Hickok Tube Testers.

SET Man · « **on:** 24 Feb 2007, 07:07 pm »

Hey!

Guys! I picked this Hickok 6000 tube tester up couple of days ago.

Don't ask me how much I paid for it..... I think I paid a bit more than I should

But its in condition of which I consider to be excellent for it age and only a few nicks outside the case. Sorry about the photo.... a late night snapshot

The inside is very clean, except one thing that really puzzled me....

Although the inside is very clean and those contacts look pretty good. Switches turn nicely. But ! There are funny white powdery stuff on metal parts... mostly on what look like steel or aluminum. What is it?

I cleaned most of the powdery stuff off with ProGold G5. Also, I spray all contacts and switches. And at first after I cleaned those contacts the tester works well right after. But the next day the tester acted strangely... I couldn't get it to set the line voltage right.

I think I must have over spray and got some of the caps and resistors wet or something

After a day or two with it gut out drying. The tester now work like it was when I got it. I retested the same 12AU7 tube of which is new as show in the picture and it tested about the same.... I think it is now 10 Mohm more. According to the chart it listed as 2200 Mohm, I think this is minimum right? Anyway, the new 12AU7 I tested at 2550. But now after cleaning it tested at 2700.

But according to the guy I got it from he tested my 6000 machine and compared to his calibrated Hickok 600 machine and said that my 6000 is only 10Mohm off. Not bad for it age and sound accurate

Anyway, I've always wanted a tube tester. I know I should have bought this couple of years back when the price was lower. But! This is a nice machine and it is one of the later model before they stop making something like this.... the chart dated 1960. And the good thing is that the info for this machine is wildly available

But somehow I can't find a setting for 300B tube

Now I have question for those of you who have tube tester especially Hickok model....

First, should I change the tube rectifiers to solid state replacement? You know those 83 tube do cost quite a bit

Will this be a good idea?

Second, how long should I wait until I press the test button after I plugged the tube that to be test in? I've seen the result to be different with 30secs and a few minutes after I plugged in. Seems like the longer I left the tube in the higher it read.

Third, since this machine had been compared well with calibrated but not been professionally calibrated. So, dose anyone here have a calibrated Hickok tube tester? Will it be possible if you could help me? I want to send you a tube or two so you could test them on you machine than noted the result, than send them back to me so I could see how accurate my 6000 machine is?

Finally I've got my own tube tester!

The other machines that I did considered were Mil TV-7 , Hickok 553A and 600/A

Anyway, comments and help would be greatly appreciated.

Take care,
Buddy

Levi · « **Reply #1 on:** 24 Feb 2007, 07:18 pm »

Congrats on the tube tester purchase! I always wanted to get one but could find a shop that will properly calibrate them for me (cheap). I knew a guy who replaced the tube rectifier with solid state and it worked just like new. It can be done but it needs to be re-calibrated afterwards. Is it worth the time and money? This is up-to-you.

My suggestion is to just leave it the way it is since it is actually working. You only going to use the tester once in awhile anyway(?)

SET Man · « **Reply #2 on:** 24 Feb 2007, 07:30 pm »

Quote from: Levi on 24 Feb 2007, 07:18 pm

Congrats on the tube tester purchase! I always wanted to get one but could find a shop that will properly calibrate them for me (cheap). I knew a guy who replaced the tube rectifier with solid state and it worked just like new. It can be done but it needs to be re-calibrated afterwards. Is it worth the time and money? This is up-to-you.

My suggestion is to just leave it the way it is since it is actually working. You only going to use the tester once in awhile anyway(?)

Hey!

Well, I've been thinking about getting it calibrated... there is one guy Roger Kennedy but he is in CA I think and shipping will cost a lot.

You know there are calibration instruction... maybe I could do it myself.

And to my surprised. I've tested tubes in my amp the 6EA7 and they have been in use for a few years and they still good. Hmmm... seem like the tubes do last longer than I've first thought. But with out tester I wouldn't know

Let's see.

Take care,
Buddy

markC · « **Reply #3 on:** 24 Feb 2007, 07:40 pm »

I've got a 533A. It was supposed to have been calibrated 1 yr. before I purchased it. (5 years ago)
I believe that the values on the chart are average for a new tube-that's what the manual says.
When I test, I let the machine warm up for 5 min. before inserting a tube. Then I let the tube warm for at least 1 min. before taking readings. I always get a higher reading on a warmed up tube than on a cold one. I'd be happy to test some of your tubes and see how the readings of the 2 machines compare.

