Hallo again! Long time did nothing, but lately try to progress.
To remind you - Analogmetric DAC.
First my attempts was with tube output with some Russian tube 6N24P with gain about 30 in SRPP. But I decided to replace it with bigger gain. First used 6N2P, again Russian, again SRPP, but sound was a little rough. Then exchanged with ECC83. Only this I have on hand. But began humming. Not big, but hum. Sound was more open and bright, this tube. I did try it in single end from it datasheet. And in cathode follower. But always humming.
So, for now, I finish my work with tubes. I'm not ready to spent amounts for other tubes.
And today, I experiment with 5532 🙂
Just with 1/2 per side, with 40 Ohms I/V resistor. Actually with trimmer.
Things are working. DAC is dead silent. Just must to increase the gain.
But now I think about some improvements, and need a little support of you.
May I miss the output capacitors? If use 5534 or TL071, which are with adjustable offset? And is there some benefit in this?
To remind you - Analogmetric DAC.
First my attempts was with tube output with some Russian tube 6N24P with gain about 30 in SRPP. But I decided to replace it with bigger gain. First used 6N2P, again Russian, again SRPP, but sound was a little rough. Then exchanged with ECC83. Only this I have on hand. But began humming. Not big, but hum. Sound was more open and bright, this tube. I did try it in single end from it datasheet. And in cathode follower. But always humming.
So, for now, I finish my work with tubes. I'm not ready to spent amounts for other tubes.
And today, I experiment with 5532 🙂
Just with 1/2 per side, with 40 Ohms I/V resistor. Actually with trimmer.
Things are working. DAC is dead silent. Just must to increase the gain.
But now I think about some improvements, and need a little support of you.
May I miss the output capacitors? If use 5534 or TL071, which are with adjustable offset? And is there some benefit in this?
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Which power supply? They are a lot. That Analogmetrics, or any?
So, I increased the 5532 gain and reduced I/V resistor to 30 Ohms. Here You are, the scheme I use. Just the R10; R11 values are changed and added output capacitors.
And again, what if I try to Null the offset, and miss the capacitor? Is there something wrong in this idea, and why everybody use capacitor?
So, I increased the 5532 gain and reduced I/V resistor to 30 Ohms. Here You are, the scheme I use. Just the R10; R11 values are changed and added output capacitors.
And again, what if I try to Null the offset, and miss the capacitor? Is there something wrong in this idea, and why everybody use capacitor?
Attachments
Yes you can null the offset using the adjust pins.
Your tube circuit hums because you must use larger capacitance on B+ and a DC heater with very large capacitance and short wires. Can you show your tube circuit?
Even if you use oversampling you should use a low pass filter.
Your tube circuit hums because you must use larger capacitance on B+ and a DC heater with very large capacitance and short wires. Can you show your tube circuit?
Even if you use oversampling you should use a low pass filter.
The cathode follower is from here:The Valve Wizard
The single end is from ECC83 datasheet tables, with resistors for smallest THD. My circuit looks really like a nest 🙁
BUT!!! One thing I done. Because of lack of high voltage, to get 300V I used a voltage doubled rectifier, instead Bridge rectifier.
Yes, I was going to ask you about the filter.
The single end is from ECC83 datasheet tables, with resistors for smallest THD. My circuit looks really like a nest 🙁
BUT!!! One thing I done. Because of lack of high voltage, to get 300V I used a voltage doubled rectifier, instead Bridge rectifier.
Yes, I was going to ask you about the filter.
That circuit is not right for a TDA1541 output stage.
You don't need 300V for an E88cc. Use 150V or 160V. Even 120V will work 🙂
Build the circuit in the attached schematic. Sorry the IV resistor got cut off. It is 100 Ohm. But you can use anything from 80 ohms and up to 100ohms . Don't worry about the output compliance. Get the circuit working then worry about fine tuning.
You wont need the inductors.
Use a capacitance multiplier on your B+ see the attached picture.
The transistor wont get hot because your circuit will only draw about 20mA.
I use a 2sc5200 because I had them in my parts box. You can use a cheaper power transistor if you prefer.
