Hi guys. I am interested to build a class a or ab amp...I think!
Currently listen to class d tpa3255. I dont need all the power it can provide. Average UK living room although soeakers aren't particularly sensitive. I run through a Salas DCG3.
What would be a good start for a first build? And are there any projects with gerbers rather than boards to purchase from the States. Have recently popped my JLPCB cherry.
I wouldn't have room or budget for a massive 4u chassis for heatsink so a design with sensible currents and dissipation would be ideal. CPU heatsinks A La XRK a possibility? Some nice sinks on AliExpress 200x40x68 and 600g. Any use?
Also I get bewildered with the transistor unobtainium/matching thing so readily available preferably from Mouser would be handy.
Maybe I ask too much but if you have any advice for a start into class A then I would appreciate it.
Thanks
Currently listen to class d tpa3255. I dont need all the power it can provide. Average UK living room although soeakers aren't particularly sensitive. I run through a Salas DCG3.
What would be a good start for a first build? And are there any projects with gerbers rather than boards to purchase from the States. Have recently popped my JLPCB cherry.
I wouldn't have room or budget for a massive 4u chassis for heatsink so a design with sensible currents and dissipation would be ideal. CPU heatsinks A La XRK a possibility? Some nice sinks on AliExpress 200x40x68 and 600g. Any use?
Also I get bewildered with the transistor unobtainium/matching thing so readily available preferably from Mouser would be handy.
Maybe I ask too much but if you have any advice for a start into class A then I would appreciate it.
Thanks
My suggestion only -
Parsi just did a layout and provided gerbers for the FH9 from Apexaudio.
It’s a MOSFET amp so a slightly warmer sound more like tube or class A (IMO) and very robust with easy to find parts from Mouser.
A standard 2U case/heatsink is more than enough.
1-pair of outputs you can run on +/-35 up to +\-50Vdc.
I have listened to it’s bigger 2-pair output brother the FH11/12 for 2 years and enjoy it.
Search for this thread “100W Ultimate Fidelity Amplifier” and go to post #13710 and everything’s there for you.
Parsi just did a layout and provided gerbers for the FH9 from Apexaudio.
It’s a MOSFET amp so a slightly warmer sound more like tube or class A (IMO) and very robust with easy to find parts from Mouser.
A standard 2U case/heatsink is more than enough.
1-pair of outputs you can run on +/-35 up to +\-50Vdc.
I have listened to it’s bigger 2-pair output brother the FH11/12 for 2 years and enjoy it.
Search for this thread “100W Ultimate Fidelity Amplifier” and go to post #13710 and everything’s there for you.
Thata great thabkyou I shall have a look at that thread.....looks sizeable but that means some good feedback and support which is probably what I need!
I have a spare 35v 500va trafo that gives me about 48v.
I have a spare 35v 500va trafo that gives me about 48v.
with such Voltage the AB 100 can also be considered as an option (there are NP originals and Prasi gerber files)
The court thread is long and will have to be read and found by yourself.
AB100 Class AB Power Amplifier
48V will be too high for class A.
other option:
FH9HVX - Budget Conscious 100w Class AB for Lean Times
The court thread is long and will have to be read and found by yourself.
AB100 Class AB Power Amplifier
48V will be too high for class A.
other option:
FH9HVX - Budget Conscious 100w Class AB for Lean Times
Don’t get discouraged when you read that 100W thread, it has 30-40 designs and schematics but only ~12 with gerbers, BOMs and readily available parts.
The FH9/11/12 are MOSFET, if you want BJT look for AX11/14.
That transformer would be a good fit for a FH9 in a 2U/3U case and provide about 75w at 8 ohms.
Good luck and have fun with the journey.
Thanks guys and just a quick one if I may.
Just reading the last pages and I saw this comment by yourself bullitstang.....cool name BTW.
Quote
"If you like tubes or a laid back sound go for the mosfet if you like a lively and open sound go fir the BJT option. Both sound great."
I think I would prefer the BJT. So are the AX11/14 suitable with sensible heatsinks etc as per my first post.?
Thankyou
Just reading the last pages and I saw this comment by yourself bullitstang.....cool name BTW.
Quote
"If you like tubes or a laid back sound go for the mosfet if you like a lively and open sound go fir the BJT option. Both sound great."
I think I would prefer the BJT. So are the AX11/14 suitable with sensible heatsinks etc as per my first post.?
Thankyou
Yes but if you want to use that 48vdc transformer, I would highly suggest a 2-pair AX14, because you would be at the ragged edge of the 5200/1943 outputs suggested in the design, or switch to their bigger brother and go with the MJW3281/1302, which are 200V and 200W parts (comes in to-247 (MJW) and to-264 (MJL) case sizes)
Bonsai, SX Class A with common parts and available pcb(many options). Ovation sx-Amplifier: A 15 W Class A Current Feedback Amplifier
Class A SX Bonsai by thimios - YouTube
Class AB, two many options,plenty of Apex, plenty of VZaudio, Ostripper Slewmaster e.t.c....e.t.c.
If you want to subscribe in my chanel, you can see some of them in function.
All these are tested, measured for function and distortion, good performance.
You can take help for problem resolve.
In most cases there aren't difficult or expensive parts, not snake oil here!
Class A SX Bonsai by thimios - YouTube
Class AB, two many options,plenty of Apex, plenty of VZaudio, Ostripper Slewmaster e.t.c....e.t.c.
If you want to subscribe in my chanel, you can see some of them in function.
All these are tested, measured for function and distortion, good performance.
You can take help for problem resolve.
In most cases there aren't difficult or expensive parts, not snake oil here!
Last edited:
Also check out Bonsai's kx class A/AAB amp. Excellent performer.
kx-amplifier: A very high performance 28 Watt class A Current Feedback Amplifier
kx-amplifier: A very high performance 28 Watt class A Current Feedback Amplifier
go to user CP---Edit Signature---then paste link of your channel and click save signature
Attachments
Last edited:
Using Prasi's excellent layouts and gerbers i have ordered both the AB100 and Apex FH9. Seeing as they both run on similar power rails. And also similar voltage to my class d set up currently so I have a trafo good for all them. Ordered some of Prasis cap mx and also compact crc psus too.
these are class AB amplifiers (their current consumption is not constant) .. CRC is not needed and will not be effective ... these amps are hum-free with a normal capacitor filter if properly assembled . good luck with your project!
Hello jmk04, In CRC , you might experiment with replacing R with a thick link and compare for your self which you might like.
Yes I can try that. So can I make performance of these amps worse by using CRC instead of plain cap bank?
I assumed a CRC would always be better.? But I am not experienced with them.
I assumed a CRC would always be better.? But I am not experienced with them.
no way you are making them worse...., CRC is good , no problem. just experiment yourself and see which one you like. This is DIY, so its all about doing and learning. I used CRC (net R was 0.167 ohms =1ohm x 6 nos of 2512 ) on a class AB amp, and I love it.
capmx is more suitable for class A amps, which have more or less constant current draw..
capmx is more suitable for class A amps, which have more or less constant current draw..