How to bench mark various components.  - Page 1
Forum section: electronics / beginners

author: chinoy
author_rank: Regular Contributor
timestamp: July 03, 2022, 05:18:12 pm
content: Ok I find the crowd on this board a lot more friendly. So Im asking here.I know its an Audio related question and I should probably ask it on an audio forum. But my questions on audio forums seem to upset a few audiophiles.Here is the back story. I have a new scope. I have a new hobby. Audio.The plan is to build a budget setup for my workshop.And if I can get it to sound like my dads old amp from the 70s that would be nice.Id like to use the best parts possible. How would I bench mark say a full wave bridge rectifier. ?35 to 50 amps. Is the rating of the part. My transformer is a 26-0-26 15 amps.I know high end audio guys brag about using fast diodes in their power supplies.I have 4 different brands of this part. In two different form factors. How do I bench mark this part to pick the best one.What parameters do I need to test and how ?.Same question goes for Caps. I have 4 different brands of caps all the same value 15,000 UF 63 volts. How do I pick the best brand.A friend runs and audio shop and any part I ask for he gives me 4-5 brands and says use the best.Same goes for pretty much all the parts. Transistors, op amps, audio IC chips etc. In our country even the guys selling the parts sometimes dont know whats legit and whats a poor copy. So they leave it to the customer to pick.

author: chinoy
author_rank: Regular Contributor
timestamp: July 04, 2022, 12:31:05 pm
content: Ok so i did some reading and to answer my own question as it hasn't got any response.The two parameters to bench mark the full bridge diode is voltage drop i.e. lower voltage drop is better. Next is switching speed the unit that has the higher switching speed is better. And lastly to chk which one heats up the least under full load.Using a function generator gives a better idea.https://youtu.be/kLX4ZFzzFDg

author: Grandchuck
author_rank: Super Contributor
timestamp: July 07, 2022, 05:55:14 pm
content: If you are talking about 50 or 60 Hz rectification, how does a fast diode make any significant difference?

author: Shock
author_rank: Super Contributor
timestamp: July 08, 2022, 02:30:07 pm
content: Audio is a very contentious subject. You could build one amp with an over-engineered power supply and not notice any change in component choice. You could totally notice a problem on the second, and on a third amp the effect may be actually desirable.I suggest sourcing books on audio power supply design, amp design and performance testing and gather schematics with parts lists on designs you are interested in. Most high end audio designs use suitable high reliability parts and should have the amps performance clearly defined.The designers skill typically far exceeds the advice you will get on a forum and you have to consider "better" in electronics is *measurable* but subjective based on application and design goals.Common audio tools are multimeter, signal gen, oscilloscope, spectrum/distortion/audio/software based analyzers, dummy load.Fake components can be avoided by using a quality supplier. No quality supplier would risk their reputation by contaminating their inventory with potentially defective or inferior parts, it's a costly mistake. USA/Japan/Taiwanese/South Korean/German established brands are what you need to aim for and ignore anything without a datasheet.Along with inspection, component datasheets have specs (that are measurable) to confirm a components quality and genuine (may require a test circuit). Buying components off ebay/aliexpress or the corner store is totally avoidable and you're likely just helping fake vendors stay in business further and rip others off.

author: chinoy
author_rank: Regular Contributor
timestamp: July 11, 2022, 05:52:32 pm
content: Extremely sound and sane advise.I started off wanting to replace a STK. It took me 6 months to figure out no matter where in the world you but it from its a fake.The original manufacturer shut down production years ago. People who have the originals and know the value will not sell it. They keep it for their own repairs.All the popular ICs have been faked. All of them are no longer in production or on back order for 1-2 years.Ta7293, LM3886 Toshiba 1943 etc.Everything is down to component quality.I figured the same that at 50hz speed is really not an issue but all the audiophools love to brag about their super fast diodes on their PSU boards.I asked my Audio guru which is the best. He said there is no best. Every ear is different. Build a few amps. Listen to them all and picj the one you like the best. Which is what I am in the process of doing. Have a spectrum analyzer, loads, scope, rev s/w. Need to get a good mic of rev though.