Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Preamps and Effects => Topic started by: mensur on February 19, 2009, 08:45:24 PM

Title: Waves GTR3 Preamp
Post by: mensur on February 19, 2009, 08:45:24 PM
Hi guys, i need help!!!
I designed the preamp based on the interface manual specs:

OUTPUT BALANCED XLR:
Output impedance: 50 ohm
S/N: >105 @ line level, >70 @ mic level (S measured at 1%, 1 Khz, A Weighted)
Response: 20-20Khz , -3dB @11Khz, -5dB @ 20Khz
THD+N: <0.005 (< -90dB) @ -10dB below max sensitivity level
Sensitivity: 1.1Vrms @ line level, 2.5 Vrms @ mic Level
Gain: 11dB @ line level, -28dB @ mic level. ±1.5dB.

(http://www.fileden.com/files/2008/12/25/2237836/Waves%20GTR%203.jpg)

Is preamp OK, is it balanced output?
Voltage supply range is from 9-24V.
Title: Re: Waves GTR3 Preamp
Post by: phatt on March 01, 2009, 09:34:56 PM
Hi,
    In Answer to your Q ,,No it's not balanced output.
Sounds like you need to do some research if you want hi spec bal output.
I believe Rod Elliot at ESP may still have some Bal output ideas on his pages I think.
Might help also if you give us some idea of what you are trying to achieve
as not everone may know what  a Waves GTR3 Preamp is used for,,well I have no idea?
Cheers, Phil.
Title: Re: Waves GTR3 Preamp
Post by: phatt on March 02, 2009, 02:09:10 AM

Your rather LARGE Schematic got me thinking about the pains I went through when messing with Fet ideas some years ago ,,,So this Schem might help you out.
You can run into trouble with noise and this will reduce that issue somewhat.

Also in regard to balanced circuits why not just jump on "Jensen Transformer Site".
Heaps of balanced circuit ideas with explanations on their pages, all free to download and try.
Phil.