SET Man · « **Reply #4 on:** 25 Feb 2007, 06:42 pm »

Quote from: markC on 24 Feb 2007, 07:40 pm

I've got a 533A. It was supposed to have been calibrated 1 yr. before I purchased it. (5 years ago)
I believe that the values on the chart are average for a new tube-that's what the manual says.
When I test, I let the machine warm up for 5 min. before inserting a tube. Then I let the tube warm for at least 1 min. before taking readings. I always get a higher reading on a warmed up tube than on a cold one. I'd be happy to test some of your tubes and see how the readings of the 2 machines compare.

Hey!

Thanks Mark

Yes, I experience the same thing when I tested tube as you said. I guess it is better to let the tube warm up to to the point where is stabelized than measure.

And yes, I think 1min is about right.

As for your offer of comparing tube. I might take it. But since you are in Canada I want to see if I could find someone with calibrated Hickok machine here in the US. Dealing with Canadian Postal won't be fun.... you probaly could get things faster from Asia than from Canada via Postal Service

So, anyone here in the US have a calibrated Hickok tube tester?

Anyway, have you ever tested new 12AU7 tube? How much it read after fully warm up?

Take care,
Buddy

GBB · « **Reply #5 on:** 25 Feb 2007, 06:54 pm »

Buddy,
I've got a calibrated TV-7D/U. If you feel like sending some tubes my way, I"d be glad to measure them and send them back.

---Gary

SET Man · « **Reply #6 on:** 25 Feb 2007, 06:58 pm »

Quote from: GBB on 25 Feb 2007, 06:54 pm

Buddy,
I've got a calibrated TV-7D/U. If you feel like sending some tubes my way, I"d be glad to measure them and send them back.

---Gary

Hey!

Cool!

Gary

Gary, please PM me your address and I will send you 2 or 3 tubes over... sometime later next week. Thanks.

Take care,
Buddy

Scott F. · « **Reply #7 on:** 25 Feb 2007, 07:13 pm »

Quote from: SET Man on 24 Feb 2007, 07:07 pm

The inside is very clean, except one thing that really puzzled me....

Although the inside is very clean and those contacts look pretty good. Switches turn nicely. But ! There are funny white powdery stuff on metal parts... mostly on what look like steel or aluminum. What is it?

Hiya Buddy,

What you are seeing on the aluminum is oxidation. It can be cleaned with a good aluminum cleaner such as Mothers. I've got some that has actually turned a yellowish color on my old HH Scott 299.

Now if you see that same 'oxidation' on your solder joints, that is a different animal. That would be tin pest. Tin pest is the breaking down of the solder joint due to exposure to low temperatures (usually). If you find any in the unit, you should take some solder wick and sop up what you can then reflood the joint. That should take care of it.

Nice find BTW

SET Man · « **Reply #8 on:** 25 Feb 2007, 07:35 pm »

Quote from: Scott F. on 25 Feb 2007, 07:13 pm

Quote from: SET Man on 24 Feb 2007, 07:07 pm
The inside is very clean, except one thing that really puzzled me....

Although the inside is very clean and those contacts look pretty good. Switches turn nicely. But ! There are funny white powdery stuff on metal parts... mostly on what look like steel or aluminum. What is it?

Hiya Buddy,

What you are seeing on the aluminum is oxidation. It can be cleaned with a good aluminum cleaner such as Mothers. I've got some that has actually turned a yellowish color on my old HH Scott 299.

Now if you see that same 'oxidation' on your solder joints, that is a different animal. That would be tin pest. Tin pest is the breaking down of the solder joint due to exposure to low temperatures (usually). If you find any in the unit, you should take some solder wick and sop up what you can then reflood the joint. That should take care of it.

Nice find BTW

Hey!

Thanks Scott.

I was a bit worry at first but after I cleaned it a bit with ProGold G5 Everything looks fine

I see... those solder joints still good actually which is a good thing

And everything else look great! The roll chart still turn smoothly and still nice and pretty much white not yellowed up like in some other machine... and it dated from 1960

You know maybe someone here know this.... I don't have 300B tube right now but still I would like to know the setting for it but I can't find the setting anywhere even on the internet.

