• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

HYBRID- Schematic

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#4
I so far like this project and i am going to tackle it. I cant for the life of me find the author.. I plan on changing some parts though..
 

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#6
jleaman said:
I so far like this project and i am going to tackle it. I cant for the life of me find the author.. I plan on changing some parts though..
Click to expand...

I think I'll give that design a go as well, would you have the schematic for the power circuit? I'm wondering how I should go about making the power supply to give me +35VDC and -35VDC...... a TLE246 maybe?
 
#7
pho_boi said:


I think I'll give that design a go as well, would you have the schematic for the power circuit? I'm wondering how I should go about making the power supply to give me +35VDC and -35VDC...... a TLE246 maybe?
Click to expand...

Im going regulated. Im also going to do it with just the standard bridge rectifier with a 6.3 vold and a 35 + - capacitance bank. Just a simple circuit. The ill start changing values maybe change the tube then of course the out put transistors to other ones that could handle more current. Maybe add 2 more out put fet's THEN ill go regulated psu and regulated psu for teh tube..

I'm trying to figure out how to make a tube part in Eagle GOOD luck with this for me > O (
 
#8
jleaman said:


Im going regulated. Im also going to do it with just the standard bridge rectifier with a 6.3 vold and a 35 + - capacitance bank. Just a simple circuit. The ill start changing values maybe change the tube then of course the out put transistors to other ones that could handle more current. Maybe add 2 more out put fet's THEN ill go regulated psu and regulated psu for teh tube..

I'm trying to figure out how to make a tube part in Eagle GOOD luck with this for me > O (
Click to expand...


I'm pretty new to the tube scene, and so far I've only had goes at building hyrbids. Would it be too rude for me to ask to have a look at your final schematic? I really would like to build a nice sounding hybrid because my first hybrid using sijose's design on headwize wasnt all that great.

thanks 🙂
 
#10
Re Hybrid schematic.

Jason,

For a good explaination of this Borbely linestage ripoff and how to improve and enhance it go to www.tubecad.com and download March 2001 and then April/May 2001. Have fun! Somewhere on that site is correspondence from Erno Borbely regarding the schematic you have posted.

Cheers,
Steve.
 
#14
Tyimo said:
Hi!

Do not build that hybrid circuit of Essential audio!!!
It is not working as it is!!
You could try the original Ernõ Borbély Hybrid line amp, thats working well!

Greets:

Tyimo
Click to expand...


What part of this doesnt work. ? How do you know it doesnt work. ? have spare parts around so im going to try it see what i get.. Do you have a link the schematic or some reading material for the one i should build ?

J'
 
#15
I'd like to repeat a tip or concern here that I've mentioned before in other threads. The gate of a MOSFET exhibits large and variable capacitances. I think that the gate should not be connected directly to the relatively high-impedance plate. The resulting RC time “constant” creates significant phase shift in the audio band. The problem is that the RC time “constant” really isn’t a constant at all. The capacitance varies significantly as voltages swing on the MOSFET. This creates the potential for frequency / phase intermodulation distortion which is pretty ugly. Furthermore, the large value of capacitance simply loads down the plate at higher frequencies, not good even if it were constant. I would suggest driving the MOSFET gate from a very low impedance source to shorten the time constant as much as possible and reduce (but not eliminate, sadly) the amount of phase shift in the audio band. Perhaps a cathode follower intermediary stage would be best (being careful of stability with the capacitive load).
 
#18
I have only seen the 3rd edition. The amp was presented as an exercise in voltage level shifting and the use of high gm tubes as cathode followers to drive the FETs.

I reviewed Jones's book on Amazon. My take is very similar to yours- if you're going to do something irrational like using tubes, you might as well engineer it properly. Needless to say, my review was extremely positive. I thank planet 10 for twisting my arm into buying a copy.
 
#19
Hi J!

I have built and it was totaly instable and disaster:The fets and some resistors and some caps was blow out! I know also few diyers who built it and got the same result!! I know only one man who could got to working the amp: Alexander from Zeuslab-Russia.
There are some old threads where you could find "negativ" infos about this amp: PassHybrid.
I also spoken with the original designer: Mr. Erno Borbely and He told me that this cicrcuit (Generoso Cozza's) can not working as it is.... (even not the kit version from Cozza!, because Ralf bought it and the result was the same)
The story is long, you could get some info from TubeCad too.
Greets!

I would like to ask about the TubCad Hybrid version: could I use IRFP240 instead of the BUZ900?

Tyimo
 
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