The Berning amp uses sweep tubes and screen grid drive. It also runs right at the edge of class B, hence the low idle current. The peak current will still be as high as a conventional class AB amp. I have tried this with other sweep tubes (6AV5's) and it works quite well. Screen grid drive requires a tube with a sensitive screen grid. This can often be determined by the maximum screen grid voltage, the lower the better. An EL-34 won't work here.
To get a low idle current, you must operate close to class B , this requires a tube that is linear at very low currents. I haven't tried it, but again I don't think that an EL-34 will work here.
To get a low idle current, you must operate close to class B , this requires a tube that is linear at very low currents. I haven't tried it, but again I don't think that an EL-34 will work here.
6LF6 are unobtanium these days. Take a look at the EA2101 schematic where Berning used paralleled 6JN6.
His schematics are a great tutorial on how to do screen drive. Optimal idle currents vary with load impedance, particular tube used, plate voltage and the like. You'll need to determine it experimentally. Figure it will be between 2 and 10mA.
His schematics are a great tutorial on how to do screen drive. Optimal idle currents vary with load impedance, particular tube used, plate voltage and the like. You'll need to determine it experimentally. Figure it will be between 2 and 10mA.
Someone suggest me, please
I decide to use EL519 for amplifier project in stead of 6LF6 of Berning EA-2100 but I have something wrong, It used 10mA each power tube !!! 100WRMS ?!?
How do I design OPT ?
: 700V Plate, 10mA bias, 100WRMS ?
: K of OPT?
: Henry of Primary & Secondary ?
: Wire size, Turn ratio ?
Regard
analog guy
I decide to use EL519 for amplifier project in stead of 6LF6 of Berning EA-2100 but I have something wrong, It used 10mA each power tube !!! 100WRMS ?!?
How do I design OPT ?
: 700V Plate, 10mA bias, 100WRMS ?
: K of OPT?
: Henry of Primary & Secondary ?
: Wire size, Turn ratio ?
Regard
analog guy
How much power do you want in your car amp. I used the 6AV5 in a screen drive amp that delivered 80 watts RMS at clip and 3% distortion at 50 watts with no feedback anywhere in the amp. 6AV5's are under $5 each in most tube stores and they fit an octal socket. There is a 12 volt version the 12AV5. They are available on Ebay for $1.50 each!
The amplifier runs at a B+ level of 550 volts and uses a 6600 ohm output transformer. The idle current is low, about 10 mA per tube I think. Just remember that the amp will draw about 200 mA per channel at full crank. Your power supply should be able to supply this much on signal peaks.
My amp is still in the prototype stage, but can be seen here. It is at the bottom of the page.
http://www.tubelab.com/6AV5.htm
The amplifier runs at a B+ level of 550 volts and uses a 6600 ohm output transformer. The idle current is low, about 10 mA per tube I think. Just remember that the amp will draw about 200 mA per channel at full crank. Your power supply should be able to supply this much on signal peaks.
My amp is still in the prototype stage, but can be seen here. It is at the bottom of the page.
http://www.tubelab.com/6AV5.htm
New project completed
EL509 sgreen drive enchance triode PP
+720 Vp
+360 cathode follower drive
+300 pre drive
-145 grid bias
10mA idle !!!
I used schematic of Berning EA-2100 but I used EL509 instead of 6LF6
Next time I'll design PCB of SMPS for use it in my car (100WRMS per channel !!!)
...Good impact bass (not aggressive) and widely sound stage that I never heard from other PP amplifier...
EL509 sgreen drive enchance triode PP
+720 Vp
+360 cathode follower drive
+300 pre drive
-145 grid bias
10mA idle !!!
I used schematic of Berning EA-2100 but I used EL509 instead of 6LF6
Next time I'll design PCB of SMPS for use it in my car (100WRMS per channel !!!)
...Good impact bass (not aggressive) and widely sound stage that I never heard from other PP amplifier...
Attachments
Tube bias?
Hi, Gents:
We don't need to care about what type of tubes? AF, RF, Osc, Horizontal output, Vertical. output-----etc.
When we want to use a tube, we must know where do you want the tube to work on? To utilize a tube, we must have it's EG-IP curve, If for class A SE, then you bias the tube to it's linear est district, if for AB PP, set the bias according to AB1, AB2, or B requirement. If set the quiescent current too low, the tube will work on class B, or below. Then crossover distortion become large. If U set the EL34 to a few ma, then u will get extreme distortion due to class B gets most power and most distortion.
If the quiescent current too low, you have to rise up the B+, or set the bias lower, too little quiescent current just put the tube work on a nonlinear district, U won't get good sound out, and is not advised.
SOUND BETTER WITH RIGHT QUIESCENT CURRENT
Hi, Gents:
We don't need to care about what type of tubes? AF, RF, Osc, Horizontal output, Vertical. output-----etc.
When we want to use a tube, we must know where do you want the tube to work on? To utilize a tube, we must have it's EG-IP curve, If for class A SE, then you bias the tube to it's linear est district, if for AB PP, set the bias according to AB1, AB2, or B requirement. If set the quiescent current too low, the tube will work on class B, or below. Then crossover distortion become large. If U set the EL34 to a few ma, then u will get extreme distortion due to class B gets most power and most distortion.
If the quiescent current too low, you have to rise up the B+, or set the bias lower, too little quiescent current just put the tube work on a nonlinear district, U won't get good sound out, and is not advised.
SOUND BETTER WITH RIGHT QUIESCENT CURRENT
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.