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Thread: Philips GP390 Ceramic cartridge NOS 1970s

  1. #1
    Join Date: Oct 2011

    Location: Nothamptonshire

    Posts: 142
    I'm Sharif.

    Default Philips GP390 Ceramic cartridge NOS 1970s

    This is a interesting Ceramic cartridge that I was told about from one of my old school teachers.

    Curiosity got the better of me and so I brought a NOS 1970's Philips GP390 Ceramic Cartridge for 37.50.

    Very little information on the web but what I can find was this was the pinnacle of ceramic phone cartridges.

    I've added a few photos.







    Well how does it sound!

    Well it sound very good fast and detail this is not what I‘ve been lead to believe about Ceramic cartridges

    Sound wise it very neutral detailed and dynamic with no sibilance like a good MC.
    I especial like the absence of record surface noise, vocal are so natural and drum kits sound just right.

    Bass is a little lean but what is there is very clean and focused,
    Hopfully the bass will be sorted with a modified MM phonostage that I have planned.

    It track like a mountain goat and I could not hear any mistracking at 1.7g

    A bit about the cartridge technical spec:

    It has a none removable stylus that’s bonded to the body it also is a has a low output that suitable to feed a MM phonostage.

    Type: Philips GP-390 HIFI Cartridge
    Concept: Ceramic
    Capacitance: 1.2 nF
    Impedance: 1.5 K Ohm, DC
    Load: 47K Ohm
    Sensitivity (1 kHz): 1mV/cm/s 5cm/sec: 5mV
    Output: 8 mV
    Frequency range: 20Hz to 20 KHz
    Channel separation: 20 dB
    Channel balance: within 2 dB
    Compliance: 12*10-6 cm dyne
    VTF: 1.5 to 3.0 g
    Cantilever: Aluminium tube
    Stylus: Spherical diamond, bonded, 0.6 mil (15 m)
    Vertical tracking angle: 15
    Moving mass: 1.4 mg
    Net weight: 5g

    I had an issue with hum but may have found the problem.
    This is to to with my arm wiring as it is unshielded and design to work with a balances phonostage.

    It’s hard to believe this is a ceramic cartridge.

    Sharif
    Last edited by Audioflyer; 14-11-2015 at 13:45.

  2. #2
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 3,421
    I'm Alan.

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    Well that's a new one to me a low output ceramic. Thanks for posting the details Sharif
    Firebottle - for the no bottleneck approach.

    I love Hendrix for so many reasons. He was so much more than just a blues guitarist - he played damn well any kind of guitar he wanted. In fact I'm not sure if he even played the guitar - he played music. - Stevie Ray Vaughan

  3. #3
    Join Date: Jan 2009

    Location: Essex

    Posts: 15,277
    I'm openingabottleofwine.

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    Ceramic cartridges require different equalisation to that used with electro-dynamic types. This is because the output from a piezoelectric cartridge depends on the transverse amplitude of the groove excursion, whereas with electro-dynamic cartridges, the output depends on the transverse velocity of the groove excursion. That is, you cannot use the usual RIAA equalisation with ceramic cartridges. What preamp are you using?
    Have you listened to this month's choice in the Album Club?

    Barry

  4. #4
    Join Date: Oct 2011

    Location: Nothamptonshire

    Posts: 142
    I'm Sharif.

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    I've read some where that you could use a 'capacitor resistor T network' to form the characteristics of a MM cartridge thus would then work into a standard MM phonostage.

    I would like to find out a bit more about this cartridge but the there is so little on the internet.

    These are the bits of details I've found on the internet and it was design to work in to a standard MM phonostage.

    The GP390 seem to be fitted with a some form of EQ/actuator network.
    Not sure what components are in it but probing around on the track side of the small pcb with a multimeter confirms that there is some sort of a resistor network.
    It would be interesting to see what's inside but I can't get it apart without damaging it as the stylus assembly is bonded to the body.

    Snippets that I have found point to a very advance ceramic material of the time develop by Philips and use today in high quality ceramic capacitor.

    If the information is right, I've seen some claim that this ceramic material has a freedom from distortion and a frequency extends between sub sonic to ultrasonic with perfect regularity (high frequency quotes 100Khz to 1Mhz).

    The cartridge resonance frequency of stylus is about 15.5Khz much the same as a lot of modern MM cartridge. I think if the cantilever moving mass was reduce and a nude elliptical tip was fitted this would elevate resonance frequency out of the audio band.

    Sharif.
    Last edited by Audioflyer; 14-11-2015 at 17:45.

  5. #5
    Join Date: Jan 2009

    Location: Essex

    Posts: 15,277
    I'm openingabottleofwine.

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    Hi Sharif,

    I did occur to me that Philips might have fitted a suitable compensation network to the cartridge, so it can be used with a preamplifier offering RIAA equalisation.

    If they had not, I'm sure you would have noticed it as the frequency response would be far from flat.

    Good review by the way - we always like to hear of vintage audio components that have slipped 'under the radar'.

    Regards
    Barry
    Have you listened to this month's choice in the Album Club?

    Barry

  6. #6
    Join Date: Oct 2011

    Location: Nothamptonshire

    Posts: 142
    I'm Sharif.

