Good morning VladimirK
Whats better, to use like in your case a lot electolits in paralel or one but with a big value?
By the way the signal cant omit the c3 and c4 in Andrea design
Could i increase a current in power follower to 4Amp.?
Whats better, to use like in your case a lot electolits in paralel or one but with a big value?
By the way the signal cant omit the c3 and c4 in Andrea design
Could i increase a current in power follower to 4Amp.?
About c3 and c4, it is so obvious, that I get a kind of stress when people decide important to mention it.
Important is to "design" these c3&c4 in a consonant way with as high quality as possible.
Empirically, and by measuring dielectric losses, I have found that a cluster of small low-esr elecrolytes + 100uF polypropylene shunt measures at 3-20kHz and sounds better than big ones + shunt.
4A current is not a problem, I use 4,8A in my 50W Zen9 monoblocks, where I use triplets of transistors.
For this specific transistor pairs, I decided to come a bit douwn from 4A to 3,85A.
I already mentioned it above in this thread, I was lucky to by them for 47USD/pcs.
Current price, especially in Europe, seems to be 2..3 times higher.
However, I belive K1529 and K1530 will also work good.
Thanks, to expencive for me 🙂
I also have Marantz Pm 44 SE. The original current was 50mA per transistor. I increase it to 100mA, but i cant notice any difference in sound. What do you think, could i go much higher for example 500mA per transistor, is it worth?
I also have Marantz Pm 44 SE. The original current was 50mA per transistor. I increase it to 100mA, but i cant notice any difference in sound. What do you think, could i go much higher for example 500mA per transistor, is it worth?
Thinking about tweaking industrial gear, I guess most effective could be replacing caps, potentiometers, putting shunts, i.e. parts substitution.
Modding only idle current will not make drastic changes.
My english is very weak, so i dont understand that about "idle current will make drastic changes" sorry im asking again 🙁
It means that increasing will improve the sound of this comercial product, and actually whats - idle 🙂
It means that increasing will improve the sound of this comercial product, and actually whats - idle 🙂
Oh i see, modding will NOT make drastic changes.
I think incrised idle current will give better THD
I think incrised idle current will give better THD
I wanted to say that "by only increasing current we shall not make big changes of positive character"
VladimirK,
OK, I consider the intrinsic capacitances of RD100HHF1 small.
Any power supply, including the capacitors, is necessarily in series with the load, even in Andrea`s and your amplifier. The capacitor bank in his amp is ridiculously meager; a serious bottleneck.
OK, I consider the intrinsic capacitances of RD100HHF1 small.
Any power supply, including the capacitors, is necessarily in series with the load, even in Andrea`s and your amplifier. The capacitor bank in his amp is ridiculously meager; a serious bottleneck.
I have that PF99 (Andrea design) i like a lot middle and high region, but bass is not so good. If i understood you guys i should put a lot off smaller capacitors on the output to increase the value to 22.000 mF or more, and ill get the better bass?
An alternating (output signal) current does not go through VT5, since the current source VT2-VT3-VT4, being close to an ideal current source, does allow for this takes place. This is the most specific point of Andrea's schematics.
Small capacitor bank is simply a consequence of this fact.
Because of the "electronic choke" action, composed of VT5-R13-C8, in my schematics, even at 4A current consumption, the rail voltage ripples are well below 1mV peak-to-peak, and their shape is smooth and resembles sine-wave.
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Yes, shure, you might want to try the "cluster" output cap I am speaking about. At this, polypropylene shunt not less than 50uF is obligatory.
VladimirK,
Actually, VT5 should be a bipolar and I would refer its base voltage to the output.
That's a supposition not a fact.
Actually, VT5 should be a bipolar and I would refer its base voltage to the output.
The fact of no alternating output signal current from the power rail after VT5 is measured easily. One might want, for instance, to use scope (indicating current through small shunt resistor) as well. Very instructive would be compare two scope pictures for Ciuffolli follower and Macura follower, under similar output signal conditions.
As for bipolar for VT5, I would also appreciate it, provided that one use a darlington pair. On the other hand, I am not sure, from dynamical properties, that darlington is better than MOSFET.
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Interesting observations. My observations at commercial amplifiers were exact contrary. Maybe the reason therefore was always the choice of the capacitor brand. Last example I recall was from the German brand "Einstein", model "The Amp" - go for some pics to
Einstein "The Amp", Verstärker/Receiver - HIFI-FORUM
Please let me know the brand of your capacitor used in your capacitor bank unit. I will download then the data sheets therefore.
BTW - some caps intended for computer boards looks after short use time like follow:
"bad caps" - Google Search
http://www.punj.co.uk/punjwebfiles/electronics/mbbadcap.html
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I tend to agree wit Vladimir that the power supply caps are not in the signal path..this i due to the fact at the speaker voltage sving is not referenced to the normal GND like on usual amplifiers but to the regulated V+.....This is one point where the design truly stands out... normally the power supply play two roles....one is to provide current to the speakers +/- alternating with the signal...the other role is maybe even more important is to maintain the GDN at 0.volts So the speaker currents cant modulate it...This is why on normal amplifiers the power supply caps are directly in the signal path as the speaker current flows through them....!!
Here the PSU bank just needs to hold the ripple sufficiently low so the mosfet regulator can deliver a totally clean 56 V...4 amp current....different use and different requirement...
Can see why a +/- version will be totally different...🙂
Here the PSU bank just needs to hold the ripple sufficiently low so the mosfet regulator can deliver a totally clean 56 V...4 amp current....different use and different requirement...
Can see why a +/- version will be totally different...🙂
In dreams, I would use Black Gate NX - series, 1000uF x 36pcs (or Similar Elna Cerafine).
Actually, I managed to have only a bag of Jamicon WG 680uFx63V, and use 36pcs of them per channel, and a shunt consisting of 2pcs of Mundorf 68uFx400V polypropylene caps. With these values and numbers, I measured impedance module vs frequency in double logariphmic scale, and I did not observe specific resonant small deeps or bumps. I had only one quite flat and wide deep in 3-10 kHz region, with characteristic impedance growth to the left and to the right from it.
Looking datasheets of other manufacturers (Panasonic, SamWha, Rubycon etc.) one can see that all of them have low-esr computer boards intended caps, with dielectric losses specified at 100kHz. Panasonic and SamWha even better than Jamicon.
I can foresee objections again a cluster of small caps, because of bigger parasitic inductance induced by assembling structure. One must not be afraid of this parasitic inductance, copper wire itself does not bring too much injury to sound. On the other hand, a kind of injury caused by big electrolytics is not studied in detail (soundwise), but this injury is unnatural and unpleasant, sound becomes "dark" and "plain".
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