More than just one of us here, but happy to help,
Here is another thread on just such a desire, essentially what you desire to measure harmonic distortion is more for a FFT function or proper spectrum analyser, but others may know better ways for low frequency measurements,
https://www.eevblog.com/forum/testgear/rigol-ds1054z-fft-for-audio-spectrum/
And here is a video showing you most of the method,
Here is a freebee that you can start with, oscilloscope, spectrum analyzer, signal generator -
https://www.zeitnitz.eu/scope_en
Note protect your sound card inputs -
http://www.daqarta.com/dw_0all.htm
http://www.edaboard.com/thread259543.html
Regards, Dana.
I watched this other video on setting up a workbench for building and repairing amps:
I watched this other video on setting up a workbench for building and repairing amps:
Well you can toss that $2500 figure in the garbage, it's not going to cost anywhere near that,
especially in America where second hand HP equipment goes for pennies.
Any advice on exactly what equipment to purchase that will meet all of our needs in building small Pre-Amps & Amplifiers?
What does everyone think about this?:
D-lab recommends how to repair tube amps best oscilloscope Iwatsu SS-5702
Here is a freebee that you can start with, oscilloscope, spectrum analyzer, signal generator -
https://www.zeitnitz.eu/scope_en
Note protect your sound card inputs -
http://www.daqarta.com/dw_0all.htm
http://www.edaboard.com/thread259543.html
Regards, Dana.
One is totally free, why not try it first? The other has a varying cost depending on capability and may ultimately prove more useful at the high cost levels. But I would try the free version first.
Actually, I wouldn't use either of them. I'm not a fan of using my expensive PCs around high voltage stuff. I might do it if I had a disposable PC and sound card but, at the moment, I don't. For a similar reason, I hesitate to recommend the Digilent Analog Discovery that is ideal for what you are doing. It has the advantage of being a test instrument, not a sound card. But it connects to the PC's USB port and that makes me nervous for high voltage projects. I do use it for 5V kinds of things and I rarely work on anything over 15 volts.
There are isolation devices for USB but I have never investigated how they work and how much protection they provide.
https://www.amazon.com/Isolator-5000-Dongle-Medical-Applications/dp/B00QU232UM/ref=pd_sim_267_7?ie=UTF8&dpID=31RFpMlMzGL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&psc=1&refRID=G66P22SRXJYWB4PYNW4Y
http://store.digilentinc.com/analog-discovery-2-100msps-usb-oscilloscope-logic-analyzer-and-variable-power-supply/
I strongly recommend to buy as little equipment as you can because it's a misconception that you need to rush out and spend large, it won't help completing your projects and only take away funds that could be otherwise spent on assembly and parts.
Typically you would upgrade your bench as you see the need, but if you have a lot of money to throw at it then by all means say so and start spending up.
Do look for a couple of multimeters suitable for measuring AC/DC voltages rated for 1000V (avoid cheap Chinese when it comes to safety). You can find lots of information already here on the forums regarding brands, measuring voltage/current and biasing is easier with multiple meters. I'd budget at least $50 each for something secondhand. Your multimeter will be your most used piece of test equipment.
An audio signal generator can be had for free if you use a PC or cheaply using a home made circuit. On Ebay you can find cheap Chinese kits and generators starting at about $20.
Capacitance, ESR tester. Chinese on Ebay $20.
Oscilloscope, anything you can get your hands on, it needs to be two channel (which most are) to easily compare input to output.
Spectrum analyzer, a PC does a really good job, spectrum analyzers tend to be expensive so do not rush into this without doing proper homework on how spectrum analyzers work and importantly what you need to know when buying one.
Distortion analyzer, probably software again or later after you have made some progress you can consider upgrading.
Dummy loads can be expensive to make however a great "hack" is to use Utilitech 240V Universal (water heating) elements in different configurations to make 4/8/16 Ohm non reactive dummy loads. These were sold by lowes.com item #362342 for ~$9 each, see down below for a video explaining usage.
Google "Dim bulb tester" (aka the poor mans Variac), this is a reactive current limiting that allows you safely test your amp during it's maiden voyage.
Eventually you may want to invest in a Variac which allows you to slowly bring up amps to working voltages and also when used with transformers doubles as a handy way to get different AC voltages on the fly.
