cap, audio?, or bipolar cap needed?
XRK use a Oscon 25SEPF330M+T
C5 should be a mica cap
C3, C6, C7, C17...0.1uf 50VDC 5%, X7R...KEMET C412C104J5R5TA or similar
C8 1µF/35V...?
C10, C11 1pF...filter for the MOSFETS...mica needed?
C13, C14, 1µF...same like C8...but what?
please give me feedback.
thank you in advance
chris
caps: (partnumbers from digikey)
C1 any MKP 2,2µ or the bipolar nichcion UES are fine 10µ....or a Clarity cap...whatever..max LS 35mm
for the Supply caps ...C12, C15, C9, C16
is there a need for Audio caps? e.g. UKZ 470µF/50V...UKZ1H471MHM...about 2 euros
or is the pana EEU-FM1H471 okay?
C4 220µF/ polar cap, audio?, or bipolar cap needed?
XRK use a Oscon 25SEPF330M+T
C5 should be a mica cap
C3, C6, C7, C17...0.1uf 50VDC 5%, X7R...KEMET C412C104J5R5TA or similar
C8 1µF/35V...?
C10, C11 1pF...filter for the MOSFETS...mica needed?
C13, C14, 1µF...same like C8...but what?
please give me feedback.
thank you in advance
chris
Attachments
hy
about FX4
in post 10683 prasi show the schematic and his layout. i search for the FX4 gerber but with all entries in the search window i cant find.
can you help for this gerber?
thanks
chris
Hi mr mail.
I need had to incrase my apex TB3 out put voltage...almost 3 to 4 volt.
Now how i can do it?
Hi Joel
at post 14186 you show us your AA9MD. i want to kindly ask you about a BOM for this amp. Please can you provide me this?
i found the file: APEX AA9 MD-REV3 BOM-PARTS SIZE...i miss:
C11, C12, C13, C14, C15, C16, C17, C18 270µ/50V ?
and C19 -33nF MKP?
...its not clear for me.
thanks
chris
Hi Chermann.
I don't have a BOM. I followed board labelling and schematic.
Most of the resistors, diodes and BC546's and MPSA92's I have in my supply so just stuffed the boards and then ordered Caps,
BD139's and BD140's, and all O/P devices..
This amp is very easy to build.
Note: The heatsinks are warm at about 62C. The o/p devices are only slightly warm to touch. I'm using Bergquist thermal pads and they transfer heat very well and have switched to Berquist exclusively and have stopped using hard insulators and thermal grease..
The bias is set to 1.2A, about 140ma per emitter pair. I was able to see the crossover notch at 20khz on the scope, and then dial it out..
To note. on my first AA9MD I installed Omni semi o/p devices. On the latest unit I'm using Multicomp pro O/P devices and feel they work just the same.
The name printed on the o/p devices is MOSPEC
Oh, sorry for your question C11 - C14, I'm using 100u 50v. I believe this value is not crucial but check with others first..
I'm trying to locate C19 - dont see it!
I don't have a BOM. I followed board labelling and schematic.
Most of the resistors, diodes and BC546's and MPSA92's I have in my supply so just stuffed the boards and then ordered Caps,
BD139's and BD140's, and all O/P devices..
This amp is very easy to build.
Note: The heatsinks are warm at about 62C. The o/p devices are only slightly warm to touch. I'm using Bergquist thermal pads and they transfer heat very well and have switched to Berquist exclusively and have stopped using hard insulators and thermal grease..
The bias is set to 1.2A, about 140ma per emitter pair. I was able to see the crossover notch at 20khz on the scope, and then dial it out..
To note. on my first AA9MD I installed Omni semi o/p devices. On the latest unit I'm using Multicomp pro O/P devices and feel they work just the same.
The name printed on the o/p devices is MOSPEC
Oh, sorry for your question C11 - C14, I'm using 100u 50v. I believe this value is not crucial but check with others first..
I'm trying to locate C19 - dont see it!
Last edited:
Hi joel
nice to hear from you. i am so "strange" i have to have a BOM, i had the FX8, now i am ready with FH9 xrk mod (i can use a lot of FX8) now i just want to have AA9MD. jop man are some times "strange" .
Thanks for the hint of the heat...if i will build this amp i know it from handling my Class A M2 builds and my ACA premium.
C11-C18 : yes the pitch is 8mm so its should about 100µF up to 470µF with 50V
C19 is just in the schematic i see. it is in parallel with C1 the input cap. here i just find the information that it should be 33nF? and MKP...i have a lot of caps for input cap.
o/p - output device: (normaly i order at digikey) i have no experience in darlington BJT
important is that TO220 should not be this plastic housing = TO220 SIS !!!
i found:
BDW93 -delivery open
BDX33C, TIP142T, 2N6388G, TIP102/TIP107,
"normaly" darlington are huge in hfe....do you try some BJT (TO220) with less hfe???
e.g. TIP 31C
which overall gain do you measure at AA9MD?
kr
chris
nice to hear from you. i am so "strange" i have to have a BOM, i had the FX8, now i am ready with FH9 xrk mod (i can use a lot of FX8) now i just want to have AA9MD. jop man are some times "strange" .
Thanks for the hint of the heat...if i will build this amp i know it from handling my Class A M2 builds and my ACA premium.
C11-C18 : yes the pitch is 8mm so its should about 100µF up to 470µF with 50V
C19 is just in the schematic i see. it is in parallel with C1 the input cap. here i just find the information that it should be 33nF? and MKP...i have a lot of caps for input cap.
o/p - output device: (normaly i order at digikey) i have no experience in darlington BJT
important is that TO220 should not be this plastic housing = TO220 SIS !!!
i found:
BDW93 -delivery open
BDX33C, TIP142T, 2N6388G, TIP102/TIP107,
"normaly" darlington are huge in hfe....do you try some BJT (TO220) with less hfe???
e.g. TIP 31C
which overall gain do you measure at AA9MD?
kr
chris
Thanks! Yes, AA9MD, I have C19 installed, 320p
The overall gain I didn't make note of it, just power out at clipping into 4/8 ohms- VRMS output was 16-17, VRMS input was under 1 but close to 1 but I will check.
I avoided O/P's with plastic cases. MOSPEC have metal backs and look the same as Omni's but with a wider gain spread between NPN and PNP
I don't know about switching to BJT outputs. I've been trying to fit time into simulations with Micro cap - Long way to go with that!
Spectrum analyzer would be nice as well..
Joel
The overall gain I didn't make note of it, just power out at clipping into 4/8 ohms- VRMS output was 16-17, VRMS input was under 1 but close to 1 but I will check.
I avoided O/P's with plastic cases. MOSPEC have metal backs and look the same as Omni's but with a wider gain spread between NPN and PNP
I don't know about switching to BJT outputs. I've been trying to fit time into simulations with Micro cap - Long way to go with that!
Spectrum analyzer would be nice as well..
Joel
thanks joel.
i dont know what you mean with switching to BJT, but i want to ask about BJT because actually i have no experience with them. general i know that every gain you get you gain also the noise - thats the reason why i am asking about low O/P BJT with less hfe. i am fine with 12-15 (20) dB overall gain at my amps.
chris
i dont know what you mean with switching to BJT, but i want to ask about BJT because actually i have no experience with them. general i know that every gain you get you gain also the noise - thats the reason why i am asking about low O/P BJT with less hfe. i am fine with 12-15 (20) dB overall gain at my amps.
chris