Nice work, test will be very interesting, sound of no feedback preamp (vs CFA or VFA) with 300V/us slew-rate.
Regards
The two inputs KSC1845 and KSA992 should have similar (identical if possible) Hfe to minimize DC offset. Thermally tie them together with shrink tubing.
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
Blessings, Terry
http://www.diyaudio.com/forums/atta...100w-ultimate-fidelity-amplifier-apex-mm3.jpg
http://sound.whsites.net/p06-f1.gif
Attachments
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
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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
That is cool looking - nice job, Terry.
Yes, dual mono for beter channel separation.
Terry is a master of diy etching , layout is really nice and compact. congrats!
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Thanks Mr. Mile,
I am your student, following and learning from your PCB's.
reg
Prasi
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
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
Attachments
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
regards Olaf
Nice work, with 1k trimpot you can set THD to minimum.
What is PSU for preamp?
Regards
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Triac soft start
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
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
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