Amp poop

November 21st, 2012, 01:03 PM
Yupp, I got it real bad:shock:

I'm a sucker for dragging home weird and "pooched" amps, but this one takes the cake.

It is an early '60's Dynachord Hall Jazz. A really retro looking thing that holds lots of promise. The seller simply said "It worked years ago, but now nothing" How many times have we heard that? :lol::lol::lol:

So I drag her home and open her up...only too find...the root cause of its demise - Mus musculus


I sent the seller a few pics and he was kind enough to offer a full refund. I told him nah, I did not contact you to get money back, but you should consider a cat.

I'm going to give it a go, a while back I scored a mid 60's Hohner that is like a AC30 that thinks its a Fender Twin. Just an amazing amp. I'm thinking this one hold promise as well.


Let the poop cleaning begin.


November 21st, 2012, 01:06 PM
haha, when I read the title I didn't actually expect a literally crappy amp! I hope it cleans up nice and works great for you!

November 21st, 2012, 02:09 PM
LOL, good luck man

November 21st, 2012, 02:36 PM
I worked on electrical stuff in restaurants for a while

Rats and mice really like climbing into equipment and chewing wires

November 21st, 2012, 04:14 PM
I cleaned out some mouse turds from my '69 Princeton after buying it. Luckily though they were only in the bottom of the cab with some shredded tissue. It appears to have been a brief home for a cute critter. The chassis luckily was clean and sparkly like the day it left the factory.

Delta Blues
November 21st, 2012, 04:51 PM
Turds for tone.

November 21st, 2012, 06:25 PM
That's taking Mojo to whole new level...

November 21st, 2012, 06:42 PM
leave the turds in, no problem getting the brown sound out of that one.

November 21st, 2012, 07:16 PM
Good Luck.

Delta Blues
November 21st, 2012, 07:26 PM
leave the turds in, no problem getting the brown sound out of that one.

This but never sing through the mic you use on this amp.

November 21st, 2012, 08:07 PM
leave the turds in, no problem getting the brown sound out of that one.


Prairie Dawg
November 22nd, 2012, 01:04 AM
It's not as bad as it looks. I overhauled a Silvertone 1396 Twin Twelve and mice had gotten into the upper chassis and used it as a latrine/winter quarters. I had to rebuilt the small chassis-a tube socket, about ten caps and some resistors. It needs a good cleanup so you can see what you're doing and to remove the smell of rodent piss. I don't know whether you have Hanta virus up your way but it is dangerous so wear a particle mask when you're doing the cleanup.

November 22nd, 2012, 05:43 AM
That mouse should get shocked twice a day. Yes, wear a dust mask! Nice collection.

January 28th, 2013, 06:49 AM
Iīm off the the shop in a sec but will post some pics as i get home this evening.
If the PCB for the reverb is all that is shot and the tank and trafo for it checks out iīd def make that reverb work again.

Get a friggin litre of rubbing alcohol and an 1" wide brush...cut it down ītil it become stiff...and pour the rubbin alcohol over there..
If you happen to have compressed air around that is a bonus,if not...whatever..alcohol will vaporate soon enough.

I made the one i rebuilt into a 3 stage jobbie. Worked ok all said n done. OEM speaker is a 10" one.
Baffle is easy enough to unbolt. Do so and hog it out to a full 12". Mind you,the cab is rather shallow....bringing that youīll have to be anal about speaker depth AND girth of speaker magnet or itīll bottom out vs the lower end of the chassis.

All done tho they make for a rather neat 18w bluesrock combo all said n done.

January 28th, 2013, 07:02 AM
Pre CBS mice are better.

January 28th, 2013, 03:26 PM
You really know your s____ ! Seriously, the amp's kinda cool and I hope you get it up and running.

January 28th, 2013, 06:12 PM
For some stock shots first..
(Just a replaced resistor as the amp was DOA and i wanted to make sure it ran as supposed)



The reverb unit resides at the floor of the cab. Incl the reverb trafo. I recap,this is by far the best sounding spring reverb iīve ever encountered. IF it can be resurrected,just trust me...do so.
Itīll put the famed Fender reverbs to shame..



