A Modern Loftech TS-1 Audio Test Set

Where we discuss new analog design ideas for Pro Audio and modern spins on vintage ones.
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JR.
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Re: Loftech TS-1 Schematics

Post by JR. »

pascal.verdet wrote: Sun Nov 05, 2017 4:09 am Hi,
In fact, I want just to have a modern test bench, to replace very old, gen, freq, and voltmeter.
I'm looking around the PIC, because with a handful of components, you can get the voltmeter,
the frequency counter the dB meter, and cherry on the cake, you can also directly generate a frequency ???
In fact in my first generation drum tuner using a 8 bit PIC I generated usable sine waves from the PWM output. I actually used two PWM outputs with one scaled to provide more resolution but still far from clean sounding sinewaves. Pure enough to vibrate the drumheads at only one frequency at a time though. :lol:

or drive an external frequency generator,
The AD9835 allows the user to make sine waves from 1Hz up to 25MHz with better than 1Hz resolution.
With which, we will certainly have a "cleaner" signal
Cheers,
Microprocessor control is good IMO, but modern micros can just about do the entire gig inside one chip... 8-)

Sorry I do not mean to co-opt you project but like i said I have been thinking about this a very long time.

JR
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JR.
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Re: Loftech TS-1 Schematics

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mediatechnology wrote: Sat Nov 04, 2017 2:13 pm I'm starting to be reminded of the NTI products: http://www.nti-audio.com

Maybe its just me but I hate the thought of a Smartphone interface due to fat-finger.
agreed, but from a development POV it is cost effective.
It would be interesting to put the TS-1 beside an NTI and compare the amount of time it takes users to get "800 Hz at -23 dBu" or some other oddball combo into a load. I'm thinking the TS-1's "analog" user interface would get me there quicker. The single scroll wheel selecting level and function bothers me.
I think a TS-1 but with a smart rotary encoder instead of simple full range pot could be faster yet.
Not sure what Pascal's goal is but having a modern board in a TS-1 style box with big bright LEDs seems appealing to me. I've never had interest in the NTI stuff for analog.

If one did go whole hog DSP for tone generation and analysis I'd put a mic and low bit rate recorder in it to produce voice circuit-identifier messages. If you're in a broadcast TOC and you've got tone coming at you from 14 different sources its hard to identify where its coming from or if you have the right circuit. The generator could announce its circuit ID and location. A small monitor amp with miniature internal speaker tied to the input would also be useful at the far end of that tone.

I did a product I called "The Identifier" using ISD chips that alternated between message and tone. It ran for weeks on 4X AA batteries and was low-cost enough to be disposable. It read out the circuit ID, provided reference level and let other people know that circuit was in-use.
My thought process on a TS-1 revisit is evolving.... I have two TS-1 around my shop, with one still working (mostly). Not bad for 30+ years in the field. I bet there are lots of these out in the wild still used (if working) and loved by their owners. What the world might like is a drop in PCB that could replace the guts of the original TS-1 and perform all the original functions, perhaps even better, but more alike than different (like an old friend).

If i could replace the LED with LCD display, I could easily support good battery life. As I already suggested a smart rotary encoder for frequency could be faster and easier to hit spot frequencies... a similar smart level encoder could use the same algorithm for tweaking fine levels.

Covering the +20dBu output might require using an output transformer since I would run this from a low voltage battery rail. That +20dBu does not need to drive low Z but 600 ohm would be really nice... Original TS-1 had 51 ohm resistor in series with output (from a TL074 op amp so 2k drive capability) and measured the drop to impute load impedance. (of course with a micro, the impedance measurement could do the lookup table in the micro).

I bet a lot of people would pay a few hundred US dollars to bring their TS-1 back to life. Better control interface and battery power would be huge pluses.

I'll need to soak this in beer for a few nights. 8-)

JR
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mediatechnology
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Re: Loftech TS-1 Schematics

Post by mediatechnology »

I bet there are lots of these out in the wild still used (if working) and loved by their owners. What the world might like is a drop in PCB that could replace the guts of the original TS-1 and perform all the original functions, perhaps even better, but more alike than different (like an old friend).
Heathkit is using that approach for some of their classics: https://shop.heathkit.com/shop

I think the TS-1 user interface based on a rotary encoder for frequency would be very cool.

