Culture, using the babelfish I can understand the text, some words are not translated but using the logic it's easy to understand. Thank you.
In my opinion this design it's very interest because the majority of hybrids designs avaliable in the web are Class A ones, but not in thes case. Where I live the components stores are poor, even heatsinks are hard the get, so I'm thinking to build this one, as everything needed I easily can get.
Of couse I gonna modify the original project, as everything that I've built. I'm thinking to use some 6BQ7, maybe a tube rectifier too.
Regards for all.
In my opinion this design it's very interest because the majority of hybrids designs avaliable in the web are Class A ones, but not in thes case. Where I live the components stores are poor, even heatsinks are hard the get, so I'm thinking to build this one, as everything needed I easily can get.
Of couse I gonna modify the original project, as everything that I've built. I'm thinking to use some 6BQ7, maybe a tube rectifier too.
Regards for all.
ilimzn said:
I don't think ilimzn is referring to Nishiki or Elektor hybrids.
He surely means those two other circuits attached.
--------------------------
Elektor Hybrid has got a a softstart circuit on separate PCB.
For an initial period,
a relay will short input to ground level and so also block any input signal.
This way the DC-offset will stay very low during warm up.
--------------------------
Thanks for the info, Tyimo.
So you say the Borbely Hybrid Headphone Amp can be unstable?
I wonder why?
But I think is no problem add one small cap, some pF,
in the correct place, to cure this easily.
--------------------------
Very true, this Elektor Triode-SRPP / MOSFET Hybrid version
runs in Class AB.
With 100 mA idle current in that
Complementary output stage of MOSFET: 2SK176 + 2SJ56
lineup
With both boards stuffed and ready to fire up I got to wondering if a DC Servo board wouldn't make a lot of sense here. With the addition of the Velleman K4700 speaker protection circuit it only makes sense to correct the potential for DC offset drift.
So, anyone have any ideas for the addition of a DC servo circuit? Up to now I have never designed/used any.
The Velleman kit I have has been modified to allow a warm up time for the tube front end of 22 seconds before it will latch up the relay to the output stage. Should I also ground the input of the amplifier until the tube front end becomes stable?
So, anyone have any ideas for the addition of a DC servo circuit? Up to now I have never designed/used any.
The Velleman kit I have has been modified to allow a warm up time for the tube front end of 22 seconds before it will latch up the relay to the output stage. Should I also ground the input of the amplifier until the tube front end becomes stable?
DC servo circuit
There is no reason why you want to add a servo controlled mechanisme. Using the potentiometer offset can be set within +/- 50mV. At first test run you should connect no speaker and adjust offset and bias and do this a few times after 1 / 5 and 10 minutes. Offset will go up and down a little but this is no problem. First 'real' run you should use a simple cheap speaker, if this goes okay you can try your normal speakers.
All grounds should be 'grounded' at all times. Cathode of the Cathode follower will start at zero when switched on and will increase to +120VDC or so. It causes no 'plops' on the speaker.
These servo circuits do have inluence on the overall sound, opamp is critical as the capacitor used.
The K4700 velleman kit only is protection and it is not really needed, but in case the output fails the DC protection will be switched in.
Wim
There is no reason why you want to add a servo controlled mechanisme. Using the potentiometer offset can be set within +/- 50mV. At first test run you should connect no speaker and adjust offset and bias and do this a few times after 1 / 5 and 10 minutes. Offset will go up and down a little but this is no problem. First 'real' run you should use a simple cheap speaker, if this goes okay you can try your normal speakers.
All grounds should be 'grounded' at all times. Cathode of the Cathode follower will start at zero when switched on and will increase to +120VDC or so. It causes no 'plops' on the speaker.
These servo circuits do have inluence on the overall sound, opamp is critical as the capacitor used.
The K4700 velleman kit only is protection and it is not really needed, but in case the output fails the DC protection will be switched in.
Wim
Wim,
Thanks for the reply. I by no means meant that there was a problem when I mentioned the Velleman protection kit or the addition of a DC servo on your design. I like to be safe and protect my speakers in the event of an output failure. With respect to the DC servo circuit I am a believer in keeping a firm grip on DC offset. Granted you have made provisions in your design for DC offset correction. The possibility still might be there for a DC offset problem. I am not an expert by any means but I cannot see the DC offset being rock solid. Granted some DC servo circuits do have an effect on sound but I believe the possibility exhists for a properly designed circuit.
Thanks for the reply. I by no means meant that there was a problem when I mentioned the Velleman protection kit or the addition of a DC servo on your design. I like to be safe and protect my speakers in the event of an output failure. With respect to the DC servo circuit I am a believer in keeping a firm grip on DC offset. Granted you have made provisions in your design for DC offset correction. The possibility still might be there for a DC offset problem. I am not an expert by any means but I cannot see the DC offset being rock solid. Granted some DC servo circuits do have an effect on sound but I believe the possibility exhists for a properly designed circuit.
smoking-amp said:I was reading some stuff over at John Broskie's Tube Cad Journal and there is a mention of an interesting hybrid published in Electronics World, October 1995 by Jeff Mcauly titled "Hot Audio Power" The only library around here that carries the magazine has the page turn out of it.
Anyone happen to have a schematic for it?
Don
Attachments
more about why the Nishiki hybrid design is not published on DIYaudio.com
I will update my website regarding the Nishiki Hybrid design begin january or so and I will post the complete circuit. But until than people could (should?) buy the AudioXpress if they are interested or buy for just 20 euros the complete manual including a complete set of datasheets as mentioned on my website.