Try this tube circuit then report back. I think you will like it 🙂
You don't need 300V for an E88cc. Use 150V or 160V. Even 120V will work 🙂
Build the circuit in the attached schematic. Sorry the IV resistor got cut off. It is 100 Ohm. But you can use anything from 80 ohms and up to 100ohms . Don't worry about the output compliance. Get the circuit working then worry about fine tuning.
You wont need the inductors.
Use a capacitance multiplier on your B+ see the attached picture.
The transistor wont get hot because your circuit will only draw about 20mA.
I use a 2sc5200 because I had them in my parts box. You can use a cheaper power transistor if you prefer.
Try this tube circuit then report back. I think you will like it 🙂
Attachments
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Thanks!
You are talking about E88cc (6n11).
In my circuit I use ECC83 which with lower voltage shows higher THD.
In the beginning, I used a Russian substitute 6N24P for E88CC, of course things are not the same, and it sounded dark, compared to ECC83 now.
Thats why I gone to OP-AMPs, to get silent output. Of course, now must to compare it with the first my tube stage, to see which is better.
About the I/V resistor. Don't You think, 80-100 Ohms resistor is too big for 1541? Recommendations, as I know, are for about 33 to 47 ohms, even less. Maybe use that big value, because of small E88/6N11 gain(30) By the way, the same does and Lampizator in his tube output stage.
P.S. Oh! Maybe You get me wrong?
When I speak, the output now is dead silent, this means there is not noise at all, when no music. The OpAmp stage works.
You are talking about E88cc (6n11).
In my circuit I use ECC83 which with lower voltage shows higher THD.
In the beginning, I used a Russian substitute 6N24P for E88CC, of course things are not the same, and it sounded dark, compared to ECC83 now.
Thats why I gone to OP-AMPs, to get silent output. Of course, now must to compare it with the first my tube stage, to see which is better.
About the I/V resistor. Don't You think, 80-100 Ohms resistor is too big for 1541? Recommendations, as I know, are for about 33 to 47 ohms, even less. Maybe use that big value, because of small E88/6N11 gain(30) By the way, the same does and Lampizator in his tube output stage.
P.S. Oh! Maybe You get me wrong?
When I speak, the output now is dead silent, this means there is not noise at all, when no music. The OpAmp stage works.
Use a 6n1p Russian tube.
No i dont think 100 ohms is too much. I personally use 91 ohms. You might be able to measure more distortion with 100 ohms but you are unlikely to hear it. The quality of the resistor will afect the sound more!
I understand that you want a silent output. Im not sure this can be achieved with tubes? I think there will always be some small hiss.
Do you think using an IV resistor with the op amp gives better sound than using an op amp with virtual ground?
No i dont think 100 ohms is too much. I personally use 91 ohms. You might be able to measure more distortion with 100 ohms but you are unlikely to hear it. The quality of the resistor will afect the sound more!
I understand that you want a silent output. Im not sure this can be achieved with tubes? I think there will always be some small hiss.
Do you think using an IV resistor with the op amp gives better sound than using an op amp with virtual ground?
No, I didn't try. I ask for simplicity.
Well, I have 6N1P, also and 2P.
From the first, I have good memories like an output of PCM56. Must check and with 1541.
The second, 6N2P, I used with this DAC, but sound a little rough.
Generally, tubes or not tubes is the question 🙂
My modest opinion is, tubes circuits looks simpler, but more harder to tune.
Lately, I have better results with "sands". Just for sample, my DIY transistor amp, sound better than my SRPP with EL34.
Well, back to the tubes 🙂
Direct compare with my OpAmps.
First I begin with 6N24P (6Н24П). It's ready for use.
Forgoten sound.
Comparing with 5532, OpAmp is disaster. Flat sound, just some middles.
Replacing with good old TL072, better. More bass, smoother sound.
But tube performs best. Even more bass, more space, solid and soft sound.
Hum is unnoticed, just at high level volumes, much over then usable levels of amp.
I may live with this tube, if don't feel a little lack of highs.
