As Vunce mentioned output current is +/-1mA. This is similar to AD1862. Value of the IV resistor depends on your tube stage and the output level you are aiming for. Look at designs tagged in post #1 or even better, look for the boards designed by Michelag, since it has been proven to work nice.
You can try reducing that 100R, let's say to 75R and see if it sounds better. I think that even 50R should not be a problem. Normally you will have a lower voltage at the output.
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In that case, we could already talk about grounded grid circuits, especially if the tube has an amplification factor greater than 50.
The problem with ECC88 and 50R could only be in a worse signal-to-noise ratio.
The problem with ECC88 and 50R could only be in a worse signal-to-noise ratio.
Not only in THD, but also that the AD1862 sees a lower impedance at its current output (ideally it would be 0R).
This is why grounded grid circuits are better but they also have their drawbacks.
For me in that case the best is Ei 6HM5 with amplification greater than 70 times and the input impedance is below 10R. EC86 would also be a good choice, but I've never tried it.
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That would be great! I have a few ECC88 type tubes that are not being used. What a great community.
You really don't need 2vrms on output with a preamp in line, unless you want to drive amp directly (which is still too much if you use class D monsters). Lower load on iout will always be better. Since this is diy, really just look at your own system and how much gain you actually need, and apply accordingly.
Thanks for the information. I have ordered some of the SMD AD1865. Much less expensive than the DIP version so I'll skip the group purchase for now.
@grunf Is this the circuit you used? For C1, 1000uf... what type of cap do you use?
Would the D3A in triode mode (mu 70) be good enough for the grounded grid circuit?
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Not 0R or you can not convert curent into voltage, no?. Let say fw m Ohms at least.
D3A, I was said you need at least to match both and it is candidate to oscillation if you take not great cares.
Input at cathodes are said to sound not as good as grid with I/V, no ? Am I wrong ?
D3A, I was said you need at least to match both and it is candidate to oscillation if you take not great cares.
Input at cathodes are said to sound not as good as grid with I/V, no ? Am I wrong ?
Can anyone confirm these chips have not been used already requiring them to be desoldered from previous install?
by the hell, why going with ad1865 when having better chips like the ad1862, tda1541a or pcm 56/58, pcm 1702, ????
The only advantage of a standalone chip is imho to make it starground routing,not classical plain ground layer seen from a EMC/EMI point of view, am I wrong ?
The only advantage of a standalone chip is imho to make it starground routing,not classical plain ground layer seen from a EMC/EMI point of view, am I wrong ?
that's the old version for my DAC, here's the new one for AD1862
For C3(C1) put two UES1E102MHM in parallel with a good polypropylene cap.
I'm not sure that D3A is a good idea for a grounded grid, it's easier to do it with EC86,6S4P,6HM5... or even ECC88.
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They are AD1865R 28pin SOIC package, brand new. Good to go. You need adapters to fit the 24pin DIP footprint however.
@zoom777 waiting for Mouser order so I can build up the DAC boards.
Why not try them? Cheap and easy to find. Easy to use - only 5V supplies. Some people I trust say it's worth a listen, so is the PCM58 apparently. AD1865 is in the ranking as best multibit DAC.
20bit vs 18bit 😉 If I can I will try the lot, Miro has essentially developed a platform to plug in different DACs. PCM1704 is the hardest to find as legit for a sensible price.
Did you not like the 1865?
Why not try them? Cheap and easy to find. Easy to use - only 5V supplies. Some people I trust say it's worth a listen, so is the PCM58 apparently. AD1865 is in the ranking as best multibit DAC.
20bit vs 18bit 😉 If I can I will try the lot, Miro has essentially developed a platform to plug in different DACs. PCM1704 is the hardest to find as legit for a sensible price.
Did you not like the 1865?
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Also Andrea Ciuffoli liked it very much - seems to suit a tube stage?
https://www.audiodesignguide.com/DacEnd/index.html
https://www.audiodesignguide.com/DacEnd/index.html