HP400F Meter Wet Slug Tantalum Capacitor Reforming

This is where we talk about testing, measuring and repairing things. Sometimes we have to repair the equipment we use to test, measure and repair other things. It's an endless cycle of fixing the broken things we need to fix other broken things.
Audio1Man
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Re: HP400F Meter Wet Slug Tantalum Capacitor Reforming

Post by Audio1Man »

By changing the 0.01uf cap to about 0.064uf the BW would be about 15.7 kHz, however it should only be used as a ref not a true calibrated standard.
My 2.2uf cap is about 400Hz and it is a debug tool for HUM FINDING. it is much lighter & smaller than the AP & computer.
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mediatechnology
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Re: HP400F Meter Wet Slug Tantalum Capacitor Reforming

Post by mediatechnology »

Audio1Man wrote: Fri Feb 08, 2019 1:28 pm By changing the 0.01uf cap to about 0.064uf the BW would be about 15.7 kHz, however it should only be used as a ref not a true calibrated standard.
My 2.2uf cap is about 400Hz and it is a debug tool for HUM FINDING. it is much lighter & smaller than the AP & computer.
Duke
+1 on not lugging the AP and computer. We're trying to get JR to do an updated TS-1.
Do you run your meter on batteries for your hum-finding expeditions?
I've never used those binding posts.
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JR.
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Re: HP400F Meter Wet Slug Tantalum Capacitor Reforming

Post by JR. »

mediatechnology wrote: Fri Feb 08, 2019 6:07 pm

We're trying to get JR to do an updated TS-1.
I've been tempted to do a digital version of the TS-1 for decades now, ever since I crossed over to the dark (digital) side but it is against my religion to design hardware that can be accomplished with a smart phone and cheap/free software. I don't even own a smart phone, but maybe I should get one and learn how to program it. :lol:

I messed around with a DSP micro on the bench with nice 16b DAC built in that could cover the next generation TS-1 sine wave generation. In fact I had it making 8 or 10 sine waves simultaneously for an advanced drum tuner... Spraying out a bunch of tones then reading the drum response back with FFT gave a quick read of drum voicing, after only a handful of iterative steps to zero in on key resonances. Unfortunately drummers do not appreciate the technology I already sell, so I have little reason to expect they would embrace an even more expensive version.
===
As I recall the TS-next was caught up in a little feature creep. "just add this one thing and it would be perfect". :lol:

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Gold
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Re: HP400F Meter Wet Slug Tantalum Capacitor Reforming

Post by Gold »

JR. wrote: Sat Feb 09, 2019 9:02 am
mediatechnology wrote: Fri Feb 08, 2019 6:07 pm

We're trying to get JR to do an updated TS-1.
I don't even own a smart phone, but maybe I should get one and learn how to program it. :lol:
The first one to design a hardware/software audio test set for an iPad will have a nice business on their hands. If I had the money or the knowhow I would be all over that. Not a full AP replacement but more like NTI instruments or a Portable One.

An iPad mini and an interface box of the same form factor would make a great test set the size of a multimeter.
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mediatechnology
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Re: HP400F Meter Wet Slug Tantalum Capacitor Reforming

Post by mediatechnology »

I would definitely go with a tablet.
As someone who is using an Android phone like a tablet for streaming it's very difficult to turn off phone features and a lot of the other apps, spyware (Google services) and unnecessary processes to provide an uninterrupted control surface.
Running a test routine that might take a minute or two to complete and have it uninterrupted by a call or text would be a PITA.

A tablet is definitely the way to go.
Tablets are proving themselves in a lot of point-of-sale applications.
I see more and more as cash registers and even tied into the cash drawer.

WRT to the TS-1 I think I asked for a real analog-derived square wave from the digital generator output.
In another thread you suggest banging circuits with square waves so the request doesn't seem that out-of-line.

