Thats one interested!
Since people seem a bit afraid of this "strange new twisted" Zen-amp, I have too fuel the fire a bit....
One gain stage, two transistors, minimal design,SuSy-feedback-amp-design,no capacitors on the output, the same beautiful soundquality as SoZ-SuSy-inductansloaded, (i hope) but with less heat and 200 watt clean power!!!! Anyone realy interested in building one???
Since people seem a bit afraid of this "strange new twisted" Zen-amp, I have too fuel the fire a bit....
One gain stage, two transistors, minimal design,SuSy-feedback-amp-design,no capacitors on the output, the same beautiful soundquality as SoZ-SuSy-inductansloaded, (i hope) but with less heat and 200 watt clean power!!!! Anyone realy interested in building one???
Promising...
I just imagine a nice article about zenitron. And a gallery with people's zenitrons....
I wish people try it. 100 w with 45% efficiency sounds attractive...
I might not say more before I try it. I surely will, when time permits.
Hopefully more people with show their interest about this....
Regards
Vix
I just imagine a nice article about zenitron. And a gallery with people's zenitrons....
I wish people try it. 100 w with 45% efficiency sounds attractive...
I might not say more before I try it. I surely will, when time permits.
Hopefully more people with show their interest about this....
Regards
Vix
Okeyisoo.....
The Zenitron is a pushpull amp, a bit similar to both the SoZ version 7 and Zen version 5. It can run in lean class A/B but with a bit more distortion. It can even run in class C I think but 50% crossoverdistortion is not very pleasing to listen to.
My thought was a heavily biased class A/B amp,running 2 amperes through each half of the circuit with two 45 volt supplies. It should work in class A up to about 30 watts or so with quite low distortion. That will cover 95 % of the music played through the amp. When a peak hits the amp will deliver 100 - 150 watts of power without clipping the signal but with an increase of distortion, very much similar to a singelended amp in general but with a lot more power.
The problem is that you have to use very high power fets or match several very closly and parralell them.
My prefered fets would be ISOTOP or SOT227 types. 200 volt,500 watts and 50-150 amperes of current. The will run at 50-90 watt continous dissipation depending on the voltage of the supplyrails and the amount of current you want.
Do I have to say that this is a very exprimental design. I have one working prototyp at home and I have not yet come around to realy try it out with a good powersupply. It sound far better than I expected and gives me 10 clean watts with two very small and weak PS.
The amp will give a lot more current than the bias setting. This is a big difference to the normal Zen amp or the Son of Zen.
A bit update on the safety. A removed the capacitors so if one fet fails the big choke will provide a low resistans path for the current to circle around the speaker and not through it. That will probably not save a tweeter but should save a bass speaker.
The Zenitron is a pushpull amp, a bit similar to both the SoZ version 7 and Zen version 5. It can run in lean class A/B but with a bit more distortion. It can even run in class C I think but 50% crossoverdistortion is not very pleasing to listen to.
My thought was a heavily biased class A/B amp,running 2 amperes through each half of the circuit with two 45 volt supplies. It should work in class A up to about 30 watts or so with quite low distortion. That will cover 95 % of the music played through the amp. When a peak hits the amp will deliver 100 - 150 watts of power without clipping the signal but with an increase of distortion, very much similar to a singelended amp in general but with a lot more power.
The problem is that you have to use very high power fets or match several very closly and parralell them.
My prefered fets would be ISOTOP or SOT227 types. 200 volt,500 watts and 50-150 amperes of current. The will run at 50-90 watt continous dissipation depending on the voltage of the supplyrails and the amount of current you want.
Do I have to say that this is a very exprimental design. I have one working prototyp at home and I have not yet come around to realy try it out with a good powersupply. It sound far better than I expected and gives me 10 clean watts with two very small and weak PS.
The amp will give a lot more current than the bias setting. This is a big difference to the normal Zen amp or the Son of Zen.
An externally hosted image should be here but it was not working when we last tested it.
A bit update on the safety. A removed the capacitors so if one fet fails the big choke will provide a low resistans path for the current to circle around the speaker and not through it. That will probably not save a tweeter but should save a bass speaker.
Here is a picture of my centertapped choke I made last night. It weights 17,5 kg. 2 x 170 mH, 0,6 ohm DC-resistance. It should be good for about 400 watt outputpower. Im not going to run it that hard now. Maybe if I build Susan Parkers Zeus amp. Takes some paralleling of devices though.
