feedback connections for tubes

[SUPERMAGOO]

is the feedback connection for tubes realy necessary?. is it for correcting fase only or does it have another function?

 

[gyraf]

I think you need to rephrase your question - it does not really make sense (to me, at least)..?

Jakob E.

 

[SUPERMAGOO]

it's difficult for me expressing myself in english :sad: .im from argentina.im builder of clones.i do la2, and 1272 neve and work fine.i build 12au7 compressor of PRR but doesnt work.my question its about feedback conections on tube preamp circuit.i read a dictionary and try again.thank you for your time.

 

[pstamler]

[quote author="SUPERMAGOO"]is the feedback connection for tubes realy necessary?. is it for correcting fase only or does it have another function?[/quote]

It depends on how you define "necessary". It's possible to build excellent circuits (such as preamps) using feedback connections around tubes. It's also possible to build excellent circuits without using feedback, if you design the circuit to operate that way. Removing the feedback from a circuit that is designed to use it will usually not produce good results.

It has other functions besides correcting phase (which it doesn't always do). Well-designed feedback can lower the distortion level of a circuit, allow it to be less sensitive to changes in the tubes' characteristics with age, and/or tailor frequency response in a desired way. Some forms of feedback also lower the output impedance of a circuit.

In short, feedback can be one of many useful tools for the designer; you can design with it, or without it, but simply removing it from a circuit is usually not a good idea.

Peace,
Paul

 

[SUPERMAGOO]

thank you paul.its just what i needed to know!!!!! :grin: .have you got any interesting schematic?.what do you think about ua610 preamp?.im about to make a preamp.im between g9 or old ef86 neve preamp. in the first stage of preamp which one generates more musical harmonics? pentodo or triodo?

 

[gary o]

Hiya Supermagoo.. im not quite as knowledgable as most on here but I like to experiment, I made a RCA BA1A mic pre that has a feed back circuit, so I thought id see for myself what it would sound like without it, it sounded fatter & warmer hard to discribe, I suppose the distortion went up but in a nice way, I now have a switch for clean & flat & fat & warm I dont suppose this would work on all designs but was good for me on this one.

cheers .....Gary O.

 

[SUPERMAGOO]

thank you gary .it`s good idea.i will improve your advice!