• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Has anyone used this regulator?

Status
Not open for further replies.
Jump to Latest
#21
SpreadSpectrum said:
I just nip em in the bud. I don't have any sophisticated noise-measuring equipment but noise is unmeasurable on my scope at that point. I used to be able to see little tiny sharp jagged things at a rate of 120Hz before I started doing this.

QUOTE]

SpreadSpectrum,

Can you give more detail on the snubbing you use?

Are you using standard 1n4007 or UF or other "Hex"?

I use UF soft recovery diodes! 🙂

Regards
M. Gregg
Click to expand...
 
#22
jean-paul said:
Hi, it probably will work but it is playing with fire. The dangerous moment is when switching it on. Because of the quite large cap at the output it could be that the voltage over the 317 exceeds the max. values by a large margin. Maybe TL783 is a better choice.

I remember Elektor using a 400 V max. rated reg but unfortunately I don't remember the typenumber. That one was also a 3 pin reg.


I found a few regs using parts that are rated for such high voltages.

http://www.linearaudio.nl/t-reg-2.htm
Click to expand...
If you'll check very closely, the LM317 will get only 6 volts across input and output, also at startup.
 
#23
SpreadSpectrum said:
Sy, is the noise you are talking about random noise or high frequency stuff that the Maida is less effective at calming?
Click to expand...

Random noise, mostly HF. A few caps knocks it down a bit, but for a cascode phono stage, I'd probably use a quieter reg- it's a good spot for a shunt. With my current phono stage, the PSR is so high that a Maida would probably work fine (I use a simple two transistor discrete reg there).
 
#24
M Gregg said:
SpreadSpectrum said:
I just nip em in the bud. I don't have any sophisticated noise-measuring equipment but noise is unmeasurable on my scope at that point. I used to be able to see little tiny sharp jagged things at a rate of 120Hz before I started doing this.

QUOTE]

SpreadSpectrum,

Can you give more detail on the snubbing you use?

Are you using standard 1n4007 or UF or other "Hex"?

I use UF soft recovery diodes! 🙂

Regards
M. Gregg
Click to expand...

A resistor in series with a capacitor put across the transformer secondary. Values calculated based on leakage inductance and distributed capacitance of the transformer.

I am using Fairchild stealth diodes.
Click to expand...
 
#27
M Gregg said:
DT,
Was this with high gain circuits such as "Phono" or with line stage as well?

Regards
M. Gregg
Click to expand...

Hello M Gregg All,
I am using HD 600 Sennheiser headphones to listen to vinyl.
The RIAA preamplifier is an Aikido powered by a PS-1 wired point to point.
The line stage is an Aikido Cathode Follower powered by a PS-2 solo and separate Heater regulator.
The Single End Triode headphone amplifiers are powered by PS-2 solo and separate heater regulators. The set' idle at 50ma each.
There have been various pieces used including a 6SN7 Aikido line stage. (Too much gain.)
The RIAA always had the PS-1. The PS-2’s were added to the ACF and headphone amplifiers (dual mono) with the headphones on my head there is no hum, buzz or hiss audible, dead silent. The regulated PS’s offer great localization and kick you in the teeth slam. They deliver solid sound with no added color.
DT
All just for fun!
 
Last edited:
#29
M Gregg said:
SpreadSpectrum,

"Stealth Diodes" So you have noticed switching spikes also on these!

Thank's for the info.

Regards
M. Gregg
Click to expand...

Actually, no. The switching spikes were on some other ultrafast recovery diode. The quiet regulator uses stealth diodes and a snubbed transformer secondary.

Some people see the diodes as the root cause of the noise. I would say that Q is the key to taming this type of noise. The reverse recovery is only the hammer that rings the bell. You can't avoid hitting it if you want your DC, so you might as well hit it as softly as you can(soft recovery) and have your hand on it to quit it from ringing(proper RC snubber).
 
#31
Ah, OK. That depends on the selection of the trimpot and the parallel resistor. With the values shown in the RLD article, the effective resistance range for the set resistor goes from 42k7 to 46k6. The feedback resistor is 200R, so the output voltage can be adjusted from 1.25(42700/200 + 1.25) = 268V to 1.25(46600/200 + 1.25) = 293V.

The circuit should have at least 20V or so across it to regulate. That can be decreased by decreasing the Zener voltage, if necessary.
 
Status
Not open for further replies.
Top Bottom