That's a step in the right direction. Thanks Woody. The next big thing is the CCS, I am making the assumption that it's optimized for 24v and a Enhanced mode mosfet, but maybe just throwing this together is the right thing to do.
Probably it lacks a resistence to set the output impedance , say 20 ohm ?
More , since the Dfets are selfbiasing , why not try the ccs with them ?
Grazie
Thanks Stefanobilliani for looking.
From the altered F2 schematic, I removed the output resistors since the DeLite doesn't use them, all other thinkings looking somewhat similiar.
your right about the self-biasing bit, so self biases I belive with the 20R light bulb resistor, or 100-200watts of power resistors.
So maybe the CCS isn't in it's correct element here. But I am not sure I understand your reaction.
In my pic, C1's polarity is backwards. Oops.
I was also considering this since in F2, C4 acts as a slow turn on. That was one of my goals.
From the altered F2 schematic, I removed the output resistors since the DeLite doesn't use them, all other thinkings looking somewhat similiar.
your right about the self-biasing bit, so self biases I belive with the 20R light bulb resistor, or 100-200watts of power resistors.
So maybe the CCS isn't in it's correct element here. But I am not sure I understand your reaction.
In my pic, C1's polarity is backwards. Oops.
I was also considering this since in F2, C4 acts as a slow turn on. That was one of my goals.
I believe the resistance of the lightbulb gives this amp an output impedience
of ~20 ohms with the light bulb doing double duty acting as a curent source and
adding some damping factor like the bank of resistors in the F2. Replacing
it with a ccs will up the output power but leave us with a pure current source
amp without any damping factor.
of ~20 ohms with the light bulb doing double duty acting as a curent source and
adding some damping factor like the bank of resistors in the F2. Replacing
it with a ccs will up the output power but leave us with a pure current source
amp without any damping factor.
My modest contribution...
MobileMe Gallery
heatsink are diy.... they're cold...
I am listening to the Beatles now, using one amp only since the other is capricious... (light changes its intensity on its own, bad sound, etc...).
The one I am listening now is very much alive... I need to give it more listening, but so far... Success!!!
MobileMe Gallery
heatsink are diy.... they're cold...
I am listening to the Beatles now, using one amp only since the other is capricious... (light changes its intensity on its own, bad sound, etc...).
The one I am listening now is very much alive... I need to give it more listening, but so far... Success!!!
Pendergast, Nice work.
My heatsinks don't get too warm either, power supply resistor does though.
Beatles in Mono, well that's the way it was supposed to be.
I also spy a single speed road bike! Also nice.
My heatsinks don't get too warm either, power supply resistor does though.
Beatles in Mono, well that's the way it was supposed to be.
I also spy a single speed road bike! Also nice.
Hey Stefano,
That it not an option as the FET already sets the current. Two different wills trying to set the standard🙂.
But the close relative to a CCS, the gyrator will work as this one is an AC-CCS and a DC constant voltage source.
This will rise the Zout considerably as the RDC of the bulbs almost alone sets the Zout of the present design. So not an option after all.
My "en"lite
No depletion, but IRFP240. Anyway, it sounds pretty good, even nicer to look at (other lights off). Transistor biasing ala F2 but resistors value are 10X larger since only these are available in my junk tray. Does larger value biasing resistor affect performance?
BTW, reason for choosing depletion transistor is just for ease of biasing or because of its special sonic attribute? Can anyone share their experience with both delite and enlite comparison.
No depletion, but IRFP240. Anyway, it sounds pretty good, even nicer to look at (other lights off). Transistor biasing ala F2 but resistors value are 10X larger since only these are available in my junk tray. Does larger value biasing resistor affect performance?
BTW, reason for choosing depletion transistor is just for ease of biasing or because of its special sonic attribute? Can anyone share their experience with both delite and enlite comparison.
Attachments
Hello ,
Does not happens also in Zen V9 the same thing , the jfet
are selfbiasing , and the current source current has somewhat to be trimmed
for best results ?
If the light bulbs set the Zout , why not the CCS at the same place plus a resistor output -ground as seen many times in the Zen series .
The resistor also helps a lot to equalize the response of the driver , an effect that I like a lot .
They don't fight if you have some DC feedback to hold the
operating point. It doesn't take much, as in the circuit
shown above.
😎
operating point. It doesn't take much, as in the circuit
shown above.