At that time the Pioneer version will be finished (this project is slow because my time is limited these days). I made a circuitboard that excpets either a 5965 or 6N3P as long-tailed with CCS and a 6N1P as cathode follower. Board is made in such way that you can use also a current source (IXYS) for the cathode follower. The final amp will use a complete PC88 circuit (photo attached). The PC88 is not a ECC88 or PCC88.
Other thing why I don't mention all details on my page is the fact that I made an version with better specs. Sound differs, because the used driver tube is very suitable for audio. Driver stage is different and output stage yields 100 watt into 5 ohm at 0.3% distortion (output stage set to +/-38VDC), this with no overall feedback. Some known magazine is interested to publish it and it will maybe be published, will know this in some weeks I hope. Project will be including a very nice professional housing all for a very interesting price; the intention of the project, good sound for good money
So stay tuned and please be patient, if interested of course
Wim.
www.wdehaan.demon.nl/
I will update my website regarding the Nishiki Hybrid design begin january or so and I will post the complete circuit. But until than people could (should?) buy the AudioXpress if they are interested or buy for just 20 euros the complete manual including a complete set of datasheets as mentioned on my website.
At that time the Pioneer version will be finished (this project is slow because my time is limited these days). I made a circuitboard that excpets either a 5965 or 6N3P as long-tailed with CCS and a 6N1P as cathode follower. Board is made in such way that you can use also a current source (IXYS) for the cathode follower. The final amp will use a complete PC88 circuit (photo attached). The PC88 is not a ECC88 or PCC88.
Other thing why I don't mention all details on my page is the fact that I made an version with better specs. Sound differs, because the used driver tube is very suitable for audio. Driver stage is different and output stage yields 100 watt into 5 ohm at 0.3% distortion (output stage set to +/-38VDC), this with no overall feedback. Some known magazine is interested to publish it and it will maybe be published, will know this in some weeks I hope. Project will be including a very nice professional housing all for a very interesting price; the intention of the project, good sound for good money
So stay tuned and please be patient, if interested of course
Wim.
www.wdehaan.demon.nl/
Attachments
A circlotron, now you're talking!
The Atma-Sphere uses the same basic idea with 6AS7 outputs, but deletes the phase splitter and uses the second half of the input tube in a long-tailed pair configuration (allowing for balanced inputs).
You can bias it any way you like. The original 50's EV tube versions were class AB. The Sumo 9 was a sliding bias class A/AB.
Just make sure you temperature compensate your bias for the FETs you choose, the lateral FETs (as shown) don't need this of course.
The Atma-Sphere uses the same basic idea with 6AS7 outputs, but deletes the phase splitter and uses the second half of the input tube in a long-tailed pair configuration (allowing for balanced inputs).
You can bias it any way you like. The original 50's EV tube versions were class AB. The Sumo 9 was a sliding bias class A/AB.
Just make sure you temperature compensate your bias for the FETs you choose, the lateral FETs (as shown) don't need this of course.
I fired up the Nishiki modules today. I'm impressed, darn impressed. To be honest I had my doubts as to the DC offset tracking and the bias control. The modules ran smoothly after setting the DC offset and bias. I ran them up on a load and there was no bias run away, no nasty oscillation, no glitches on the scope just a pure clean sine wave.
After being satisfied that they were going to run without any problems I hooked them up to my speakers without the aid of the Velleman speaker protection kit I purchased.
I am still shaking my head wondering how these little modules can sound so clean and clear. They seem to have the good qualities of the tube line stage and the clarity and quickness of a real good soild state amp. They have nice bass and a smooth liquid mid and high frequency.
As one could expect these modules are going to need a hefty signal so I would not be afraid to hook them up to a line stage with a LOT of gain. I ran them with my Aikido 6Au6/5687 line stage without any glitches, noise, or problems. I can hardly wait until I try Wim's new line stages with it.
Bottom line..... are they worth buying?
With out a doubt they are well worth the money and effort. They provide a real nice reproduction of the material presented to them without coloration. I have listened to other hybrid amps and NONE have come close to this one. A well engineered product that I can recommend without second thoughts.
After being satisfied that they were going to run without any problems I hooked them up to my speakers without the aid of the Velleman speaker protection kit I purchased.
I am still shaking my head wondering how these little modules can sound so clean and clear. They seem to have the good qualities of the tube line stage and the clarity and quickness of a real good soild state amp. They have nice bass and a smooth liquid mid and high frequency.
As one could expect these modules are going to need a hefty signal so I would not be afraid to hook them up to a line stage with a LOT of gain. I ran them with my Aikido 6Au6/5687 line stage without any glitches, noise, or problems. I can hardly wait until I try Wim's new line stages with it.
Bottom line..... are they worth buying?
With out a doubt they are well worth the money and effort. They provide a real nice reproduction of the material presented to them without coloration. I have listened to other hybrid amps and NONE have come close to this one. A well engineered product that I can recommend without second thoughts.
burnedfingers, saying this you make me spend more money that I can't spend.
I'm saving money for a new set of speakers at the same time I want to build this project and another one, just with tubes.
I will make some sacrifice and wait until next year to start this project.
Good lock for me and congratulations for you.
Regards.
I'm saving money for a new set of speakers at the same time I want to build this project and another one, just with tubes.
I will make some sacrifice and wait until next year to start this project.
Good lock for me and congratulations for you.
Regards.