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Very low sound coming through δ1

delta1

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Re: Very low sound coming through δ1

Postby astrouk1 » August 21st, 2012, 5:05 pm

They're TX2575 Z-Foils from Texas components. The ROUTs on the δ2 and the pots on the β22 are also Z-Foil.

I went with Texas on their price and "audio discount". I wanted to give Caddock's Z-Foils in the UK a try, the lead spacing would have fitted perfectly but there was quite a big difference in price between the two, even with import tax from the US to UK. In any case they only go up to 100k, so the RP0 resistors consist of two 100ks in series.

I haven't connected the XLR output or the 2nd input yet as I was using solid core for the signal wire, which was a bit of a mistake, it's very difficult to route in such a confined space.

I tried some philips silver mica caps for the 100 & 33pf on the β22 boards. I also bought some Philips 550C & 560C transistors off ebay, but after testing them, I was convinced they were fakes, they didn't have the Hfe of the "C" grade transistors. I used the Fairchilds, they worked out well.

There's also a ε12 near the driver boards. I made up shielded wires for almost everything as I was concerned about interference in such a "compact" build, but the output's whisper quiet, no hum, buzz or hiss.

I was thinking of putting an illuminated knob, but decided against it as I've built this in South America, lots of light would make the amp a target for every bug around.

I'm just packing for my travels but I'll post pics of the inside of the Power Supply once I get back.
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Re: Very low sound coming through δ1

Postby amb » August 21st, 2012, 5:10 pm

Nice, those Z-foils must have cost quite a bit. :shock:
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Re: Very low sound coming through δ1

Postby astrouk1 » August 21st, 2012, 5:24 pm

The majority were around $11 each with the 92K & 100Ks at $20. They're matched to 0.05% for that through and they'll do the exact values you need. It worked out cheaper than buying a ready made audiophile pot. Many of them are several hundred dollars and have maybe one or two Z-Foils. I would like to make an RN55 δ1 to see if I can hear a difference and that I haven't bought snake oil! All I can say is that the sound is great, but I don't have a lot of experience with which to compare these things.

Above all, there's the appreciation that you're listening to something you've built yourself.
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Re: Very low sound coming through δ1

Postby amb » August 21st, 2012, 5:27 pm

astrouk1 wrote:Above all, there's the appreciation that you're listening to something you've built yourself.

Yes, that's absolutely the best part of the whole experience. :geek:
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Re: Very low sound coming through δ1

Postby anorphirith » July 3rd, 2018, 12:05 am

I just bought a SuSy Dynahi that has a defective D1,
the seller (not the original builder) described the problem as "being stuck at a low volume" so I'll try all the troubleshooting steps listed in this thread first!
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Re: Very low sound coming through δ1

Postby amb » July 5th, 2018, 8:38 am

Only one channel? Or both? Did you try connecting a pot instead of the δ1 to see if that works? And why are there two missing chips?
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Re: Very low sound coming through δ1

Postby anorphirith » July 11th, 2018, 10:39 am

So I finally got some time to do some testing.
I bypassed the D1 all together, the Dynahi is working perfectly and very loud so the problem is coming from the D1.

at full volume very faint sound is coming through, but there's definitely more noise than actual music.
The LCDuino is working well,
the motorized pot is working well
the relays click proportionally to the pot change, although I didn't test all the relays individually.

I'm guessing that like astrouk1 one of the relays has gone bad, so I will test each relay individually and see what I get.
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