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well when you become serious about building real good SE amplifiers you need one of these
Test Speed:Fast: 2.5, medium : 2, Slow: 1 (times / sec.)
Test terminal configuration:The BNC test line
Test signal frequency:100Hz, 1kHz,7.8kHz
Test signal level:1.75Vrms(max)
R:0.0002 Ω - 10.000MΩ
C:0.1 pF - 10000uF or more
L:0.01 μH - 1000 H
If you pickup one of these from ebpay make sure they send you the Correct power transfomrer mine came with 220v pri and it was suppose to be 110v
so I just happen to have some old totally enclosed Radioshack center tapped transformer around and mounted it outside the case close to the IEC connector In my thinking it was an upgrade :)
You know, you can get a Dayton Audio "DATS" box for about a hundred bucks and measure those things at about any audio frequency, even get an impedance curve from it. DATS (and Woofer Tester, LAUD, Praxis, a number of others through the years) all measure impedance via a bridge setup and are not limited to a few test frequencies.
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I have bought one of these XJW01 and I am trying to measure the inductance of my Lundahl Double-C primaries interstage transformer....and I am confused by the results:
When I switch kt on, kt goes into Auto and 1khz measurement frequency and when the primary is connected, kt gives me for a fraction of a second a measurement of above 200H (target:210H for a LL1692AMPP). After that it falls down to about 24H, which is significant lower than expected.
When I press theRNG=Range-Buttom, it shows me again for about a second or so a high valje like 175H before it goes back to 24H.
So, the questions is: What is the correct result ?
You could have the impression that its PSU is not steong enough to deliver enough juice to hold the right measurement or something....Which would not bother me if I would know that the first second shows indeed the right result...
I do not understand why pressing the RNG buttom first gives me a new measurement and than goes back....can you reproduce my findings ?
> I have bought one of these XJW01 and I am trying to measure the
> inductance of my Lundahl Double-C primaries interstage
> transformer....and I am confused by the results:
Large coils must be measured at 50, 60, 100 or 120 Hz.
I would suggest you to use step down transformer (e.g. 220V -> 12...50V), resistor and voltmeter in order to measure and calculate primary inductance. Google is your help for formulas.
For a hobby Chinese products are a real budget savers.
You can find on this device here:
Additionally, there are positive feedback posts on Russian DIY forums.
PS. I'm dealing quite a lot with Chinese parts, hardware and machinery. While they may cost much less then comparable from USA, EU or Japan manufacturers, these cost savings often come with questionable precision, awkward workarounds and hackwork, buggy software. Not always, but quite often.
For example, I have Atten oscilloscope with large screen which was great for its cost (at least on paper) and comparable to Agilent at one third of the price.
It arrived in time and it works. However:
1) It's input amplifier have poor signal/noise ratio compared to Pro counterparts. Still OK because I have relatively high signal levels.
2) Software is buggy, when one try to write readings on USB memory stick, it may do so, and may not, only god knows why. Manufacturer agreed to reflash software free o charge, but request to send oscilloscope back to China, for shipping and customs at my expense both ways. It doesn't make any sense, however.
I totally agree you really need to know what your getting yourself into
2 china products that are very good one is this digital LCR and another is this signal generator http://www.ebay.com/itm/221508521898?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
has a very good square wave Rise and fall time of ≤100ns perfect for amplifier testing without adding rc filter to slow it down and music is much slower then 100ns but its a good test plus this unit has real good bandwidth for audio testing/sweeping. IMO EXCELLENT
Did you mean to post a link to a digital LCR?
Look for XJW01 LCR meter on Amazon, eBay and Aliexpress. This model seems to be discontinued.
On Aliexpress they are available at around $100 but assembly is UNFINISHED, as stated in listings. I don't know what is missing.
This LCR was a "KIT" the main board was stuffed and soldered but you have to put it all together and make some cabling
Yes there maybe a new model that will/can test at 100kc but for what we do this unit is works fine. IMO every experimenter should have one just for matching R's L's C's plus so much more
Serious SET hobbyist needs LCR meter that can measure inductance of the OPT at variable frequency from 20Hz-20KHz. Any LCR meter that is fixed to measure at 100Hz/1KHz/10KHz; etc. points are not very useful IMO.
Also, variable Voltage signal of about 20Vrms and selectable Vsource of 30/ 50 /600 /1K ohms.
.Thou shall not stand where I type for I carry a bottle of Certified Audiophile Air and a Pure Silver Whip.
> Serious SET hobbyist needs LCR meter that can measure variable inductance from 20Hz-20KHz.
Certainly exists yet too expensive for hobby use.
Generator, resistor and true RMS voltmeter is enough for this purpose.The rest is simple calc job.
The Genrad LCR Digibridge is much higher quality. More expensive, yes, but not made in China. At $200-300, the used Genrads are a "serious" bargain.
Buy Chinese. Bury freedom.
Hi TK my particular model was compared directly to the very expensive agilent units the difference was .115%!
Hell they use the same Autobalancing Bridge principle just like good expensive ones :)
and for you guys needing to use an inexpensive tool to measure primary IMP this will do it!!! it will also measure the shunt capacity across choke reactor.
"Hi TK my particular model was compared directly to the very expensive agilent units the difference was .115%!"
Getting an analog circuit to hit a specification is rather easy. Keeping it there in light of environmental as well as component aging is a totally different matter.
That's what you buy with HP, Tektronix, and other established test equipment manufactures.
yeah you go ahead by them dinosaurs of test equipment and keep paying to have then calibrated every other year...
Mine just hit a button and it calibrates itself!!
plus its NEW not some 20 year old machine that takes 20 mins to stabilize before you can even use it. you guys are missing the point its as good as the expensive stuff and if it dies in 5 years they will have an even better unit i can buy just as inexpensive and be good for however long.
really you have to look at the bigger picture plus if there was a competing USA company that made a similar product/similar price I would be all over it but we dont and so my money goes much farther in this hobby
you guys have fun
Against what? How stable is the calibration reference?
Hint, why did Dynaco choose 1.56 volts for the bias setting in their famous amps. That required a non standard cathode resistor. Why 1.56 volts?
It's all about the accuracy of the reference. Otherwise any so called calibration is relative.
Also, you only need to calibrate those old dinosaurs once a year if you are doing work that requires traceable calibration certificates. That doesn't mean they need yearly calibration to remain accurate - and surly accurate enough for hobbyist audio use.
The Mind has No Firewall~ U.S. Army War College.
Alkaline batteries did not commercially exist back then.
Am aware Dave... merely implying that alkaline tend to run higher voltages... in my experience.
The Mind has No Firewall~ U.S. Army War College.
Even this well-considered argument is captive to the necessity of the unit remaining functional. Chinese products carry an inherent risk of default in that regard. :)
Buy Chinese. Bury freedom.
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