Home Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

RE: Poor Design for a Preamp

Tre made the suggestion to use 68k+22k resistors to give me a dropping output level but not to limit upper frequency. Tried this ides with a 6N7 preamp I also had noise issues with and it worked well.Even with my DIY shieldless lead (175pF) into 100K upper 3db was 37KhZ. 6N7 are power tubes and Im not sure of they have a very high frequency range or not. Regardless I'm happy with 37K.

Applying the same 68k+20k idea to the 01a preamp gave me noise level outputs of 1.9mV and 0.9mV a big improvement over the ~4.0mV with the 300k+100k setup. At good volume only by putting my ear to my 93db sensitive 12" woofers do I hear the slightest hum then only in the left channel.

Good result for two preamps so far and two to go. Lucky I have a good collection of Rs to mod the others.
| retro-thermionic |


This post is made possible by the generous support of people like you and our sponsors:
  McShane Design  


Follow Ups Full Thread
Follow Ups

FAQ

Post a Message!

Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Subject:
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.