    Default

    The further evolution of the ceramic cartridge by Micro-Acoustics.

    http://www.roger-russell.com/sonopg/micropg.htm

    It look like they had taken a copy of the Philips GP390 (made from 1967-1968) and lower the moving mass of the stylus to remove the resonance frequency out of the audio band.

    The cutaway view of the 2003e model is probable what the Philips GP390 looks like inside with the exception of the eq circuit board which is on the back with the contact pins.

    Sharif.

  7. #7
    Join Date: Jan 2008

    Location: Forest of Dean, Glos & Cambrian mountains, Wales

    Posts: 8,498
    I'm Jerry.

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    As mentioned elsewhere, based on the superb sound Sharif was extracting from his system at the Scalford show last Sunday I have invested in one of these cartridges.

    Ouch, it's bright for the first half hour!

    But settling down now and both the detail retrieval and precision of the lateral stereo imaging is excellent indeed!

    This is going to be interesting ...
    Jerry

    Main systems:
    Spotify Premium streaming, DAC3 NOS TDA1543. Pure Sound L10 preamp, Pass X150 power amo. Speakers: MBL 116F. Atratus3 i/c & Western Electric 16GA spkr cables. ProJect and Nordost Magus power cables

    Headphones: Fostex T50RP mk3, AKG 551, JBL Synchros S700, B&O H6, PSB M4U-1, B&O Form 2 & 2a and Sony XBA-H1 & SoundMagic E50 IEM headphones

    2nd system: Spotify Premium streaming / Pioneer DV-535, Audiolab MDAC, Black Cat power amp, Chario Syntar 100T speakers. Headphones: Beyerdynamic DT-150, SoundMagic E10 IEM headphones

    3rd system: Portable CD player, Kinter MA-180 T amp, Klegg Symphony 102 speakers

  8. #8
    Join Date: Aug 2010

    Location: East Midlands

    Posts: 154
    I'm Hugh.

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    Quote Originally Posted by jandl100 View Post
    As mentioned elsewhere, based on the superb sound Sharif was extracting from his system at the Scalford show last Sunday I have invested in one of these cartridges.

    Ouch, it's bright for the first half hour!

    But settling down now and both the detail retrieval and precision of the lateral stereo imaging is excellent indeed!

    This is going to be interesting ...
    Please keep us posted. This cartridge in Sharif's system was one of the show highlights for me.

  9. #9
    Join Date: Oct 2011

    Location: Nothamptonshire

    Posts: 142
    I'm Sharif.

    Default

    Quote Originally Posted by jandl100 View Post
    As mentioned elsewhere, based on the superb sound Sharif was extracting from his system at the Scalford show last Sunday I have invested in one of these cartridges.

    Ouch, it's bright for the first half hour!

    But settling down now and both the detail retrieval and precision of the lateral stereo imaging is excellent indeed!

    This is going to be interesting ...
    Hi Jerry.

    Yes my was bright when I bought it and need about 10-20 hour to settle down. This may just be down to the elasticated element that hold the ceramic component loosening up.

    After about 30 hours it should sound neutral with the bass end opens up and with some of the best detail and dynamic's I've heard form any cartridge that I've listen to in the passed.

    Just another thing start the tracking at 1.7g and increase it by 0.1g and have a listen each time, I settled for a tracking weight of 2.1g.

    Sharif.
    Last edited by Audioflyer; 22-03-2016 at 19:02.

  10. #10
    Join Date: Jan 2008

    Location: Forest of Dean, Glos & Cambrian mountains, Wales

    Posts: 8,498
    I'm Jerry.

    Default

    Thanks for the advice, Sharif.
    It's at 1.7g at the moment, I've only just now seen your tracking weight comment - I guess you edited it in after a while?.

    A couple more hours on it now, and as per your expectation it's still rather forward/bright, although nowhere near as fierce as it was to start with - so I've swapped for now from my 'wide open' Audiolab 8000PPA 'stage to the rather more 'comfortable' sounding phonostage in my vintage Marantz receiver* - which also has the advantage of tone controls! - so a little tweak down on the treble is welcome at the moment.

    No complaints - a lovely open, detailed and well focused sound. Not at all what I would have expected from a ceramic cartridge! I'm happily listening to LPs now with it, I'll let it run in for a week or 2 before making any critical judgements.

    * Marco may recall hearing the Marantz's phonostage on his visit here a year or so ago - it was my in-use 'stage at the time, and very nice it is, too.
    Jerry

    Main systems:
    Spotify Premium streaming, DAC3 NOS TDA1543. Pure Sound L10 preamp, Pass X150 power amo. Speakers: MBL 116F. Atratus3 i/c & Western Electric 16GA spkr cables. ProJect and Nordost Magus power cables

    Headphones: Fostex T50RP mk3, AKG 551, JBL Synchros S700, B&O H6, PSB M4U-1, B&O Form 2 & 2a and Sony XBA-H1 & SoundMagic E50 IEM headphones

    2nd system: Spotify Premium streaming / Pioneer DV-535, Audiolab MDAC, Black Cat power amp, Chario Syntar 100T speakers. Headphones: Beyerdynamic DT-150, SoundMagic E10 IEM headphones

    3rd system: Portable CD player, Kinter MA-180 T amp, Klegg Symphony 102 speakers

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