MOAAH
New member
tweed":114fwptk said:
Haha, just noticed the OP terminals! So it's not totally stock
Haha, just noticed the OP terminals! So it's not totally stock
tweed
New member
Hoping to give this thing a whirl today and I got one stupid question to start off with. I have to connect a speaker obviously, and when I look on the back the connectors have been modified such that I can't tell what ohm speaker to connect. It used to have 4 and 8 ohm connections but those have been removed and two new terminals added with no numbers. Can I just put an DMM on this connection, with the amp powered off and get a somewhat close enough reading to tell what direction to go in? 
tweed
New member
set the meter to 20K Ohm and the readings were all over the place then it eventually falls back to 0.00
Anyone have any tips on seeing what impedance the speaker terminals are on this amp?
Anyone have any tips on seeing what impedance the speaker terminals are on this amp?
Nigel Tufnel
New member
I would just hook it up to a cab and not worry too much. If you have an 8 ohm cab that would be ideal as there wouldn't be too much of a mismatch either way if it's looking for 4 or 16 ohms. People make way too big of a deal about impedance matching, there are certainly amps that out there that don't take it well but most take it just fine, it will just affect the tone and maybe shorten your tube life a little depending on the match. No biggie man, fire it up.
tweed
New member
Well I hooked up a speaker and fired her up. She's dead. No lights on any tubes, the power light doesn't even light up. I check the main fuse in the back and its not blown. Have no idea where to go from here...
Gainiac
Well-known member
tweed":1f1c40r2 said:
Ok, Stop fkn around and Hit that FKN thing with your HM strat, a pedal and send to a cab in 4 ohms... It'll wake right up an work fine.....
Nigel Tufnel
New member
Sounds like the power trans is dead man, it could be some thing else but I would bet on the pt. If you're really wanting to learn how to mess with amps you could get a hammond pt or something cheap and get it working. It looks like it would be a pretty neat platform for a build but I guess you should just ask yourself if you want to put money into it.tweed":1n5qyd5s said:
tweed
New member
MOAAH
New member
tweed":1icviq6y said:
Set your VOM/DVM to high AC volts and check if there is any voltage on the secondary side of the PT.
The the HV should be about 350AC. These wires go from the PT to the rectifier tube. Just check pin #s 1 and 7. Also check the end of the power cord(primary side of PT), it could be the plug or power cord is fucked.
4 -> 16 ohms is fine for testing, 8 is prolly best.
See ya after your next report...
R
RoccaforteAmps
New member
Generally, these don't sound very good for guitar.
The reason is, they used output transformers
with very limited bandwidth.
I went though this many moons ago buying
all kinds of tube pa and hifi amps to convert
over for guitar.
I learned it's better (unless its free) to spend
the money on a real guitar amp. FWIW
The reason is, they used output transformers
with very limited bandwidth.
I went though this many moons ago buying
all kinds of tube pa and hifi amps to convert
over for guitar.
I learned it's better (unless its free) to spend
the money on a real guitar amp. FWIW
R
RoccaforteAmps
New member
Nigel Tufnel":30v5n1m9 said:
What if he has a bad power switch, or cable end, or wire?
I doubt its the transformer, and without testing everything
ahead of it nobody really knows for sure......
MOAAH
New member
Funny thing, guitars have a limited bandwidth, which falls well within the average range of a PA.RoccaforteAmps":15iectaq said:
Generally, some of these amps have poor iron thou, plus strange NFB and stuff. Any and all of which can be changed out.
Plenty of amps have been converted, the Bogen Challenger being a popular favorite.
MOAAH
New member
Guess you missed this post:RoccaforteAmps":3crlb4m4 said:
That would test everything ahead of the PT.MOAAH":3crlb4m4 said:
Many folks started out modding old stuff...you can't make a chev into a cady, but you can sure learn a few things rebuilding it.
duesentrieb
Well-known member
Hey tweedy, I'm just converting this (the one I have was heavily fucked though 
)
into this:
All that was left from this 38 years old sucker are chassis, Partridge trannym Dagnall OT and two sockets. Everything else was "crappyfied" from unused/recycled parts I had flying around somewhere in the "crap-lab"
)
into this:
All that was left from this 38 years old sucker are chassis, Partridge trannym Dagnall OT and two sockets. Everything else was "crappyfied" from unused/recycled parts I had flying around somewhere in the "crap-lab"
tweed
New member
duesentrieb":2r7fss6m said:Hey tweedy, I'm just converting this (the one I have was heavily fucked though
into this:
All that was left from this 38 years old sucker are chassis, Partridge trannym Dagnall OT and two sockets. Everything else was "crappyfied" from unused/recycled parts I had flying around somewhere in the "crap-lab"
Nice!! Im not that advanced yet Olaf lol. I still haven't had time to dig into this lafayette and figure out if the switch is bad or not. I got tied up in a million other family things and the amp is on the back burner for now.
MOAAH
New member
duesentrieb":1yvf0qc6 said:Everything else was "crappyfied" from unused/recycled parts I had flying around somewhere in the "crap-lab"
Nice work, as always! I note you're using relays on this one, have you quit using ICs for switching or are those just what you had laying around?
Nothing crappy about those Illinois caps, but it's kinda funny how they are called that, yet made in Japan
"Crap-lab", LOL.
Nigel Tufnel
New member
I was just speaking from my own experience, or maybe my own bad luckRoccaforteAmps":2t9t6dq4 said:
because I've picked up a few little old pa amps like that under similar circumstances and 2 of em had blown pt's. One had a bad power tube and a blown fuse. Not really knowing how much tweed knows about poking around inside amps I was reluctant to tell him to go digging in with his meter (no offense tweed). I don't want to get anyone shocked or killed, if the pt is dead it probably wouldn't be an issue unless he caught the mains but not knowing for sure I kept my diagnosis short. So tweed if you know how to safely poke around in there I'm sure one of us guys can help you figure it out. Good luck 
MOAAH
New member
It's my badNigel Tufnel":3le288b1 said:So tweed if you know how to safely poke around in there I'm sure one of us guys can help you figure it out. Good luck
I asked him via PM if he had some experience, I guess that is something that should have been brought out here. Anywho, he does have a bit
R.
tweed
New member
MOAAH":1utd1saf said:It's my badNigel Tufnel":1utd1saf said:So tweed if you know how to safely poke around in there I'm sure one of us guys can help you figure it out. Good luck
I asked him via PM if he had some experience, I guess that is something that should have been brought out here. Anywho, he does have a bit
R.
I do have some experience, although its limited. I will give it a whirl when I have some free time. Probably wont be till later on this week or weekend though. All sorts of silly crap popping up this week.
MOAAH
New member
tweed":16hhf3la said:MOAAH":16hhf3la said:It's my badNigel Tufnel":16hhf3la said:So tweed if you know how to safely poke around in there I'm sure one of us guys can help you figure it out. Good luck
I asked him via PM if he had some experience, I guess that is something that should have been brought out here. Anywho, he does have a bit
R.
I do have some experience, although its limited. I will give it a whirl when I have some free time. Probably wont be till later on this week or weekend though. All sorts of silly crap popping up this week.
It's all good man! I'll keep an eye out for your next report. Hope it's something simple like the AC plug or switch