why not use a ccs anode load, say dn2450 cascode, or something like the morgan jones cascode, then try LED or stick with a resistor in cathode?
Yes! I see it! But CCs anode load, it is very hot! And the sound is not like!
Use led in the cathode, i like the sound!
Hi kevinkr!
Well thank you!
Well yes, the LM317 can not be the best, I used Jfet replace it! I recently tested the following schematic, and I enjoyed it! 6h30pi particular tube,
Thank you and hope you add comments to this pre!
With tube 6h30 i like:
Anode = 90V, 40mA/ Tube
6h6 I like:
Anode = 170V, 40ma/Tube
This is other circuit, Please see it!
Thanks
Quanghao
Simple balanced pre-amp. I did something similar long ago and also experimented with cross-connected cascodes, excellent balance, but too much noise with the Amperex E82CC I was using at the time. Consider using a cascode CCS with a small negative supply (-12V or so), CMRR will be greatly improved. (Ability to reject hum, and other common mode noise)
I'd think you might want to increase the plate load resistor values slightly? _ I haven't checked rp for this type, but bear in mind that with differential connection it will be much higher than you think. (twice or more is possible)
Simple balanced pre-amp. I did something similar long ago and also experimented with cross-connected cascodes, excellent balance, but too much noise with the Amperex E82CC I was using at the time. Consider using a cascode CCS with a small negative supply (-12V or so), CMRR will be greatly improved. (Ability to reject hum, and other common mode noise)
I'd think you might want to increase the plate load resistor values slightly? _ I haven't checked rp for this type, but bear in mind that with differential connection it will be much higher than you think. (twice or more is possible)
yes! it is very nice idea . the circuit follow the basic with CCS + bias!
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why not use a ccs anode load, say dn2450 cascode, or something like the morgan jones cascode, then try LED or stick with a resistor in cathode?
Hi admus!
Led biass, the sound is very detail, Like!
Thanks
no problem. LED + Css anode load has given me good results in similar designs.
Hi adamus ! im not like the sound use CCS!
Hi all!
you can down the circuit and measure about the pre in this linhk:
http://www.quanghao.com/product.php?id_product=72
thanks
I just finished Pre 818, just watch it
very nice board quan!
I just finished Pre 818, just watch it
Very nice pcb! If those two Solen caps are in the signal path I have found that several other equally inexpensive brands sound much more transparent. I particularly like the Clarity SA which shouldn't cost much more.
Any updates, quang??
Yes!
the updat it is good! i sent circuit later
Quanghao, what is the gain of this pre, and is it adjustable?
Hi!
gain= 21.6dB
Output imperdance: 500 Ohm
Please go to here see my update:
http://www.diyaudio.com/forums/tubes-valves/202336-best-preamplifier.html#post2816584
Thanks all!
Quanghao
http://www.diyaudio.com/forums/tubes-valves/202336-best-preamplifier.html#post2816584
Thanks all!
Quanghao
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