And the other thing I wish I could do with this machine is to test my KR Audio 842VHD tube... but since this tube is a modern triode tube I don't think anyone will have or know the setting for this tube

Thanks for the info Scott.

I think this machine will be part for my system from now on and it should last for many years to come.

Now I don't have to guess if my tubes still good or not

Take care,
Buddy

Scott F. · « **Reply #9 on:** 25 Feb 2007, 07:38 pm »

Buddy,

Don't know if they have it but check the BAMA site (Boat Anchor Manual Archive).
http://bama.sbc.edu/

They have a HUGE selection of old manuals and tube sheets on line. Great site plus they are free

markC · « **Reply #10 on:** 25 Feb 2007, 07:40 pm »

Hey Buddy,
I just got a pair of N.O.S 5963 tubes, (indutrial type 12au7). One tested 2750/2800 while the other tested 1850/1900-That one is going back! I pulled another pair of mildly used 5963's out of my tube stash and they tested 2850/2900 and 2900/3000. I find that all new or N.O.S, ( that are good), tubes test substantially higher than the chart indicates.

GBB · « **Reply #11 on:** 25 Feb 2007, 07:55 pm »

Quote from: SET Man on 25 Feb 2007, 07:35 pm

You know maybe someone here know this.... I don't have 300B tube right now but still I would like to know the setting for it but I can't find the setting anywhere even on the internet.

And the other thing I wish I could do with this machine is to test my KR Audio 842VHD tube... but since this tube is a modern triode tube I don't think anyone will have or know the setting for this tube

Buddy,
Conventional wisdom is to use the settings for a 50 tube - except you need to remember to change the filament voltage from 7.5v for a 50 to 5.0v for the 300B. Comparing datasheets for the two tubes:

http://www.mif.pg.gda.pl/homepages/frank/sheets/021/5/50.pdf
http://www.westernelectric.com/products/300b/300B.pdf

one sees that the transconductance for the 300B is about 2.5x higher than the 50 so you need to adjust the "normal" reading by that same factor.

The KR842 is similar to a 300B but it needs about 50% higher grid voltage and even then draws more current.
You'll just have to dial in the grid voltage until it shows a "reasonable" transconductance and then remember those settings. You can then see how it changes with time and when it drops too far then you know its time for new tubes.

---Gary

SET Man · « **Reply #12 on:** 25 Feb 2007, 11:05 pm »

Quote from: GBB on 25 Feb 2007, 07:55 pm

Quote from: SET Man on 25 Feb 2007, 07:35 pm
You know maybe someone here know this.... I don't have 300B tube right now but still I would like to know the setting for it but I can't find the setting anywhere even on the internet.

And the other thing I wish I could do with this machine is to test my KR Audio 842VHD tube... but since this tube is a modern triode tube I don't think anyone will have or know the setting for this tube

Buddy,
Conventional wisdom is to use the settings for a 50 tube - except you need to remember to change the filament voltage from 7.5v for a 50 to 5.0v for the 300B. Comparing datasheets for the two tubes:

http://www.mif.pg.gda.pl/homepages/frank/sheets/021/5/50.pdf
http://www.westernelectric.com/products/300b/300B.pdf

one sees that the transconductance for the 300B is about 2.5x higher than the 50 so you need to adjust the "normal" reading by that same factor.

The KR842 is similar to a 300B but it needs about 50% higher grid voltage and even then draws more current.
You'll just have to dial in the grid voltage until it shows a "reasonable" transconductance and then remember those settings. You can then see how it changes with time and when it drops too far then you know its time for new tubes.

---Gary

Hey!

Gary, thanks for the info.

I found the "Obsolete Tube Chart" on the net. To my surprise I didn't find 300B tube on the list.... Hmmm... I think I better go over it again

But the 50 is listed on the chart. So, 6000 could do 50 tube for sure

Now with you info I could now test the 300B tube.

Yes, the KR Audio 842VHD is very similar to 300B. If I remembered correctly it can be use in 300B tube amp as long as the amp could handle the 2 amps filament current.

Seem a bit complicated to test

I think I will just leave them.... they do last very long anyway.

Thanks Gary.