I'm going to try a soft tuning. Increasing little the current, changing the output capacitor and so.
After that, I'll test and 6N1P, 6N2P - the Lampizatot buffers.
About I/V resistor. Think, more gentle sound is with smaller values. Keep about 30.
Direct compare with my OpAmps.
First I begin with 6N24P (6Н24П). It's ready for use.
Forgoten sound.
Comparing with 5532, OpAmp is disaster. Flat sound, just some middles.
Replacing with good old TL072, better. More bass, smoother sound.
But tube performs best. Even more bass, more space, solid and soft sound.
Hum is unnoticed, just at high level volumes, much over then usable levels of amp.
I may live with this tube, if don't feel a little lack of highs.
I'm going to try a soft tuning. Increasing little the current, changing the output capacitor and so.
After that, I'll test and 6N1P, 6N2P - the Lampizatot buffers.
About I/V resistor. Think, more gentle sound is with smaller values. Keep about 30.
CTEF
Sounds like a winner! You mentioned I/V resistor value. Have you tried different resistor quality in this position?
Sounds like a winner! You mentioned I/V resistor value. Have you tried different resistor quality in this position?
No, not jet 😱
That DAC works, doesn't mean everything is ready. I wish more.
Thanks Erin for schemes!
But for now I want to finish job with mine.
Here you are some man, who use similar to mine circuit for ECC83. Here, people report, also, that with SRPP we can't get good Highs.
http://www.diyaudio.com/forums/digital-line-level/157940-tubed-ccda-i-v-amp-tda1541.html In this circuit, I just must try to clean my supply. I have and another trafo with higher output voltage. Will build new supply for ECC83.
The Erin supply uses huge amount hi-voltage capacitors. I haven't such on hand, but use 1H choke.
About I/V resistor. I mentioned, for now use 100 ohms trimers to adjust best value. I have no choice for best quality resistors, to try. And have doubts, my factory system may reproduce such details, while my DIY system is in progress and not ready jet
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the TDA1541A datasheet mentiones
at 4mA full-scale output this translates to 12.5 ohms max if i interpret correctly. Else it will be even lower at 6.25 ohm. So.. 30 ohms I/V resistor means distortion!
at 4mA full-scale output this translates to 12.5 ohms max if i interpret correctly. Else it will be even lower at 6.25 ohm. So.. 30 ohms I/V resistor means distortion!
Yes, such things 🙂
Folks report, about 30 ohms is a working compromise.
What about the Lampizator, uses 100 ohms load 😉
Folks report, about 30 ohms is a working compromise.
What about the Lampizator, uses 100 ohms load 😉
I started with 90 per lampizator recommendation. Based on body of knowledge among many 1541a users on this site settled on around 60 for one 1541a. Many would suggest 30 is low but easy to try different values. Your idea of using a trim pot to get a sense of what you like is smart. However it is likely not a premium resistive element, and per my earlier post, when you get the rest of your system sorted out, this one simple element will make more impact on sound quality than most other items. I am now winding my own resistor which is very inexpensive but rewarding.
Yes, after tests, I'm going to change the trim, with resistor. If You share how tho wind resistor, thanks. I have a few winding resistors on ceramic core.
Today I exchanged output capacitors. But also I droped and SA7220 on it place. What to say, maybe I am not ready to sacrifice the top-highs. You know the sound of NOS, but they miss me.
One simple, and one Pedya Rogic DAC
So, Happy New Year, everybody, and Good Luck!
Today I exchanged output capacitors. But also I droped and SA7220 on it place. What to say, maybe I am not ready to sacrifice the top-highs. You know the sound of NOS, but they miss me.
Well, a few.
One simple, and one Pedya Rogic DAC
So, Happy New Year, everybody, and Good Luck!
Attachments
diy I/V
ctef
post 258 in this thread explains diy resistor.
http://www.diyaudio.com/forums/parts/6760-resistor-comparison-test-tantalum-26.html#post3758151
ctef
post 258 in this thread explains diy resistor.
http://www.diyaudio.com/forums/parts/6760-resistor-comparison-test-tantalum-26.html#post3758151