JCM800 2203x Hum

[jsessions]

Nope. He just judged what you mentioned about the issue and that you came from pedal building and now try to fix an amp with essential knowlegde missing and his advice has been correct (and was also a reason why I kept my mouth shut as I could smell the missing experience). People like him (and also me with ~30yrs in this trade) get a feeling on how competent people just by reading/hearing problem statement and if an advice will end as a success or disaster and with the comments you gave later in this tread regarding Ken's response I know that disqualified / blacklisted yourself to several people.
On a side note said I dunno believe that just changing the heater wiring as per MB did solve the issue, it is more likely that you had a bad solder joint or lead dress issue somewhere which has now been resolved unintentionally. I worked on 2203/2204 which had heater wires not even twisted and had been at an acceptable level of noise, even when being +40yrs old and having weak filter caps.

I think you are right because I started rolling preamp tubes again in v1 and there were a couple that brought some of the noise back to a level similar to it was after fixing the initial blown trimmer issue.

Yes I am inexperienced and I made this clear in the beginning. I don’t appreciate being mocked and characterized as some idiot who watches a single youtube video and thinks I know everything about amps. I have respect for people that have put years into this trade. I just wanted an opportunity to get my feet wet and I expressed I knew how to work safely so I don’t see why it is such a big deal.

If people want to disqualify me because I made a joke about Ken being grumpy, so be it. Im sure the man doesn’t appreciate being put on a pedestal as many around here seem to do anyway.

 

[jsessions]

I dont think we are here to teach, but to advise either way.

As for heater wiring well the original JTM45 had twisted pairs for that reason and they had to be very tight, i should know as i made yards and yards of them and in those days all i had was a hand brace and a bench vice, red and black all the way down my garden.

I can fully appreciate the comment about not only being the twisted pair so by replacing them not only used tight twisted pairs but had to unsolder and re-solder which renewed all of the heater joints.

As for the insults then as i have said before i have broad shoulders, all it shows how low some can go because they don't like what they read, and that is the truth which hurts.

If i was a bit closer then even at my age i would still whip there arses.

The twists before I redid the heater wiring were very loose to say the least and it does seem to be that there were a multitude of contributing factors.

Perhaps I should make my way across the pond and we can settle this the old fashion way. I’m kidding of course but all jokes aside I never wanted to end up fighting with anyone here. I came here to learn but maybe I was asking for too much. Perhaps I was a bit overly reactive and sensitive to what you said, but to be fair the characterizations and telling me I need to go to college for 5 years before working on an amp seemed unhelpful at best. I apologize for offending you. I was offended as well by some of your initial comments but I should have just let it go.

 

[LRT#1]

I my self am a licensed electrician that specializes in controls. I went through the same BS when trying to get help on my jcm900. As I said before to find a legit tech around my aria i have to travle quite a distance. Thats how I ended up here myself. This has been a place to learn how these amp operate.
Im glad there is still people here that are willing to assist in troubleshooting. Ampmadsintist was a big help for me when nobody else was willing to help. As long as you followed his direction to the T he was there for you. I just hope that otheres here are willing to do the same for people like my self, where there is nobody local. There are people that just shouldn't get into these amps but if a person has basic understanding of electronics why not help.
If i fryed an amp by making a mistake or not following instruction its my fault not yours

 

[Gutch220]

This is who i was refering to i do know where he is

where did he go?

 

[Ken Underwood]

You guys do not understand what i am trying to get at, just carry on but don't expect a good tech to undo what cock up`s you make because he will march you right out of the door

For the guys who appreciate my opinions then sadly i am taking a back seat from now on

 

[Pete Farrington]

Folk may wish to consider the concern felt when someone that has no experience of working on live mains equipment, nevermind high voltage valve amps, requests in depth guidance on how to get their amp working right, ie beyond just ‘try another valve’’.
A fried amp is far from being the worst case scenario, rather the consequences are potentially fatal.

 

[Dblgun]

Wow, time has obviously softened reality.

Ken, you and I are 180 degrees opposite in our thinking. As a tradesman I served an apprenticeship where I learned from those knowlegable in the trade. In return for this training I was often relegated to the dirty or menial portions of the work that was accomplished. As I progressed though the years I became the teacher and had a number of tradesman who apprenticed with me. I left the trade long ago but still practice it as a hobby and often help those who have an interest.