Square waves, as Brian pointed out, are also useful in testing large consoles' low frequency tilt from bad coupling caps. I've used it on more than a few MCI JH-500 consoles myself.
I also use square waves to find the null point of boost/cut EQ's. A few degrees of control rotation off-center stand out vividly.

I think the reluctance may have been to use a 30 cent analog comparator and switch/transmission gate instead of the ringing DAC output that was the deal-breaker for you.
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JR.
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Re: HP400F Meter Wet Slug Tantalum Capacitor Reforming

Post by JR. »

mediatechnology wrote: Sat Feb 09, 2019 11:36 am I would definitely go with a tablet.
As someone who is using an Android phone like a tablet for streaming it's very difficult to turn off phone features and a lot of the other apps, spyware (Google services) and unnecessary processes to provide an uninterrupted control surface.
Running a test routine that might take a minute or two to complete and have it uninterrupted by a call or text would be a PITA.

A tablet is definitely the way to go.
Tablets are proving themselves in a lot of point-of-sale applications.
I see more and more as cash registers and even tied into the cash drawer.
I do not own a tablet either...
WRT to the TS-1 I think I asked for a real analog-derived square wave from the digital generator output.
In another thread you suggest banging circuits with square waves so the request doesn't seem that out-of-line.
Microprocessors make square waves all day long... I might even be able to remap the processor pin between analog DAC output and digital logic. But indeed this is the kind of feature creep I see... My view of this is simple relaxed performance troubleshooting gear, not full specification bench gear.
Square waves, as Brian pointed out, are also useful in testing large consoles' low frequency tilt from bad coupling caps. I've used it on more than a few MCI JH-500 consoles myself.
I also use square waves to find the null point of boost/cut EQ's. A few degrees of control rotation off-center stand out vividly.
Do you have any reason to expect that a DAC generated square wave would not work satisfactorily?
I think the reluctance may have been to use a 30 cent analog comparator and switch/transmission gate instead of the ringing DAC output that was the deal-breaker for you.
Do you mean Gibbs phenomenon? Sounds like a cosmetic concern, but I don't remember what the output bandwidth was. I suspect the square wave would be square enough for 99% of applications. (BTW the TS-1 did not make square waves and more like a digital version could)

I would indeed be opposed to using unnecessary analog glue, especially if coding a TS-1 into my new tablet. :roll:

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mediatechnology
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Re: HP400F Meter Wet Slug Tantalum Capacitor Reforming

Post by mediatechnology »

I don't care how you make the square wave just that it has one.

The LF tilt test is very useful for a field testing.
If you can get a 100, 1k and 10 kHz clean square wave out of an audio DAC or port pin go for it.

As to a SmartPhone or Tablet interface would I have to carry two things into the field and keep two sets of batteries charged?
From that perspective it seems like having a front panel and only having to carry one box would be better.

How would they interface?
Bluetooth? WiFi?
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JR.
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Re: HP400F Meter Wet Slug Tantalum Capacitor Reforming

Post by JR. »

Ideally I would use the tablet sound chip... KISS

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Re: HP400F Meter Wet Slug Tantalum Capacitor Reforming

Post by mediatechnology »

Dunno about iPads but iPhones no longer have headphone jacks.
If you use an Apple-specific port there's no Android market.
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Re: HP400F Meter Wet Slug Tantalum Capacitor Reforming

Post by Gold »

I would use USB to connect the interface to the iPad. The lightning connector is just USB 2.0. You could use WiFi to have multiple devices talk to each other. That way the price of entry can be free with limited functionality software. You could use any USB 2.0 compliant interface or buy the fancy interface that is pre calibrated and makes lunch for you.

I don’t know if Android is capable of everything necessary to make an audio test set work. A windows tablet is still a windows device. Some may find that to be an advantage. I think the limited functionality and ease of use of iOS would make it feel more like a dedicated test set than a computer.
Last edited by Gold on Sat Feb 09, 2019 3:27 pm, edited 1 time in total.
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