I implemented a voltage divider before, it works well and you can do that if you feel that the CCS adds complexity
In my experience here are some of the benefits:
1) Having the CCS helps with PSRR
2) better frequency response. The Vref voltage node has a higher impedance.
3) The goal isn't always to set voltage HT/2, this arrangement helps you to adjust easily the voltage you want and have enough swing range to ensure the top MOSFET operates with sufficient VDS
Not difficult to implement, however everyone can implement their own variances
This circuit does can do 1.5Mhz, and sounds really nice.
In my experience here are some of the benefits:
1) Having the CCS helps with PSRR
2) better frequency response. The Vref voltage node has a higher impedance.
3) The goal isn't always to set voltage HT/2, this arrangement helps you to adjust easily the voltage you want and have enough swing range to ensure the top MOSFET operates with sufficient VDS
Not difficult to implement, however everyone can implement their own variances
This circuit does can do 1.5Mhz, and sounds really nice.
Ale,
Yes, I will test the boards again with the dummy load before inserting them in the circuit. It work before as they were not in the chassis so no short. I will keep you posted as I am not home right now, for a few days, doing business.
Stocktrader200, did not get the chance to measure that before the rectifier blew. I will keep that in mind once the rectifiers arrived.
Thanks again guys, I will keep you posted.
Abe
Yes, I will test the boards again with the dummy load before inserting them in the circuit. It work before as they were not in the chassis so no short. I will keep you posted as I am not home right now, for a few days, doing business.
Stocktrader200, did not get the chance to measure that before the rectifier blew. I will keep that in mind once the rectifiers arrived.
Thanks again guys, I will keep you posted.
Abe
Great idea! I will do that when I get the chance as I believe I have some bridge rectifiers at home.
Thanks!
Hi guys!
Bad news. The rectifier blow out took the power transformer HV. Hammond 370JX spec for HV winding DCR is 84.7 ohms. I am only getting 7.2 ohms. SV winding of Yellow-Yellow is 0.2 ohms, spec is 0.32 so that's okay.
Using a bridge (RED=RED connected to ~ and ~b of the bridge)AQ
it seems lke
Oh well, looks like I need another transformer.ik77
Bad news. The rectifier blow out took the power transformer HV. Hammond 370JX spec for HV winding DCR is 84.7 ohms. I am only getting 7.2 ohms. SV winding of Yellow-Yellow is 0.2 ohms, spec is 0.32 so that's okay.
Using a bridge (RED=RED connected to ~ and ~b of the bridge)AQ
it seems lke
Oh well, looks like I need another transformer.ik77
If you use bridge rectifier (~,~,+,-) aka graetz, and connect RED to ~, RED to ~, the output voltage / between bridge + and - / will be over 700V!!!
If you also connect transformer center tap RED/YEL to bridge: it's a total short circuit, you will destroy the bridge two diodes and maybe a transformer too (if no fuse in the CT-bridge line)!
Connect SINGLE diode anodes to REDs and CT to 0V, connect diodes cathodes together, this is +.
If you also connect transformer center tap RED/YEL to bridge: it's a total short circuit, you will destroy the bridge two diodes and maybe a transformer too (if no fuse in the CT-bridge line)!
Connect SINGLE diode anodes to REDs and CT to 0V, connect diodes cathodes together, this is +.
Yes, I realized my mistakes. Thank you euro21, I will report back when I received the transformer.
Update:
I finally received the transformer. Hook it up, measured well on B+ etc.
Measurements for R-L on the gyrator board as follows:
TP1: 30.2 mA, and 30.1 mA
Pin1 of 01a: 7.4V and 7.4V
Top of Cathode R: 4.3V, and 4.23V
Input from source to Grid: ~1.9 V at max volume
Plate V: 120V, 121V
It's making music, finally!
Thanks again to all that helped me, Merry Xmas Happy New Year!!!!
I finally received the transformer. Hook it up, measured well on B+ etc.
Measurements for R-L on the gyrator board as follows:
TP1: 30.2 mA, and 30.1 mA
Pin1 of 01a: 7.4V and 7.4V
Top of Cathode R: 4.3V, and 4.23V
Input from source to Grid: ~1.9 V at max volume
Plate V: 120V, 121V
It's making music, finally!
Thanks again to all that helped me, Merry Xmas Happy New Year!!!!
I'm glad you like it. The 01a has a level of detail and clarity on the sound that is the best in my experience. Most of the DHT preamps sound fantastic but this one is a step ahead. Hence why so many are building it now. Unfortunately is getting more expensive.
perhaps Thomas Mayer will manufacture this tube in the future? I'd be great
Cheers
ale
perhaps Thomas Mayer will manufacture this tube in the future? I'd be great
Cheers
ale
You have not seen yet graphite anode 801 prices. :-(
Compared to their prices 201a is a "cheap thrills".
You have not seen yet graphite anode 801 prices. :-(
Compared to their prices 201a is a "cheap thrills".
In the past I've sold quite a few 10Y, 26, 46 and 01A to others. I'm hoarding what I have left....
These tubes are so old - nearly a century soon - that I should imagine it all depends on the condition the tubes are in. I doubt if the manufacturer is that significant, but by all means prove me wrong.
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