Have new tubes - Can I really install them myself??

  • Thread starter Thread starter mad-axeman
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mad-axeman

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Guys,

I purchased 6 EL34 winged C power tubes (3 matched pairs) for my early model Herbert (no external bias points), with the intention of having a respected local tech install them, and bias my amp properly, as I have never done it before. As I was speaking to him, and explaining that I wanted to watch, because I thought I could do it in the future, he went into a rather lengthy discourse about various test equipment that would be necessary, and how I am not qualified to understand it anyway.

I thought from various posts, and the Diezel website tech corner, that with a DDM, and some care, it would be something the average tinkerer could handle. I have experience with building pedals and other electronic projects. Do I really the expertise and equipment that he refers to, or is it overkill? When I read the directions on the Diezel webpage, I really don't see anything that I couldn't handle; as a matter of fact, it seems pretty straight-forward. I don't know that I would need a Bias-Rite either.

So what brings me here truthfully, is that the tech can't get it done for a few weeks, with no exact guarantee on completion, and I am way past due for replacement; I can hear a significant tone difference. My band is also just about ready to start auditioning new bass players, and I need my amp now.

I see the amp and the tubes just ready to go, and am just dying to do this myself, if at all possible.

If anyone would be kind enough to pass on some wisdom, I would be so very grateful. I need my tone back!!!

Thanks so much in advance to you all,

Stu
 
Here's some wisdom, he was once not qualified to understand it himself, and even though there is some inherent danger, as long as you know it can kill you, and your going to be careful, do it. He probably doesn't want to lose business, which is understandable. It's really VERY simple, but can bite you if your not careful.

Later on,

-Nick
 
Nick, thanks so much for the follow up. I kinda suspected exactly as you said, but just wanted to be certain. Have you done it yourself?

I actually had a few questions regarding the detailed instructions on the Diezel homepage, and if you've done this before, I am sure you could easily answer them, if you're willing ;)
 
Hey duder,

Sure, If I can't get to it and/or answer I'm sure Peter and Duesy can. Going to be busy the next few hours, so I'll try and check in.

Later on,

-Nick
 
Sounds great! Here we go....

First question is in reference to step 5, which says:

"install croco leads and hook them to your DMM, set to 200mA (!) DC (!)"

my question is how to hook up the leads. there are metal tabs (2 on each side of fuse holder) - do i just connect to one of 2 metal tabs; one on each side of the same fuse holder? Also, how do determine which side to connect pos/neg leads, or is it maybe marked on the board?

Second question is in reference to step 6, which says:

"now (not earlier!) hook to mains + cab, vol = 0 and switch on (both, power and standby)"

my question is what do we mean by mains + cab here? Is this simply saying to connect the head to the cabs (i use 2 4X12s) and power cord to outlet?
also on this step, which volume are we talking about here? I am supposing it's the master of course, but V1 or V2; should i just keep both masters on 0 and be safe?


Believe it or not, I am not an idiot :lol: :LOL: , I just want to be 100% clear, so i don't end up causing more problems than i solve, or.... dying :)
 
Sounds great! Here we go....

First question is in reference to step 5, which says:

"install croco leads and hook them to your DMM, set to 200mA (!) DC (!)"

my question is how to hook up the leads. there are metal tabs (2 on each side of fuse holder) - do i just connect to one of 2 metal tabs; one on each side of the same fuse holder? Also, how do determine which side to connect pos/neg leads, or is it maybe marked on the board?

Second question is in reference to step 6, which says:

"now (not earlier!) hook to mains + cab, vol = 0 and switch on (both, power and standby)"

my question is what do we mean by mains + cab here? Is this simply saying to connect the head to the cabs (i use 2 4X12s) and power cord to outlet?
also on this step, which volume are we talking about here? I am supposing it's the master of course, but V1 or V2; should i just keep both masters on 0 and be safe?


Believe it or not, I am not an idiot , I just want to be 100% clear, so i don't end up causing more problems than i solve, or.... dying
Sounds great! Here we go....

First question is in reference to step 5, which says:

"install croco leads and hook them to your DMM, set to 200mA (!) DC (!)"

my question is how to hook up the leads. there are metal tabs (2 on each side of fuse holder) - do i just connect to one of 2 metal tabs; one on each side of the same fuse holder? Also, how do determine which side to connect pos/neg leads, or is it maybe marked on the board?

Second question is in reference to step 6, which says:

"now (not earlier!) hook to mains + cab, vol = 0 and switch on (both, power and standby)"

my question is what do we mean by mains + cab here? Is this simply saying to connect the head to the cabs (i use 2 4X12s) and power cord to outlet?
also on this step, which volume are we talking about here? I am supposing it's the master of course, but V1 or V2; should i just keep both masters on 0 and be safe?


Believe it or not, I am not an idiot :lol: :LOL: , I just want to be 100% clear, so i don't end up causing more problems than i solve, or.... dying :)
Click to expand...

To question 1: If you look at the pics you will see a red wire and a white wire, that red is the positive and the white is just a jumper to the negative. Positive left tabs, negative right tabs, and so on for each fuse(I don't know if the position or way the fuses are oriented changed at all with different boards possibly, so check with Peter, but if it looks like that photo then your good). I'm almost positive its on the board, usually is, I biased a friend of mine's <300 herbie but it was a while back. I have the handy dandy external version. :)

To question 2: Yes hook up to a cab and to the power outlet, and set both masters to zero.
 
Thanks man! Much appreciated. I am going for it today. I'll keep you all posted on my results.

If I can do this successfully, I'll be ecstatic, as I always prefer to work on my own stuff whenever possible.

Wish me luck!

:rock:
 
DONE!!!!

Success! I must say that I'm a little peeved that this tech acted like the process was so difficult. I guess I understand, but really, most people probably wouldn't even contemplate doing this, so he should have been cooler when he saw my interest. Particularly if he's so busy that he can't get to my amp for 2 weeks!!!

Oh well, screw him. I'm doing this myself from now on. Now if anyone has any questions going forward, I'd be more than happy to help any way I can.

Peace,

Stu
 
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