Marantz Jumpers
- Thread starter pjf610
- Start date
Decatur Greg
Super Member
If you're referring to the pre amp to power amp jumpers I'm not sure, but there's nothing magic about them. In fact, I believe the inner contact is the only one that matters. Someone who serviced my 2325 just used two pieces of thick copper wire and bent it into a U shape to fit into the inner contacts. I've left them in and never had any problems or noticed a problem with the sound.
Blue Shadow
Waiting for Vintage Gear from this century
I don't know for sure so I looked and the OM for the 2250B is missing the pages that discuss the pre-power connections. Looked at the SM and it appears the use of the power amp input defeats the preamp output to the power amp section. The preamp output looks to be continuous to the jack and the power amp unless the power amp section has an RCA input connected. There are no pictures of jumpers on the 2250b on the web. Someone knows for sure but there are units that have and internal way to disconnect the pre-power when they are used separately. Maybe we'll get confirmation soon.
Decatur Greg
Super Member
I think the 2325 is the same, you don't have to use jumpers. I know didn't have any problem before I took it in to be recapped and there were no jumpers on it. The tech said it was a good idea to use them anyway. I've had to take a couple of things back to him since then... so I'm not sure if I trust everything he says now.
Steven Tate
CEO Flat Forehead Soc.
Those internal jumpers can get wonky and introduce static or other garbage into the signal. But they usually can be easily cleaned with Deoxit. No reason to use external jumpers if it is otherwise operating properly. The jacks are just there in case you want to separate the Pre from the main amp Of course, older Marantz models don’t have the internal jumpers and require the external ones.
My 2226B doesn have jumpers but the 1030 amp does. I made them from some RCA ends and a couple of pieces of 12AWG or maybe 14AWG copper wire pulled out of a piece of scap romex. Only the internal pins are used. The grounds are not.
ragtopolds6
Active Member
you need jumpers for the 2325...just picked one up and it didn't have them would not work..pluged in looped rc jacks and pow it came to life..previous owner caned
it because of that...lol my gain
it because of that...lol my gain
wurlyman
Active Member
Somebody messed yours up because a 2325 doesn't need external jumpers. I know, I have one and the jumpers are internal and it has worked fine for 41 years
Steven Tate
CEO Flat Forehead Soc.
+1. I have a 2325 — internal jumpers. In fact, mine were the source of hard-to-find noise. Someone recommended I Deoxit them, and it worked.
ragtopolds6
Active Member
hum..i wounder if manufacture year matters mine is 5/77...will have to look at mine a little closer
blhagstrom
Mad Scientist, fixer.
He is correct.
The internal contacts are just spring contacts.
Like relay contacts.
They only open and close with no friction to cause self cleaning.
Deoxit may help, but without any rubbing, there is no physical scrubbing involved.
Using jumpers is a sure way to eliminate the possibility that the contacts may have poor connection.
I make bent copper jumpers.
10 gauge copper works well.
Just short RCA interconnects are good too.
Steven Tate
CEO Flat Forehead Soc.
Easy to test. Plug in some RCA’s and see if you get sound. Hard to believe both internals would have such bad connection that you got zero sound - unless somebody messed with them or they weren’t there in the first place.
blhagstrom
Mad Scientist, fixer.
I have seen a lot of 40 year old gear with no sound because of bad connection.
catrafter
Marantz Specialist
Some Marantz gear requires jumpers with a 'shield' connection to work properly, 2230, 2245 and 2270 come to mind. If you use 'u' jumpers that just connect the center of the Pre-Main jacks it could lead to noise or even speaker smoking oscillation.
A short dual RCA jumper cable will work in a pinch.
Tom
A short dual RCA jumper cable will work in a pinch.
Tom