An externally hosted image should be here but it was not working when we last tested it.
Big iron!
Wow, that's one massive choke. I'm curious about the use of PVC insulated wire vs. the more common 'magnet wire'. Will this exhibit enough inter/intra-winding capacitance to be of concern? With 170 mH it only takes 400 pF to drop the resonance into the audio frequencies, yes?
Cheers,
LarryO
Circlomanen said:
Wow, that's one massive choke. I'm curious about the use of PVC insulated wire vs. the more common 'magnet wire'. Will this exhibit enough inter/intra-winding capacitance to be of concern? With 170 mH it only takes 400 pF to drop the resonance into the audio frequencies, yes?
Cheers,
LarryO
I have no idea!?! I will have to plug it in and see/ measure what happens.If this doesnt work out as I want it to I will have the winding company rewind them to me with magnetic wire.
There is a small transformer and winding company here in sweden that I buy things from. They have laminationstacks in all sizes. The biggest one I have seen there is something like 5 times bigger. I couldnt lift it. A bit expensive though.
180 watt from THE ZENITRON!!!!
I just managed to get 180 watts from my small Zenitron amp before any audible onset of clipping. Im using a 300 VA 2 x 24V transformer and getting two floating supplyrails at 33 volt. I have 2 x 4700 mF capacitors,then 2 x 1,6 mH chokes and then 2 x 75000 mF capacitors again. One of tha drawbacks of the Zenitron is that it has to have a dead quiet powersupply, and that is not enough. (close though)
I run 600 mA quiesent current through each half of the circuit.My heatsink cant take more heat.But I would love to run more, I think it will sound even better.
The very very fun part of it is that I get that "direct" open lively sound the Zen-amp gives you, but backed up by tremendous power. Im running my small downsized WO subwoofer now since that is the only speaker I have that can take that kind of power.I shakes my apartament so hard I cant run the amp any higher.My CD player starts to jump tracks!!
I just managed to get 180 watts from my small Zenitron amp before any audible onset of clipping. Im using a 300 VA 2 x 24V transformer and getting two floating supplyrails at 33 volt. I have 2 x 4700 mF capacitors,then 2 x 1,6 mH chokes and then 2 x 75000 mF capacitors again. One of tha drawbacks of the Zenitron is that it has to have a dead quiet powersupply, and that is not enough. (close though)
I run 600 mA quiesent current through each half of the circuit.My heatsink cant take more heat.But I would love to run more, I think it will sound even better.
The very very fun part of it is that I get that "direct" open lively sound the Zen-amp gives you, but backed up by tremendous power. Im running my small downsized WO subwoofer now since that is the only speaker I have that can take that kind of power.I shakes my apartament so hard I cant run the amp any higher.My CD player starts to jump tracks!!
Welcome back to earth Circlomanen....
The amp must have at least half peak current running through the fets all the time....Otherwise it will produce excessive amounts of distortion.
Maybe its a bit too much to ask for voltage gain,low distortion,low output impedance and 200 watt output power without much quiesent current and heatdissipation from only one gainstage.
It will work very good to about 50 watts or so with out to much heat. 200 watts are certainly possible but it will require large heatsinks and paralleling of devices.
The amp must have at least half peak current running through the fets all the time....Otherwise it will produce excessive amounts of distortion.
Maybe its a bit too much to ask for voltage gain,low distortion,low output impedance and 200 watt output power without much quiesent current and heatdissipation from only one gainstage.
It will work very good to about 50 watts or so with out to much heat. 200 watts are certainly possible but it will require large heatsinks and paralleling of devices.
Circlomanen said:
How very cool to have that resource handy. Maybe they can measure the parasitic capacitance for you? If not it should be fairly easy to do yourself either by sweeping through the audio frequencies and monitoring the impedance of the choke .or. by wiring up your "1:1 transformer" with the primary as a load and watching the frequency response on the seconday windings. Hopefully, it'll be flat out to at least 80 KHz.
Also, in the revision you published in Post #50, I have two questions:
(1) Why did the ground reference disappear from the middle (symetry point) of the circuit?
(2) Is the 10K R the feedback? If so, then i assume that as signal appears across the speaker one or another of the input nodes (junction of 1K and 10K) will deviate from 0v. Yes? Without DC blocking caps at the signal imputs, how does that impact the source device's output requirements?
Great stuff, Circlomanen!
Cheers,
LarryO
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