Recent content by mondialfan

  1. mondialfan

    Aragon 4004 Series 2 (Not Mark 2) ??

    I hate to say it but I take issue with Kusiak's statement that ALL transistors with Mondial or Aragon printed on them are in fact Toshiba's. Most if not all of them are in fact RCA/Motorola transistors. I know what you're thinking, but he's Mike Kusiak from Mondial so certainly he knows better...
  2. mondialfan

    Should be a 25k pot. You can install a new 20k Log Alps Blue in its place.

    Should be a 25k pot. You can install a new 20k Log Alps Blue in its place.
  3. mondialfan

    Aragon 4004 Series 2 (Not Mark 2) ??

    There is no Series 2 that I've ever seen. This looks like a feeble attempt at creating something that it's not. I also notice that the person that installed the sticker used a pen to put a roman numeral "II" on the serial # sticker. Upload a picture of one of the channel boards and I can tell...
  4. mondialfan

    Acurus & Aragon amplifier bias with A150 test graph

    Measure DC mV across any one of the eight vertical .5ohm 2W resistors located at the bottom of the channel boards. Do NOT try and reach in the powered up amp with a set of bare probes to do this. You need a set of minigrabbers. Power the amp off, hook up the minigrabber connectors to the...
  5. mondialfan

    Acurus & Aragon amplifier bias with A150 test graph

    I'm sure that Mondial's procedure is a "better safe than sorry" adjustment. Better to have customers check and adjust when hot than cold to allow for possible production differences.
  6. mondialfan

    Acurus L10 problem

    Measure voltage drop from JFET source to drain on one jfet, then multiply X .00509. This is dissipation for one jfet. Then multiply that total X 2 to get total package dissipation for each JFET pair.
  7. mondialfan

    Acurus L10 problem

    Overall gain of the L10 should be unaffected by changing the volume pot from 25k to a 20k ohm. Maybe there's something strange going on with your volume pot? What is the output voltage from the source component that your feeding the L10 with? Is it > 2V?
  8. mondialfan

    Adcom 5300 Schematics

    The small board and transformer supplies +12V to the protection/muting circuits on each channel board. It can be bypassed but to be safe the overheat switch has to be wired in differently to keep thermal protection active. It sounds to me like you should be getting the seller to reimburse you as...
  9. mondialfan

    Acurus L10 problem

    Not really a mystery, do a search for Zobel network. There's one hanging on the output of your Acurus or Aragon amplifier, there's also one on the feedback side of the complimentary input on your Acurus amplifier. Increasing the capacitance lowers the frequency cutoff. The resistance dissipates...
  10. mondialfan

    Acurus L10 problem

    Here's how you want to construct the CRC, just replace 291r with 25r. Your AC mains ripple will drop drastically across the resistor. I'd go with a larger secondary capacitor. Probably 1,000uF or larger.
  11. mondialfan

    Acurus L10 problem

    You have something connected improperly. A CRC filter with a 291 ohm resistor in the current path should produce probably 8 to 9 volts drop across it in the Acurus pre. What was the DCV measured across the resistor in the filter? This is too much resistance for an RC filter in this pre. You're...
  12. mondialfan

    Aragon 4004 MkII Question w/ pics

    Well that busts my last theory of your last shorter amp being an early pre-production version. This amp is a mid-production serial #, so anything I come up with will just be speculation. Its hard to understand why they'd have two versions of case size coming off the line especially in this...
  13. mondialfan

    Aragon 4004 MkII Question w/ pics

    I'm confused, too many amps for my old brain. Is this also the amp pictured in Post #11?
  14. mondialfan

    Acurus L10 problem

    I've heard good things about TKD but never tried one myself, so I'll be interested in what you think of them.
  15. mondialfan

    Acurus L10 problem

    Lowering the value of R16/R17 will not affect the bias in the Acurus to any significant degree. You'd need to cut the trace between the gates of Q7/Q8 and put a variable resistor there using a very low value of 100ohms or so. However I do not recommend this. The jfet's will conduct with the gate...
Back
Top Bottom