Hello All,
Regarding oscillation with application of the 10m45 Tubelab uses a 1K ohm between the G pin and the load to damp possible oscillation.
Hiss looks like tall grass on the FFT. Teeth on a comb?
DT
All just for fun!
Regarding oscillation with application of the 10m45 Tubelab uses a 1K ohm between the G pin and the load to damp possible oscillation.
Hiss looks like tall grass on the FFT. Teeth on a comb?
DT
All just for fun!
This is a quest for higher fidelity NOT a science project 😉
Actually per the previous exercise, measuring the voltage across the trimpot
(in this case it varies between 2.9V to 3.1V) and then dividing that with the cold value of the trimpot will give the current. I would take precaution to measure the voltage as quick as possible after startup so that the trimpot does not get heated up and affect readings.
This is done with the assumption that the CCS device will always give out constant current values even at cold startup and does not need to warm up like a tube.
Is that hiss similar to using NOS carbon resistors like Allen Bradley? Perhaps you have used carbon resistors to set the current on the IXYS? That could induce some hiss.
That's the picture. Harmonic noise and hiss on the ear and high comb's teeth all over on FFT when oscillation on the scope. Since my scope is 20MHz I could have missed something small nuisance higher, very possible, so the hiss was the sign when the FFT was not disturbed.
Not only with the Ixys (used 1k metal fillm gate stopper). The worse was with Jung's combined depletion & LM317. Enhanced mode cascode was the less hiss, as much as with the gain increase VS resistor anode, BJT cascode was bad also.
EMU Tracker Pre 24bit/48k on Pioneer Hill. The FFT did not get disturbed. My scope is 20MHz. Did not get any tell tale signs on both. Hiss was less if I used less ccs current.
P.S. Thanks for the replies, I wanted to know if something else must have went wrong, since you all say no added hiss experiences with ccs, it surely was something else. Happened to my mate too on another preamp. Exactly the same report. Could it had been messing with the Maida regs we had during those experiments? The gyrator anode load was good on hiss on the same systems, if that is a clue BTW.
Hello
A more direct answer to your IXCY10M45 hiss question.
I have used several 10M45s’s with LM1085's mostly in power supplies. What I have running now are power supplies to tube RIAA pre-amp, tube buffer and tube headphone amplifier. With my ears I hear the silence at the pauses in the music, no hum or hiss, this is much improved from the CLC power filtering I was using before. I am refining my use of the tools, E-MU 1212, Pete Millett’s sound card interface, AudioTester 3.0 and Teck 465 scope. From the FFT there is grass but it is well mowed at ~110db down, 60 and 120 Hz are about 6db above that. I do not think that there is oscillation as applied.
DT
All just for Fun!
A more direct answer to your IXCY10M45 hiss question.
I have used several 10M45s’s with LM1085's mostly in power supplies. What I have running now are power supplies to tube RIAA pre-amp, tube buffer and tube headphone amplifier. With my ears I hear the silence at the pauses in the music, no hum or hiss, this is much improved from the CLC power filtering I was using before. I am refining my use of the tools, E-MU 1212, Pete Millett’s sound card interface, AudioTester 3.0 and Teck 465 scope. From the FFT there is grass but it is well mowed at ~110db down, 60 and 120 Hz are about 6db above that. I do not think that there is oscillation as applied.
DT
All just for Fun!
Hello Will,
After reading all the voltage regulator articles in GlassAudio and AudioXpress from over 20 years I came across the PS-1 and family of LM1085 and IXCY10M45S voltage regulators at Tubecad.com
PS-1 Solid-State Regulator Kit
I assembled several of these things point to point on perf board. They did a good job. Now that John sells Kits I use them.
The Computer Aided FFT shows better results by putting the transformers, rectifiers and Capacitor, Choke, Capacitor for ripple smoothing in a separate box and the regulator board right at the point of use in the amplifier. Putting the transformers, rectifiers and a first stage of filtering in a separate enclosure I find that the 60, 120 and higher multiples of 60 Hz are 6 or 9 db improved.
I hear No hum or hiss in the headphones. Silence takes effort but it is golden.
It was easier to get a battery operated 4562 RIAA preamp to 4562 OP-Amp plus BUF634 headphone amplifier quiet. I much prefer the tube setup for all the SET reasons.
DT
All Just For Fun!
After reading all the voltage regulator articles in GlassAudio and AudioXpress from over 20 years I came across the PS-1 and family of LM1085 and IXCY10M45S voltage regulators at Tubecad.com
PS-1 Solid-State Regulator Kit
I assembled several of these things point to point on perf board. They did a good job. Now that John sells Kits I use them.
The Computer Aided FFT shows better results by putting the transformers, rectifiers and Capacitor, Choke, Capacitor for ripple smoothing in a separate box and the regulator board right at the point of use in the amplifier. Putting the transformers, rectifiers and a first stage of filtering in a separate enclosure I find that the 60, 120 and higher multiples of 60 Hz are 6 or 9 db improved.
I hear No hum or hiss in the headphones. Silence takes effort but it is golden.
It was easier to get a battery operated 4562 RIAA preamp to 4562 OP-Amp plus BUF634 headphone amplifier quiet. I much prefer the tube setup for all the SET reasons.
DT
All Just For Fun!
Did you ever compare it to a Mosfet Maida?
P.S. They look like essentially the same thing to me. One uses enhanced mode to have enough VGS for the 317, the other uses depletion mode to use less parts around the shield MOSFET and a low drop out reg to be able to work under the less VGS. The one with the depletion must have some benefit in common reg use due to less capacitance. Although an IRF820 would compare. Make a CCSed HV shunt someday if you fancy. Its head and shoulders above Maida style many people feedback to me.
P.S. They look like essentially the same thing to me. One uses enhanced mode to have enough VGS for the 317, the other uses depletion mode to use less parts around the shield MOSFET and a low drop out reg to be able to work under the less VGS. The one with the depletion must have some benefit in common reg use due to less capacitance. Although an IRF820 would compare. Make a CCSed HV shunt someday if you fancy. Its head and shoulders above Maida style many people feedback to me.
Hello Salas and All,
No I have not tried a Mosfet Maida regulator. I have been eyeballing your Salas HV Shunt Regulator. The next piece of gear I want to build is a line level crossover, Lots of possibility for noise. I have a 100 2SK170BL’s coming in the mail.
In search of higher fidelity and lower noise a dedicated computer with quality soundcard and audio analyzer software is a valuable tool.
BTW this is a hobby to me. My day job is mechanical engineering. I rekindled the interest in audio and electronics sorting through HVAC controls (they used to be pneumatic) and Variable Speed Drives for fans and pumps.
DT
All Just For Fun!
No I have not tried a Mosfet Maida regulator. I have been eyeballing your Salas HV Shunt Regulator. The next piece of gear I want to build is a line level crossover, Lots of possibility for noise. I have a 100 2SK170BL’s coming in the mail.
In search of higher fidelity and lower noise a dedicated computer with quality soundcard and audio analyzer software is a valuable tool.
BTW this is a hobby to me. My day job is mechanical engineering. I rekindled the interest in audio and electronics sorting through HVAC controls (they used to be pneumatic) and Variable Speed Drives for fans and pumps.
DT
All Just For Fun!
- Status
- Not open for further replies.