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llwhtt 9th February 2013 12:23 AM

Sound Technology 1700B
 
I have a Sound Technology 1700b but no input cable. What is the correct cable to use, the book says "twisted pair", make it or buy it?

Craig

PChi 10th February 2013 11:54 AM

No one else has answered so my best attempt is to make it yourself. Unless you need the best common mode noise rejection when twisted pair with an overall screen would be best.

I think that the input connections are just 4 mm terminal post sockets. Possibly the spacing is the 'standard 0.75 inch' so a 'BNC female to double stacking banana plugs adaptor' could be useful for testing single ended equipment. Common mode noise, apart from mains harmonics, is usually not a problem (grosss generalization).

Elvee 10th February 2013 04:09 PM

If you use its balanced capabilities, you need indeed a shielded twisted pair.

If your sources are mainly unbalanced, you can use shielded or coax cable, and strap the (-) and ground posts.
That is the configuration I use myself in 99%+ of cases

llwhtt 20th February 2013 11:47 PM

I found a cable that should just fine- Pomona #1167-36, getting one from Mouser.

Craig

toxic ingestion 13th December 2013 05:27 AM

How do you like the 1700b? I have a chance of picking one up and wondered what you thought of it. Thanks.

Elvee 13th December 2013 07:55 AM

I like it, but be sure to test it properly before you buy, because some of the parts do not age very well: the carb comp resistors, switch contacts, analogue optocouplers, potentiometers, etc.

Make it measure its own THD on the most sensitive scale: if there are such issues, they will generate extra noise, and the measurement floor will be too high

TerrySt 13th December 2013 04:01 PM

I have a 1700b also. When working, they are very nice instruments. The only complaint would be the size. They eat up a lot of work bench space. But the are capable instruments and seem to work well.
I like that the calibration procedure can be done without any expensive , rare equipment. It pretty much uses itself to calibrate itself. A good voltmeter, frequency counter and oscilloscope is all that is needed.
But if it isn't working, they are a bear to work on. Depending on which options it has, it can be difficult to get to the bottom side of the boards. The manual suggests for most repairs you cut the leads of the bad component on the top side and tack the new part to the remnants of the leads. For some parts that is not possible. Getting the boards out so you can work on them can be done, but it requires patience. Take careful notes and pictures, because none of the manuals I have found online show the board interconnects very well.
Check that the oscillator works in the low distortion setting. When you switch it to this position, it should turn off the LED and settle in. If if clicks back and forth from fast response to low distortion, then you have some work to do. Hopefully just an alignment, but the circuit uses a light dependant resistor that can fail. It is obsolete, so finding a new part that works may require some circuit modifications and re-tuning. There is info on the web on how to do it though.

Terry


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