Couple of problems about voltages and bias.

[printman73]

My 45 sounds good, plays good and for the most part is pretty quiet. BUT!!!, when I was messing around with the 6L6's AND THE KT-66's I remeasured all of the voltages again (just for practice) and found 2 issues. When I measured pin 1 of v1, v2 and v3 I noticed the voltages a little higher than what was shown in my build sheet specs. v1 pin 1 was measuring 245 instead of 180. v2 and v3 were a little higher but not much more, within 10%. When I tried to set the bias on pin 8 of v4 and v5, I couldn't even get a reading on my el cheapo digital voltage meter. Am I doing something wrong? I did set the meter to milliamps. It did not budge. 00000 Should I try it again with a better meter? I set the bias pot about midway and I'm playing it there for now. Sounds great but I'm not sure how much tolerance there should be on the voltage readings. Will it just burn out the tubes (12ax7's) faster or am I staring at a problem that will do more harm?

Thanks for any info I can get.

P.S. I am using Classic Tone Output and Power trannies.

[Elad E]

not sure the milliamps(mA) setting would work - the bias resistors (pin 8 ) should be measured on the Multimeter's millivolts (mV) setting and the reading in mV represents the same value in mA (i.e. a 43 millivolts reading at pin 8 on the meter means the cathode current is 43 milliamperes).

also, I doubt the 12ax7s could be harmed by the bias setting though I could be wrong. the output tubes on the other hand may very well red plate or arc when bias exceeds 70% plate dissipation, keep an eye on the power tubes plates when biasing, if they red plate you are probably well over 45mA and/or the tubes are faulty.

edit: regarding the higher voltages measured on the preamp tubes - I use the ClassicTone iron and get similar voltages.
when I inquired the more seasoned members commented that it is completely normal and very much in line with vintage specimen to feature readings higher than whats in the PDF's spec sheet.
I also remember a comment about the Metro transformers being initially speced to run colder and prolong tube life and thus the values in the charts are slightly lower than what's common.

[printman73]

Thanks, Elad E. I am starting to figure out how to use this site and I was reading that very fact about the Classic Tone iron. I was probably rambling not knowing how to ask the question about the pre amp tubes. I know they aren't involved with biasing but was asking if the higher voltage would burn them out quicker. You answered that question and I thank you. If anything I am running a little cold on the power tubes just to be safe and until my son brings his good meter over. My meter doesn't have a Millivolt setting. Ignorance had me trying the Milliamp settings. The whole thing started when I was trying to use the 6L6's and then I started blowing fuses. Then I realized I was using fast blow instead of slo blow. I do know that will make a big difference. The big positive that I got out of this whole situation is I got back into my 5E3 that I built a couple of years ago and realized how good it really sounded through my new 4 x 12 mojotone cab w/8 ohm wizards. I got it for my JTM-45. At any rate many, many thanks. My hats of to this site.

Printman73

[printman73]

Well, my son came over and we checked the bias and it was almost perfect. Dimed it and cut post master and wow!!! The new cab was all that was missing. I was short on funds but found a person 2 hours North of me that wanted my Sheraton and valve jr that I turned into a champ with a Blackheart 12" cab. I got the mojotone 4 x 12 with Wizard Eminence speakers and we are both happy. This thing is it. I have the FMT tele with humbuckers and split coil and I could go from AC DC to Hendrix with the split of the coils and the harmonics and bell tones were hair raising. I never had that kind of clarity out of any amp before. All I had to do was change the pick attack and dig for what I wanted. I had to take the guitar away from my son and I didn't quit until an hour and a half later. Thanks for having such a good amp plan. I'm thinking of some changes but I might never touch this amp again. I'm just happy to just play it. Almost wish I was gigging again. Well, I might put the effects loop return on it so I can run my old gt 6 with 4 cables. Thanks for having such a great forum. I found a lot of answers buried deep inside.

Finished but never done!!! Printman73

[Elad E]

pretty much sums up what I think of this amp - it's crazy good!

talking about the Sheraton - i've be GASing for one for quite some time and found some contradicting opinions on whether the MiK or MiC ones are the ones to get. which one you had?

[printman73]

I had the China one. Put a brass stop tail and a roller bridge and a bone nut. Had sustain all day long. Played real easy and was a beautiful guitar. I just didn't like the ring of the body when I was unplugged. Stupid reason I know but after playing my old lead players 67, 335 I really saw the difference. Besides I am really just a Fender type of guy. You might find a place that has several and play them all, maybe one will speak to you or maybe you can find a Korean on CL. At any rate good luck in you search. I think my next project will be to build a Warmouth strat. A light one.

[Elad E]

sounds like a great guitar - definitely on my wish list. I thought I was a Fender guy too until I got my first Les Paul. sold my Strat (crafted in Japan) shortly after.
while I'm sure the Les Paul is the guitar for me (my playing sucks the least on Les Pauls ) I really feel like I need to have a Strat around. being the nitpicker I am I decided I'd rather go the Partscaster route and skip the garden variety Strats (or the pricey CS guitars) at the local Fender distributer.
so far I only purchased an MJT Strat body which should be here in a week or two. I highly suggest checking Mark and Matt's stuff if you don't mind the whole relic thing (I love the look and I love the feel of worn nitro finishes. I also feel they resonate better but thats me).

[printman73]

Elad really, really look before you waste your gas. If your Paul is the real deal you might not like the Sheraton. I mean it is nicely made but just like the Paul the 335 was really a set point for me to compare the Sheraton to. Try to find a good Korean or even older one but I usually don't see those anymore. I almost bought a 60's Casino about 20 years ago for 350.00 but missed it. It was really built nice and played like butter. Never have seen one again since. I've had many teles and strats and I really like the high end MIMs and the highway one strat. I really like the Callaham trems. The 50s or 60s road worns happen to be my favorite. So I will build a 3s strat with about a 3 pound body and put a warmouth neck with stainless steel frets. Thinking about the 7 1/4 soft v. At any rate that's my plan to complete my building journey. Something to compliment the JTM45. After all I just want to sit and play now. What's that? Do I hear Jimmy callin'. Got to go.

[Elad E]

thanks Printman,
I'm going to build a 60s style Strat and see if that puts an end to my GAS (yeah right...).
I got my humbucker needs covered with my R8 and it never ceases to amaze me with the plethora of sounds I can get between it, the JTM45 and my overdrive pedals. that being said I'm interested to see how a semi hollow like a 335 or a Sheraton would influence my playing as I noticed the feel and look of a guitar/bass often inspires me to play differently.