Sound quality is the first step. What you described sounds a bit like out of phase stereo signals. Next would be to swap the + and - leads on ONE of the inputs OR outputs. Or you could test it by swapping the speaker leads on ONE speaker. If that resolves the issue, then you need to go over your wiring and find out where you crossed the signals.
The circuit is the VSPS but with single rather than dual opamps. Since the power supply is 100% shared I don't really why you wouldn't just use NE5532 but maybe it was to make the stripboard layout simpler.
The "no bass too much treble" complaint usually means the RIAA eq. is wrong. Wrong value, C1 C2 switched, resistors switched, that kind of thing. You'll have to carefully check that yourself. Incorrect RIAA means the frequency response is massively wrong, its pretty easy to identify as a result.
If it sounds basically correct but just slightly (but still pretty obvious) weak bass or prominent treble, then maybe the op amps are unstable. If you removed all the capacitors from the main board to the external power supply I wouldn't be surprised if you have oscillation.
Finally, it is quite possible that the cartridge is broken or worn out or badly aligned. Remove the VSPS and check is a known good phono stage to confirm the TT is ok.
Thank you both for your replies. I didn't have much time this weekend but i checked what you suggested. Seems like a turntable problem as both resistors and capacitor values are correct.
I don't have someone near me to test my vsps though. Is there a way to emulate a riaa curve on my pc and use a filtered file for testing?
I don't have someone near me to test my vsps though. Is there a way to emulate a riaa curve on my pc and use a filtered file for testing?
Ortofon SL15 noise
Hi there
I am all new to this page. I decided to try out this phono stage for my cartridge because this design pops up all over. I build the unit with all the fancy parts on a little test board and when all well but one problem
with no RCA`s connected and input shorted the stage is completely quiet with no noise or humms. But when I connect the cartridge then there is a lot of noise on both channels and the music is playing.
Ortofon SL15
Output voltage = 0.04mv
Impedance = 2ohms !!
You will see the cartridge is only 2ohm, and R1 is set to 2ohms. So if I connect the SUT inline then no noise but gain is not correct but no noise.
Some say I must try a 10ohms resistor in series or parallel or what can be the problem ??
Hi there
I am all new to this page. I decided to try out this phono stage for my cartridge because this design pops up all over. I build the unit with all the fancy parts on a little test board and when all well but one problem
with no RCA`s connected and input shorted the stage is completely quiet with no noise or humms. But when I connect the cartridge then there is a lot of noise on both channels and the music is playing.
Ortofon SL15
Output voltage = 0.04mv
Impedance = 2ohms !!
You will see the cartridge is only 2ohm, and R1 is set to 2ohms. So if I connect the SUT inline then no noise but gain is not correct but no noise.
Some say I must try a 10ohms resistor in series or parallel or what can be the problem ??
I assume you built the phonoclone. I'm surprised it is quiet with the inputs shorted. Normally the phonoclone becomes super-noisy when you do that (since that knocks the gain of IC1 up to open loop).
Your cartridge is in the "exotic" category.
R2 must be about 500 ohms in principle, but I think it is best to be conservative here and try 100 ohms.
See if that can get things working cleanly.
Your cartridge is in the "exotic" category.
R2 must be about 500 ohms in principle, but I think it is best to be conservative here and try 100 ohms.
See if that can get things working cleanly.
Hello. I bought the VSPS 300 dual mono and while I look forward to sending, I've been playing with the LT Spice simulator.
In these years I have turned over to vinyl, and I built some phono preamplifiers.
Two of them are P06 R.E. SOLIDPHONO and TNT.
Both with very good performance and perhaps better than many phono stages that are in aplificadores recognized brand.
So as I said I have simulated the RIAA of these answer I have appointed and the VSPS I'm waiting.
The three very close to the real RIAA, with some caveats: the P06 has increased from 10 Hz to 2 dB to 0.2 dB arriving at 200 Hz; SOLIDPHONO away from RIAA - 0.22dB at 10Hz and 18kHz. The rest of the response departs less than that (have adjusted the measuring capacitors and resistors with precision multimeter to reach 0.1%, using series resistors and parallel capacitors); VSPS and respecting the RIAA curve almost perfectly, but since the 8khz will increase until it reaches 40 khz 1.8dB.
Maybe it does not interest me so much respect for the RIAA curve, but present a pleasant sound; not tired; the details are present, that the instruments are separated; the voices are real and excel; the soundstage is wide and has depth.
All this is to some extent I mentioned preamplifiers.
All this is to some extent I mentioned preamplifiers.
