• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Another Maggy Thread

If it's the 2.7K resistor that's frying it won't have anything to do with back end of the amplifier.

It is just in the front of the amplifier where you have the issue, I agree it is strange, hence why
I'm suggesting something like a resistor measuring wrong but marked right or a bad socket maybe.
 
Yep it goes with the territory don't it Jay?

Start working wth these low power amps, next thing yu know more sensitive speakers
are wanted. I'm working on a 3-way with JBL 2225 15" woof, 2118 8" midbass and the
2404 baby butt cheek tweeter all in seperate cabs. Sounds pretty good now, was not
all that promising at first but more digging and it's working.

That WT3 (Woofer tester 3) from parts express is a very handy tool, I was able to dial
in the system impedance very nicely! :thmbsp:
 
Kegger said:
Yep it goes with the territory don't it Jay?

Start working wth these low power amps, next thing yu know more sensitive speakers
are wanted. I'm working on a 3-way with JBL 2225 15" woof, 2118 8" midbass and the
2404 baby butt cheek tweeter all in seperate cabs. Sounds pretty good now, was not
all that promising at first but more digging and it's working.

That WT3 (Woofer tester 3) from parts express is a very handy tool, I was able to dial
in the system impedance very nicely! :thmbsp:
Click to expand...

Is there a thread?:scratch2:
 
I should start but I haven't yet, it's all been on my own with a lot of experimenting, I'm
sick with a pretty bad cold an just haven't felt upto writing up a thread for it as of yet.

I will eventually and document the tools I used to get where I am.
 
Hey Kegger---got it working with no fried resistors. :D I am alittle ashamed to say what the problem was... the 180k resistors on the 6EU7 were 180R instead of 180K. They were marked right too, just my silly mistake. Thanks for pointing me in the direction of the problem. The amp sounded good thru some cheap expendable speakers I was using when I fired it up. That's as far as I got with it, gonna take some voltage measurements later to make sure everything is where it should be or if i need to tune it alittle. I'll post some pics later also. Thanks again, Stan:thmbsp:
 
Good Job Stan!!

I for one am very glad you were honest with what the problem was, we all can make the
same kinda mistake very easily, I've done it myself! What you found was presicely where
I thought the problem was in your first post when I suggested the 150K resistor may not
be what it seemed to be. :)

It is these kinds of mistakes where you have to track down the problem that in the long
run "can" be quite beneficial in the understanding and diagnosing of the issues that just
may arrise from time to time. (good learning experience)

I'll be curious your thoughts on the sound after some listening, :thmbsp:
 
So I've been listening to the maggie today thru my diy voigt pipes and 6sn7 aikido preamp and it sounds great. I won't use all the fancy adjectives, all I know is I like what I hear. Thanks again kegger for your help. I took some voltage readings----getting 302vdc od the el84 plates and 10vdc on the cathodes. On the 6eu7 getting 160vdc on plates . Do these seem alright? Here are some pics, Stan
 

Attachments

  • P1000894.jpg
    P1000894.jpg
    138.7 KB · Views: 82
  • P1000928.jpg
    P1000928.jpg
    82 KB · Views: 93
  • P1000935.jpg
    P1000935.jpg
    77.8 KB · Views: 66
Not BAD voltages, But if you could get the output plates to say 292v instead, (loosing 10 volts)
Would probably have them last longer and still give same performance, this would take changing
out the 4.7uf cap for say a 2.5uf cap, that would probably about do it I think. :)

Other then that looks nice, I like the layout, :thmbsp:
 
found the problem

stanbp64 said:
So I've been listening to the maggie today thru my diy voigt pipes and 6sn7 aikido preamp and it sounds great. I won't use all the fancy adjectives, all I know is I like what I hear. Thanks again kegger for your help. I took some voltage readings----getting 302vdc od the el84 plates and 10vdc on the cathodes. On the 6eu7 getting 160vdc on plates . Do these seem alright? Here are some pics, Stan
Click to expand...

I found the problem:

It looks way too nice!

Good work on that one!

You should see my Scott 222c with it's EL84s --> 441 V on the plates! Awesome sound. I don't recommend it though. Only think I think about on this issue is what tubelab and Jim Mcshane opine, adjust the bias! That probably does not apply to your fabulous amp though.

I am about to work on my voltage divider to try to get mine down on the Bogen J330 - I say about because my shoulder has stopped screaming at me when I lie down so I know that in a week or two I will be able to pick it up without re-injuring it.

The things I go through to give free food to po folks :banana:

Not even my ministry and I keep doing it LoL (I am supposed to play guitar and sing and junk, how is that giving out free 25 lb turkeys? HOW?!!)

Great work

Dan
 
Thanks guys. No, it doesn't need the preamp---though the aikido does give it alittle more oomphh. I have hooked it straight to a Zen mp3 player and it sounded great too, with plenty of power. I'll replace that cap soon to drop the voltage abit. Hey Knife, how's the modded 175 going?
 
Excellent news here.:thmbsp: I especially like the woodwork, but the craftsmanship on everything is very good.:yes: I know these little Maggies sound great with just a little speaker synergy, but something about soldering on one yourself, makes it even better.:music: So...................what's next?:D
 
Thanks Jayman. You are right, building these amps and having them work (well, maybe after alittle troubleshooting) and sound wonderful is a great feeling. I am addicted!! My wife is moving me out to storage building out back as soon as I get power ran to it.... she is tired of my amp stuff all over the den and my working at the kitchen table. I was thiking of building the modded 175 mentioned earlier in threador maybe a 93xx. I also wanted to build something and try to sell it on epay--- just to make enough to support my audio habit:D Also gonna spend some time in the speaker forum, wanna make new enclosures for some 8' audionirvana drivers. I think it is great that you guys are willing to share your knowledge and experience to help others on the road to tube happiness.:thmbsp:
 
Hey fellers, I picked my little project up again last night and mounted some components. I haven't polished or cleared any of the copper and brass yet, but you get the idea. Now she's just sitting here begging for a circuit. So, what did we figure out here, as far as which circuit is best? Do we have a final schematic? I think this was a 80 something amp??:scratch2:
 
Last edited:
I think we were waiting on you for a schematic.:D I believe it was a 93xx amp. I will be watching with interest as I am ready to put together another amp. I can't keep up with you guys as my free time doesn't allow it but the info is great to refer to. Great looking amp so far BTW!!
 
Thanks Stan, I guess I'll take a stab at a schematic, then we can get some input and maybe decide on the "uber" Maggie circuit.:thmbsp:
 
jaymanaa said:
Thanks Stan, I guess I'll take a stab at a schematic, then we can get some input and maybe decide on the "uber" Maggie circuit.:thmbsp:
Click to expand...

Thats sounds good. It'd be good to have a final & best circuit for the 2 most popular Mag chassis. 175/85 and the 93xxx. That 9302-00 I did that my sister got for Christmas has only got a couple upgrades but Ive got another in the works and my eyes are peeled for more.

I havent forgot ya' Knife.

and Jay...thats gonna be a killer all the way around. Visually excellent.
 
resound said:
Thats sounds good. It'd be good to have a final & best circuit for the 2 most popular Mag chassis. 175/85 and the 93xxx. That 9302-00 I did that my sister got for Christmas has only got a couple upgrades but Ive got another in the works and my eyes are peeled for more.

I havent forgot ya' Knife.

and Jay...thats gonna be a killer all the way around. Visually excellent.
Click to expand...

Sweet!

in 2 weeks I will be back to working on tube amps and I will need lots of projects.

Jay will be the king of all Maggies when he finishes that one.

Knife
 
You must log in or register to reply here.
Back
Top Bottom