You seem irritated when someone with less knowlwedge seeks it from those with the experience to provide some assistance. If you do not see the value in contributing to those who seek to learn I respect that even though I do not feel the same. On the other hand, to repeatedly chide those who seek assistance and insinuate that any repair they may make would be "cocked up" seems selfish.

In 1963 you would have been a teenager who participated in the assembly of the first of what would become the iconic Marshall amplifier. This was obviously prior to your ascending to electronics savant. This was really cool stuff and lead to much greater things as the years went by. The fabrication and assembly techniques displayed in the early examples show a lack of general understanding of fabrication techniques, metallurgy and results of the mixing of fastners that were not compatible. These "short cuts" resulted in failure of chassis and brinelling between the host material and items attached. Band-aids were applied to minimize the shortcomings of the design until the design and metals used were updated.

Some years ago I visited with a stock maker who apprenticed with and later became a master stock maker for Purdey. The conversation turned to apprenticeships and a test stock he still had from his beginning in the trade. He spoke about how unacceptable it would have been to stock a fine gun with something so crude. Ken, had you brought me one of those "cocked up" amplifiers and presented it as something to provide to a customer I might have marched you right out the door. Or, I might have considered you were just getting started and put forth the effort to teach you how not to take short cuts but rather complete the task using the proper techniques, tools and materials. Everyone starts somewhere.

 

[LRT#1]

Wow, time has obviously softened reality.

Ken, you and I are 180 degrees opposite in our thinking. As a tradesman I served an apprenticeship where I learned from those knowlegable in the trade. In return for this training I was often relegated to the dirty or menial portions of the work that was accomplished. As I progressed though the years I became the teacher and had a number of tradesman who apprenticed with me. I left the trade long ago but still practice it as a hobby and often help those who have an interest.

You seem irritated when someone with less knowlwedge seeks it from those with the experience to provide some assistance. If you do not see the value in contributing to those who seek to learn I respect that even though I do not feel the same. On the other hand, to repeatedly chide those who seek assistance and insinuate that any repair they may make would be "cocked up" seems selfish.

In 1963 you would have been a teenager who participated in the assembly of the first of what would become the iconic Marshall amplifier. This was obviously prior to your ascending to electronics savant. This was really cool stuff and lead to much greater things as the years went by. The fabrication and assembly techniques displayed in the early examples show a lack of general understanding of fabrication techniques, metallurgy and results of the mixing of fastners that were not compatible. These "short cuts" resulted in failure of chassis and brinelling between the host material and items attached. Band-aids were applied to minimize the shortcomings of the design until the design and metals used were updated.

Some years ago I visited with a stock maker who apprenticed with and later became a master stock maker for Purdey. The conversation turned to apprenticeships and a test stock he still had from his beginning in the trade. He spoke about how unacceptable it would have been to stock a fine gun with something so crude. Ken, had you brought me one of those "cocked up" amplifiers and presented it as something to provide to a customer I might have marched you right out the door. Or, I might have considered you were just getting started and put forth the effort to teach you how not to take short cuts but rather complete the task using the proper techniques, tools and materials. Everyone starts somewhere.

You said this better than i could have ever thought to do myself.
It took me years to accept the fact that i needed to release my knolage to the trade im in. Im not an amp tech but i have had several apprentices under my wing in the trade. If the knolage isn't released things die off for good because nobody can work on it. I was an apprentice once myself and am grateful for it.

 

[jsessions]

Parts arrived today and I just got finished installing them. Trimmer replaced, a few carbon resistors replaced with metal film, bright cap replaced with an MLCC. Zero hum. It sounds the way it should have when it arrived on my doorstep. I just ordered a few books to further my knowledge and I'm looking at maybe building a Champ or something simple to learn on in the near future. Sorry for all the drama, I had no idea what I was getting into by posting on here. Thank you @Dblgun for the well-written alternative perspective, it was enlightening and reassuring.

 

[LRT#1]

You guys do not understand what i am trying to get at, just carry on but don't expect a good tech to undo what cock up`s you make because he will march you right out of the door

For the guys who appreciate my opinions then sadly i am taking a back seat from now on

I understand where you are coming from but most members here dont have someone like you locally. I get that you get paid for doing the work on these amps but I and most members aren't going to travle to have you do the work. It's not like people are asking about mods that were successful and yours

 

[LRT#1]

.

