Author Topic: Sunn model T Maintenance and cap change  (Read 7631 times)

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Offline thehornedone

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Sunn model T Maintenance and cap change
« on: August 17, 2010, 10:22:48 pm »
So surprisingly google didn't help me much with this.  About to be the proud owner of an all stock, minty first gen model T from an estate sale.  Original tubes and everything.  Before I play this beauty for too long, I know I need to, at the very least, replace the filter capacitor. Now where the hell can I find a suitable replacement?  The rest of the electrolytic caps should be easy.

Offline thehornedone

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Re: Sunn model T Maintenance and cap change
« Reply #1 on: August 17, 2010, 10:48:11 pm »
Well, I found a good post on this topic:

http://sunn.ampage.org/sdp/index.php/topic,3999.0.html

anything else I should know?

Offline loudthud

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Re: Sunn model T Maintenance and cap change
« Reply #2 on: August 18, 2010, 09:25:08 am »
I'm happy to see the Search function works!

Quote
anything else I should know?

Messing around inside a high power tube amp should only be done by persons with the proper training.
Serious injury or death could result.

Offline mike_sims

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Re: Sunn model T Maintenance and cap change
« Reply #3 on: August 19, 2010, 01:49:03 am »
do you happen to live in Pa or Md?
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Offline thehornedone

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Re: Sunn model T Maintenance and cap change
« Reply #4 on: August 23, 2010, 09:24:53 am »
I'm happy to see the Search function works!

Quote
anything else I should know?

Messing around inside a high power tube amp should only be done by persons with the proper training.
Serious injury or death could result.

Don't worry. Any activity inside of an amp I don't consider "messing around".  I know what the dangers are and I refuse to pay hundreds of dollars to someone with the proper training just because they have the training.  I can change out the caps myself in less than an hour (there are only 6 that need replacing) for 60 bucks, the cost of the parts...or I can pay a tech 400 dollars to do the job, which is what I've heard of people spending for a model T recap, and that's probably not even getting the best caps.  The choice is simple as long as I discharge the caps, tranformer, chokes, and don't go and poke at the power and output section without shielding.

Offline EdBass

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Re: Sunn model T Maintenance and cap change
« Reply #5 on: August 23, 2010, 11:10:24 am »
I refuse to pay hundreds of dollars to someone with the proper training just because they have the training.

Spoken like someone with huge potential for making hilarious You Tube videos!

I can pay a tech 400 dollars to do the job, which is what I've heard of people spending for a model T recap, and that's probably not even getting the best caps.

To those people who would actually spend $400 for a freekin' filter cap replacement; PM me, have I got a deal for you!!  :wink:

The choice is simple as long as I discharge the caps, tranformer, chokes, and don't go and poke at the power and output section without shielding.

Yep, no need for any of that training crap; it sure sounds like you have a handle on it.
Uhmm… How exactly do you go about discharging a transformer or choke? Also, what type of “shielding” do you use to safely poke at AC filter sections?

Don’t forget to get that camera rolling before you begin working…

Seriously though, all joking aside; try really hard to avoid discharging a big burly electrolytic cap using one hand for + and the other hand for -. That puts your heart in the circuit, and none of us need to see THAT video. :-o

Offline thehornedone

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Re: Sunn model T Maintenance and cap change
« Reply #6 on: August 23, 2010, 01:20:38 pm »
Uhmm… How exactly do you go about discharging a transformer or choke?

When I said discharge caps, transformers, and chokes...I meant discharging caps to avoid shock from caps, transformers, chokes.  All of those can induce shock in a recently powered amp, though most stored charge is obviously in the capacitors. Transformers and chokes do retain charge themselves for a very short amount of time.

Also, what type of “shielding” do you use to safely poke at AC filter sections?

Electrician's gloves, rated up to 20,000 volts. Can't be too careful. Next question.



This amp hasn't been turned on in years, but I still plan to treat it like an unloaded gun and take all the appropriate precautions. I've worked on every amp I own at one time or another and have never gotten shocked. And, yes, I scoff at the prices charged by most trained professionals.  It's kind of like when guitar techs say you shouldn't adjust your truss rod yourself because you might snap the neck, only you might stop your heart in this case.
« Last Edit: August 23, 2010, 01:39:37 pm by thehornedone »

Offline mike_sims

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Re: Sunn model T Maintenance and cap change
« Reply #7 on: August 23, 2010, 05:49:08 pm »

Yep, no need for any of that training crap; it sure sounds like you have a handle on it.
Uhmm… How exactly do you go about discharging a transformer or choke? Also, what type of “shielding” do you use to safely poke at AC filter sections?

Don’t forget to get that camera rolling before you begin working…

Seriously though, all joking aside; try really hard to avoid discharging a big burly electrolytic cap using one hand for + and the other hand for -. That puts your heart in the circuit, and none of us need to see THAT video. :-o

So if your car needed repairs and you were knowledgeable of how to do the repairs and had experience doing it, would you take it to a mechanic and get ripped for hundreds of dollars? I don't think so. I notice some members on this board have sort of a fascist vibe going on, because he doesn't want to do what you would do he's gonna kill himself and should be lowered to the level of youtube fail? I don't think so.

If you know what you're doing, dude and have done it before and have experience - go for it. I'm sure everyone is just giving you precaution which is understandable, but don't mind the sarcasm from the "guru's" on here.  :wink:
MAXIMUM VOLUME YIELDS MAXIMUM GOATS

1974 Sunn Model T
1975 Sunn Model T
2 Sunn 412L cabs

Offline EdBass

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Re: Sunn model T Maintenance and cap change
« Reply #8 on: August 23, 2010, 08:26:54 pm »
So if your car needed repairs and you were knowledgeable of how to do the repairs and had experience doing it, would you take it to a mechanic and get ripped for hundreds of dollars? I don't think so.

How is taking your car to a trained professional to be repaired getting “ripped”? I take my cars to real mechanics for just about everything, even though when I was in school I worked spinning wrenches at an auto repair shop.
Most of my cars are still under factory warranty, so it’s not a good analogy to the amp thing, but for what it costs to have my oil changed at a dealership, it’s flat not worth my time to do it myself.
So, to answer your theoretical question; Yes, I usually take my cars to factory trained professional, and yes I know how to do the majority of the work myself, but no, I don’t feel I’m being “ripped” by doing so.
I’m paying for the convenience of not interrupting my schedule, getting it fixed properly, and most importantly having fiscal recourse in the event it isn’t done to my satisfaction.
 
I notice some members on this board have sort of a fascist vibe going on, because he doesn't want to do what you would do he's gonna kill himself and should be lowered to the level of youtube fail? I don't think so.

Actually I would do it myself unless I was busy. Since it’s a hobby for me, I actually enjoy working on and learning about vintage amps.
There is nothing “fascist” in my comments. I and other posters on this forum who have some experience with working on these amps generally try to warn the less experienced members about the hazards of going past the  “No user serviceable parts inside” warning labels in an attempt to be helpful, not “fascist”. In turn some of the seriously knowledgeable members correct my oversights as well.
In this case, Loudthud tried to caution, the OP posted assurance that they knew what they were doing, took a pot shot at those who actually DO know what they are doing; in essence inferred that years spent training were worthless, and then proceeded to post statements confirming  novice experience at best. IMO the quotes I took from the original posts by thehornedone are indicative of someone who does not in fact have knowledge enough to safely work on a big voltage tube amp. Even the rebuttal to my attempted humorous post contains factoids that are inaccurate, but the points were made, so c'est la vie.

If you know what you're doing, dude and have done it before and have experience - go for it. I'm sure everyone is just giving you precaution which is understandable, but don't mind the sarcasm from the "guru's" on here.  :wink:

Which brings me to this question;
What’s it to you? To me it seemed like the situation was resolved; I reemphasized Loudthud’s caution, thehornedone saved face by rebutting my posts, points made and taken, situation resolved in a clean fashion. Done and finished.
Why show up and try to re stir the pot? Were you trying to defend thehornedone? It seems to me that thehornedone can handle themselves, and seemed to take my post in the lighthearted manner it was intended, why stick your nose in and throw around inflammatory words like fascist?




If you are still upset by my reining you in on your Model T fairy tale in late July, or by my PM to you regarding foul language in open forum in May, take it to PM rather than try to assert yourself in open forum and risk looking foolish.

Offline mike_sims

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Re: Sunn model T Maintenance and cap change
« Reply #9 on: August 23, 2010, 09:04:01 pm »
giving advice is one thing, but being a smart ass about it is kind of childish. People come to this forum for help with stuff and unfortunately, there are members like you, Ed. Instead of being humble and welcoming to members, giving real technical advice, you reply in a condiscending manner about  something that was already properly pointed out with bold red font. Honestly, i could care less about your outlook on Model T's or your weird, nothing-better-to-do web language enforcement PM's, they speak for themselves. I did get a NOS model T for a steal and so did a buddy of mine recently, so yeah, no need for "bad web blood".

 how would you feel if you went into an establishment looking for some kind of advice or help and the guy "helping" you was no help at all, but treated you like an idiot. But I'm sure that's never happened to you since you're the all knowing, right?

And what was so "Fairy Tale" about my post? Oh that's right, didn't you "stick your nose" in my post and "stir the pot" several times? Talk about the pot calling the kettle black. And what's wrong with defending another member? You're right, fascist might have been too steep, "web bully" seems to fit you more. I can't imagine why you have so much "smite" on this thing.
« Last Edit: August 23, 2010, 09:13:47 pm by mike_sims »
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1974 Sunn Model T
1975 Sunn Model T
2 Sunn 412L cabs

Offline EdBass

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Re: Sunn model T Maintenance and cap change
« Reply #10 on: August 24, 2010, 08:41:43 am »
I thought I mentioned that if you were still upset about being "moderated" you should take it to PM. Maybe you could start your own forum and post whatever you want.

For the time being, stick to the topic and don't use open forum for personal assaults against myself or anybody.

Got it?





At least for the time being I'm leaving your little tirade up. I think sometimes it's pretty funny to witness a ignorance induced meltdown. Kind of an example of how NOT to post.

Offline biltmore

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Re: Sunn model T Maintenance and cap change
« Reply #11 on: August 24, 2010, 08:55:46 am »
Just my 2 cents here (sorry, OP).

People who have don't have extensive experience with electronics or don't know how to discharge a filter cap have absolutely no business messing around inside of an amplifier. EdBass, loudthud, and many others on here have probably saved a couple people from killing themselves. Some people come onto this forum thinking, "this is an old amp that's not in working condition .. it can't be to hard to fix. I'd rather do it myself, since I don't have a tech near me or I'm broke."

There's nothing elitist about the guru's replies, and they're not trying to tell you you're a @#$(@# idiot. Their replies might seem knee-jerk-ish to some, to me it's par for the course when you have someone posting about messing with their amp and it sounds like they have NO idea how they even work. Ed's replies are hardly condescending, in fact they're down right appropriate in these situations. You don't go around giving detailed technical advice to someone that doesn't even know how an amplifier works. I build stompbox effects and know how to discharge filter caps, and even I don't mess with my amps.
« Last Edit: August 24, 2010, 03:01:11 pm by biltmore »

Offline thehornedone

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Re: Sunn model T Maintenance and cap change
« Reply #12 on: August 24, 2010, 10:46:32 am »
Just to steer this thread back to the point for people who may happen upon it in the future...I have another thread titled "Sunn model T popping breaker?" where I intend to share my troubleshooting experience of the particular model T I'm recapping.  The one mentioned at the start of this thread ended up falling into the hands of another :(, so I ended up buying a non-working one on eBay, which is still going to need the recap, which is likely the source of the amp's problem: drained filter cap.


And I can see why people would discourage someone untrained from working on a guitar amp when they seem to not be knowledgable; it could potentially save one from injury or death.
« Last Edit: August 24, 2010, 11:31:49 am by thehornedone »

Offline mike_sims

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Re: Sunn model T Maintenance and cap change
« Reply #13 on: August 24, 2010, 02:37:26 pm »
For the time being, stick to the topic and don't use open forum for personal assaults against myself or anybody.

I think sometimes it's pretty funny to witness a ignorance induced meltdown. Kind of an example of how NOT to post.
:lol: that's funny... I don't think any of the EdFollowers see the contradiction here. But anyways...

and yeah, back on topic. I figured you scored the circuit breaker tripping one off there. Think about it though, I've seen them go for that price in horrible, HORRIBLE condition. Hopefully it's nothing major, I doubt it is though.
« Last Edit: August 24, 2010, 02:45:55 pm by mike_sims »
MAXIMUM VOLUME YIELDS MAXIMUM GOATS

1974 Sunn Model T
1975 Sunn Model T
2 Sunn 412L cabs