Tram D201 hi fi

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Goldfinger
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Tram D201 hi fi

Postby Goldfinger » Mon Oct 03, 2016 5:27 pm

Receive:
Change C435, C431, C619 to .22uF - 400V or higher polyester/mylar or disc

Transmit:
Change C606, C612, C615, C617 to .22uF - 400V or higher polyester/mylar or disc

Transmit and receive:
Change C623 to .22uF - 400V or higher polyester/mylar or disc

This will widen the RX and TX all the way from the mic jack


Direct inject through a .22uF - 400V or higher polyester/mylar or disc straight into pin 9 of V600, leaving the mic gain wide open for proper grid bias.
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Big Boss Man
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Re: Tram D201 hi fi

Postby Big Boss Man » Mon Oct 03, 2016 10:52 pm

Thanks Goldfinger. One quick question...can I use polypropylene caps? I have plenty of those in the shack. If it must be polyester let me know and I will get an order together.
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Goldfinger
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Re: Tram D201 hi fi

Postby Goldfinger » Tue Oct 04, 2016 10:30 am

Poly is fine. The voltage rating is what's important.
If you are going to inject only and not use a mic, you only need to change the caps after the injection point
(C615, C617 and C623)
The TTC will still work on the injected audio.
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Goldfinger
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Re: Tram D201 hi fi

Postby Goldfinger » Mon Oct 17, 2016 4:14 pm

I missed a couple on the receive.
C417 and C429 should be changed as well. C429 is on the terminal strip next to the volume pot. the center leg of the pot connects to one end. It's tight in there so I always leave the stock cap and just solder the new one in parallel.

You will still get satisfactory results using a little lower value cap. I just modified one with all .15uF 400V polyester and it still had nice bottom.
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