Hello
I used to have a great tester. A Hickok 539c . Then I thought I would never have tube stuff again. I sold it. Stupid me. I was wrong.
I have a few 6DJ8/6922/7308 military pulls I need to test.
I live in central Denver - near Cheesman Park
If there is a better to forum to post on, please let me know.
Happy to trade use of the tester for beer or ??
thanks!
Peter Rudy
PS Audio
I used to have a great tester. A Hickok 539c . Then I thought I would never have tube stuff again. I sold it. Stupid me. I was wrong.
I have a few 6DJ8/6922/7308 military pulls I need to test.
I live in central Denver - near Cheesman Park
If there is a better to forum to post on, please let me know.
Happy to trade use of the tester for beer or ??
thanks!
Peter Rudy
PS Audio
I live in Denver and can check the state of my tube testers this weekend. One is more basic emission and another is decent but may need a rectifier replaced.
Tube testers are something I know about spent some months of work adjusting/replacing many parts in my Avo VCM MK4 .
Personally I would not buy an "emission tester " , I have had several UK makes of emission testers and they don't compete with a tube tester that actually applies a signal to the grid of the tube as part of a transconductance test.
I would buy the one needing a replacement rectifier but what is the model a Hickock ?
Personally I would not buy an "emission tester " , I have had several UK makes of emission testers and they don't compete with a tube tester that actually applies a signal to the grid of the tube as part of a transconductance test.
I would buy the one needing a replacement rectifier but what is the model a Hickock ?
I have a Knight KB-600B and a Hickok model 752.
The 83 tube Hickok died. I plan to replace it with a proper silicon option It seems you have to be careful when buying replacement rectifiers as some do not have same balance..
Antique Radio Forums • View topic - Solid State 83 tube for Hickok tube testers
The 83 tube Hickok died. I plan to replace it with a proper silicon option It seems you have to be careful when buying replacement rectifiers as some do not have same balance..
Antique Radio Forums • View topic - Solid State 83 tube for Hickok tube testers
Very interesting link I downloaded the webpage and screenshot the info & circuit although Hickock tube testers are not prevalent in the UK --so thanks for providing that.
In days gone by various top end tube manufacturers made their tubes to a universal standard with little deviation and you could rely on the specs from one tube manufacturer to another ,for example Mullard in the UK/Europe / Osram /etc but now Standards have changed and if you are expecting old equivalent book specs you have to buy REAL /genuine NOS .
An older version of the Avo VCM used the same type of circuit involving a tube but later versions changed to solid state but one large resistor is vital in value to the accuracy of the AVO .
I managed to get an old UK TV mains dropper resistor after trolling through a large box of parts I bought from a radio shop that closed down , it was the exact value at 0.1 % but it was very large at 50 watts .
Hickock,s generally get a good write-up and if buying one I would buy the more expensive models ,I have added many tube bases as well as smashing low emission tubes for their pin sections to make up conversions .
Its easy to do as long as you copy a well known and used pin layout as the AVO can put different connections on each base by means of roller switches on the top , that hasn't changed its code since the 1930,s .
Your Hickock 752 looks good as it tests GM (mutual conductance ), don't know anything about the Knight which I take to be a purely US model but personally after looking at the specs it reminds me of UK emission testers .
Hickocks would be the USA type I would chose.
In days gone by various top end tube manufacturers made their tubes to a universal standard with little deviation and you could rely on the specs from one tube manufacturer to another ,for example Mullard in the UK/Europe / Osram /etc but now Standards have changed and if you are expecting old equivalent book specs you have to buy REAL /genuine NOS .
An older version of the Avo VCM used the same type of circuit involving a tube but later versions changed to solid state but one large resistor is vital in value to the accuracy of the AVO .
I managed to get an old UK TV mains dropper resistor after trolling through a large box of parts I bought from a radio shop that closed down , it was the exact value at 0.1 % but it was very large at 50 watts .
Hickock,s generally get a good write-up and if buying one I would buy the more expensive models ,I have added many tube bases as well as smashing low emission tubes for their pin sections to make up conversions .
Its easy to do as long as you copy a well known and used pin layout as the AVO can put different connections on each base by means of roller switches on the top , that hasn't changed its code since the 1930,s .
Your Hickock 752 looks good as it tests GM (mutual conductance ), don't know anything about the Knight which I take to be a purely US model but personally after looking at the specs it reminds me of UK emission testers .
Hickocks would be the USA type I would chose.
I was able to build a replacement for the 83 rectifier in the 752. A 6sn7 measures what I would expect. I will go through a little calibration check tomorrow morning.
If worldwidebeagle wants to test something, I am sure we can arrange something. Just send me a PM.
If worldwidebeagle wants to test something, I am sure we can arrange something. Just send me a PM.