The only thing I would suggest about using an LCD display is that it be big and back-lit. As big as a gas pump LCD.

You really need to be able to sit the "TS-2" on a console at the patch bay and read the level of what you're calibrating from across the room with big bold digits.
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JR.
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Re: Loftech TS-1 Schematics

Post by JR. »

mediatechnology wrote: Sun Nov 05, 2017 2:42 pm
I bet there are lots of these out in the wild still used (if working) and loved by their owners. What the world might like is a drop in PCB that could replace the guts of the original TS-1 and perform all the original functions, perhaps even better, but more alike than different (like an old friend).
Heathkit is using that approach for some of their classics: https://shop.heathkit.com/shop
I bought a ton of heathkit back in the day, but far from because they were classics, because they were cheap and I was poor. :oops:

I think the TS-1 user interface based on a rotary encoder for frequency would be very cool.
I would love to make it the same but better.

The only thing I would suggest about using an LCD display is that it be big and back-lit. As big as a gas pump LCD.
My original thought was trying to reuse the old metal, but the punched out hole in that face plate is scarcely bigger than four man74s and a few LEDs.... I was already leaning toward a single vertical board in parallel with face plate, maybe replace the faceplate too,,, But keep the general configuration. Maybe replace the push buttons with dome switches, Combo XLR/1/4" input that didn't exist back then could be cool... I used the switch inside the 1/4" jack to disconnect the sine wave output from the dB meter input but with a microprocessor brain I can probably figure what mode is wanted based on what is coming in.

You really need to be able to sit the "TS-2" on a console at the patch bay and read the level of what you're calibrating from across the room with big bold digits.
except you have to be pretty close to change anything...

I will register your vote for Large back lit LCD....(I will look at what standard configurations are out there. )

With battery power I will probably let it put itself to sleep, and wake up automatically in last mode it was in (if i can?.... of course I can... maybe?).

I want one of these already.... 8-)

JR

PS: I could make it a bunch smaller, but i like the concept of sticking it in the old case.
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mediatechnology
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Re: Loftech TS-1 Schematics

Post by mediatechnology »

except you have to be pretty close to change anything...
Not necessarily. You may be reading level at a patchbay and adjusting a trim 20 feet away.
The last time I calibrated the PTS I needed a big meter for that very reason.
I want one of these already....
I think a lot of people would.
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Re: Loftech TS-1 Schematics

Post by pascal.verdet »

I think the TS-1 user interface based on a rotary encoder for frequency would be very cool.
I'm really for that !
or why not : http://micromite.org/shop/micromites/mi ... 28pin-kit/
sine.jpg
sine.jpg (51.5 KiB) Viewed 28729 times
I think we can save lot of space, and it's most user friendly ?
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mediatechnology
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Re: Loftech TS-1 Schematics

Post by mediatechnology »

pascal.verdet wrote: Mon Nov 06, 2017 6:26 am
I think the TS-1 user interface based on a rotary encoder for frequency would be very cool.
I'm really for that !
or why not : http://micromite.org/shop/micromites/mi ... 28pin-kit/
sine.jpg
I think we can save lot of space, and it's most user friendly ?
Wow. The Micromite backpack is very cool.
3579545 is a familiar number to me LOL.

Setting aside the TS-2 for a minute why not make a "Backpack" into a Sifam-looking VU or PPM replacement?
Or maybe a VU/GR meter with user-selectable "skins" e.g. Modutech, Sifam, Triplit, Simpson etc.
pascal.verdet
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Re: Loftech TS-1 Schematics

Post by pascal.verdet »

Yes, we can ...
http://sch-remote.com/PID-EVOR04.php
snp03.png
snp03.png (62.75 KiB) Viewed 28722 times
snp02.png
snp02.png (27.37 KiB) Viewed 28722 times
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mediatechnology
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Re: Loftech TS-1 Schematics

Post by mediatechnology »

Wow and only $75 US.
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Re: Loftech TS-1 Schematics

Post by JR. »

I am not enthusiastic about trying to merchandise this, but tempted to make one, because I can... 8-)

A LCD with alpha numeric display could deliver a ton of info. (Don't know if it will be easy to read from across the room. )

JR
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