Welcome to Solid State Guitar Amp Forum | DIY Guitar Amplifiers. Please login or sign up.

March 28, 2024, 05:38:41 AM

Login with username, password and session length

Recent Posts

 

Yamaha G100-115 II reverb tank

Started by Scoticus, January 24, 2017, 11:50:04 PM

Previous topic - Next topic

Scoticus

Hello all
just scored a G100-115 series two
does anyone know what reverb tank It should have ?
the bag is still there but no tank.


Anybody own one of these ? If so could you take a look at your tank for me.
I found the service manual for the series 1 which called out the tank as an Accutronics 4AB2C1A
I also found the service manual for the series II which did not call out the tank. I thought maybe the Yamaha part numbers would match but they don't.
I called our local tech today and he said he thought that the tanks would be the same but he was not 100% sure.
any of this ringing a bell for anyone

thanks,

Enzo

You have both manuals?  great.  Forget the tank number, look at the circuit.  Do both use the same drive circuit?  If the circuits are the same, then the tanks are too.  I think both are driving low impedance loads.

Scoticus

Enzo, Got your response this AM did not have  time to go over the schematic very well and I have to say I don't have a good grasp of how the whole schematic thing works. That said the component values were different which I expect means its a different circuit.

I got on chat with Yamaha parts department, The guy did not know what a reverb tank was although his language made me think he's an Aussie. Do they call it something else?
anyhow he said the Accutronics number is 1EB2C1A.
I was not too sure he understood so I clarified that it was a G100-115 series 2. He replied that that was correct.
Does that seem plausible?

thanks


J M Fahey

Post-the-schematic-here  :grr :grr

Scoticus


phatt

Accutronics  1EB2C1A = 600 Ohm Drive (DC resistance ~ 60Ohms) Short tank
Accutronics  4AB2C1A = 8 Ohm drive     (DC resistance ~ 1 Ohm)  Long tank
Other than that the rest is the same but they will not be interchangeable.

One big clue here is *Obviously the tank length*,,,,, So is the Bag long or short? :tu:

Good tank Info here; https://www.amplifiedparts.com/tech-corner/spring-reverb-tanks-explained-and-compared
Phil

Scoticus


DrGonz78

#7
So...
G100 series 1 reverb = 4AB2C1A
G100 series 2 reverb = ??? >>> 4AB2C1A
G100 series 3 reverb = 4EB3C1B
JX30-50 type amp reverb = 1EB3C1B

As I had followed along I took time to crop all the G100 type reverb circuits to analyze them all. Also, I even started look at the Yamaha JX series amps reverb circuit too. I found a picture of the JX40 type reverb as being 1EB3C1B. At least that is the best I can make out on the picture I found online. Figured I would just post all these in one place so they are here for the looking.
"A person who never made a mistake never tried anything new." -Albert Einstein

Scoticus

#8
Awesome!
So I need to grab the 4AB2C1A.
anyone recommend a brand ?
anything to avoid?

been looking around the web and not coming up with the 4AB2C1A
is this unobtainable?
anything  else that will work?
how about the 4AB2C1B ?

Enzo

Look up the codes for the pans.  The last chharacter is the mounting plane, and really, that is not all that critical.

Scoticus

Right,
So, open side down but the rest will be the same.

Thanks to all you guys.
I appreciate it.

Scoticus

OK,
So, I got my new reverb tank from MOJOTONE. 4AB2CIB, so that's correct except for the tank mounts with the cavity down rather then up.
Hooked it up and it works great. I just used regular RCA cables from a stereo.
As I said, it works but I am wondering if there is a preferred way to do this. My amp didn't come with the tank or cables so I'm wondering what is correct.
Coax cable?
I would like to have 90 degree plugs and build the cables myself or find something that fits pretty well. Any suggestions ?
thanks,

Enzo

Write this on your wall so you can see it now and then as a reminder:

These are just guitar amps, not NASA lab equipment.  There is nothing precise about them.


It is just a reverb, like a zillion others  Plain old shielded cables are all we need.  Cheap RCA patch cords are fine.   You can probably find RCA cords that already have right angle plugs on them.  I know I used to sell them.

Just mount the pan open side down, no need to turn it into a trash bin.  I recommend you put it in a vinyl reverb pan bag.  Most places that sell pans also sell the bags.  The whole open side up or down thing is just a matter of how high the innards sit. Make sure to leave the soft grommets in the mounting holes, and NEVER screw down the pan tight.

The only real issue yet to watch for is feedback.  If you pan doesn't feedback, you have no issue.

Scoticus

OK,
thanks Enzo, I'll remember that.
I get it, just want it to be tidy and correct.

phatt

I read that Leo Fender used to purchase seconds for all his resistors and caps. :dbtu:
Now clowns go chasing exotic parts in the vain hope of finding the magic.  :loco

If you want a great guitar amp don't over think it. 8)
Phil.