Take care,
Buddy

SET Man · « **Reply #13 on:** 25 Feb 2007, 11:18 pm »

Quote from: markC on 25 Feb 2007, 07:40 pm

Hey Buddy,
I just got a pair of N.O.S 5963 tubes, (indutrial type 12au7). One tested 2750/2800 while the other tested 1850/1900-That one is going back! I pulled another pair of mildly used 5963's out of my tube stash and they tested 2850/2900 and 2900/3000. I find that all new or N.O.S, ( that are good), tubes test substantially higher than the chart indicates.

Hey!

Mark, I bought a matched pair of new 12AU7 Ei Elite.. the gold pin one a while back. But one of the tube was very noisy in my pre. So, I took them out but never bother returning them...

Anyway, I tested the good one on my 6000 and it read about 2750 to 2800. Pretty much like your NOS 5963

So, I guess our testers seem to work properly and copared well between each other than!

I think I will take the listed value on the chart as minimum than

Oh! the other noisy new 12AU7 tested to be around 2750 also but the meter instead of holding steady it kept falling down

Well, no wonder it was very noisy in pre

Well, the good thing about having a tube tester is that now I could test all tubes before I install them in my pre. This sure make me feel better and of cause now I will know if those NOS tube sellers is ripping me off or not!

Mark, thanks for the info on the 12AU7.

Take care,
Buddy

markC · « **Reply #14 on:** 25 Feb 2007, 11:25 pm »

Hey Buddy,
That's good to know, because thats Exactly what my tube did that tested poorly. Started off low on scale compared to a good one and then dropped further as I held the button.
It's great having a tube tester aint it!

Levi · « **Reply #15 on:** 26 Feb 2007, 01:31 am »

Hi Buddy,

I have a couple of new old stock matched 6922 Amperex PQ USA tubes that you can use as a reference.
3 pairs of matched 6H23/6922 Rocket Logo from upscale audio also you can test with your tube tester.
I am sure Kevin has a good tube tester you can match against your tube tester as a reference.

Levi · « **Reply #16 on:** 26 Feb 2007, 01:38 am »

Does your tube tester can test Microphonics? Don't get confused with bad tube versus Noisy tubes

.

Quote from: SET Man on 25 Feb 2007, 11:18 pm

Anyway, I tested the good one on my 6000 and it read about 2750 to 2800. Pretty much like your NOS 5963 So, I guess our testers seem to work properly and copared well between each other than!

Quote from: SET Man on 25 Feb 2007, 11:18 pm

Oh! the other noisy new 12AU7 tested to be around 2750 also but the meter instead of holding steady it kept falling down Well, no wonder it was very noisy in pre

Take care,
Buddy

SET Man · « **Reply #17 on:** 26 Feb 2007, 01:52 am »

Quote from: Levi on 26 Feb 2007, 01:38 am

Does your tube tester can test Microphonics? Don't get confused with bad tube versus Noisy tubes .

Quote from: SET Man on 25 Feb 2007, 11:18 pm
Anyway, I tested the good one on my 6000 and it read about 2750 to 2800. Pretty much like your NOS 5963 So, I guess our testers seem to work properly and copared well between each other than!

Quote from: SET Man on 25 Feb 2007, 11:18 pm
Oh! the other noisy new 12AU7 tested to be around 2750 also but the meter instead of holding steady it kept falling down Well, no wonder it was very noisy in pre

Take care,
Buddy

Hey!

Levi, No the Hickok 6000 doesn't have microphonic test but I know this.

The bad 12AU7 is not microphonic, it is very noisy... a sign of bad tube.

Every tubes have some microphonic. But we are talking about noise here, a bad one will show more and that is a bad sign.

Take care,
Buddy

Levi · « **Reply #18 on:** 26 Feb 2007, 01:53 am »

We can also try this nos that I just bought from eBay.

They said it was new old stock.

SET Man · « **Reply #19 on:** 26 Feb 2007, 02:03 am »

Quote from: Levi on 26 Feb 2007, 01:53 am

We can also try this nos that I just bought from eBay.

They said it was new old stock.

Hey!

Yup, those will do

All I have to do is convert the scale reading of the TV-7 to mOhm scale.

And this way if we see that is way off than that's mean the seller is ripping you off than!

Well, bring them over and see. So, far the reading of my 6000 seem pretty good and comparable with MarkC's 533A. Should be good enough for now until I send some tube to Gary and get them back to compare.

Take care,
Buddy