I hope the VSPS 300 the excess as there are many compliments on the web.
The last, have simulated the three preamplifiers using one of my cartridges, Audio Technica AT440MLa loaded with 100pF and 47kohms and seen that the frequency response in the three preamplifiers falls from the approximately 15kHz to reach about -2.5 db 20kHz.
This is so?
Greetings waiting for VSPS 300 kits.
In these years I have turned over to vinyl, and I built some phono preamplifiers.
Two of them are P06 R.E. SOLIDPHONO and TNT.
Both with very good performance and perhaps better than many phono stages that are in aplificadores recognized brand.
So as I said I have simulated the RIAA of these answer I have appointed and the VSPS I'm waiting.
The three very close to the real RIAA, with some caveats: the P06 has increased from 10 Hz to 2 dB to 0.2 dB arriving at 200 Hz; SOLIDPHONO away from RIAA - 0.22dB at 10Hz and 18kHz. The rest of the response departs less than that (have adjusted the measuring capacitors and resistors with precision multimeter to reach 0.1%, using series resistors and parallel capacitors); VSPS and respecting the RIAA curve almost perfectly, but since the 8khz will increase until it reaches 40 khz 1.8dB.
Maybe it does not interest me so much respect for the RIAA curve, but present a pleasant sound; not tired; the details are present, that the instruments are separated; the voices are real and excel; the soundstage is wide and has depth.
All this is to some extent I mentioned preamplifiers.
All this is to some extent I mentioned preamplifiers.
I hope the VSPS 300 the excess as there are many compliments on the web.
The last, have simulated the three preamplifiers using one of my cartridges, Audio Technica AT440MLa loaded with 100pF and 47kohms and seen that the frequency response in the three preamplifiers falls from the approximately 15kHz to reach about -2.5 db 20kHz.
This is so?
Greetings waiting for VSPS 300 kits.
Richard, I have assumed the phono cable capacitance that have measured and is 90pF. I have added 10pF to reach the MSRP value of the cartridge.
I've noticed that the preamplifier circuit is foreign to this change in frequency response that occurs when you connect the magnetic capsule.
It works as you well say so as a step low.
My question is, if the frequency response by introducing a magnetic capsule falls from de14-15khz, then to want a preamp it hits 20-25khz over ?.
Why my amp Rotel has a frequency response of 10Hz to 100kHz if the sound source arrives at 15kHz ?.
Sorry for the questions that have nothing to do with the phono amplifier circuit. Regards, Joseph.
(And I look forward to my VSPS 300 !!!!!!!.
If you can explain to me clear the land connections between the pre encluosure and source enclousure . As the shield braiding umbilical cord is connected. It has always given me a headache that point and I have solved in different ways, but which is not correct).
I've noticed that the preamplifier circuit is foreign to this change in frequency response that occurs when you connect the magnetic capsule.
It works as you well say so as a step low.
My question is, if the frequency response by introducing a magnetic capsule falls from de14-15khz, then to want a preamp it hits 20-25khz over ?.
Why my amp Rotel has a frequency response of 10Hz to 100kHz if the sound source arrives at 15kHz ?.
Sorry for the questions that have nothing to do with the phono amplifier circuit. Regards, Joseph.
(And I look forward to my VSPS 300 !!!!!!!.
If you can explain to me clear the land connections between the pre encluosure and source enclousure . As the shield braiding umbilical cord is connected. It has always given me a headache that point and I have solved in different ways, but which is not correct).
I'm having some trouble understanding what you wrote.
Well, it is easy enough to design a phono stage with a (RIAA corrected) response up to 100 kHz or more. That's a measurement made driving the input from the low impedance output of a function generator, not from a phono cartridge.
Anything above 30 kHz is moot since there is simply no musical information recorded in the record groove at higher frequencies, nor could the cartridge reproduce it even if it was there, nor could you hear it if the cartridge could somehow reproduce it.
The VSPS chassis connects to the turntable chassis with a wire connected to a ground lug, in addition to the usual phono cable connecting to the tonearm/cartridge. There is no special requirements regarding this connection. A braid, or simple wire, will work fine.
Well, it is easy enough to design a phono stage with a (RIAA corrected) response up to 100 kHz or more. That's a measurement made driving the input from the low impedance output of a function generator, not from a phono cartridge.
Anything above 30 kHz is moot since there is simply no musical information recorded in the record groove at higher frequencies, nor could the cartridge reproduce it even if it was there, nor could you hear it if the cartridge could somehow reproduce it.
