Search found 8 matches
- Wed Sep 02, 2009 4:29 pm
- Forum: Technical Discussion
- Topic: VVR adjustment started to introduce some noise
- Replies: 5
- Views: 2425
VVR Noise
If you are getting voltage control, no need to replace Mosfet. After seeing your reply I checked my amp VVR with a scope on the output of the Mosfet feeding the output transfomer. (Carefully measure using a 0.1uF 600V cap in series with scope probe) Very clean, no noise except when at maximum a litt...
- Sun Aug 30, 2009 6:03 pm
- Forum: Technical Discussion
- Topic: VVR adjustment started to introduce some noise
- Replies: 5
- Views: 2425
Typo on Mosfet connection
Small typo in my last comment the output of the Mosfet is the SOURCE connection going to the output transformer and screens.
I need more coffee!
good luck!
I need more coffee!
good luck!
- Sun Aug 30, 2009 5:39 pm
- Forum: Technical Discussion
- Topic: VVR adjustment started to introduce some noise
- Replies: 5
- Views: 2425
VVR Noise
It may be the VVR Mosfet oscillating at high frequencies causing the audible white noise. Most of the VVR circuits do not bypass the pot wiper or power connections with .01 up to 0.1uf 600V caps to ground. Your filter caps may have aged some and may be contributing to this symptom. Ask the VVR desig...
- Sun Aug 30, 2009 2:34 am
- Forum: Technical Discussion
- Topic: VVR
- Replies: 5
- Views: 2942
VVR Source
Go to Hall Amplification for starters. VVR3 is a single Mosfet voltage regulator. Simple cathode biased amps can get by with one Mosfet reg. It gets more complicated if you have a fixed bias amp. http://hallamplification.com/main.html?src=%2F#2,2 The VVR and PPMV are both good to have. You can back ...
- Tue Aug 25, 2009 2:35 pm
- Forum: Technical Discussion
- Topic: Making Vox Night Train footswitchable?
- Replies: 4
- Views: 4460
Re: Making Vox Night Train footswitchable?
Hello, That is the one thing the NT missed is remote footswitch feature. All is possible if you are good at modifying or have a tech to help out. The thick gain is too high to let run wide open. so you will need a second gain pot for Thick mode. (Small front panel hole with a pot adjustable behind f...
- Sun Aug 23, 2009 4:46 pm
- Forum: Technical Discussion
- Topic: Vox Night Train Schematic
- Replies: 31
- Views: 28435
NT15 Amp similar to Park
Cool! That is the closest so far. Lift the feedback loop from OT and place it on the first amp stage cathode. (with appropriate value changes) BTW Some players I have heard using this amp like the thick mode best. Which tosses out the tone stack and gives you more gain. But I still like the Bright/T...
- Thu Aug 20, 2009 10:57 pm
- Forum: Technical Discussion
- Topic: Vox Night Train Schematic
- Replies: 31
- Views: 28435
Vox Night Train Design
Hello everyone, In my investigating the NT amp more, I found a few minor errors in the schematic that was posted last month. Sorry!!! The amp does work fine with prior error but changing the third gain stage plate resistor brings amp up to exact copy. (and voltages are closer) Some of the input part...
- Tue Jul 28, 2009 1:01 am
- Forum: Technical Discussion
- Topic: Vox Night Train Schematic
- Replies: 31
- Views: 28435
Vox Night Train Schematic
Had this amp for a week to draw the schematic. Happy building!