Buying a Multimeter as I learn how to maintain this stuff...

sweetbeats said:
Okay, point well-taken, BUT...would you agree integration time is a lesser issue compared to the difference between RMS and peak-to-peak measurement?? I mean, some of this is relative to the operator and their studio and equipment, and once the test equipment is on board, even if it might vary by some small amount from somebody else’s studio and test equipment, it’ll be consistent calibration to calibration for the OP, and close enough to targets specified in the service manual. At least that’s my thinking.
Click to expand...
Warning, thread hijack. So, I have what is now an older HP400 solid state voltmeter, and an older Tektronix scope, I also have an older Fluke DVM (can't remember the model number) and an older Wavetek signal generator. Recommendations for a place to get them calibrated?
 
Blue Jinn said:
Warning, thread hijack. So, I have what is now an older HP400 solid state voltmeter, and an older Tektronix scope, I also have an older Fluke DVM (can't remember the model number) and an older Wavetek signal generator. Recommendations for a place to get them calibrated?
Click to expand...
I would bet odds to sausages that Fluke will service and calibrate the DMM and that is basically all you need. The Fluke is then used to check the other kit. I bet it won't be far out. Find the model numbers then trawl the Net for manuals, search antique radio societies and 'ham' radio clubs. There are a lot of electronics hobbyists in the world. With a manual you can likely calibrate the rest of the kit yourself.

But, and I think I have said this before? You don't need NPL grade kit to fix tape machines...'s'all relative but if you are serious you must spend the dosh on a good test tape.

Dave.
 
Years ago when I used to operate an electronics repair company, the service contracts I had with companies like Pioneer and Sony required both minimum test gear and annual calibration. I used a local company here in MA called Hayes Instrument Service. They are still around and still do both service and calibration of test gear. Any area with tech industries should have similar companies available to them.

I got rid of most of my test gear years ago but still have a couple of O-scopes. I've an HP digital and Hitachi 4 channel analog. I prefer the older analog for audio work even though the HP's original cost was thousands more.
 
I just hit my head on a leather case that fell off the shelf - inside was my Avo meter, which wasn't the one I thought I had - it's an Avo 40. No idea if it still works - but I'll give it a a go!
 
Update - I just bought a cheap digital 20MHz scope. Never had a digital one and I'm totally sold on the audio applications. I honestly didn't realise all the neat advantages over my old Tektronix CRT scope. This is what I bought and the price here in the UK was below £200. I calibrated the probes with the 1K 5V test signal and then tried out the various features and the best bit is the measurement menu - you can measure RMS, peak to peak, frequency and loads of other parameters and display these under the trace on the screen. I squirted some audio into it from the computer here and my MacBook puts out just over 600mV p-p on a 1KHz test tone. I really can't see me using a conventional digital multimeter when this is so easy compared to my old scope. Even adjusting the timebase is easier - press a button and it grabs the waveform and locks.

I also note my MacBook has a small DC component on the audio - connecting the cable just raises the trace about .2V before the audio is brought up. I've not even scratched the more advanced menus yet. In value for money terms I'm very pleased
 
Perhaps I could clarify. The HP Digital I have is old and boots Windows. It is more suitable for logging a lot of digital logic signals. The complexities of the features often get in the way and prefer simplicity. I got it from my wife's company when they moved to contract manufacturing and shut down the tech lines. This was probably a $20k+ scope originally and now is essentially working electronic scrap. The new digital scopes are far different as they are essentially what the Fluke Scope Meters used to be.
 
I've just back into tape stuff with the recent Tascam Midistudio 688 purchase and the Tascam 238 which is coming later this month. The 688 needed quite a bit of fixing (and still needs a bit more) but I need to gain some more knowledge in managing to do this. I came across this YouTube channel, which along with others seems really useful, especially when dealing with schematics.

