100W Ultimate Fidelity Amplifier

[apexaudio]

MM4

Phono MM preamp

 

[btesize]

Hello everbody.

I will built Fx8 bimo mod
which transistors must be match ?

 

[apexaudio]

Hi, here is a layout for the P20. At the weekend I'll test it. A PCB is ready. The output capacitor I have omitted, all my amplifiers have capacitors at the input.
I will report and upload the sprint file if everything works.

regards Olaf

Nice work, test will be very interesting, sound of no feedback preamp (vs CFA or VFA) with 300V/us slew-rate.
Regards

 

[apexaudio]

I couldnt find any mistakes in the sch and layout of MM-28, so here are both.
reg
Prasi

Nice work, very compact size for 28 transistors preamp, thank you.
Regards

 

[xrk971]

Hello everbody.

I will built Fx8 bimo mod
which transistors must be match ?

The two inputs KSC1845 and KSA992 should have similar (identical if possible) Hfe to minimize DC offset. Thermally tie them together with shrink tubing.

 

[btesize]

The two inputs KSC1845 and KSA992 should have similar (identical if possible) Hfe to minimize DC offset. Thermally tie them together with shrink tubing.

Thank you [emoji120]


Tapatalk kullanarak iPhone aracılığıyla gönderildi

 

[still4given]

I decided to go with the MM3 phono circuit for this. It is much smaller. It looks like the circuit will be at least as good as Rod Elliot's P06. I etched and populated them this after noon and will get it tested soon.

Blessings, Terry

http://www.diyaudio.com/forums/atta...100w-ultimate-fidelity-amplifier-apex-mm3.jpg
http://sound.whsites.net/p06-f1.gif

 

[apexaudio]

I decided to go with the MM3 phono circuit for this. It is much smaller. It looks like the circuit will be at least as good as Rod Elliot's P06. I etched and populated them this after noon and will get it tested soon.

Blessings, Terry

http://www.diyaudio.com/forums/atta...100w-ultimate-fidelity-amplifier-apex-mm3.jpg
http://sound.whsites.net/p06-f1.gif

Nice work, use 10nF MKS
Regards

 

[still4given]

I just noticed I had one of the rail caps inverted. It is fixed now.

 

[prasi]

Hey Terry

you where looking for a preamp ? this is not the same as the one you was looking for and I think you might want to try out, it came out too big but I think is better because that will make it a lot easier to etched the traces are lot thicker than usual I mean if you want it to try out, let me first check everything a couple of time before I post the PDF files, here is the image 🙂

maybe later or tomorrow

Regards
Juan

Mr. Mile,
1. Would you recommend a output coupling capacitor for SB 3.1 pre amp? and would a 10uF NP be sufficient?
2. for the zener shunt supply, would it be ok to use 24V zener for 24 VAC supply voltage?
reg
prasi

 

[xrk971]

That is cool looking - nice job, Terry.

 

[apexaudio]

Mr. Mile,
1. Would you recommend a output coupling capacitor for SB 3.1 pre amp? and would a 10uF NP be sufficient?
2. for the zener shunt supply, would it be ok to use 24V zener for 24 VAC supply voltage?
reg
prasi

10uF with 100nF in parallel will be OK... like in P6 and MM4
24VAC after rectifing give about 35VDC... 24V zener will be OK but I use 20-22V zener or 28-30VAC.
Regards

 

[apexaudio]

That is cool looking - nice job, Terry.

Yes, dual mono for beter channel separation.

 

[evanc]

Terry, very cool. You never cease to amaze. What you and x do in a few hours takes me days.

 

[prasi]

Terry, very cool. You never cease to amaze. What you and x do in a few hours takes me days.

Terry is a master of diy etching , layout is really nice and compact. congrats!

 

[prasi]

10uF with 100nF in parallel will be OK... like in P6 and MM4
24VAC after rectifing give about 35VDC... 24V zener will be OK but I use 20-22V zener or 28-30VAC.
Regards

Thanks Mr. Mile for your answers
regards
prasi

 

[prasi]

Nice work, very compact size for 28 transistors preamp, thank you.
Regards

Thanks Mr. Mile,
I am your student, following and learning from your PCB's.
reg
Prasi

 

[olafk]

P20

Hi, here is the P20 finished. I have not tested much yet, but it sounds very good. Here are some pictures together with a FR50. The square wave looks so bad because my cheap signal generator is so bad 😉. The picture shows 50kHz. P20 is recommended! I'll try a little more tomorrow or later.

regards Olaf

 

[apexaudio]

Hi, here is the P20 finished. I have not tested much yet, but it sounds very good. Here are some pictures together with a FR50. The square wave looks so bad because my cheap signal generator is so bad 😉. The picture shows 50kHz. P20 is recommended! I'll try a little more tomorrow or later.

regards Olaf

Nice work, with 1k trimpot you can set THD to minimum.
What is PSU for preamp?
Regards

 

[Vrystaat]

Triac soft start

PSU for FX100 include all this exept soft start. Use this soft start circuit.

Gooday all. Have anybody build this circuit and used it succesfully? I have read it is not a good idea to switch a transformer at at zero current crossing. I have a BTA40-600A triac and would want to use it for a softstart. Do one get a suitable opto that will switch the triac at peak power to reduce inrush current. Post 6095 🙂