Dr.Mavashi
neonderthalotonalogist
Talk to me peeps. I know they are like 40% of ECC83s gain, but I hear the can be very interesting tone wise, how would you use one in british voiced amp pushed with an OD for metal typa stuff? Thanks.
12AV7s
- Thread starter Dr.Mavashi
- Start date
missionamps
New member
Re: 12AV7s
I find that, randomly, they can be a little microphonic so buy a bunch... they are super cheap.
Slightly darker and little tiny bit muddier then a 12AY7 and they like to be biased a little hotter then a 12AY7.
The last time I used any was in a 35 watt, 4x10 harp amp I built for Kenny Dore and I biased them with about twice the idle current of a 12AY7 or 12AX7.
I find that, randomly, they can be a little microphonic so buy a bunch... they are super cheap.
Slightly darker and little tiny bit muddier then a 12AY7 and they like to be biased a little hotter then a 12AY7.
The last time I used any was in a 35 watt, 4x10 harp amp I built for Kenny Dore and I biased them with about twice the idle current of a 12AY7 or 12AX7.
Dr.Mavashi
neonderthalotonalogist
Re: 12AV7s
Wait, I know I am an amp retard, but I thought that you dont bias the pre-amp tubes ......
Wait, I know I am an amp retard, but I thought that you dont bias the pre-amp tubes ......
missionamps
New member
Re: 12AV7s
Almost every preamp tube circuit I can think of is self biased in some way or another so you would probably never do anything to an existing circuit to change the preamp tube bias.
I tweak, mod and build amps from scratch. I frequently set the bias of preamp tubes in such a way to alter the tone, the harmonic content and distortion products... trying to achieve some kind of tonal goal based on the circuit or the actual type of preamp tube use, as in the case of the 5965 or 12AV7.
This trick is also helpful when tweaking for clean or distorted, fat or thin, fizzy or glassy, and also when setting up an instrument specific amp like a harp amp vs a guitar amp. Etc.
All vacuum tubes (transistors too) must be biased correctly or they will not turn on or they will be turned on so hard they will overheat and blow up.
Almost every preamp tube circuit I can think of is self biased in some way or another so you would probably never do anything to an existing circuit to change the preamp tube bias.
I tweak, mod and build amps from scratch. I frequently set the bias of preamp tubes in such a way to alter the tone, the harmonic content and distortion products... trying to achieve some kind of tonal goal based on the circuit or the actual type of preamp tube use, as in the case of the 5965 or 12AV7.
This trick is also helpful when tweaking for clean or distorted, fat or thin, fizzy or glassy, and also when setting up an instrument specific amp like a harp amp vs a guitar amp. Etc.
Dr.Mavashi
neonderthalotonalogist
Re: 12AV7s
Wow Bruce I am a bit confused now, I was told that if you wanna swap pre-amp tubes you just swap them, you don't need to bias them. Also, my amp Laney AOR Pro-Tube series I(six knobs) is known for being one the most sensitive amps to pre-amp tube swaps out there, but in a good way meaning really good, different tones depending on the tubes. I play more or less what could fall into a high gain territory, I push it with John Spina TS9, but I am into different kind of high gain as well, so for example I am really enjoying the combination of high gain and gold pin ECC83 tube in it now, but are you saing I could re-bias my pre-amp for more gain as for example my high gain Ecc83s are in V2 and V3 so are you saingy I could "step things" up in those to Vs to really get the most out of those higher gain tubes ? Thank you. I've also pm'ed you for another question.
Wow Bruce I am a bit confused now, I was told that if you wanna swap pre-amp tubes you just swap them, you don't need to bias them. Also, my amp Laney AOR Pro-Tube series I(six knobs) is known for being one the most sensitive amps to pre-amp tube swaps out there, but in a good way meaning really good, different tones depending on the tubes. I play more or less what could fall into a high gain territory, I push it with John Spina TS9, but I am into different kind of high gain as well, so for example I am really enjoying the combination of high gain and gold pin ECC83 tube in it now, but are you saing I could re-bias my pre-amp for more gain as for example my high gain Ecc83s are in V2 and V3 so are you saingy I could "step things" up in those to Vs to really get the most out of those higher gain tubes ? Thank you. I've also pm'ed you for another question.
Zhangliqun
Questionologist
Re: 12AV7s
You don't NEED to bias preamp tubes, but apparently if you can if you want to and know what you're doing (I don't).
But you do have to bias new power tubes. You may occasionally need to rebias power tubes you've had in there a while because the bias can drift a bit over time.
You don't NEED to bias preamp tubes, but apparently if you can if you want to and know what you're doing (I don't).
But you do have to bias new power tubes. You may occasionally need to rebias power tubes you've had in there a while because the bias can drift a bit over time.