 
Just came across some more resources for anyone trying to learn online about electronics and audio in particular.
Here's a great response with some great suggestions:

ask.metafilter.com

How to teach myself audio electronics

I'd like to teach myself electronics with a focus on audio. I'm starting with this book. What should I do/read from there?
ask.metafilter.com ask.metafilter.com

This led me to this:

Audiologica

tangentsoft.net tangentsoft.net

Which lead me to the reference book:


I've also recently subscribed to this guy, Tetrakan on You Tube who repairs a lot of cassette multi-trackers:



Hope that lot helps you intrepid electronics explorers.
 
rob aylestone said:
Update - I just bought a cheap digital 20MHz scope. Never had a digital one and I'm totally sold on the audio applications. I honestly didn't realise all the neat advantages over my old Tektronix CRT scope. This is what I bought and the price here in the UK was below £200. I calibrated the probes with the 1K 5V test signal and then tried out the various features and the best bit is the measurement menu - you can measure RMS, peak to peak, frequency and loads of other parameters and display these under the trace on the screen. I squirted some audio into it from the computer here and my MacBook puts out just over 600mV p-p on a 1KHz test tone. I really can't see me using a conventional digital multimeter when this is so easy compared to my old scope. Even adjusting the timebase is easier - press a button and it grabs the waveform and locks.

I also note my MacBook has a small DC component on the audio - connecting the cable just raises the trace about .2V before the audio is brought up. I've not even scratched the more advanced menus yet. In value for money terms I'm very pleased
Click to expand...
Rob, I have absolutely no use for that 'scope but having skipped through the .pdf manual I want one! It looks SO much fun!

Have to see how the lekky bills pan out then maybe an early Crimble prezzie to ME!

Dave.
 
That Art Of Electronics PDF is a keeper. The beginning sections are what I learned some 40 years ago, then totally forgot when I dropped it later on. I DL'd it for reference.
 
ecc83 said:
Rob, I have absolutely no use for that 'scope but having skipped through the .pdf manual I want one! It looks SO much fun!

Have to see how the lekky bills pan out then maybe an early Crimble prezzie to ME!

Dave.
Click to expand...
Scopes are a bit like monitor speakers - the cheap ones will get you going but once you've used one of these


you won't want to go back. The display on the Keysight is so much better than the £200 'scopes and the huge memory means that you can capture a few seconds of signal and then zoom right in to see what is really going on at the point where things go wrong. I'm not doing enough electronics to justify one though - my ancient Hameg works well enough but is a bit big and bulky so I'm very tempted by a Picoscope.
 
rob aylestone said:
Update - I just bought a cheap digital 20MHz scope. Never had a digital one and I'm totally sold on the audio applications. I honestly didn't realise all the neat advantages over my old Tektronix CRT scope. This is what I bought and the price here in the UK was below £200. I calibrated the probes with the 1K 5V test signal and then tried out the various features and the best bit is the measurement menu - you can measure RMS, peak to peak, frequency and loads of other parameters and display these under the trace on the screen. I squirted some audio into it from the computer here and my MacBook puts out just over 600mV p-p on a 1KHz test tone. I really can't see me using a conventional digital multimeter when this is so easy compared to my old scope. Even adjusting the timebase is easier - press a button and it grabs the waveform and locks.

I also note my MacBook has a small DC component on the audio - connecting the cable just raises the trace about .2V before the audio is brought up. I've not even scratched the more advanced menus yet. In value for money terms I'm very pleased
Click to expand...
Thanks for this Rob! Refreshing to hear in relation to being told to get a vintage oscilliscope of which most seem broken or quite expensive in Australia. Any idea how how it goes in the low Mv range? Would it read cleanly from 50-150?
 
It seems to perform quite well - it's getting on for a year (last July) so has just become another tool in the box and I don't really think about it. I do the obvious audio things, but I also deal in radios, mostly the kind of stuff you stick on boats, but a bit of business and ham kit, and it's a handy tool for things like sorting external mics and things like that. It seems pretty noise free at the bottom end, although with the gain up you do seem to get the steps in the waveform more visible, so low level sine waves are visibly castelated but the display is easy to read - I just suspect the actually accuracy must be a little less - on an old fashioned scope you'd sort of see a level of say 50 and a teeny bit mV, this might suggest 50 or 55mV when the resolution steps open up. For what I do, it's absence of signal, noisy or clean signals at various levels that are the usual results, and already it's been very useful for spotting things a meter would have hidden - a digital waveform that should have been 5v/0v but the 0 wasn't 0 on the scope, it was 2V - the meter would have suggested all was fine, and fiddling with it sitting across the left and right output indicates something - I've not quite worked out what the non-mono content really signifies, but it looks pretty!
 
You must log in or register to reply here.
Back
Top