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Old 27th August 2012, 07:10 PM   #2801
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Originally Posted by maxlorenz View Post
Ah! Thank you, Shaan!

I would like to, if my first attempt is a success, make a modular amp and try different output sections...for example, I wonder how a Sziclai pair would work here, or if it would ruin the performance or if it is just impossible to use it...for that, I will have to study first what the *** is a Sziclai pair, to begin with
I know this is becoming a long thread, but as far as I remeber, there were someone who did exactly that and proposed several output configurations.
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Old 27th August 2012, 08:00 PM   #2802
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... oscilation... due to stray capacitance between gate/source and heat sink.
Very classical. It is always a good precaution to fold the gate's leg 90° apart from the Drain/Source ones, shorten-it to the minimum and sold the gate resistance directly on it.
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Old 27th August 2012, 08:18 PM   #2803
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Hello,
Is the 10 uF capacitor on Shaan's schematic not needed on the very nice PCB that Alex designed for us?

Last edited by Cambe; 27th August 2012 at 08:24 PM. Reason: Grammar
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Old 27th August 2012, 08:37 PM   #2804
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Thanks to Nico and Esperado for the warnings about oscillation.
I believe now that maybe it is not a good idea to make one own's PCB in a "knife and copper" fashion...
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Old 27th August 2012, 11:40 PM   #2805
shaan is offline shaan  India
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Originally Posted by Cambe View Post
Hello,
Is the 10 uF capacitor on Shaan's schematic not needed on the very nice PCB that Alex designed for us?
A capacitor is necessary for DC isolation of SSA from music source which may not have very low offset and may alter the input bias current balance resulting in dead speaker due to offset. It also ensure a set-and-forget setup. Alex has made space on the board for this cap but with reduced value, which may decrease bass response. 10uF is a bit large I know. You can use a 4.7uF with almost equal bass performance. Also, although I used a bipolar electrolytic here, I strongly reccommend a film type(MKP, MKT, PAPER IN OIL etc.).
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Old 27th August 2012, 11:49 PM   #2806
shaan is offline shaan  India
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Default Elegant!

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Originally Posted by Esperado View Post
Very classical. It is always a good precaution to fold the gate's leg 90° apart from the Drain/Source ones, shorten-it to the minimum and sold the gate resistance directly on it.
Thanx for the great tip. I will always follow this from now on.
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Old 28th August 2012, 03:36 AM   #2807
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Yes, I see thats what I thought Shaan, just wasn't sure. Thank you for responding to my question about it. Shaan, you are one of the best P2P implementers I have seen in along time! I wish I could just watch and study your tecnique while you build something Like this project and others!
This thread along With along with the TSSA posting's, really is showcasing some very talented artists.
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Old 28th August 2012, 05:22 AM   #2808
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Shaan, you are one of the best P2P implementers I have seen in along time! I wish I could just watch and study your tecnique while you build something Like this project and others!
Yes,his work deserves credit..
Cambe,
You have to draw a one layer PCB layout and just copy it to the breadboard...
It`s relatively simple.. Needs allot patience, Just like fine needle work
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Old 28th August 2012, 07:03 AM   #2809
shaan is offline shaan  India
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Originally Posted by Cambe View Post
Yes, I see thats what I thought Shaan, just wasn't sure. Thank you for responding to my question about it. Shaan, you are one of the best P2P implementers I have seen in along time! I wish I could just watch and study your tecnique while you build something Like this project and others!
This thread along With along with the TSSA posting's, really is showcasing some very talented artists.
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Originally Posted by BenY View Post
Yes,his work deserves credit..
Cambe,
You have to draw a one layer PCB layout and just copy it to the breadboard...
It`s relatively simple.. Needs allot patience, Just like fine needle work
Thanks for the kind words. And as BenY said, it takes patience. However, I don't start with a pcb design and copy to the breadboard, instead I just go with the visuals of the schematic and put the components as they are visually situated in the schematic and in the end I get a design. It always works and errors can be eliminated, as all the boards I assembled has worked without letting the smoke out of the wire. I think anybody can make a decent P2P when the schematic is as beautiful and natural as the SSA. Credit goes to all the kind hearted contributers and specially to LC. He gifted me and many with the sound we look for.
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Old 28th August 2012, 12:09 PM   #2810
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I strongly reccommend a film type(MKP, MKT, PAPER IN OIL etc.).
I know that electrostatics have bad reputation and it is justified on the long time (~ 10 years life). But, regarding their "sound", there is nothing i fear when i use them as coupling capacitors. The only complaint we can make is their self at Hf, but, in the input, adding an extra filtering little pole brings more benefit than inconvenience.

Never, never use mica or tantalum ones in the signal path, because of their resonances.
Just take care to get a nice max voltage margin (> 30%).

For filtering, a common, -and bad- practice is to parallel big electrolytics with little film caps. It will bring a resonance in the impedance curve because of the self of the electrolytic. The best practice is to parallel little caps instead of using big values. (Impedances are lower and they divide themselves).
16X1000µf will gives an impedance ~8times lower than a big single 10 000µf one.
Because each little one has more than half the impedance of the big one at hf, and they divide their impedance by 2 each time you double their number.

If you want to parallel various values, never go more than a 1/10 difference: 1000µf +100µf+10µf+1µf. electrolytics Then, you can add your 0.1µf film capacitor for hf.

On my side, i avoid any "high end" "audiophile" capacitance like hell.

On the contrary, i find a big difference with resistances qualities. I always use metallic film ones instead of carbon. I found carbon to give a "grainy sound".

For high power resistances, where HF is critical (gate resistance), avoid wired ones, and use thick film instead. Wired ones are very good for power, before filtering caps, because they are low priced and they add their self to the hf filtering for free ;-).

Just my two cents.
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