Hi all...
I have recently bought a scope and a function generator to be able to measyre gain and do some analyzis of my mojos and for trobleshooting.
Anyhow... after Reading about it in numerous articles on the net I am still confused and uncertain on how to get it right. Being a total "scope virgin" I would like some advise on how to hook it up with the generator and how to read the figures.
Ok, I understand that this is a huge question but I will narrow it down to my level to get things started
If I have a tube preamp and want to measure the overall gain I have read that I send a 1kHz tone to the input... connect the ch1 probe to the same spot and connect the ch2 probe to the output and measure the ratio between the two.
Then I should have number for calculating the gain (dBu???)... but I also have read that when calculating dBm I need the Resistance. But I do not know if it is the DCR of the input transformer or what?
And... If I have a balanced input and output... Is it enough to measure on one leg of the secondary or do I have to measure both?
As you understand there are a some questions here for me to understand
I can do the math but as for now my Readings are pretty strange I guess since the gain of the preamp is lower than the signal sent from the generator and would result in a gain of 1 -2 dBu and there must be much more?
Help is very much appreciated.
Best regards
/John
I have recently bought a scope and a function generator to be able to measyre gain and do some analyzis of my mojos and for trobleshooting.
Anyhow... after Reading about it in numerous articles on the net I am still confused and uncertain on how to get it right. Being a total "scope virgin" I would like some advise on how to hook it up with the generator and how to read the figures.
Ok, I understand that this is a huge question but I will narrow it down to my level to get things started
If I have a tube preamp and want to measure the overall gain I have read that I send a 1kHz tone to the input... connect the ch1 probe to the same spot and connect the ch2 probe to the output and measure the ratio between the two.
Then I should have number for calculating the gain (dBu???)... but I also have read that when calculating dBm I need the Resistance. But I do not know if it is the DCR of the input transformer or what?
And... If I have a balanced input and output... Is it enough to measure on one leg of the secondary or do I have to measure both?
As you understand there are a some questions here for me to understand
I can do the math but as for now my Readings are pretty strange I guess since the gain of the preamp is lower than the signal sent from the generator and would result in a gain of 1 -2 dBu and there must be much more?
Help is very much appreciated.
Best regards
/John