hi, I am just rebuilding my vinyl gears after stopping for almost 20 years.
TT: Project Perspective with 9" tonearm
Cart: Shure V15VxMR
Phono pre: Project Phono SE
My other gears as follows: -
Accruphase DV-55P CD player
Mark Levinson 38S pre
Mark Levinson 430 power
JM Lab Micro Utopia Be speaker
The sound from CD is OK for me but when I play vinyls, the bass is a bit thin although the dynamic is miles better than CD. I went through the circuit of the Phono SE and can see there could be a number of improvements: -
1. Do not use the original AC/AC adaptor and use an external AC/DC PSU with regulator. Bypass DC terminals are available on the Phono SE box.
2. Change the RIAA circuit components.
3. Place a good and suitable capacitor across the +ve and -ve main supply as decoupling.
4. Of course, the last alternative is to chage it completely to a new one (I prefer tubes).
Does anyone have experience in modifying the Project Phono SE before? Can he/she share me some clues?
Sunny
Hong Kong
TT: Project Perspective with 9" tonearm
Cart: Shure V15VxMR
Phono pre: Project Phono SE
My other gears as follows: -
Accruphase DV-55P CD player
Mark Levinson 38S pre
Mark Levinson 430 power
JM Lab Micro Utopia Be speaker
The sound from CD is OK for me but when I play vinyls, the bass is a bit thin although the dynamic is miles better than CD. I went through the circuit of the Phono SE and can see there could be a number of improvements: -
1. Do not use the original AC/AC adaptor and use an external AC/DC PSU with regulator. Bypass DC terminals are available on the Phono SE box.
2. Change the RIAA circuit components.
3. Place a good and suitable capacitor across the +ve and -ve main supply as decoupling.
4. Of course, the last alternative is to chage it completely to a new one (I prefer tubes).
Does anyone have experience in modifying the Project Phono SE before? Can he/she share me some clues?
Sunny
Hong Kong
http://www.diyaudio.com/forums/showthread.php?s=&threadid=21833&highlight=
is a diyAudio thread on this subject.
Do you use the search function on this board?
is a diyAudio thread on this subject.
Do you use the search function on this board?
The thread I referenced is for the Phono Box, not the SE version.
I don't have either, and I haven't seen a thread on the SE version. Perhaps you could be the first to research mods for the SE version here?
I don't have either, and I haven't seen a thread on the SE version. Perhaps you could be the first to research mods for the SE version here?
Thank you for pointing the errors in Phono Box but mine is SE.
The RIAA is the first point that I try to figure out but I'm not a EE guru and is not able to calculate the component's value.
Is there anyone can provide his/her finding?
Sunny
Hong Kong
The RIAA is the first point that I try to figure out but I'm not a EE guru and is not able to calculate the component's value.
Is there anyone can provide his/her finding?
Sunny
Hong Kong
I think you want to verify the frequency response of the RIAA equalization of your Phono Box SE.
The best way to do this is by testing, but you will need a signal generator or special vinyl test record to apply known audio frequencies to the inputs of your Phono Box SE, and an accurate AC voltmeter to measure the outputs. Access to these tools is not difficult but some technical ability is needed.
If you are trying to find the correct component values, you will first need the circuit schematic, since there are several different types of RIAA circuit designs, each with their own set of formulas for calculating values. I don't have this schematic.
Thin bass can be due to a tonearm with low effective mass used with a low-compliance cartridge, but you have a medium-mass tonearm with a medium to high compliance cartridge, so if anything this should boost bass a little. Is the dynamic stabilizer brush up or down? You may get better bass response with the brush down, remember to add 0.5g VTF to compensate for the brush being down.
Thank you Nuvistor for your suggestion. I have signal gen and oscilloscope therefore I'll try to measure the frequency response first before I take further action.
I seldom play with the brush down because it affects the trackson on those records that are not flat. I'll try to add 0.5g to see how it works.
By the way, is there anyone here have the Phono Box SE circuit?
Sunny
Hong Kong
I seldom play with the brush down because it affects the trackson on those records that are not flat. I'll try to add 0.5g to see how it works.
By the way, is there anyone here have the Phono Box SE circuit?
Sunny
Hong Kong
If you are using signal generator with oscilloscope for voltage measurement then you should consider "inverse RIAA" circuit between signal generator and phono preamp input, do a Google search on "inverse RIAA" for more information. If you apply signal generator directly to phono preamp input you will see large changes in gain vs. frequency due to the RIAA equalization.
Finally decided not to do any modification on the Project Phono Box SE. Too lazy.
I bought an ASR Mini-basis phono preamp and I must say it worths every dollar when compares to the Project SE. It is very musical and frequency response is balance. Silent background and the Double Bass is very very clear. I love it.
Sunny
I bought an ASR Mini-basis phono preamp and I must say it worths every dollar when compares to the Project SE. It is very musical and frequency response is balance. Silent background and the Double Bass is very very clear. I love it.
Sunny
I heard the Emitter amps by ASR (formerly Schrader & Rompf) are great as well, anyone ever heard these?
Regards,
Jarno.
Regards,
Jarno.
After I test the ASR phono preamp, the salesman demonstrates it with the Emitter II Exclusive (US$12000) with battery power supply to me. I must say it is wonderful.
The listening environment is not the best, even with one window opened! After I bought the phono preamp, he also demonstrate CD source from SONY SCD-1 (US$3000) which is famous for its "hard" sound in HK market. The speaker is only a pair of JMR Trente speaker (US$2100/pr). Background is very silence and reproduction is very musical. Vocal is sweet and clear and sound stage is very outstanding. I can easily separate noices from outside and from speakers. I would say it even out-performs my ML38S + ML431 combination. I hope I will not ending up changing my ML because of buying the phono amp.
Sunny
The listening environment is not the best, even with one window opened! After I bought the phono preamp, he also demonstrate CD source from SONY SCD-1 (US$3000) which is famous for its "hard" sound in HK market. The speaker is only a pair of JMR Trente speaker (US$2100/pr). Background is very silence and reproduction is very musical. Vocal is sweet and clear and sound stage is very outstanding. I can easily separate noices from outside and from speakers. I would say it even out-performs my ML38S + ML431 combination. I hope I will not ending up changing my ML because of buying the phono amp.
Sunny
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