 

[Ken Underwood]

I understand where you are coming from but most members here dont have someone like you locally. I get that you get paid for doing the work on these amps but I and most members aren't going to travle to have you do the work. It's not like people are asking about mods that were successful and yours

What ever are you talking about man, i don't get paid anything in fact when all of this started then i did not get paid anything then, so please don't assume that i do.

 

[XTRXTR]

I have always had a genuine respect for people that have years of experience. When I interned at Pfizer R&D during my BSEE program I learned more from the electronic techs in the lab than from work any of the EEs and MEs I was assigned.

I knew nothing about tubes from university, I learned my first bits from Lord Valve who was kind enough to answer my questions when I called or came into his shop. He doesn't suffer fools either but for some reason helped this one out. He didn't make it easy either. There was no internet let alone YouTube or this forum. I'd come in after reading some tube stuff in the old Naval Electronics books and try my best to let him know I was studying. He always threw a wrench into what I thought I learned and I would go back and study some more. He is a great resource for tube amp knowledge. One thing I never did was bite the hand that was feeding me.

The fact you have a resource here that was involved in the developing of the greatest amp ever made should put you on your best behavior. The probability this forum exists because of that amp... There are infinite ways it could have gone but it was successful. I don't understand the lack of this perspective. What is wrong with placing one upon a pedestal or simply approaching with respect? Respecting those that have come before you has a foundation in humanity and civilization. Elders know more shit, plain and simple. What you may perceive as grumpy is just the multitude of layers of knowledge that come with the experience they have decided to bestow upon you.

This forum and others like it is the modern day equivalent to the Oracle, or council of elders. You seek answers and the forum provides.

 

[Dblgun]

This forum and others like it is the modern day equivalent to the Oracle, or council of elders. You seek answers and the forum provides.

I could not agree more. This forum and others like it are a boon for those who want to learn more about the subject. Several have created entire websites to assit and educate those to a technology that is no longer learned by traditional means.

 

[jsessions]

I have always had a genuine respect for people that have years of experience. When I interned at Pfizer R&D during my BSEE program I learned more from the electronic techs in the lab than from work any of the EEs and MEs I was assigned.

I knew nothing about tubes from university, I learned my first bits from Lord Valve who was kind enough to answer my questions when I called or came into his shop. He doesn't suffer fools either but for some reason helped this one out. He didn't make it easy either. There was no internet let alone YouTube or this forum. I'd come in after reading some tube stuff in the old Naval Electronics books and try my best to let him know I was studying. He always threw a wrench into what I thought I learned and I would go back and study some more. He is a great resource for tube amp knowledge. One thing I never did was bite the hand that was feeding me.

The fact you have a resource here that was involved in the developing of the greatest amp ever made should put you on your best behavior. The probability this forum exists because of that amp... There are infinite ways it could have gone but it was successful. I don't understand the lack of this perspective. What is wrong with placing one upon a pedestal or simply approaching with respect? Respecting those that have come before you has a foundation in humanity and civilization. Elders know more shit, plain and simple. What you may perceive as grumpy is just the multitude of layers of knowledge that come with the experience they have decided to bestow upon you.

This forum and others like it is the modern day equivalent to the Oracle, or council of elders. You seek answers and the forum provides.

I came here with good intentions but I’m not going to kiss ass to someone over twice my age that is mocking me like a child. I don’t care who you are or how old you are, it was totally uncalled for and unnecessary. I respect that people worked hard before me and were pioneers of their time, but it doesn’t give them a free pass to be an arsehole. The fact some of you see yourselves as the modern day oracle is very telling. There is a serious problem of an over-inflated sense of self importance and a border-line superiority complex going on with some of you here. You do realize we are talking about fixing guitar amplifiers and not finding solutions to cure cancer and achieve world peace right? Get a grip. You all can have fun guarding your precious little corner of the internet. Had I known I was walking into a den of bitter old men I never would have made the original post. To those of you that helped me, thanks, I am truly grateful and will do my best to do that for others as my knowledge and experience grows. Later

 

[Seanxk]

@jsessions , I wouldn't worry about it. You came here with a humble explanation of your abilities and a problem with your amp, all good and I hope you stick around.
But you don't know who's who and how would you?, your reaction to the first few unhelpful posts was fair and so were your others, '' you seek answers and the forum provides '' 99% of the time they do.