Of course the wiring should be in series, not parallel.
Connect one wire of the 2.5 volt winding with one wire of the other 2.5 volt winding. Measure the AC voltage of the unconnected wires. If it's about 5-6 volts, then they are in phase and OK. If it's almost 0 volt, switch the wire of one winding and the voltage should now measures about 5-6 volts. Proceed similarly with the 3.15 volt winding by connecting one of its wires with the above correctly connected 5 volt windings to get the required 8-9 volts AC voltage.
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Sorry, I just got info from diyclub.biz.
R80-36 primary (0-110) x 2 /SCN: scondary (260-230-0-230-260)(200mA), 2.5-0-2.5(3A), 3.15-0-3.15) X 2(3A)
2.5-0-2.5(3A) is already a 5 volt winding, use the 2 ends, not the center tap.
Join one end wire of the 5 volt winding with one wire of 3.15-0 winding. Check the AC voltage, it should measure 8.15 volt AC now. If you only got about 2 volts, switch the connecting wire of the 3,15-0 winding.
Hope I make it clear now.
R80-36 primary (0-110) x 2 /SCN: scondary (260-230-0-230-260)(200mA), 2.5-0-2.5(3A), 3.15-0-3.15) X 2(3A)
2.5-0-2.5(3A) is already a 5 volt winding, use the 2 ends, not the center tap.
Join one end wire of the 5 volt winding with one wire of 3.15-0 winding. Check the AC voltage, it should measure 8.15 volt AC now. If you only got about 2 volts, switch the connecting wire of the 3,15-0 winding.
Hope I make it clear now.
LC filter
If i want to remove the filter, I assume i just bridge the induction (wire in place of) and remove the capacitor and remove R30 to R34.
looking at the schematic, that leaves the 5687 with the 200r as its gridleak resistor?
is this ok - I know upper limits on gridleaks exist (for bias reasons) but is there a lower limit?
If i want to remove the filter, I assume i just bridge the induction (wire in place of) and remove the capacitor and remove R30 to R34.
looking at the schematic, that leaves the 5687 with the 200r as its gridleak resistor?
is this ok - I know upper limits on gridleaks exist (for bias reasons) but is there a lower limit?
Yes please, if you can. I was also interested in a more precise schematic for the I/V stage (can't quite understand all the values/tubes), and is that a 10K resistor between the 15K and 2nd tube (what is it exactly?)
PSU appears OK (+/-85V @ 50mA + heaters).
TIA
R23 and R24 are responsible for DAC I/V conversion and I believe better leave them next to the DAC chip.
The Rg for this tube is maximum 1MOhm as per datasheet. There is no minimum. You can short grid to floor as you would do with a volume control to minimum.
Adamus I believe you are correct about removing R30-34. I was initially thinking of not using a filter and I vaguely remember a post about not needing R30-34.
Used the scope to probe various areas of the DAC board. It appears I have signal out. Tomorrow I will try to get some quantitative numbers. It does not appear I am amplifying the signal however.
I first tried to reduce the anode voltage from the 110V I was seeing. Changed R3 (PS) from 22k to 47k. 100V on anode. OK for now.
Cathode bias is 3.8V. Thanks Adamus.
Filament voltage is 6.34V using 7119s.
On the scope I see about what leaves the DAC board at the output of the I/V board (qualitatively).
The relay is working. Hear click right after power is applied and again when power is removed.
Any grounding tricks I might have missed.
I'll try a different set of tubes but I wouldn't guess both are bad.
Other thoughts?
I first tried to reduce the anode voltage from the 110V I was seeing. Changed R3 (PS) from 22k to 47k. 100V on anode. OK for now.
Cathode bias is 3.8V. Thanks Adamus.
Filament voltage is 6.34V using 7119s.
On the scope I see about what leaves the DAC board at the output of the I/V board (qualitatively).
The relay is working. Hear click right after power is applied and again when power is removed.
Any grounding tricks I might have missed.
I'll try a different set of tubes but I wouldn't guess both are bad.
Other thoughts?
Play a pure tone, 1khz or the like. Then measure the output of the dac board, if you get good analogue output then it can only be the I/V board.
Measure and ensure the wave gets the other side of the resistors R21-24 and R9-12. If you still get signal there then pull out the valves and measure the pins 2 and 7 to ensure that the wave reaches there.
If it does then pop back in the valves, then measure pins 1 and 9. You should have a displacement of ~90v then superseded onto that you should have the audio signal.
If it's there then you know there's nothing wrong with the power supply. If you get no wave there, but you do at pins 2/7 (input pins) then it's a supply issue.
EDIT: Aha, just read that you get the output of the DAC board on the output of the I/V... If that is the case then measure voltage onto pins 4 and 5. Measure conductivity of the outputs to gnd, it should read very minimal.
