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I have not yet experimented with different values of Zener, but it seems that the wattage rating of the zener is more important than the voltage range. A 0.5w zener is not robust enough to withstand no load and instant power cut without blowing both the zener and the mosft. I have a few 1w zeners that I want to play with soon. MEPER used a 5w, but I don't he has stress tested his implementation yet.
upstream circuit is usually not having enough cojones to scorch 500mW zenner
that , if zenner is on this side of mosfet's gate resistor
if you put zenner ditto between S and G , gate resistor is also limiting what needs to be limited
however , if and when you're counting on Big Cojones of upstream circuit , 5W zenner is maybe just up to the task ........ 1W is just a smidge better than 500mW
so , stay with 500mW , no need for more
I made a few changes to my ACA LCLC filter PSUs to work perfect with MoFo. The schematic shows the changes. For ACA the output was about 24V at 1.4A. Now I have about 26V at 3A. The ripple is still low. About 2-3 mV pp. I biased MoFo to 3A. About 80W is burned pr. side. The big heatsinks seems no more to be "overkill". The reach about 53-54 C. I have no problem so far with power on/off but have not tried to stress test by "playing" with the power connector to the MoFo. I power on/off at the 230V side.
It is difficult to leave the room when it is playing. It sounds very good and relaxed. Deep sound stage. It is like a triode…...but with more bass power than a 300b can deliver. I go via a 1000 VA isolation trafo. I have two outputs. The 1:1 and a lower voltage output. About 200-210 VAC. It will be perfect for ACA so I can still use the PSUs for the ACAs (has to be tried).
It is difficult to leave the room when it is playing. It sounds very good and relaxed. Deep sound stage. It is like a triode…...but with more bass power than a 300b can deliver. I go via a 1000 VA isolation trafo. I have two outputs. The 1:1 and a lower voltage output. About 200-210 VAC. It will be perfect for ACA so I can still use the PSUs for the ACAs (has to be tried).
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I think the caps are an old invention......they are 4-pole caps. Jensen has a white paper about them here:
http://jensencapacitors.com/CustomerData/Files/Folders/4-pdf/5_4pole.pdf
.....but did I make some other mistakes in the schematic?
http://jensencapacitors.com/CustomerData/Files/Folders/4-pdf/5_4pole.pdf
.....but did I make some other mistakes in the schematic?
Application note about some usage......but not as LCLC filter usage......but CLC:
http://jensencapacitors.com/Custome...-pdf/13_4-pole-capacitor-application-note.pdf
http://jensencapacitors.com/Custome...-pdf/13_4-pole-capacitor-application-note.pdf
the inductive input supply allows a substantially sinusoidal ripple, ie without sawtooth peaks, moreover the ripple is indifferent to the increase of the load. The price to pay over the important encumbrance is the internal resistance of the inductance that causes a significant voltage drop.
But .... in the end .... have you compared with a supply with capacitive input and have you noticed a significant "best sound"?
The LCLC filter PSU is the only one tested with ACA so far. I had plans to get the Meanwell PSUs and use them to compare. Also to have a portable set of amps I could carry and take with me so friends etc. could try them.
I know I get a large voltage drop over the first choke. the AC to the rectifiers are 38 volts and the voltage at the first cap is approx. 28 VDC. So I can use 40 VDC caps. Without load the voltage at the caps is just about 40 VDC. They can take it.....even if you get a bit above 40 VDC. I have bleeders (2 x 470 ohm which maybe should be lower because the current now is 3A with load). I still need to test more without load to be sure nothing goes wrong if the fuse blows (I have a 4A fast fuse at the output of the PSU and everything should survive if fuse blows).
