Other time I appear !!!.
This time to tell you that I'm surprised with the performance of this phono stage. Amazing dynamics; impressive but nice serious and do not interfere with the media and acute; musical details that appeared; clear and natural voice.
A large preamplifier.
I can not compare to the "high-end" because my budget will not allow it.
If I compared with a few DIY and Technics brands such as; Yamaha; Aiwa; Nad; Rotel.
The resulting higher is the VSPS 300. It is clear that all tests with different preamps were with the same settings on my modest audio system (boxes B & W DM602, wires Van den Hull C122 BIWIRING; amp Rotel RA 970BX; turntable Aiwa 2400 1982; Cartridge Audiotechnica AT440MLa and Pickering V15).
And did not believe what seems to be true is to be hoped that the capacitors are "burned" for the circuit to sound better.
As I am, I said something weird happens. The preamplifier was mounted on aluminum boxes separated by a triple shielded cable and grounded.
It is completely silent, but depending on how or where this cable hubique one appears Hummm volume to "12 o'clock".
If I find a suitable position for this cable, Humm disappears.
Grounding this according to how AndrewT and advised me RJM.
Greetings and recommend this phono stage.
This time to tell you that I'm surprised with the performance of this phono stage. Amazing dynamics; impressive but nice serious and do not interfere with the media and acute; musical details that appeared; clear and natural voice.
A large preamplifier.
I can not compare to the "high-end" because my budget will not allow it.
If I compared with a few DIY and Technics brands such as; Yamaha; Aiwa; Nad; Rotel.
The resulting higher is the VSPS 300. It is clear that all tests with different preamps were with the same settings on my modest audio system (boxes B & W DM602, wires Van den Hull C122 BIWIRING; amp Rotel RA 970BX; turntable Aiwa 2400 1982; Cartridge Audiotechnica AT440MLa and Pickering V15).
And did not believe what seems to be true is to be hoped that the capacitors are "burned" for the circuit to sound better.
As I am, I said something weird happens. The preamplifier was mounted on aluminum boxes separated by a triple shielded cable and grounded.
It is completely silent, but depending on how or where this cable hubique one appears Hummm volume to "12 o'clock".
If I find a suitable position for this cable, Humm disappears.
Grounding this according to how AndrewT and advised me RJM.
Greetings and recommend this phono stage.
Hey All,
I built the VSPS about 5 years ago and have always been impressed with it and had fun building it! I recently moved and got my record setup all going again and realized that the left channel on my record player has really weak highs and sounds generally quieter than the right channel. I've troubleshot the whole system and determined that something is going on with my VSPS. Any ideas on where to begin to troubleshoot this issue? Maybe a blown capacitor? Also, after moving and re hooking the system up I may have had the input and the output RCA jacks reversed, can hooking the system up in this way damage any of the components?
Thanks in advance.
John
I built the VSPS about 5 years ago and have always been impressed with it and had fun building it! I recently moved and got my record setup all going again and realized that the left channel on my record player has really weak highs and sounds generally quieter than the right channel. I've troubleshot the whole system and determined that something is going on with my VSPS. Any ideas on where to begin to troubleshoot this issue? Maybe a blown capacitor? Also, after moving and re hooking the system up I may have had the input and the output RCA jacks reversed, can hooking the system up in this way damage any of the components?
Thanks in advance.
John
Reversing the input and output connections should not have damaged anything, no.
If this is the stereo VSPS then the shared power supply means the problem is probably a cold solder joint somewhere on the left channel signal path.
I'd probably re-flow all the connections on the L side before doing anything else. There aren't so many that this is tedious. Next, I'd replace the op amp.
If this is the stereo VSPS then the shared power supply means the problem is probably a cold solder joint somewhere on the left channel signal path.
I'd probably re-flow all the connections on the L side before doing anything else. There aren't so many that this is tedious. Next, I'd replace the op amp.
I'm interrested by a Phonoclone built but I have some questions. Maybe it has been before in the thread, but I must confess I was too lazy to read it entirely from the start and a quick search didn't give me answers.
I apologize if somebody have to repeat the same things again and again.
I'm planning to use it with my SPU cartridge (0.2mV, 2ohms).
Concerning gain, the original Phonocube have 75dB but with the gain calculator of the Phonoclone, results are always around 60-65dB. Playing with the Excel file, I discovered that increasing R2 value increases gain.
For example, for my cartridge, the gain calculator give me R1=2ohms, R2=100ohms, gain=64dB. With R2=300ohms, gain is 73dB. Almost as much as the original 47lab phono.
Is it possible to use these values without changing anything to the schematic?
Concerning R1 value, how accurate does it have to be compared to the cartridge impedance? There's more choice with 2,2ohms resistors than with 2ohms, hence my questions.
In the BOM, R7, R8, R21, R22 are carbon resistors. Is there a specific reason for this?
Thanks.
I apologize if somebody have to repeat the same things again and again.
I'm planning to use it with my SPU cartridge (0.2mV, 2ohms).
Concerning gain, the original Phonocube have 75dB but with the gain calculator of the Phonoclone, results are always around 60-65dB. Playing with the Excel file, I discovered that increasing R2 value increases gain.
For example, for my cartridge, the gain calculator give me R1=2ohms, R2=100ohms, gain=64dB. With R2=300ohms, gain is 73dB. Almost as much as the original 47lab phono.
