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Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Thu Feb 20, 2014 1:34 am
by Gone Fission
Was sorely tempted to get one that came up on CL cheap recently. Couldn't justify it, though. Don't need that kinda volume.

Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Thu Feb 20, 2014 1:44 am
by fishtankdork
fuck that amp is hot, ive never even heard of it, ima be on the look out for one now tho. is the reverb foot switchable? 4 channels to plug random shit in? shit i would prob have the weirdest shit mic'd up next to my plugged in guitar.

Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Thu Feb 20, 2014 1:53 am
by Hyphen Nation
theres one that's been "dumbled" by Fuch's on Portland's Craigslist right now. What ever Dumbling this means...
http://portland.craigslist.org/mlt/msg/4335027360.html

Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Thu Feb 20, 2014 2:07 am
by fishtankdork
that kinda seems like a good deal? or am i crazy.

Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Thu Feb 20, 2014 2:12 am
by Hyphen Nation
I don't know actually…I feel like you can still score a PA-100 for the $400-$600 range if you are patient. This seems like a bit more than that, and I don't really think I understand what Fuch's did to it. If you say you're only holding onto the transformers and the chassis, I'm not sure what I am buying? I know that that iron is important, but what the hell happened to the circuit?

edit: ok, just went back to the Fuch's site. If you like his amps, this seems like a raging deal...

Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Thu Feb 20, 2014 2:19 am
by fishtankdork
yea fuchs are pretty balla

and i guess it would be like having 4 fuchs in 1? hahaha this fender pa100 shit is awesome.

Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Thu Feb 20, 2014 3:13 am
by rustywire
Now that's a good score...I've wanted one, just to hear how it sounds with a bass. And 2x15 cab.
I bet dat tone is so thuddy boom boom. If (when) you put together a video, def plug that killer project bass of yours (wife's) into it.

And remember to periodically throw that tall font Muff in ze chain :animal:

Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Thu Feb 20, 2014 10:23 am
by skullservant
Reverb is indeed footswitchable. I need to make a switch for it, but there is a jack for the reverb.

Got the new tank in last night. HOLY HELL what a difference. 3 springs, long tank. Fucking bliss.
Subtle up until about 3-4 on the dial, then pretty swampy from 4-7, then 7-10 is totally DRIP territory

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One of the Ruby's called it quits last night, so I need to get a new quad of 6L6's ASAP. For the time being it's got 2 Ruby's, 1 Sovtek, and 1 Fender 6L6 and I REALLY don't want to play it like that.

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Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Thu Feb 20, 2014 4:49 pm
by theavondon
Dude, I used to use my 135 on bass through a 2x15 and it was the tits. Also, I hear the inputs are a different impedance that's not ideal for guitar, and you can get more gain just by modifying that.

Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Thu Feb 20, 2014 5:01 pm
by skullservant
Interesting! I'll have to look up stuff about the impedance tonight, might be worth a try!

Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Thu Feb 20, 2014 7:18 pm
by Gone Fission
Comparing schematics to a Twin Reverb of the same era, you'll see that the power section and reverb are about the same, but the preamp and eq stuff is odd. Pretty easy to futz with most of the values to more familiar guitar and bass ranges, but you might need to swap some pots if you want the usual volume pot values.

I would split the cathoded on the inputs, tune each input triode a little differently, and use different eq variations for each channel. Like try the Bax/James type eq with tapped treble pot from the early sixties brownface amps on one channel, verbatim blackface/silverface with fixed midrange on another.

The Prowess Amplifiers site has schematics for the PA-100 and most eras of Twin for comparison. Haven't seen an interior layout diagram, but you can probably get far with a SF Twin layout and schematics of each.

Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Fri Feb 21, 2014 1:18 pm
by vegedge
skully are you modding each channel separate? or just one for od? each being different would be cool if you could switch between them!

Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Fri Feb 21, 2014 4:05 pm
by skullservant
Gone Fission wrote:Comparing schematics to a Twin Reverb of the same era, you'll see that the power section and reverb are about the same, but the preamp and eq stuff is odd. Pretty easy to futz with most of the values to more familiar guitar and bass ranges, but you might need to swap some pots if you want the usual volume pot values.

I would split the cathoded on the inputs, tune each input triode a little differently, and use different eq variations for each channel. Like try the Bax/James type eq with tapped treble pot from the early sixties brownface amps on one channel, verbatim blackface/silverface with fixed midrange on another.

The Prowess Amplifiers site has schematics for the PA-100 and most eras of Twin for comparison. Haven't seen an interior layout diagram, but you can probably get far with a SF Twin layout and schematics of each.
TEACH ME YOUR WAYS/COME OVER AND HELP ME
vegedge wrote:skully are you modding each channel separate? or just one for od? each being different would be cool if you could switch between them!
Honestly not sure if I'll be modding them at all. I MIGHT, but nothing set in stone right now.

Last night I ordered a fresh matched quad of JJ's for the head, so that will be good!

Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Fri Feb 21, 2014 4:11 pm
by Achtane
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Re: Skully's next tube amp project: Fender PA100 + 2x12

Posted: Fri Feb 21, 2014 11:59 pm
by karmablock
Can't wait to see how this turns out. I just picked one of these up.