FlaCharlie
Super Member
Yeah, I assume that most of the difference is the 2v higher wall voltage and significantly lower ESR of the film caps. Close enough. Real world listening results under normal operating conditions are the important thing.
GloTone Cockeyed Monkey - A Directly Coupled SET
- Thread starter FlaCharlie
- Start date
Have you guys looked into the Loftin/White design ? according to some, the direct connection between tubes was not the only thing going on with the L/W amps but most lump it in that basket, it also had power supply noise cancelling.
Sheldon spoke about it on DIY Audio in his short thread:
loftin white 801 amp
www.diyaudio.com
Sheldon also describes how to figure out some calculation for this amp:
www.diyaudio.com
soulmerchant had a thread too:
My New Iron for Single Ended 2a3
www.diyaudio.com
cheers.
Sheldon spoke about it on DIY Audio in his short thread:
loftin white 801 amp
loftin white 801 amp
I got inspired by Darius's musings on Loftin White amps, so I modified my 801 resistor loaded amp into a Loftin-White amp, but using a triode for the input tube, as I don't need the high sensitivity of the original. The power supply noise nulls out with the pot set at 10k (37k total), which is...
Sheldon also describes how to figure out some calculation for this amp:
3 direct coupled 2A3 amps
I have been THINKING about this !!! I remember introducing this to you here :D http://www.diyaudio.com/forums/tubes-valves/221739-nice-little-valve-amplifier.html
soulmerchant had a thread too:
My New Iron for Single Ended 2a3
My New Iron for Single Ended 2a3
Hi All, Here is a picture of my Darius Loftin-White prototype with the original "test" OPT's. The top plate is a standard 35cm x 25cm - I usually employ two of these chassis for push-pull amplifiers, so was surprised that the Loftin-White could fit in a single one! or so I thought..... The...
cheers.
You said it yourself... "according to some". This means nothing without data to support an opinion. I have built many tube amp variants, single-ended and push-pull. I have never had a noise or hum problem. I have >100dB efficient three-way horn speakers, so if something was not quiet, I would know about it.
I know there are a TON of schematics on the Internet, most of them are OK, but some are just not worth copying or building.
I know there are a TON of schematics on the Internet, most of them are OK, but some are just not worth copying or building.
Noise cancelling tends to imply some amount of out of phase noise injection. I didn't look close at the schematics so no idea if the LW design does it, but the amount of noise injection is critical to making it actually work. Get it wrong and you're just dumping noise into the circuit.
Its probably lazy advice but i think there are better results to be had from adequate traditional filter methods vs clever cancelling schemes that are meant as a work around to poor supply filtering.
Its probably lazy advice but i think there are better results to be had from adequate traditional filter methods vs clever cancelling schemes that are meant as a work around to poor supply filtering.
Engineering is about solving problems. High gain circuits indeed need good clean supplies. However, even without anti-phase injection, certain amplifier circuits exhibit a much higher PSRR than others. I'm sure you know this. John Broskie discusses this in relation to many specific topologies (SRPP, Loftin-white, cathode follower, cascode, etc.) at TubeCAD.
Jack