Read Chapter 3: Electrical Safety from this website until you fully understand every concept discussed.
http://www.allaboutcircuits.com/textbook/direct-current/
Visit these 3 youtube channels and absorb some content.
https://www.youtube.com/channel/UCUEo3LPGD1gWfGJQoE0i1Gg/videos
https://www.youtube.com/user/essoterric/videos
https://www.youtube.com/user/Stratosaurus1/videos
Could you please wright down the most valuable pieces equipment to get started that you like for the money?
QuoteCould you please wright down the most valuable pieces equipment to get started that you like for the money?
Is there a budget ? If so, say 1/2 of it because people will go over your budget very fast.
If no budget - then out of my league
Here is a multimeter I just found out about but pricey. The reason is it has two scales so you can see AC ripple (hum) on DC lines.
https://www.amazon.com/gp/product/B003TO5YUK/ref=ox_sc_act_title_2?ie=UTF8&psc=1&smid=ATVPDKIKX0DER
But I suppose that two cheap meters could do the same thing. Use cheap Harbor Freight meters (even if 9v) to measure current. This is what usually blows meters and fuses. I have several that I hook up in every power line.
Try and get a meter that does not use 9v batteries
https://www.eevblog.com/forum/testgear/multimeter-spreadsheet/
Do not buy used analog scopes, they are heavy (shipping) take up a lot of space, and easy to lose money on. I lost money on two of them. A lot of people here like them but they also like to fix them (not easy).
There are cheaper scopes than the DZ1054z (I have one of these). Search Amazon for prices and reviews.
Take a look around this site for ideas (they give members a 10 % discount)
http://www.tequipment.net/?gclid=COSgxKry180CFZOCfgodSx4CYg
Some usually good used power supplies : Power Designs, HP But it sounds like you do not need these.
Function gen (used) Wavetek Something like this maybe
http://www.ebay.com/itm/Wavetek-Function-Generator-Model-110-Sine-Square-and-Triangle-Very-Good-Cond-/371667739552?hash=item56891fa3a0:g:fkYAAOSwvg9XcZHZ
Wavetek is very good quality (made in my home town - San Diego) and the chances what you buy will work
A place to look for goodies -
https://www.eevblog.com/forum/beginners/
https://www.eevblog.com/forum/beginners/from-no-parts-to-decent-stockpile-best-approach/
Do you really mean cigar box? I wanted to build something in one and got turned off by the bar code and health warning. Old ones on ebay are really expensive.
If you buy on ebay, buy only on items people bid on. Sort on auction, then by the Most Bids first
All my dumb buys were the ones I was the only bidder.
If you do want an analog - get one from a seller who says and shows that it works (you will pay more for this service) This is the only scope I would buy on ebay
http://www.ebay.com/itm/Tektronix-Tek-465-Oscilloscope-Another-accurate-commercial-grade-instrument-/282078756772?hash=item41ad343fa4:g:lLwAAOSwNuxXbeKE
Because the seller is in the business of selling 465s I wished I would have started with one of his 465s (one of the coolest scopes ever). I was being a cheap ass and lost a lot of money.
Nice budget. If you have a Harbor Freight near you - take you son there and let him buy stuff. They sell meters (several models), wire, gadgets (like IR meter), tools (pliers, wire cutters, etc). I would buy the most expensive soldering iron they have (probably shit) and go from there. Soldering irons will be harder to pick than a scope.
And see what kind of shopping job he does. If he does good, set him on Amazon or ebay for the big stuff. See if he can pick the stuff out with you being his advisor. Let him onto this site. Let him make the decisions (with your help)
You must remember what measuring equipment was used at the time.
- Tubes tester.
- 1KVA variac with output circuit breaker.
- analog multimeter meter 20K / volt (as Avometer 8 )
- low distortion low frequency generator (Wien Bridge) (as HP-200cd)
- 8/15 ohm dummy load 100W
- Distortion analyser (as HP 331A)
- Oscilloscope 20 Mhz (one channel is enough)
- Probe / 100 2000V (to measure anode waveforms)
- Capacitor tester with leak function (as Heathkit condenser tester)
With the exception of the tube tester, everything else is very cheap.
Don't forget a 200W iron solder for chassis soldering.
NB: for repair, a tube signal tracer as Heathkit IT-12 may be usefull.
You must remember what measuring equipment was used at the time.Thank you for sharing. I have read allot about Heathkit products that people have used for years in restoring vintage radios & amplifiers.
Thanks again!