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TS500 Tape Simulator / Re: Everything works but high frequencies are getting lost somewhere

« on: November 03, 2021, 12:09:48 PM »

Thank you so much for your reply! I replaced U3 and the sound was still dark, so I took some measurements as you suggested.

I only have one 500 series power extender, so here's what I did:

- I sent a 1k sine wave to the input and adjusted the level of the send until it measured 1VAC
- I put one test probe on the 0V test point and then measured the reading at each of the other test points.

The values were as follows, the values from the working unit are on the left and the malfunctioning unit is on the right.

TP1: 0.576 -- 0.594
TP2: 2.547 -- 2.623
TP3: 0.910 -- 1.075
TP4: 0.910 -- 1.075
TP5: 0.909 -- 0.484
TP6: 0.830 -- 0.442
TP7: 1.662 -- 0.883

Test points 1-4 look fine, but 5-7 are a bit off.

Does that shed any light on how I should proceed? Thanks again for your help on this.

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TS500 Tape Simulator / Everything works but high frequencies are getting lost somewhere

« on: October 17, 2021, 11:02:09 PM »

Hello! I recently built two TS500 kits and one of them works flawlessly, while the other passes a very, very dark signal. The meter is accurate, the levels match the other unit that works well, and the bypass works and passes a clean signal. 

When I fist powered the unit up it oscillated like crazy and I discovered I had installed U5 backwards. I ordered a replacement part from Mouser and replaced the chip, and while the oscillation problem is gone it now passes a signal that sounds aggressively low-passed.

I've double-checked all the solder joints and re-flowed any joints that looked suspicious. The problem persists.

Ring any bells? Thanks for your time!