I have been an electronics hobbyist since the age of nine and an electronics engineer since the age of twenty-three. I'm in my mid-fifties now.
Assuming that neither the CD player nor your phono amplifier invert the polarity of the signal, the signal will be inverted when you do what you intend to do. Double-blind tests have shown that when you listen to very dry monophonic recordings in an acoustically dead space, polarity inversion is audible. However, with a bit of reverberation, it very easily gets masked by the reverberation. For stereo, it's important that both channels have the same polarity, which they will always have when you do the same with both channels.
Assuming that neither the CD player nor your phono amplifier invert the polarity of the signal, the signal will be inverted when you do what you intend to do. Double-blind tests have shown that when you listen to very dry monophonic recordings in an acoustically dead space, polarity inversion is audible. However, with a bit of reverberation, it very easily gets masked by the reverberation. For stereo, it's important that both channels have the same polarity, which they will always have when you do the same with both channels.
I just checked; all of the components in my system (Philips CD880, Audio Research D70 MkII, Convergent Audio Technology SL1 Signature MkIII and Martin Logan Sequel speakers) have non-inverting outputs.
Thank you. Your education explains why you are able to give me such good advice. Is there a simple way to make the output from the IRAA non-inverting? Based on your explanation, I suspect that it will likely not make much is any difference because I rarely listen to mono recordings. I have occasionally played mono signals to test a component's balance or with my FM tuner to try to improve reception of weak stations but not in a very long time.
No.
That is, to keep the polarity as is, the RC circuit would actually have to be inverting like the transimpedance amplifiers Philips normally used. I don't know any practical way to do that with an RC circuit.
Then, I will just have to build this and listen to the result. Hopefully, it be a sound that I think is better than the present line level output of the CD player.
I have a discrete dual op amp that I will install in the DIP 8 socket (maybe will test that out before I deal with trying to install this circuit because that will be easy once I put the DIP 8 socket in).
Lastly, I will build the Lampizator using the PCB that I got from member Vlad1980 in exchange for TDA1541A SI that I pulled from a shipping damaged CD880. I will probably need help modifying this to get a usable line output because I am fairly certain that his Lampizator design calls for a 100 ohm IV conversion resistor feeding the grid of a 2N2P Russian (12AX7 equivalent) tube.
Eventually I will decide which of all three I like the sound of best.
I have a discrete dual op amp that I will install in the DIP 8 socket (maybe will test that out before I deal with trying to install this circuit because that will be easy once I put the DIP 8 socket in).
Lastly, I will build the Lampizator using the PCB that I got from member Vlad1980 in exchange for TDA1541A SI that I pulled from a shipping damaged CD880. I will probably need help modifying this to get a usable line output because I am fairly certain that his Lampizator design calls for a 100 ohm IV conversion resistor feeding the grid of a 2N2P Russian (12AX7 equivalent) tube.
Eventually I will decide which of all three I like the sound of best.
Of course, or use a transformer, but audioxcel specified somewhere in this thread that the circuit has to consist of nothing but resistors and capacitors.
If the circuit does not sound good to me after I get it built and installed in my CD player, I would be open to using a transformer to make the output non-inverting unless that would cost more than I am willing to spend to find out if that would improve the sound.
You can just swap the loudspeaker terminals to hear if it makes any difference (for both left and right, connect the negative loudspeaker terminal to the positive amplifier output terminal and the positive loudspeaker terminal to the negative amplifier output terminal). Good signal transformers are usually expensive.
Indecisive and trigger fingers.
BTW: I was making a BOM on Digikey and strangely found that I could buy 25 resistors for less than 5 in some cases. SMH
I have never really looked for class1 ceramic or polypropylene capacitors before. Almost all of my previous projects were for power supplies. There are not many options available available for class1 capacitors. I found a 1% tolerance NPO / COG in 0.1uf but could not find better than 5% tolerance for 0.33uf.
BTW: I was making a BOM on Digikey and strangely found that I could buy 25 resistors for less than 5 in some cases. SMH
I have never really looked for class1 ceramic or polypropylene capacitors before. Almost all of my previous projects were for power supplies. There are not many options available available for class1 capacitors. I found a 1% tolerance NPO / COG in 0.1uf but could not find better than 5% tolerance for 0.33uf.
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I was wondering if swapping the polarity of the speaker wires would do that. Now, I know. Worse case if it sounds better when they are swapped would be that I would have to swap them back to listen to other sources. I generally don't go back and forth between sources more than every few days so it won't be a big deal.
I looked at Sowter and Lundahl transformers when I considered using transformers for I/V conversion. They were way out of my budget just to experiment with,
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MarcelvdG,
After I looked up the input resistance of my preamp phono stage (47K ohms), you said to use 52.3 for R4 but we did not revisit R2 and R3. Before I place an order for all of the components, can you please confirm or, if necessary, adjust the values below:R3 = 759.646247223 Ω -> 750 Ω rounded to an E96 value
C2 = 98.730165882 nF -> 100 nF rounded to an E6 value
R2 = 9510.7946895155 Ω -> 9530 Ω rounded to an E96 value
C1 = 334.35691799 nF -> 330 nF rounded to an E6 value
Yes, that's correct.
R1 = 10 Ω
R4 = 52.3 Ω on the board in parallel with the 47 kΩ of the amplifier
R3 = 750 Ω
C2 = 100 nF
R2 = 9530 Ω
C1 = 330 nF
R1 = 10 Ω
R4 = 52.3 Ω on the board in parallel with the 47 kΩ of the amplifier
R3 = 750 Ω
C2 = 100 nF
R2 = 9530 Ω
C1 = 330 nF
Thanks. I was about to place the order and then I remembered that you had asked about the input resistance. I read the post with values again and thought these were the adjusted values but didn't want to assume anything.
After you made post #86 I had asked about R4 but not the other values. So, I thought it would be foolish to not ask before placing an order.
After you made post #86 I had asked about R4 but not the other values. So, I thought it would be foolish to not ask before placing an order.
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OK, so you expect the DAC+iRIAA+phono preamp sound as good as vinyl. It won't. The magic sound of vinyl lies in its imperfect nature. It has a special distortion characteristic, starting from the recording, mastering through the turntable (and this can be further broken down to motor, platter, bearing, belt, mat, arm, cartridge, cables, whatever). I think the phono preamplifier plays the smallest role in it. It is the most "perfect" component, if you like to put it this way. Interesting experiment, anyway.
To be fair to OP, I don´t think he ever wrote that. The whole project started from a lack of available inputs on his pre/intg amp, as
far as I remember.
But I share your point. It´ll never sound like vinyl, and for me, I´d have settled for a input-extender-switch box with 2/3/4 in and 1 out.
As far as getting signal directly from TDA1541 with a resistor as I/V converter, I have done that a few times the Lampizator way with
6N2P for amplification. Sounds marvellous. Shall be interesting to hear OP´s final evaluation when finished. Mostly "was it worth it"??
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There is a relevant device on Tindie: https://www.tindie.com/products/paphos1580/riaa-inverse-ir100/