Hi, today i played with ecc83: i want a distorsion !!!
ive make this circuit, but sound terrible distorted and dirty, drammaticali compressed ( like a fart, or dc component ).
I think the problem is impedance.... i want insert this circuit in line in / out in my rack equipments. Line out from preamp -> circuit -> line in compressor.
Please help me!
p.s. op amp is a burrbrown opa2277p, -v is connected to ground, +v to 12 vdc. there is a 7812.
ive make this circuit, but sound terrible distorted and dirty, drammaticali compressed ( like a fart, or dc component ).
I think the problem is impedance.... i want insert this circuit in line in / out in my rack equipments. Line out from preamp -> circuit -> line in compressor.
Please help me!
p.s. op amp is a burrbrown opa2277p, -v is connected to ground, +v to 12 vdc. there is a 7812.
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Well , Running at 12ax7 at 12v isn"t going to give you a Very nice distortion , Ive tried several 12v Tube curcuits and couldn"t get anything nice sounding , the lowest voltage I was able to run the plates and still get a nice clean distortion was 45v .....
You are right about the impedance though and putting a high impedance buffer at the output is a good idea so you get the best signal transfer but instead of building the buffer and maybe finding out that is doesn"t help , just plug the output of the tube cuircuit into a effects Pedal and use that as a buffer .....
Also you should put a 500k or 1m pot between the 2 tube stages so can controll the overdrive/distortion effect .......
Cheers
You are right about the impedance though and putting a high impedance buffer at the output is a good idea so you get the best signal transfer but instead of building the buffer and maybe finding out that is doesn"t help , just plug the output of the tube cuircuit into a effects Pedal and use that as a buffer .....
Also you should put a 500k or 1m pot between the 2 tube stages so can controll the overdrive/distortion effect .......
Cheers
ive try to connect only tube, without buffers, in a high z in of premplifier. Sound better, gain is low, and level distortion is low ( old rock style ). If i use a low volume in guitar sound is very warm. I dont understand why with buffer sound low and dirty: seem not a distortion of a tube. Ok tube at 12 v is not good, but this circuit dont work. This evening i record the distortion...
No bias on the valves, far too low an HT rail, and a completely spurious opamp in front of it, ruining the input impedance.
Stick 200-300V HT feeding the valve, bias them correctly, and dump the first opamp.
Stick 200-300V HT feeding the valve, bias them correctly, and dump the first opamp.
Best if you keep the opamp fed from a suitable low voltage (assuming you still want to use it? - as it's presumably going to be feeding a guitar amp input, the valve could feed it directly) 😀
im doing a particolar fx for me. I want do build a vocal distort. There is an ic that do 2 channell mixing with eq and volume via i2c, a digital i2c pot for change gain and a i2c filter. An atmel change presets via midi and drive an lcd. For distortion i want use an ecc83, whit catodic digital potentiomer for gain setting ( i must measure voltage at k, high voltage may melt digipot, or i will use a photoresistor with led & pwm lol )
Run the Plates at a High Voltage , put a voltage divider on the output of the tube stage to knock down the output voltage to 1/10 , then put the Buffer at the ouput .... Marshal does this in some of their ValveState amps .....
12AX7 is not suppose to work well at low voltages, too much gain and no headroom. 12AU7 is suppose to work better at low voltages. I am sure if you do a quick search you will come up with a suitable circuit.
Minion, are you saying that he won't get nice distortion because he is using a 12AX7? Or because he is running it at 12 volts?
You get great distortion out of a 12ax7 but is sounds pretty farty at 12v , there isn"t enough headroom at 12v for the amount of gain in at 12ax7 , I second the suggestion to try a 12au7 at 12v as it has less gain and would need less headroom .....
I have a pre-CBS Fender Bassman amp (lousy bass amp but a good guitar amp) and it has 12 A something besides X 7s. It might be 12 AU7s. It does have less gain than all my other amps and they all have 12 AX7s.
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