Re: MY ACCUPHASE T 100
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A few comments having modded many tuners for Ed Hanlon and many customers of my own by virtue of owning two hi end audio shops in CT.
Tantalums were frequently chosen by designers in the seventies for several reasons. Beaded tantalums are mostly free from the age related issues that typically develop in electrolytic caps. Value stability and almost no leakage are
typical of beaded tantalums. BTW , tantalums used as coupling caps typically do not fail , although I have seen cheapo parts develop internal opens between the part leads and the capacitor element. Small films or audio rated electrolytic’s would be a good choice.
In the T-100 , there are 3 tantalums in the MPX decoder circuit. A 10 uf at the audio input of the decoder IC, and a pair of 1uf at the audio outputs. Both Wima and Kemit make metalized polyester caps small enough to fit in place of a beaded tantalum. I suggest purchasing the caps supplied for machine insertion as the leads are MUCH longer . The standard Wima or Kemit caps have a lead length of only 5 mm . The axial power supply bypass caps in the T-100 should be replaced with polarized caps. Nichicon HE are wonderful for power supply bypassing having very low ESR even in low values. Finding improved electrolytic caps in a axial lead format is very difficult these days . Vishay does make them but few vendors sell them. Do keep in mind that many manufacturers are slowly abandoning thru hole parts, and many distributors are not restocking thru hole parts as the demand for Surface Mount parts continues to ramp up. Most of the coupling caps on the T-100 audio boards are polyester. Metalized polypropylene in appropriate voltages and sizes are readily available. Boutique parts are of course at your option. I would point out that the Japanese builder of the Almarrow 318 SE amps uses a very standard Panasonic metalized polypropylene in the amps construction. His declaration that boutique parts offer no improvement in the amps sonic presentation makes me wonder about the value of 20 dollar passive parts when a 3 dollar part works the same.
I would not be the first person to say that an alignment by an experienced tuner tech with a premium FM stereo generator would likely make a substantial improvement in the tuners performance, considerably more than passive part swaps, so I hope you have the option of doing that. I wish you all the best in your project.
On Tue, Jun 30, 2020 at 4:40 PM Victor Dascalescu via groups.io <email@example.com> wrote:
Now I am waiting for the capacitors I ordered at HiFiCollective. Transistors I shall replace only the Q5/6/7 on both modules.