Hello,
I have some basic questions please.
So I have 2 gyrator Mu follower sand😱 circuitries to load the anodes of an ECC88 tube double triode family (here a 7023) that will output 75 V for the anodes.
A SS state rectification is planed for the HV. Should the Moglia Gyrator scheme needs extra noise or ripple filtering before it from the first smoothing cap ? Chokes are not wanted because of the price, weigth and aera.
Does it worth to put before the gyrator a first reg stage like the Tivivol HV reg for instance and to down the HV to around 100V to give a 30V margin in order to let work the gyrator? Or is it counterproductive, i.e. just push for instance 240 V direct in the HV input of the Mu follower from the first smmothing HV cap to let in dissipate the heat into the main Mu follower Mosfet radiator ?
I have not bought the HV traffo yet, so I can plan any secondary output..240V, 100V, etc. So I also could plan just the voltage room to allow the gyrator to work for a 75 V output from the Mu followed !
Thanks for your help
I have some basic questions please.
So I have 2 gyrator Mu follower sand😱 circuitries to load the anodes of an ECC88 tube double triode family (here a 7023) that will output 75 V for the anodes.
A SS state rectification is planed for the HV. Should the Moglia Gyrator scheme needs extra noise or ripple filtering before it from the first smoothing cap ? Chokes are not wanted because of the price, weigth and aera.
Does it worth to put before the gyrator a first reg stage like the Tivivol HV reg for instance and to down the HV to around 100V to give a 30V margin in order to let work the gyrator? Or is it counterproductive, i.e. just push for instance 240 V direct in the HV input of the Mu follower from the first smmothing HV cap to let in dissipate the heat into the main Mu follower Mosfet radiator ?
I have not bought the HV traffo yet, so I can plan any secondary output..240V, 100V, etc. So I also could plan just the voltage room to allow the gyrator to work for a 75 V output from the Mu followed !
Thanks for your help
A mu follower has the same power supply rejection ratio as the cathode follower at its top - so approximately mu times. For low current stages it is very easy to iclude sufficient deoupling to reduce hum to below the noise floor. I would encourage you to use cascaded RC stages as these have much better hum rejection that a single RC stage of the same total R and C. SImple class A low level audio tube amplifiers do not need stabilised supplies.
Cheers
Ian
Cheers
Ian
Be sure, that "gyrator" has at least 40-50V voltage headroom OVER the maximum anode voltage swing peek, else at larger swing the distortion is growing!
BTW cascode gyrator loaded E88CC has -about- 60dB PSRR at low frequencies (for example 20Hz) and more at increasing freq.
BTW cascode gyrator loaded E88CC has -about- 60dB PSRR at low frequencies (for example 20Hz) and more at increasing freq.
Many thanks euro21, I didn't know that...but not sure I 've got it.
Let say I load the gyrator to simulate the anode with a resistor for instance and I plan to pot for a 75 Vdc output, do you mean I need to supply with say 50V more ? O evenr more because before the CSS is stable I should have a voltage peak at powering on for some seconds before to have a stable 75V... for instance 10V over the 75V, so 85 V for illustration, = 75 V + 10 V + 50V =135 V at gyrator input needed? Is it what you meqnt, please ?
Let say I load the gyrator to simulate the anode with a resistor for instance and I plan to pot for a 75 Vdc output, do you mean I need to supply with say 50V more ? O evenr more because before the CSS is stable I should have a voltage peak at powering on for some seconds before to have a stable 75V... for instance 10V over the 75V, so 85 V for illustration, = 75 V + 10 V + 50V =135 V at gyrator input needed? Is it what you meqnt, please ?
I am not sure what a Graertz bridge is but a full wave bridge plus a CRCRC should be plenty for a few mA. The approximate hum reduction is given by 2*PI*f*R*C so 1K and 100uF will give you about 36dB reduction per stage. In my mixer power supplies I typically have three RC stages for a total of over 90dB of hum reduction.
Cheers
Ian
Ian...my bad...I wanted to write Graetz (full bridge)...I added a R and you do not want Z with diodes full bridge ...well you know me and orthograph 😉
For the noise, the tube is not too noisy by it self as it is a E188CC exactly.
Does it worth then to make a CRC for a little more ripple rejection ?
For the noise, the tube is not too noisy by it self as it is a E188CC exactly.
Each ripple rejection matters.
IMHO CRCRC filtering (few mV disturbation on output) is good for -low power- phono preamps.
IMHO CRCRC filtering (few mV disturbation on output) is good for -low power- phono preamps.
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Thank you for the input again.
Not phono for me but few 2 mA swing from a dac chip into 50 ohms. Same quiet needs...
Not phono for me but few 2 mA swing from a dac chip into 50 ohms. Same quiet needs...
You can get something like 3mV ripple with 0.1uF//VR150.
A CCS filter is really effective at removing ripple and provides good isolation, you could get away with a single filter cap.
