Bias reading dont add up....

[phil b]

Ok, so last night I was going to put in a pair of old GE6550's I had in my Einstein 100 watt. I have kt77s in there now and was gonna use a combo of both to see what they would sound like together. Anyways, I hooked up the meter to the outer pair and the reading was 112ma and 26ma for the inner pair. Could it really be that off??!! I know the history of this amp and was brought up to an amp tech by the name of Dennis Kager who is a pretty competent tech. He was the one who put in the kt's and biased it. That was probably less than a year ago. I pulled the tubes and put them on a tester and all 4 read about the same. I would think the inner pair would read better since they are running colder. Other thing is the amp sounds great. Great punch in the bottom end and lots of balls. Its also as loud as a 100 watter should be. Can the reading I am getting be true? I follwed the directions on the site and honestly it wasnt rocket science..
I'd hate to think Dennis just threw the tubes in it without biasing it properly but those readings dont match to what it should...

 

[phil b]

Anyone?

 

[synchu]

Does it sound killer? If yes, why bother.

Might the tech missed to bias properly the internal pair - why not?

 

[phil b]

Does it sound killer? If yes, why bother.

Might the tech missed to bias properly the internal pair - why not?

Well sure it sounds killer,but you always bother cause it can always sound better... I am just surprised that something like that can be missed from a guy who has quite a reputation. I guess I was curious if perhaps there was an off chance that I was doing something wrong and thats what was screwing up the readings. I didnt think it was possible to run a set of tubes that cold and still have the amp sound like it does.

 

[Ventura]

Sounds to me like one of the tubes is defective, old, worn, or losing the plot. Put the old tubes back - check with the currents with a meter. Then put the new/old tubes in, re-test. If it's still reading funky, move the tubes around, and see if the disparity in the reading follows the opposite side (pair) when they're moved to different sockets. If so, you know of the two, at least one is faulty.

Peace,
V.

 

[Duolos]

Anything is possible...

I don't understand why people say they are happy with how their amps sound but yet they toil and fret over trying to get their amp to sound .00000000123283464% better. If you are happy with it, play it like crazy. If it doesn't sound good or right, then let's get that bad boy fixed.

Why not even out the bias and see if it sounds even better?

 

[phil b]

Wow... Maybe my first post came off not as I intended. I am just a little shocked at how good the amp sounds with the two middle tubes running so cold that I thought there had to be something wrong. Hell, Boogies are biased cold but they sound good too, but on certain models if you crank up the bias they sound even better. Then running the outer pair at almost double the recommended value and not even half for the inner pair and since the amp is being used every day I figured if I tested them there should be a difference and there wasnt. Thats it. I dunno about Diezel but on alot of high gain amps if you bias the amp hot you can get it to sound better. Dynamics,harmonics. saturation...
and thats always more than .00000000123283464% better! Then there are some amps that sound like shit with the bias cranked too high.
All I wanted to know was will the amp sound like its supposed to with two tubes running so cold.
Terry, always strive for that .00000000123283464% better. Thats what will make a great amp company like Diezel legendary.

 

[Duolos]

I hear you and please don't misunderstand me. I mean nothing negative or harsh in what I said.

I can promise you that if the amp is playing and sounding as it was originally designed, you will be more then happy....this I can promise you.

 

[phil b]

Just an update..
I biased all four kt77's to what they were supposed to be and there was a slight difference but not much to have gone thru the trouble. After that I threw the Pair of 6550's on the two ends and left the two middle kt's in it and biased again. All I can say is the combo of the two are pretty fantastic!! With all 4 kt's it had killer punch in the low mids, tons of bottom end and a real top bite. For an agressive tone it was right there. What we found with the two and two combo is that the 6550's made the clean sound much warmer..{which is really not a surprise} but the gain characteristics smoothed out on the top end with still retaining most of the low end punch. All in all its just not as harsh, which is a good thing! I am not that sure I would dig all four 6550's but the combo really seemed to be pretty killer! In the end I guess there was nothing wrong with the meter and the tech just never bothered to bias the amp to begin with, but at least now things sound even better.

 

[synchu]

^That is a nice post which reminds me of something I was thinking for already some time, i.e. to combine an inner pair of KT77 and put an outer pair of EL34s?
Peter, Terry, Duesi ? Someone cares to chime in ?
What will be the bias numbers for this combo - inner and outer pair?

 

[Duolos]

65 mA

 

[synchu]

^Thanks, Terry - fast and sharp, as always ...gotta move to US, just to get you as a dealer... last days had few very frustrating experiences in EU with custom gear dealers ...

Any idea by anyone on how this combination is going to sound? (I suspect it's tricky and possibly meaningless question - but, hey, that's a discussion forum )....