Fixed a MKII Boogie Yesterday - Bad Coupling Cap

chilipeppermaniac said:
Amp Mad, Thanks for coming to our Forum. It sure is good having you around.

Hard to imagine how many folks we have on here, who either recreationally or for income have pursued electronics and amps etc for recreation or for income. We who simply use amps and seek to understand them, sure are richer for folks like you.
Click to expand...

Dude,

I have built one of these...

1598385029888.png

I am sure I could do it.. :-)
 
Amp Mad Scientist said:
I was in this band called Dragon Soup. The Soup Dragons copied our name.
When our amps and equipment broke down, there was nobody who could really fix it.
The label said: "no user serviceable parts inside."
Then I said fck it, I'm opening this thing up anyway.
That's when I started fixing amps and equipment.
Pretty soon, I was working at a local music store. Then I was a PV service center.
After that, it sort of took over my life.

Don't follow my example. :rolf:You will regret it later.
No seriously I had a lot of fun but it never made very much money so it was only for kicks.
Click to expand...

Soup Dragons....

True story...

I wrote a song once called "Soup Bowl Devil," about a hallucination of a demon coming up out of a bowl of soup to each time I tried to pull a spoonful of broth up into my spoon. There's a backstory, but I shouldn't post it publicly...
 
chilipeppermaniac said:
All this amp talk, and circuitry got my brain to just have a ( dumb question) pop into it.

I know what a variable resistor is, so, Is a bias pot considered a variable resistor? MY guess is yes.
Click to expand...
I'm no expert but recall the pot is basically a variable resistor, but it's function depends on the way it is wired in the circuit.
It can be either a variable resistor or a voltage divider, and maybe some other things.
 
chilipeppermaniac said:
Nice story, Ampmad,

Hey before I forget, I was scrolling back to the beginning of the thread and remembered I had a question I wanted to remember to ask with regards to my Laney I posted.

I seem to remember reading about " cascading" in the AOR Pro Tube Lead circuit/design. Mine is an 8 knob head 50 watt
version. From a post on Rigtalk,

Turn up all the tone controls to 10 and pull out all the boosts on them. Spend your time dialing in the 4 preamp/vol controls for different sounds when checking the amp out. the 'pull gain' knob is a cascading preamp which is footswitchable. There are 4 12AX7 preamp tubes in it.

I had one for years and I liked it. A bit noisy, but it cleaned up well with the guitar volume. Mine had metal corners and sounded a bit different than the plastic corner ones you usually see. Mine did not have the diodes in it compared to the plastic corner ones. Never could fine any info on why my head was different.

From a post I found on TDPRI,
Click to expand...

I don't know, because I can't see the schematic.
But generally all tube amps are copies of Fender. Mesa, Marshall = all copies of Fender amps. It's the same schematic, the same tone controls, and everything else.

"cascading," (a word made up by Randall Smith) = it was around since 1940s.
All it means is: one gain stage goes into another gain stage. Input > gain stage > gain stage > phase inverter > power amp.

Probably invented (for audio) by Ducane Amplification in the 1940s. The idea comes from radio transmitters.
 
Amp Mad Scientist said:
I don't know, because I can't see the schematic.
But generally all tube amps are copies of Fender. Mesa, Marshall = all copies of Fender amps. It's the same schematic, the same tone controls, and everything else.

"cascading," (a word made up by Randall Smith) = it was around since 1940s.
All it means is: one gain stage goes into another gain stage. Input > gain stage > gain stage > phase inverter > power amp.

Probably invented (for audio) by Ducane Amplification in the 1940s. The idea comes from radio transmitters.
Click to expand...

Thank you AMS. I think this is it. Pretty sure my head is the 2nd one. The original AOR 50 watt is a 6 knobber and sould be the 1st schematic. Mine is an 8 knobber with push pull pots.


 
Last edited:
chilipeppermaniac said:
Thank you AMS. I think this is it. Pretty sure my head is the 2nd one. The original AOR 50 watt is a 6 knobber and sould be the 1st schematic. Mine is an 8 knobber with push pull pots.


Click to expand...

Yes I see, copy of JCM 800 / Mesa Boogie / Hot Rod Deluxe.
But they all are basically no matter who makes it. They all use the same design.
 
Amp Mad, I am glad you got smitty's LP ok. Hope you enjoy it tremendously.

Also, with regards to my Laney amp above. I began conversing with IvanH about my issues with it and mentioned your checklist How To: you posted previously here.

He is helping me locate parts and to ID them on schematic and on my board etc,. As he is good at doing with me, he sees my issues, tells me the part specs, name, general location in the circuits etc. Then I can study the schematic and compare it to my amp to find the parts, wires, traces in PCB type boards, and I go on from there. I do my best to find parts suppliers and Ivan is also very good at knowing where to buy the good parts.
Having him and you and the other guys here, really helps me moving along in my learning and understanding of amps.

Having said all that, I am still slightly challenged with the PCB in that I must backlight the board to eyeball the paths things follow, but I am getting a lot better at that to follow the wires/traces, resistors, coupling and filter caps, diodes, pots, valves, transformers, IC's etc and translating the schematic to the hardware and vise versa.
 
chilipeppermaniac said:
Amp Mad, I am glad you got smitty's LP ok. Hope you enjoy it tremendously.

Also, with regards to my Laney amp above. I began conversing with IvanH about my issues with it and mentioned your checklist How To: you posted previously here.

He is helping me locate parts and to ID them on schematic and on my board etc,. As he is good at doing with me, he sees my issues, tells me the part specs, name, general location in the circuits etc. Then I can study the schematic and compare it to my amp to find the parts, wires, traces in PCB type boards, and I go on from there. I do my best to find parts suppliers and Ivan is also very good at knowing where to buy the good parts.
Having him and you and the other guys here, really helps me moving along in my learning and understanding of amps.

Having said all that, I am still slightly challenged with the PCB in that I must backlight the board to eyeball the paths things follow, but I am getting a lot better at that to follow the wires/traces, resistors, coupling and filter caps, diodes, pots, valves, transformers, IC's etc and translating the schematic to the hardware and vise versa.
Click to expand...

I have been playing that puppy ever since it landed.
Need some new stings today...the winding on the G string is already coming apart.
I want to find a roller bridge too or a nylon saddle bridge.
 
Amp Mad Scientist said:
I have been playing that puppy ever since it landed.
Need some new stings today...the winding on the G string is already coming apart.
I want to find a roller bridge too or a nylon saddle bridge.
Click to expand...

Even though the cat is out of the bag, after you change strings and have some time to get your impressions solidified, you should start an NGD thread.

That would be surreal!

BTW, what kind of strings do you prefer?

I have a 9-42 set of Ernie Ball Super Slinkys that I'll send on to you, if you're interested. I'll send them no-charge as sort of a consolation prize for the grief you endured while waiting for that guitar.

Let me know and I'll pop 'em in the mail.
 
I have some really slinky wound G's but they are very hard to find. And in old extra light flatwounds, but still an unwound G is a blessing. Very old Gretsch and Pyramids which haven't been made since the 60's but if you keep your eyes peeled you can locate them in perfect nick!
 
You must log in or register to reply here.
Back
Top