😎
Hi,
I am listening to this thing and woaw!!!
I am using a Quickie from Bottlehead (active preamp on batteries) and I hooked a pair of back loaded horns based on the Fostex 206 es-r . Right now, I am listening to "You Look Good To Me" (Oscar Peterson trio) and this is really wonderful!!!!
I had some problems (slow blow fuse blowing once in awhile), and the bias pots are 99 cents a piece and it shows.... But I am very pleased with this.
I will demo this to the Montreal diy show of April 24, along with other brothers in arms of the local diy community. Some have created variances on the same theme...
I might get sponsored by a sun screen lotion or sunglass company (or both), the light being so intense!
;o)
Thank you for another fun opportunity Mr Pass!
I am listening to this thing and woaw!!!
I am using a Quickie from Bottlehead (active preamp on batteries) and I hooked a pair of back loaded horns based on the Fostex 206 es-r . Right now, I am listening to "You Look Good To Me" (Oscar Peterson trio) and this is really wonderful!!!!
I had some problems (slow blow fuse blowing once in awhile), and the bias pots are 99 cents a piece and it shows.... But I am very pleased with this.
I will demo this to the Montreal diy show of April 24, along with other brothers in arms of the local diy community. Some have created variances on the same theme...
I might get sponsored by a sun screen lotion or sunglass company (or both), the light being so intense!
;o)
Thank you for another fun opportunity Mr Pass!
I haven't build this amp since I haven't bought parts for a long time, but I like the simplicity. What about trying a fixed bias SRPP type of setup. It seems like it would be simpler then the common ways of doing a current source but still use only a few more parts, like this setup:
The Tube CAD Journal,SRPP Decoded
The Tube CAD Journal,SRPP Decoded
I have a couple of those for this same circuit, and they
work like glue. But you can't read by them.
😎
work like glue. But you can't read by them.
😎
Hey Nelson,
Does work like glue mean slow and sticky or awesome?
I was wondering per chance if you have tried these depletion mode mosfets in any tube type circuits with an output transformer? I thought it would be cool to build a Champ or something like that using these mosfets.
Does work like glue mean slow and sticky or awesome?
I was wondering per chance if you have tried these depletion mode mosfets in any tube type circuits with an output transformer? I thought it would be cool to build a Champ or something like that using these mosfets.
It means reliably.
And yes, I have a project using an output transformer
scheduled for publication this summer.
😎
And yes, I have a project using an output transformer
scheduled for publication this summer.
😎
Am I hallucinating?
OK, so I finally decide to build the De-lite. Got it going no problem. Spend a day listening in my workshop then a day listening in my sun room with no problems. I brought the amp in tonight and hooked it to my Bride of Zen and Hawthorne Duets. I have a pair of t-line subs using plate amps. I put the amps in the floor one near each sub - about 8" away. Most everything sounded great except for Patricia Barber's - Ode to Billy Joe. One channel of the amp started buzzing slightly when the bass hit certain notes. I kept working trying to track the buzzing down. I finally touched the amp to see if it was hot and the buzzing diminished. I moved the amp a foot away and the buzzing totally quit. Can those light bulbs suffer from microphonics or have I just lost my mind?
TNX
Jeff
BTW - Hanging with NP is a love/hate relationship. I just kicked my McCormack DNA-1 to the sunroom and am having to start a F5, Aleph 30....something! hehe j/k At least it keeps me out of trouble. Oops, wife demanding attention. ttyl
OK, so I finally decide to build the De-lite. Got it going no problem. Spend a day listening in my workshop then a day listening in my sun room with no problems. I brought the amp in tonight and hooked it to my Bride of Zen and Hawthorne Duets. I have a pair of t-line subs using plate amps. I put the amps in the floor one near each sub - about 8" away. Most everything sounded great except for Patricia Barber's - Ode to Billy Joe. One channel of the amp started buzzing slightly when the bass hit certain notes. I kept working trying to track the buzzing down. I finally touched the amp to see if it was hot and the buzzing diminished. I moved the amp a foot away and the buzzing totally quit. Can those light bulbs suffer from microphonics or have I just lost my mind?
TNX
Jeff
BTW - Hanging with NP is a love/hate relationship. I just kicked my McCormack DNA-1 to the sunroom and am having to start a F5, Aleph 30....something! hehe j/k At least it keeps me out of trouble. Oops, wife demanding attention. ttyl