The VSPS chassis connects to the turntable chassis with a wire connected to a ground lug, in addition to the usual phono cable connecting to the tonearm/cartridge. There is no special requirements regarding this connection. A braid, or simple wire, will work fine.
You mean "[Do] I need [] an audio system with frequency response up to 100 kHz audio source if my [cartridge] only reaches 15 khz?"
The answer is "yes, you do, since if the system had less bandwidth the treble response at 15k would be attenuated still further." However, it's not a very important issue given the amount it is already attenuated by the cartridge response.
The answer is "yes, you do, since if the system had less bandwidth the treble response at 15k would be attenuated still further." However, it's not a very important issue given the amount it is already attenuated by the cartridge response.
RJ OK. Something that meant me. Anyway playing vinyl has something "different" in the acute sector. It is more natural and in more detail than in the CD.
Similarly, despite my 55 years and acute hearing to 13-14khz appreciation for vinyl difference in acute.
Greetings and when it comes you commented as VSPS serves about my other phono preamps.
(in this forum I've heard the comparison with a vintage Marantz preamplifier I have to compare, apart from that I built, a preamplifier, which they say is good with + -.. 0.2 dB RIAA and 88 db SN ratio It is a AIWA C50 1982).
My expectation is that the VSPS exceed it. I'll tell you later.
Similarly, despite my 55 years and acute hearing to 13-14khz appreciation for vinyl difference in acute.
Greetings and when it comes you commented as VSPS serves about my other phono preamps.
(in this forum I've heard the comparison with a vintage Marantz preamplifier I have to compare, apart from that I built, a preamplifier, which they say is good with + -.. 0.2 dB RIAA and 88 db SN ratio It is a AIWA C50 1982).
My expectation is that the VSPS exceed it. I'll tell you later.
It's my first post here and my first accomplished audio project.
Greetings from Poland everyone!
Thank u RJM for your great contribution and sharing VSPS project.
I've just done my copy. It has 50db gain and is based on two 5534 opamps.
I even managed to get rid of almost whole 50Hz (EU) hum by shielding. Temporarily it is powered by two 9V batteries which should least approx. 10-20 hours.
I have found old Creative Inspire 2400 2.1 speakers which I am going to use in my first turntable setup. However, the volume controller was broken few years ago. I suppose it was kind of logarithmic potentiometer working as voltage divider. It was just a part of a PC (out) - subwoofer (amp input) cable. I don't have it anymore.
My question is:
Can I add volume knob between VSPS output and Creative PC speakers?
Don't even know it's input impedance (only assume it's > 10 kohm in a wide range of frequency as it should be line-level compatible).
I tried to make this setup using headphone volume controller cable. Unfortunately, the pot is rated approximately 680 ohms at maximum. I am not sure if the opamp can drive such a small load. Moreover, considering 2.2uF coupling capacitor (neglecting 33 kohm resistor which is practically bypassed then), it is moving the corner frequency of the high pass output filter to the unacceptable freq value. If I understand it right, really small resistance attached to VSPS can cause cutting low frequencies.
What is the safe value of volume pot for VSPS?
I'd like to avoid making buffer or active volume control.
Greetings from Poland everyone!
Thank u RJM for your great contribution and sharing VSPS project.
I've just done my copy. It has 50db gain and is based on two 5534 opamps.
I even managed to get rid of almost whole 50Hz (EU) hum by shielding. Temporarily it is powered by two 9V batteries which should least approx. 10-20 hours.
I have found old Creative Inspire 2400 2.1 speakers which I am going to use in my first turntable setup. However, the volume controller was broken few years ago. I suppose it was kind of logarithmic potentiometer working as voltage divider. It was just a part of a PC (out) - subwoofer (amp input) cable. I don't have it anymore.
My question is:
Can I add volume knob between VSPS output and Creative PC speakers?
Don't even know it's input impedance (only assume it's > 10 kohm in a wide range of frequency as it should be line-level compatible).
I tried to make this setup using headphone volume controller cable. Unfortunately, the pot is rated approximately 680 ohms at maximum. I am not sure if the opamp can drive such a small load. Moreover, considering 2.2uF coupling capacitor (neglecting 33 kohm resistor which is practically bypassed then), it is moving the corner frequency of the high pass output filter to the unacceptable freq value. If I understand it right, really small resistance attached to VSPS can cause cutting low frequencies.
What is the safe value of volume pot for VSPS?
I'd like to avoid making buffer or active volume control.
The short answer, given your setup, is you can use any kind of volume control you like as long as the input is higher than 10k or so.