Rectifier - (R?)C - CCS - VR150 - plate load CCS - tube ?
Transformer secondary could be anything ~160VAC to 200VAC and load current would be ~50mADC.
A CCS filter is really effective at removing ripple and provides good isolation, you could get away with a single filter cap.
Rectifier - (R?)C - CCS - VR150 - plate load CCS - tube ?
Transformer secondary could be anything ~160VAC to 200VAC and load current would be ~50mADC.
.... I really dunno as a noob, but I like the idea of at least a simple CRC before the Mu follower, just because I do not like the idea that the smoothing cap and the reservoir cap to be the same... and I use SS rectifiers.
I have not firered up PSUDII, but grossly I will make a 47 uF/600v lythic à la Epcos a 1k/13w Dale Mexico I have then same Epcos family but 220 uF. I have also the cool HV reg from Tivicol which may have perhaps a better noise rejection but it seems same thing more or less than a Mu follower but here cap multiplier !
Well I do not want to be cunterproductive...it is just a 33 Mu low voltage tubeamp after an I/V dac stage that can output 2 V RMS... I mean the main culpritt for a B+ is the ripple not so the noise (tube having its own intrensic structural noise) ?
For the Mu follower the second stage should use what I can source at Mouser... upper position to220 DN2240 and lower position J310 if remembering what said euro21 to me in an other helper thread 🙂
I have not firered up PSUDII, but grossly I will make a 47 uF/600v lythic à la Epcos a 1k/13w Dale Mexico I have then same Epcos family but 220 uF. I have also the cool HV reg from Tivicol which may have perhaps a better noise rejection but it seems same thing more or less than a Mu follower but here cap multiplier !
Well I do not want to be cunterproductive...it is just a 33 Mu low voltage tubeamp after an I/V dac stage that can output 2 V RMS... I mean the main culpritt for a B+ is the ripple not so the noise (tube having its own intrensic structural noise) ?
For the Mu follower the second stage should use what I can source at Mouser... upper position to220 DN2240 and lower position J310 if remembering what said euro21 to me in an other helper thread 🙂
That's rock ! Not far from what I slowly try to adapt from T loesch classic circuity with the help of the Diyaudio inmates ! 🙂 
I believe T Loesch applies 75V B+.
C1 R1 L1 is the deamphasis circuitry? , I can get rid of it I believe...
You put a green led in spite of Loesch 10R for cathode biass, ok
Rmu ? 470R or around 100R ? : https://www.diyaudio.com/community/...-in-an-hybrid-mu-follower.384775/post-6986364 ...
15v zener diode through holes are not sourcable at Mouser, perhaps I will use some 12V or 16V I have,
R5 : 1K in spite of 5K , ok have both 🙂
Upper classic Mostfet are out of stock
Lower j310 are on stock 🙂
i didn't know i have to populate the 10R just before the Anode, ok
C6 : I surmise a good film one
C3 : I should reduce it to around 0.47 uf with my 47K input pre to choose a cap not too much colored 🙂
For the PI power filter i will source 120 uF : much more choice due to the supply chain problem : nipon chemicon long life 500/600V, ok
220k/47k for the heater divider (or heating elevator,)...
Just have to knock at MOUSER
thanks again, that helps a lot
I believe T Loesch applies 75V B+.C1 R1 L1 is the deamphasis circuitry? , I can get rid of it I believe...
You put a green led in spite of Loesch 10R for cathode biass, ok
Rmu ? 470R or around 100R ? : https://www.diyaudio.com/community/...-in-an-hybrid-mu-follower.384775/post-6986364 ...
15v zener diode through holes are not sourcable at Mouser, perhaps I will use some 12V or 16V I have,
R5 : 1K in spite of 5K , ok have both 🙂
Upper classic Mostfet are out of stock
Lower j310 are on stock 🙂
i didn't know i have to populate the 10R just before the Anode, ok
C6 : I surmise a good film one
C3 : I should reduce it to around 0.47 uf with my 47K input pre to choose a cap not too much colored 🙂
For the PI power filter i will source 120 uF : much more choice due to the supply chain problem : nipon chemicon long life 500/600V, ok
220k/47k for the heater divider (or heating elevator,)...
Just have to knock at MOUSER
thanks again, that helps a lot
Yes, it's Thorsten's schematic adaptation.
Upper FET:
https://eu.mouser.com/ProductDetail/IXYS/IXTP08N100P?qs=jFjNEgmwGdfXc8JRp0enOQ==
Try Rmu 470R or 100R. Only minor difference will occur (at 100R the output level a little lesser).
Upper FET:
https://eu.mouser.com/ProductDetail/IXYS/IXTP08N100P?qs=jFjNEgmwGdfXc8JRp0enOQ==
Try Rmu 470R or 100R. Only minor difference will occur (at 100R the output level a little lesser).