Is it possible to use these values without changing anything to the schematic?
Concerning R1 value, how accurate does it have to be compared to the cartridge impedance? There's more choice with 2,2ohms resistors than with 2ohms, hence my questions.
In the BOM, R7, R8, R21, R22 are carbon resistors. Is there a specific reason for this?
Thanks.
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Hi.
These indeed have been addressed somewhere in this thread. Unfortunately its getting more and more hard to find anything.
Quickly,
1. The gain calculator excel worksheet is set to give 60 dB. I did it this way because 75 dB is too high for most builds. Yes, R2 sets the gain. 100 ohms is about right for your cart, adjust as needed if you need more. R1 is not critical.
2. Carbon because I think they sound better in positions where low inductance is more important than low noise.
These indeed have been addressed somewhere in this thread. Unfortunately its getting more and more hard to find anything.
Quickly,
1. The gain calculator excel worksheet is set to give 60 dB. I did it this way because 75 dB is too high for most builds. Yes, R2 sets the gain. 100 ohms is about right for your cart, adjust as needed if you need more. R1 is not critical.
2. Carbon because I think they sound better in positions where low inductance is more important than low noise.
carbon composition are reputedly low inductance.
Carbon film have a similar helix form for the resistance element, as do metal film and metal oxide and metal wire.
Carbon film being slightly bigger than metal film and metal oxide will inherently have more inductabce due to the excess size for similar power rating that I would class them as higher inductance rather than claim they are low inductance.
And metal film have significantly more excess nosie. Carbon composition are reputedly even worse for excess noise.
Carbon film have a similar helix form for the resistance element, as do metal film and metal oxide and metal wire.
Carbon film being slightly bigger than metal film and metal oxide will inherently have more inductabce due to the excess size for similar power rating that I would class them as higher inductance rather than claim they are low inductance.
And metal film have significantly more excess nosie. Carbon composition are reputedly even worse for excess noise.
How big is the difference? Any chance it's just the turntable's anti-skate set too high?
@AndrewT
These are carbon comp. we are talking about. If you've ever cracked one open you'll know: low inductance because it's just a lump of black compressed powdery stuff in there. High noise, true, but a 47 ohm resistor in series with the output of an op amp isn't going to add anything of consequence.
These are carbon comp. we are talking about. If you've ever cracked one open you'll know: low inductance because it's just a lump of black compressed powdery stuff in there. High noise, true, but a 47 ohm resistor in series with the output of an op amp isn't going to add anything of consequence.
i agree, i used carbon comps as grid stoppers in my tube amps....
btw, this is my VSPS phono head...
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Very nice VSPS! Very slick all-in-one layout with the transformer shielded. Although mine is very quiet, i wish i had also thought of such a smart arrangement. What kind of regulation are you using on that power supply board?i agree, i used carbon comps as grid stoppers in my tube amps....
btw, this is my VSPS phono head...
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Well of course. No voltage in the circuit exceeds 25V.
It is a 500V part in the BOM because they are cheaper to buy at Mouser than the 100V part in 1% tolerance.
Hello. In a previous post, I commented that perceives Humm with the amplifier volume in about 12 hours.
It has been minimized, sounding slightly with the volume turned up.
For this I joined the PSU filter C R C.
Commented: VSPS increasingly improving the sound. AMAZING
Regards.
Does something good or harm the circuit?
It has been minimized, sounding slightly with the volume turned up.
For this I joined the PSU filter C R C.
Commented: VSPS increasingly improving the sound. AMAZING
Regards.
Does something good or harm the circuit?
An externally hosted image should be here but it was not working when we last tested it.
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Well, you effectively damped 100Hz rectifier noise by about -40dB with that additional RC (cut-off frequency is 0.63Hz). An RC filter is always a good idea with something like this that's low power consumption. I personally would have taken a bit less resistance; but if it works, that's nice Take some measurements using a PC soundcard (spectrum analyser) before and after
Take some measurements using a PC soundcard (spectrum analyser) before and after
Not much you can do to make this RC filter better; you either increase the resistance, or increase capacitance. If you really want to go over-the-top, you could add a capacitance multiplier etc etc. But then the next thing is: Johnson noise. Your input impedance is 47kOhm. That resistor in itself creates noise. To lower that, you could switch to a low-inductance phono cartridge. But then hey, you get lower output, and need to increase the gain. Causing more noise No stopping in this hobby... In any case, your phono stage is about as good as it gets. The VSPS is pretty darn good and hard to beat. Noise floor of your VSPS will be _much_ lower than the average record. Save some money, get some better phono cartridges (finer ellipticals, hyperellipticals, shibata, SAS,.. ) They'll reduce distortion, sibilance,... It's a fun and interesting hobby, and you can keep tinkering with circuits. But once and a while, it's fun to just sit back and listen to the music
No stopping in this hobby... In any case, your phono stage is about as good as it gets. The VSPS is pretty darn good and hard to beat. Noise floor of your VSPS will be _much_ lower than the average record. Save some money, get some better phono cartridges (finer ellipticals, hyperellipticals, shibata, SAS,.. ) They'll reduce distortion, sibilance,... It's a fun and interesting hobby, and you can keep tinkering with circuits. But once and a while, it's fun to just sit back and listen to the music