I know I get a large voltage drop over the first choke. the AC to the rectifiers are 38 volts and the voltage at the first cap is approx. 28 VDC. So I can use 40 VDC caps. Without load the voltage at the caps is just about 40 VDC. They can take it.....even if you get a bit above 40 VDC. I have bleeders (2 x 470 ohm which maybe should be lower because the current now is 3A with load). I still need to test more without load to be sure nothing goes wrong if the fuse blows (I have a 4A fast fuse at the output of the PSU and everything should survive if fuse blows).
surely each of us can deceive himself but not beyond a certain measure. So if you give a judgment I will take it seriously, good or bad that it is ...... but it is a free judgment and to exchange opinions makes us grow.
sontero and MEPER, please see the guidelines in the rules, specifically #3 Don't quote the entire post just above yours.
Hello, new to the scene, not an electronics or otherwise hifi audio expert, I got a few questions, so I am appealing to your kind assistance and patience:
#1. Is it correct to say the MoFo is a power amplifier that will NOT work alone but only if fed an already pre-amplified audio signal?
#2. Can the MoFo be used as an instrument (guitar, electric piano, etc) power amp or it is strictly a (hifi) audio amp? E.g. can the MoFo feed guitar speakers/cabinets or it has to drive hifi speakers.
#3. Can I feed the MoFo the output of a DigiKey multi-effect processor ie PR-55which output level is like a guitar fx pedal.
#4. is it possible to achieve different output power levels by varying the supplied power or that would require mods to the circuit?
Thank you!
#1. Is it correct to say the MoFo is a power amplifier that will NOT work alone but only if fed an already pre-amplified audio signal?
#2. Can the MoFo be used as an instrument (guitar, electric piano, etc) power amp or it is strictly a (hifi) audio amp? E.g. can the MoFo feed guitar speakers/cabinets or it has to drive hifi speakers.
#3. Can I feed the MoFo the output of a DigiKey multi-effect processor ie PR-55which output level is like a guitar fx pedal.
#4. is it possible to achieve different output power levels by varying the supplied power or that would require mods to the circuit?
Thank you!
Answers:
1. The Mofo as presented does not have voltage gain. Without a pre-amp of some kind, that limits the Mofo to a Watt or 2, depending on source.
2. Power is power. Speakers are speakers. Since it is designed for Hifi, you may or may not like the sound as an instrument amp.
3. Shouldn't be a problem.
4. You have to watch out for the maximum dissipation and voltage across the transistor. Cooling is also a consideration.
1. The Mofo as presented does not have voltage gain. Without a pre-amp of some kind, that limits the Mofo to a Watt or 2, depending on source.
2. Power is power. Speakers are speakers. Since it is designed for Hifi, you may or may not like the sound as an instrument amp.
3. Shouldn't be a problem.
4. You have to watch out for the maximum dissipation and voltage across the transistor. Cooling is also a consideration.
I have tried to find the information on how you determine the wattage in a Mofo build, but I don't have much electronics experience so it has eluded me. The Mofo or the ACA seems to be the best builds for beginners (?). The ACA seems great but I'm afraid the power is a little low for my Yamaha NS1000's at 15 watts. So in that, how does one determine the output power of the Mofo? I will be using either a Juicy Peach or Klyne SK7.4lp preamp. Also, can the Mofo be built in a balanced configuration? I also thought of building an Aikido 12vac to put in front of the Mofo but that might too advanced for me.
Any help for a novice would be much appreciated.
Any help for a novice would be much appreciated.
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> how does one determine the output power of the Mofo?
Pout = ((VDC*0.64)^2)/RL
("0.64" is 0.707 for peak-to-RMS, and 0.9 for general loss.)
IDC = VDC/RL
(This could perhaps be 0.9VDC but a hair-rich beats any-cold.)
Total DC power = 2.5 times output power
Power making heat in heatsink = also 2.5 times Pout
(Drops to 1.5X when working FULL Sine power, but you only do that on test-bench.)
Pout = ((VDC*0.64)^2)/RL
("0.64" is 0.707 for peak-to-RMS, and 0.9 for general loss.)
IDC = VDC/RL
(This could perhaps be 0.9VDC but a hair-rich beats any-cold.)
Total DC power = 2.5 times output power
Power making heat in heatsink = also 2.5 times Pout
(Drops to 1.5X when working FULL Sine power, but you only do that on test-bench.)