The other models have a fixed switch for mutual conductance so results are more accurate. Still has bias and line adjust. The shunt control is still on the tester but its used to test non mutual conductance tubes like rectifiers. My 752 Hickok tester has one of those fixed gm switches called a multiplier x1 x2 x4 x10 and x20
I usually tell people to get a 533 or (especially) 533A because, if for no other reason, the 533 series has a fixed-stop rotary-switch for the "range"/multiplier settings, instead of just the highly subjective, poorly repeatable, rotary "English" potentiometer found on the 600 series. Similar circuitry to the 600/600A otherwise, and test data is generally interchangeable between the 533 and 600, and the 533A and 600A; but the 533 series are much larger and Bless crowded internally, and therefore it is easier to get into the circuits and do any minor service or replace worn sockets or whatever. The highly compact 600 series is much harder to work on; even just bolting new socket-savers into it can be a pain. .
I am curious if the increasing variation is due to the instrument warming up. This tester contains a tube and other components whose parameters can drift with heat.
Not sure what others would use the gm for but for guitar amps and HiFi amps the kind of variation he is experiencing frankly is negligible for acceptable proper operation esp in guitar amps where some nonlinearity is actually desireable. In HIFI not so much. In HiFi tubes esp boutique amps, matching the gm of the driver tube is especially important for the minimum distortion possible in the Phase Inverter tubes. Still a few clicks off of gm would most likely be negligible unless tested on a distortion analyzer. For guitar amps typically we use gm to determine the condition of the tubes compared to what it should be as opposed to just reading the Bad-Good scale in that mode. We use gm more for matching audio output tubes when in the different variations of AB push-pull operation as the tubes need to be sharing the load equally between tubes especially when there are 4 tubes. I've also discovered on my Hickock 600A tester if I put my cathode current adaptor between the tube & tester, I can match the current draw of the power tubes which is more significant than the gm matching as you don't want one tube in the quad drawing excessive Idle current when the other power tubes are set to the spec for a given acceptable idle current. I know gm is calculated by the xnge in grid voltage vs plate current so they are all related. BTW, the introduction of the 1ohm resistor for testing cathode current barely affects the gm measurement, so there is no need to remove the adaptor to test the gm.
Is P4 the only usable function? I've only seen people use that function for any tube. Is there any other relevant data to be translated or derived from the readings you get?
SD of 30 out of an average measurement of 2350 is about 1% repeatability - most likely a lot less than the intrinsic accuracy of the instrument. Interesting stuff.
Very interesting, especially as I know little about these things and have just bought one off eBay. However, it arrived with internal damage - I need a wafer switch if anyone knows where I can get one.
You either need to get your eyes checked. Or you have a problem with that deice. If you put the controls on the correct settings you should be no more than a very small percentage error.
I just acquired a Hickok 600a that my dad had. I looks good for its age, does anyone test these for functionality? I would like to sell it. I checked on ebay and they are listed for between 200 and 350 dollars. Nice video, thanks for posting. 👍
Having used a 600A for a long time I can tell you that pushing P1 or anything else before checking for shorts can be the end of your tester..
The bias fuse should protect tester incase of shorted tube. That's what makes hickok testers so reliable
The other models have a fixed switch for mutual conductance so results are more accurate. Still has bias and line adjust. The shunt control is still on the tester but its used to test non mutual conductance tubes like rectifiers. My 752 Hickok tester has one of those fixed gm switches called a multiplier x1 x2 x4 x10 and x20
We’re the switches and pots cleaned before 10:39 the testing?
I usually tell people to get a 533 or (especially) 533A because, if for no other reason, the 533 series has a fixed-stop rotary-switch for the "range"/multiplier settings, instead of just the highly subjective, poorly repeatable, rotary "English" potentiometer found on the 600 series. Similar circuitry to the 600/600A otherwise, and test data is generally interchangeable between the 533 and 600, and the 533A and 600A; but the 533 series are much larger and Bless crowded internally, and therefore it is easier to get into the circuits and do any minor service or replace worn sockets or whatever. The highly compact 600 series is much harder to work on; even just bolting new socket-savers into it can be a pain.
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I am curious if the increasing variation is due to the instrument warming up. This tester contains a tube and other components whose parameters can drift with heat.
Are these tub testers worth money?do you know?
Not sure what others would use the gm for but for guitar amps and HiFi amps the kind of variation he is experiencing frankly is negligible for acceptable proper operation esp in guitar amps where some nonlinearity is actually desireable. In HIFI not so much.
In HiFi tubes esp boutique amps, matching the gm of the driver tube is especially important for the minimum distortion possible in the Phase Inverter tubes. Still a few clicks off of gm would most likely be negligible unless tested on a distortion analyzer.
For guitar amps typically we use gm to determine the condition of the tubes compared to what it should be as opposed to just reading the Bad-Good scale in that mode.
We use gm more for matching audio output tubes when in the different variations of AB push-pull operation as the tubes need to be sharing the load equally between tubes especially when there are 4 tubes.
I've also discovered on my Hickock 600A tester if I put my cathode current adaptor between the tube & tester, I can match the current draw of the power tubes which is more significant than the gm matching as you don't want one tube in the quad drawing excessive Idle current when the other power tubes are set to the spec for a given acceptable idle current.
I know gm is calculated by the xnge in grid voltage vs plate current so they are all related.
BTW, the introduction of the 1ohm resistor for testing cathode current barely affects the gm measurement, so there is no need to remove the adaptor to test the gm.
Im looking for info on how to calibrate a 605a
Noticed on some of the hickok 600A and 800A testers there's no switch beside roll chart what's that switch for?
Is P4 the only usable function? I've only seen people use that function for any tube.
Is there any other relevant data to be translated or derived from the readings you get?
That means your English control needs cleaning if it's dirty will cause variations even if you put it in same spot everytime.
SD of 30 out of an average measurement of 2350 is about 1% repeatability - most likely a lot less than the intrinsic accuracy of the instrument.
Interesting stuff.
Good Grief, never designed to be any better! Good enough for it's intended usage.
Very interesting, especially as I know little about these things and have just bought one off eBay. However, it arrived with internal damage - I need a wafer switch if anyone knows where I can get one.
You either need to get your eyes checked. Or you have a problem with that deice. If you put the controls on the correct settings you should be no more than a very small percentage error.
So, was the tube good?🤦🏻
hahaha I got a headache
I just acquired a Hickok 600a that my dad had. I looks good for its age, does anyone test these for functionality? I would like to sell it. I checked on ebay and they are listed for between 200 and 350 dollars. Nice video, thanks for posting. 👍
You have a 600a send me some photos I be happy to help determine value for you so can get good price. I'm looking for the 752a or TV10U