I modded this amp,and rather extensively to make it into an 18w dirty bluesrock screamer.


Word of notice. ALL,no exceptions,of the onboard capacitors-be it electrolytes or otherwise,NEEDS to be replaced. I donīt CARE if they "measure ok" cause if they havenīt sprung a leak at the moment...that moment will come soon enough. Iīve lost track of how many of the early ERA,WIMA,Siemens asf caps iīve replaced by now. They were most likely da bomb in the day,but 50 yrs later they are nothing but a menace. Replace every damn one of them if you value your life.


DIN jacks were tossed in the bin and got replaced by common teles. A masterpot,as you can see,got installed.


Cathode biased as you can gather,and rather cool at that. Measure what your specific amp wants and reset resistor value accordingly.
Thereīs no harm,on the contrary,in resetting cap value to either 47u or even 100u. Trafos will handle that.


This is the piggyback reverb PCB in OEM "unmolested" form. Ie;that is how it should look all said n done.


I went overkill for each and every one of the voltage droppin resistors. Capacitance was added in turn.

Sorry to say i never found an OEM schematic for the Hall-Jazz. The Jazz...no issues at all,thatīs to be found online and is readily available. Anyways...
I made this sucker into a 3 stage jobbie...and TBH in hindsight would i redo the whole thing today iīd opt to install yet a preamp flask and in turn remodel the PI into an LTP of Marshalleresk values. Altho the concertinas certainly can be tamed as far as their rather "jagged" behaviour,they IMO tend to be rather static once set. Sure...thereīs a number of solutions that adress that as well but when a LTP is that easy to setup...why bother.?
`N...for a meek 18watter the PI WILL come into play-like it or not.

The 3 stage jobbie tho...in hindsight..yeah..it turned out ok. Above fair iīd say. Not golden...but absolutely above fair.

If thereīs anything i can help you with as far as specifics,lemme know...

January 28th, 2013, 06:14 PM
Speaking of which.
The cab of the Jazz is rather shallow. That renders that as you replace the OEM 10" POS speaker in there..be tech about what element you replace it with.
Not only for depth but also for magnet girth as a speaker with to large a magnet will come to interfere with the amp chassis.
This was something i simply clearanced with a nibbler and a rotary file (I run a raceshop for a living so tools...as well as compressed air kind of comes with the terrirtory)

January 29th, 2013, 11:32 PM
Thanks so much for that. I'll head your advice on the caps. The challenge I have is that the tube sockets on the reverb sub board are very badly corroded. The reverb pan is fine.

Re: a schematic, I think there is one here but you need to be a member to access it:



January 30th, 2013, 12:06 AM
you go

January 30th, 2013, 11:18 AM
you go

To where? somewhereville?


January 30th, 2013, 06:06 PM
Nice work if you can get it, eh, Rumrunner. That makes that Masrshall rig you were looking at look like a diamond set in platinum, imho. OF course, thsi one looks good from the outside, too, right?

January 31st, 2013, 05:36 PM
Tubesockets on the other hand might look rather special item but theyīre not.
Have replaced numerous on Dynas over the yrs. Regular PCB novals work just fine,you just have to twist n bend the legs a little...and be patient.

īN yeah. It will be worth it. Trust me.:mrgreen:

January 31st, 2013, 06:53 PM
Neat amp! Would the "Hall Jazz" moniker be just because it has had reverb added to the "Jazz" circuit?
You need my Dynacord Cora to plug in!

January 31st, 2013, 08:44 PM
Nice work if you can get it, eh, Rumrunner. That makes that Masrshall rig you were looking at look like a diamond set in platinum, imho. OF course, thsi one looks good from the outside, too, right?

There in lies the rub. I have no problem with the weird, strange, bizarre or little known amps. In fact, I'm drawn to them like chickens to cow paddies. But when I see a Marshall, I say pass. I've still got a few years in me so I'm sure one day the temptation will grow. :grin: