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Post subject: Re: Sort of a Fender project amp
Posted: Sat Mar 29, 2014 3:20 pm
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jimolson1963 wrote:
I realize you guys don't know me from Adam so yes, I am absolutely safety-conscious and aware and it will definitely have a cover. Otherwise they would be inside the chassis. They may still end up inside in a different configuration, I made that cap board for my Bassman 100 that has severely warped, unusable boards.

I started working with electronics back in 1973-74 when was ten or eleven years old. I got into music real heavy and all I had to work with was a crappy hand-me-down stereo. My first project was tearing apart transistor radios and building cardboard boxes with multiple speakers to get better sounds. I started playing drums at 12, guitar at 13 and bass at 14 and that's been my main focus since. I love making women's hips sway with a good groove. ;)

I'm a working musician in a classic rock/blues band in mid-Michigan and actually worked on Fender amps for a short time about 25 years ago. I never got into the theory part though which is why I have so many questions now. Replacing obviously bad parts is really easy, it's when you get into the other issues that's a challenge but I'm up to it and thanks to guys like you I'm learning a LOT.

My first real electronics project was building a color organ to run off my stereo around the time I got my first drum kit when I was 12. That's when I learned about how quickly things can go bad when you aren't being safe.

I had the circuit out of the light cabinet and it fell off my dresser into my stereo chassis that was also open and started a small but momentary fire inside the stereo chassis. I quickly put it out and since then I have been all about working safely. I use clips on my meter leads so I'm not poking around in the amp and I don't wear a watch or anything else on my hands except my wedding ring. I discharge caps before touching anything inside a chassis and in general take all the normal safety steps before doing anything. High voltage doesn't scare me but I do respect it.

I'm working on several projects, Lou, which one are you referring to? The Sunn Spectrum II just needs some finishing up and it'll be ready for sale, that was just a re-cap & tube along with some jacks and pots. Oh, and a three-wire power cord.

The mini-amp I built from an old DuKane intercom amp was just to see if I could do that with very little help and I was able to, that'll get tweaked and such when I get some other things done.

The most important thing is I know my limitations and even though I have a good track record on typical amp repairs, I'm not afraid to ask questions and I love solving problems, especially those caused by someone that knows how to melt solder but not much else. Almost all of the questions I've had in the forums have been focused on my own equipment that I'm either heavily modifying or custom building. It's sort of like my tube amp capabilities are at a 4-5 and I want to push that much higher, hence the custom builds.

I have much to learn and I'm willing and eager to do so. :)


I think you've "made your bones', Jim. You seem to embark on projects in a logical fashion, have an adequate grasp of the fundamentals, and work methodically to resolve any unforeseen issues. I've seen snot-pickers behind the tech counter at a GC who didn't have a quarter of your knowledge or experience. If I have any advice at all to proffer, it'd be to shuck that wedding ring as well when working with live voltages and circuits. That goes for keyrings in a pants pocket and pens or pencils in a shirt pocket.

Rawk on!

8)

Arjay

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Post subject: Re: Sort of a Fender project amp
Posted: Sun Mar 30, 2014 8:03 pm
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jimolson1963 wrote:
Ah, yeah. That is this amp, the Yamaha solid state head I converted to the 5F6 Bassman. I unhooked the PT and tested all the leads again, then put it back in using the 127v input instead of the 110v input lead. The voltages came back at a much more reasonable level. Still trying to figure out some of the bugs and I still have no sound at all.

These are the voltages I'm reading now:

C1=247v
C2=506v
C3=505v
C4=441v
C5=434v

V1
1 - 269
2 - 0
3&8 - 1
6 - 292
7 - 0

V2
1&7 - 243
2 - 0
3 - 1
6 - 434
8 - 256

V3 (PI)
1 - 224
2 - 15
3&8 - 54
6 - 205
7 - 17



Jim, Is this the values off the Dukane amp or the Yamaha? For a tube amp, these are much more reasonable than the +1KV B+ you were getting before. But, if this is the Yamaha solid-state amp's readings ---- there is something amiss. No SS guitar amp would need much more than 50-75VDC B+.


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Post subject: Re: Sort of a Fender project amp
Posted: Sun Mar 30, 2014 10:30 pm
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jimolson1963 wrote:
....Ah, yeah. That is this amp, the Yamaha solid state head I converted to the 5F6 Bassman...


Sounds like it is now a tube amp.

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Post subject: Re: Sort of a Fender project amp
Posted: Sun Mar 30, 2014 11:33 pm
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I guess he used only the chassis of that Yamaha. He couldn't get those kind of voltage with the OEM PT out of a solid-state amp. I kinda got lost between the Dukane PA amp and the Yamaha. I need to re-read the thread. :D


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Post subject: Re: Sort of a Fender project amp
Posted: Mon Mar 31, 2014 7:52 am
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I used the parts from the DuKane amp in the Yamaha chassis after I gutted all the solid state junk out of it and modified the chassis as shown in the pics. :)

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Post subject: Re: Sort of a Fender project amp
Posted: Tue Apr 01, 2014 3:31 pm
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I decided to go back to the original full 5F6A layout including the filter caps. Doggone it if I'm not out of 8/150 so I ordered some last night.

*sigh*

Yet another delay...

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Post subject: Re: Sort of a Fender project amp
Posted: Tue Apr 01, 2014 4:07 pm
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"It's always something!" -- Rosanne Rosanna-Danna

:mrgreen:

Arjay

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Post subject: Re: Sort of a Fender project amp
Posted: Tue Apr 01, 2014 6:01 pm
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Like when they wanted to make Puerto Rico a steak. Next they'll want a salad and a baked potato. :lol:

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Post subject: Re: Sort of a Fender project amp
Posted: Tue Apr 01, 2014 6:11 pm
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shimmilou wrote:
Like when they wanted to make Puerto Rico a steak. Next they'll want a salad and a baked potato. :lol:


:mrgreen:

Looks like you and I are the only ones to remember the good old days of SNL, Mike.

:wink:

Arjay

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Post subject: Re: Sort of a Fender project amp
Posted: Tue Apr 01, 2014 7:24 pm
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Oh,.....never-mind. :lol:

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Post subject: Re: Sort of a Fender project amp
Posted: Tue Apr 01, 2014 7:40 pm
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shimmilou wrote:
Like when they wanted to make Puerto Rico a steak. Next they'll want a salad and a baked potato. :lol:


LOL! I was an SNL fan back when it was good. Waaaaay back.

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Post subject: Re: Sort of a Fender project amp
Posted: Tue Apr 01, 2014 7:55 pm
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Remember when Walter Matthau was a guest and they did the "Bad News Bees" shtick?

:lol:

Arjay

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Post subject: Re: Sort of a Fender project amp
Posted: Tue Apr 01, 2014 10:17 pm
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jimolson1963 wrote:
I used the parts from the DuKane amp in the Yamaha chassis after I gutted all the solid state junk out of it and modified the chassis as shown in the pics. :)



Ok... got it.

You guys remember the SNL skit with John Belushi as the kid in a coma. And I think Steve Martin was the MD. The family decided to pull the plug?

Or the "Claudine Longet Invitational Ski Race." With Chevy Chase and Jane Curtin as sports announcers. I think that was one of the first SNL skits banned from replay.


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Post subject: Re: Sort of a Fender project amp
Posted: Wed Apr 02, 2014 12:54 am
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I remember the Bad News Bees, with John Belushi in a bee suit, freakin' hilarious. :lol: I don't remember the coma or the ski race, but speaking of banned, I am surprised that Akroyd was allowed to continually use the phrase "Jane you ignorant $lut!" over and over on the "Point-Counterpoint" skit way back then. What a great comeback as a counterpoint! :lol: :lol:

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Post subject: Re: Sort of a Fender project amp
Posted: Wed Apr 02, 2014 3:47 am
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The John Belushi skit one was "Pull The Plug." I have seen neither that nor the "Claudine Longet Invitational Ski" since they first aired.

It is amazing what a child's mind will remember.


:lol: :lol: :lol:


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