Preamp No caps inputs

[abelma]

Hi, I am in the project to assembly an active preamplifier, tube or transistor. I did some research, and I have a lot of choices.
My question is somebody has a preamp tube (6922 or ECC88) circuit with the possibility to avoid the input cap? I think (I am a newby!) that a preamp with a interstage transformer could do the job? Or, can I modify any preamp with the addition of a interstage transformer, and how ? Thank You

[Sean]

Your preamp needs to have a ~2.5v bias on the output to match the amps input bias. I've never touched tubes so I can't help you there.

[V-bro]

The inputs of the Tripath amps carry 2,5V when the cap is not in use, this bias voltage would heat up your transformer. So it is important to make sure this is nulled somehow.

That's where my experience with this stops....

Sorry...

------X-max. can be several meters on any driver, too bad it can be done only once...------

[abelma]

Thank´s guys !
I dont know exactly of what you are talking...still learning.
Looking for most information about.
But, I remember VBro a post talking about input transformer, in the topic of direct coupling. Did you use the neutrik transformer?. Still using it, some problems?
Thanks !

[abelma]

Hi..I have an other option.
I have a preamplifier tube circuit, and it has a output cap.
Should I take away the amplifier input cap?.
Also, because I will biamp with two amp10, can I connect in parallel the two inputs channels without their input caps, having a output cap in the preamplifier?
Thank´s a lot

[V-bro]

I would remove the output cap in the preamp and leave the input caps be...

I still use the Neutrik trannies, though I also use the unshielded NTE-4 which works very well and is a lot cheaper! Do bare in mind that is has a 1:4 ratio...

------X-max. can be several meters on any driver, too bad it can be done only once...------

[V-bro]

I would remove the output cap in the preamp and leave the input caps be...

I still use the Neutrik trannies, though I also use the unshielded NTE-4 which works very well and is a lot cheaper! Do bare in mind that is has a 1:4 ratio...

------X-max. can be several meters on any driver, too bad it can be done only once...------

[abelma]

Thanks Vbro.

That means, having a 1:4 transformer, I should have a level signal output from the preamplifier very low, to match the 4 vpp input amplifier sensibility ?
Only to re confirm, having this transformer between the preamp and the amp, I could take away ALL the caps from the preamp output and the amp input ?
Also, putting in parallel the inputs in the amp10, should I have one or two transformers for each channel?

[abelma]

Thanks Vbro.

That means, having a 1:4 transformer, I should have a level signal output from the preamplifier very low, to match the 4 vpp input amplifier sensibility ?
Only to re confirm, having this transformer between the preamp and the amp, I could take away ALL the caps from the preamp output and the amp input ?
Also, putting in parallel the inputs in the amp10, should I have one or two transformers for each channel?