Those IC 'power amps' aren't! They are voltage amplifiers, they amplify the low voltage output of the phono cartridge...either moving magnet (I think the model you have is the MM one) which has a c. 3mv output and correct the RIAA pre-emphasis so it can be fed to a 300mV sensitivity amplifier input. I have the Project MM/MC version which allows use of a moving coil cartridge with c. .3mV input, and consequently requires another 20db of gain. It is an excellent phono preamp...although it may be improved by a better power supply than the 'wall wart' supplied with it. I wouldn't touch the ICs, they are perfectly adequate...ditto the capacitors.
Hi. I recently discovered my pro-ject phonobox ii's power caps have started failing, resulting in an almost unlistenable hum. i already bought replacement caps, now i'm just waiting for them to be delivered. Since i had a look around, i saw some ICs in there and even a modkit from a random website for the first phono box. I was wondering if you could help me in determining if i could switch out the chips for a meaningful improvement in sound. currently I have inside two TL071CN chips and two 2068D JRC chips. I read that the JRC chip is already a very good opa amp, but the TL071CN could be upgraded. I read that the TLE2071 would be a good replacement, but i found a lot of random chips on aliexpress and ebay. Issue is they differ even in size, one is throughole, while others can be surface mount. Would i even be able to replace them on the board. Any help would be fantastic!
Hi, I've been using the project phono box mm/mc and today i can't get any sound out of it at all. Pretty sure the box is faulty although I've not had it a year. Have you heard of this happening before? Do you know if it is a common problem? Thanks
@@jonasDoguedeBordeaux possibly. But have tested the lead with a meter and it's got 18volts when plugged in. Just no sound whatsoever and it no longer gets slightly warm when plugged in. I think it's a power supply issue but possibly something inside the box has come loose. It's really winding me up but amazon are taking the faulty box back and refunding me now. Need to get a new one.
Those IC 'power amps' aren't! They are voltage amplifiers, they amplify the low voltage output of the phono cartridge...either moving magnet (I think the model you have is the MM one) which has a c. 3mv output and correct the RIAA pre-emphasis so it can be fed to a 300mV sensitivity amplifier input.
I have the Project MM/MC version which allows use of a moving coil cartridge with c. .3mV input, and consequently requires another 20db of gain. It is an excellent phono preamp...although it may be improved by a better power supply than the 'wall wart' supplied with it.
I wouldn't touch the ICs, they are perfectly adequate...ditto the capacitors.
Hi. I recently discovered my pro-ject phonobox ii's power caps have started failing, resulting in an almost unlistenable hum. i already bought replacement caps, now i'm just waiting for them to be delivered. Since i had a look around, i saw some ICs in there and even a modkit from a random website for the first phono box. I was wondering if you could help me in determining if i could switch out the chips for a meaningful improvement in sound. currently I have inside two TL071CN chips and two 2068D JRC chips. I read that the JRC chip is already a very good opa amp, but the TL071CN could be upgraded. I read that the TLE2071 would be a good replacement, but i found a lot of random chips on aliexpress and ebay. Issue is they differ even in size, one is throughole, while others can be surface mount. Would i even be able to replace them on the board. Any help would be fantastic!
Can you list the parts that you used in this upgrade? You just mentioned them in Broad terms and not precisely what you upgraded. Hope you can help.
Hi, I've been using the project phono box mm/mc and today i can't get any sound out of it at all. Pretty sure the box is faulty although I've not had it a year. Have you heard of this happening before? Do you know if it is a common problem? Thanks
Hi m8 I have never heard of a phono stage going wrong it could be your external power supply that's failed
@@jonasDoguedeBordeaux possibly. But have tested the lead with a meter and it's got 18volts when plugged in. Just no sound whatsoever and it no longer gets slightly warm when plugged in. I think it's a power supply issue but possibly something inside the box has come loose. It's really winding me up but amazon are taking the faulty box back and refunding me now. Need to get a new one.
@@98266paul that's good news get a new one m8
Can you help me for mod phono box s?
yes mate
@@jonasDoguedeBordeaux have you a schematic?
Do you have an email or some form of contact.
XZING7 • hi madkebabs@msn.com