Measure and ensure the wave gets the other side of the resistors R21-24 and R9-12. If you still get signal there then pull out the valves and measure the pins 2 and 7 to ensure that the wave reaches there.
If it does then pop back in the valves, then measure pins 1 and 9. You should have a displacement of ~90v then superseded onto that you should have the audio signal.
If it's there then you know there's nothing wrong with the power supply. If you get no wave there, but you do at pins 2/7 (input pins) then it's a supply issue.
EDIT: Aha, just read that you get the output of the DAC board on the output of the I/V... If that is the case then measure voltage onto pins 4 and 5. Measure conductivity of the outputs to gnd, it should read very minimal.
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Yes! I have been to use it for my DAC, I will up date it later!
the sound is excellent I love it! In the future i will make PCB.
new the filament for Tube, and relay!
Do you have idea for the filament??? can you show me please??
Thank
is this ok - I know upper limits on gridleaks exist (for bias reasons) but is there a lower limit?[/QUOTE]
if No use Filter, i show the sound is more natural...
If do that, don't use R30, R31, R32,R33.in the I/V board
Adrea measure :
**Follows the measurement of the DAC board on AD1865 output without any filter, the sampling frequency 44KHz is at -35dB.***
And with Filter: **Follows the measurement of the DAC board on AD1865 output with a filter composed by a 10nF capacitor in parallel to the 200ohm resistor,
the sampling frequency 44KHz is at -35dB.
The high frequency cut-off is the result of this formula
Ft(-3db) = 1 / ( 2 * pi * R * C ) = 1 / ( 2 * 3.14 * 200 * 10E-9 ) = 79Khz***
**Follows the measurement of the DAC board on AD1865 output with a filter composed by a 100uH choke and 10nF capacitor in parallel to the 200ohm resistor (like the AudioNote DAC), the sampling frequency 44KHz is at -35dB.**
R24, R23 200 R, can use 200 to 270 R, But I like 200R or 220R.
if No use Filter, i show the sound is more natural...
If do that, don't use R30, R31, R32,R33.in the I/V board
Adrea measure :
**Follows the measurement of the DAC board on AD1865 output without any filter, the sampling frequency 44KHz is at -35dB.***
And with Filter: **Follows the measurement of the DAC board on AD1865 output with a filter composed by a 10nF capacitor in parallel to the 200ohm resistor,
the sampling frequency 44KHz is at -35dB.
The high frequency cut-off is the result of this formula
Ft(-3db) = 1 / ( 2 * pi * R * C ) = 1 / ( 2 * 3.14 * 200 * 10E-9 ) = 79Khz***
**Follows the measurement of the DAC board on AD1865 output with a filter composed by a 100uH choke and 10nF capacitor in parallel to the 200ohm resistor (like the AudioNote DAC), the sampling frequency 44KHz is at -35dB.**
R24, R23 200 R, can use 200 to 270 R, But I like 200R or 220R.
agithegreat
you said
EDIT: Aha, just read that you get the output of the DAC board on the output of the I/V... If that is the case then measure voltage onto pins 4 and 5. Measure conductivity of the outputs to gnd, it should read very minimal.
I left my DAC at the lab (home of a scope) so I can't do anything tonight but I just looked at the schematic and see two 100k resistors to ground after the output caps. So wouldn't I get 50k output to ground?
Again thanks for your help.
you said
EDIT: Aha, just read that you get the output of the DAC board on the output of the I/V... If that is the case then measure voltage onto pins 4 and 5. Measure conductivity of the outputs to gnd, it should read very minimal.
I left my DAC at the lab (home of a scope) so I can't do anything tonight but I just looked at the schematic and see two 100k resistors to ground after the output caps. So wouldn't I get 50k output to ground?
Again thanks for your help.
next week i ill try the 'filterectomy' as audio note call it, although i am now very happy with the sound of the dac, it integrates into my system superbly, but i do have relatively bright speakers (fostex 167e in MLTL).
just looking though the Audionote pages.... they charge £300 for the removal of a few components!
just looking though the Audionote pages.... they charge £300 for the removal of a few components!
pics tell a 1000 words. so you are confident the dac board is working? could you posta pic of the IV board.
Cheers
Adam
Thank you
Hopefully today I will try a workingI/V stage with the board to confirm. Given the outcome I will post. I appreciate the support from all.
Best
Bob
There are pretty cheap WIMA MKP2 (5mm pitch) series capacitors at shops like Burklin. Bad thing is that you should find somebody in Germany who send them to you
Thanks vzs, I found the WIMAs at mouser (MKP2-.1/100/5 WIMA Polypropylene Film Capacitors) for 0.533 EUR. Are the Polypropylene caps the best solution for the application?
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