The slightly longer answer is you don't want to use a high value potentiometer on the output of the VSPS, followed by a long length of interconnect cable to the amp/speakers. It is better to put the volume control at the amp input.
It seems to me the best option is to repair or replace the volume control in the creative speakers.
The slightly longer answer is you don't want to use a high value potentiometer on the output of the VSPS, followed by a long length of interconnect cable to the amp/speakers. It is better to put the volume control at the amp input.
It seems to me the best option is to repair or replace the volume control in the creative speakers.
Thank you for your quick answer.
Apart from VSPS R6 (47 ohm), opamp drives then 33 kohm res in parallel with potentiometer 10 kohm || R_load (it's the worst case, max volume). If load is 10k, effective resistance plugged after coupling capacitor is ~4.3k. 1/(2piRC) gives 16 Hz (-3dB).
I've found some info that lower bandwidth should be 10x lower than expected signal lowest freq in audio spectrum in order to avoid distortion (due to phase shift). If total load were 33k, cutoff would be at 2 Hz which suits this consideration.
On the internet you may also find shunt volume regulators (naming it preamp is an overkill in my opinion). Wouldn't it be better to add 10k resistor with 10k log pot as a variable resistor? It has minimum 10k input impedance in worst case. Varying impedance shouldn't be a problem, right?
Even though, 33k res added by you in purpose to discharge cap is parallel to load so it lowers total load below 10k (8k after some quick math).
Don't understand the problem with long cables. Do you mean loosing high frequencies because of cable capacity and high impedance seen from the point after the pot? Is one meter of shielded rca- rca cable too long?
Apart from VSPS R6 (47 ohm), opamp drives then 33 kohm res in parallel with potentiometer 10 kohm || R_load (it's the worst case, max volume). If load is 10k, effective resistance plugged after coupling capacitor is ~4.3k. 1/(2piRC) gives 16 Hz (-3dB).
I've found some info that lower bandwidth should be 10x lower than expected signal lowest freq in audio spectrum in order to avoid distortion (due to phase shift). If total load were 33k, cutoff would be at 2 Hz which suits this consideration.
On the internet you may also find shunt volume regulators (naming it preamp is an overkill in my opinion). Wouldn't it be better to add 10k resistor with 10k log pot as a variable resistor? It has minimum 10k input impedance in worst case. Varying impedance shouldn't be a problem, right?
Even though, 33k res added by you in purpose to discharge cap is parallel to load so it lowers total load below 10k (8k after some quick math).
Don't understand the problem with long cables. Do you mean loosing high frequencies because of cable capacity and high impedance seen from the point after the pot? Is one meter of shielded rca- rca cable too long?
Yes, that's what I mean. If you used 100k pot on the VSPS output, the maximum output impedance is 25k ohms driving 1m cable with perhaps 200 pF of capacitance. 3dB at 30k...
Plus any induced noise (triboelectric currents, inductive couping, etc) is shunted through 25k, generating voltage in proportion.
That's worst case, but you get the idea.
Plus any induced noise (triboelectric currents, inductive couping, etc) is shunted through 25k, generating voltage in proportion.
That's worst case, but you get the idea.
33k discharging resistor always lowers effective load (it's parallel to potentiometer and load). As I mentioned earlier, it can cause 3dB drop on the edge of 20Hz (with 10k pot and 10k input impedance of an amp).
3dB drop corresponds to 45 degrees of phase shift at ~20Hz then. Each higher frequency value is closer to -90 deg. I am afraid of distorting bass.
2Hz cutoff freq makes all frequencies in range 20-20 000 Hz to have almost -90 deg phase shift. It would be much better case...
1. Are you really sure that 10k pot will not destroy bass line?
Have you considered phase characteristics of your preamplifier? I am talking only about RC filter composed of coupling capacitor and effective load attached to it. Surely you have better insight.
2. First answer (short one) was that the input must be higher then 10k. It is impossible when using 10k pot due to parallel connection with 33k and the load. How to deal with it?
3dB drop corresponds to 45 degrees of phase shift at ~20Hz then. Each higher frequency value is closer to -90 deg. I am afraid of distorting bass.
2Hz cutoff freq makes all frequencies in range 20-20 000 Hz to have almost -90 deg phase shift. It would be much better case...
1. Are you really sure that 10k pot will not destroy bass line?
Have you considered phase characteristics of your preamplifier? I am talking only about RC filter composed of coupling capacitor and effective load attached to it. Surely you have better insight.
2. First answer (short one) was that the input must be higher then 10k. It is impossible when using 10k pot due to parallel connection with 33k and the load. How to deal with it?