Help: External speaker jack on drri, dead

[Mango Moon]

Hello All,

I've got a '65 Reissue Deluxe Reverb with the standard set of parallel-wired (Internal and External) speaker jacks, and as I understand it, as long as the internal (8-ohm) speaker is connected to the Internal speaker jack, another (8-ohm) speaker (or cab) can be connected to the External speaker jack (i.e., parallel = 8 X 8/8 + 8 = 64/16 = 4 ohm load = no worries, right?).

Problem is, when I do that, the speaker connected to the Internal speaker jack works just fine but the speaker connected to the External jack goes dead (nada). The speakers are all fine because whichever speaker I connect to the Internal jack works. Only the External jack appears dead.

What gives here anyway? The Fender manual states that this type of arrangement or configuration should not be a problem. Any ideas? Has something in the amp itself gone bad? Where do I start?

Thanks.

[Mango Moon]

A quick follow-up to this thread . . . .

As you can see from a related thread that I posted here nearly one-year ago (http://music-electronics-forum.com/t10072/), this "speaker impedance/DRRI external speaker jack" question was never thoroughly or clearly answered. Some say it should work just fine. Others say it was never designed to work and could actually damage the amp.

So, for you Fender buffs out there, what is the deal? If the External speaker jack was never designed (or intended to work with either an 8-ohm or 16-ohm extension cab), then what was the point of placing it there? In other words, if you have an 8-ohm speaker connected to the Internal speaker jack but no additional 8-ohm or 16-ohm speaker cab will ever work properly when connected to the External speaker jack, why have it?

Thanks.

[stokes]

If you have a meter,plug a jack into each socket and see if you have continuity between the two positive and two negative leads,if not re-solder the connections.

[Mango Moon]

Thanks Stokes.

I'm afraid this is a bit over my head. I've got a multimeter here and I know how to use it for the most part, but that's about it (i.e., I'm not a pro amp tech or anything, just a guitar player).

I guess what I was hoping for here is definitive confirmation from someone that the simultaneous use of two 8-ohm speakers using both the Internal and External jacks was indeed the design by Fender (i.e., that something is positively wrong with my amp), or conversely, a definitive confirmation that the simultaneous use of two 8-ohm speakers was NOT intended by design, and that what I'm experiencing is perfectly normal.

Once I determine the answer to this central question, then I'll be able to proceed with repairs if needed or warranted.

Thanks.

[Enzo]

You are trying way too hard to make this a complex technical issue.

Of course you can use an internal and external speaker at the same time.

What you cannot do is plug into the extension jack INSTEAD of the main jack. If you are pulling the internal speaker cable out of the main jack and plugging it into the external jack as a test, it won;t work. The main jack has a shorting contact, and if nothing is plugged into it, it shorts across the output of the amp.

If you have the internal speaker plugged into the main jack AND an external speaker plugged into the extension jack, and nothing comes out the extension cab. And we know the cab and speaker cord are OK, then it sounds to me like you have a bad jack.

Just because a plug clicks into a jack doesn;t mean the jack is working. If the jack contacts are a little bent, they could be making contact with the wrong points on the plug. Or the plug may push the contacts over until they touch something and ground out.

[Mango Moon]

You are trying way too hard to make this a complex technical issue.

Of course you can use an internal and external speaker at the same time.

What you cannot do is plug into the extension jack INSTEAD of the main jack. If you are pulling the internal speaker cable out of the main jack and plugging it into the external jack as a test, it won;t work.

Great!

Look "Enzo", you seem to lie in wait for these threads and then you typically pipe in with your pointed criticisms of the author's issue or the way they've worded it (you've done it several times in the past), but do me a favor will you? Keep your arrogant criticisms to yourself!

Although I certainly appreciate your "first-to-respond", "expert" views on everything, I don't need and won't accept you abrasively telling me what's "complex" or not, and further, I'll word the questions the way I care to word them. Got it? If that doesn't work for you, then kindly ignore them and move on!

Secondly, READ the thread before you go brashly advising others willy-nilly. No one suggested plugging into the External jack without having a speaker connected internally. Never said it, never implied it, period!

I simply could NOT have been any clearer in articulating what's happening here, and I strongly suggest that you resist concluding that its the amp's External jack itself, because significantly (you'll want to note this!), I have THREE (3) other combo amps sitting here (all of which have similar parallel-wired External speaker jacks), and NONE of them (none of their External jacks) work with FIVE (5) or more different 8-ohm cabs, either! Capiche?

What say you now?

[billyz]

Wow, I can't resist. If none your other amplifiers extension jacks work, then the obvious thing is you have a bad speaker cable or other such problem. I have worked on too many fenders and have never found a bad ext jack( they seldom get used). I have noted operator error in plugging into the ext jack only and no sound. so that is always the first place to look.

To answer your question about the use of the ext jack. A 4 ohm load is OK and I have personally used the ext speaker jack for that purpose and others( to develope a line level). Fender did design it for just the purpose of an external 8 ohm speaker load in addition to the internal 8 ohm speaker.

I have read Enzo post in the past and have always found his knowledge and logic to be above average. Also, I have Never detected a bit of arrogance or other immature behavior in his post.

flame on dude 8)

[Mango Moon]

I'll try this again . . .

1) Speaker #1: 12" (8-ohm) inside DRRI combo connected to 'INTERNAL' speaker jack (External jack empty); result AUDIBLE (+ sound).

2) Speaker #2: 12" (8-ohm) inside 1X12 extension cab connected to INTERNAL jack (External jack empty); result AUDIBLE (+ sound).

3) Speaker #1: Inside DRRI combo connected to 'INTERNAL' speaker jack with Speaker #2 (inside 1X12 extension cab) connected to 'EXTERNAL' speaker jack; result AUDIBLE (+ sound) at Speaker #1 but INAUDIBLE (- sound) at Speaker #2.

4) Speaker #2: Inside 1X12 extension cab connected to 'INTERNAL' speaker jack with Speaker #1 connected to 'EXTERNAL' speaker jack instead (same speaker, same cable); result AUDIBLE (+ sound) at Speaker #2 but INAUDIBLE (- sound) at Speaker #1.

Potential cause(s)?

1) CANNOT be faulty speaker

2) CANNOT be faulty speaker cable

However, since it is happening with multiple low-powered (22-40w) combo amps, the only feasible explanation (in my view) is that the overall output at the External jacks (all four amps) is too low to drive a secondary (8-ohm) speaker. I don't know what else it could possibly be.

[dwhutchens]

I just took a look at the Deluxe Reverb II schematic over at schematic heaven http://www.schematicheaven.com/fende...ereverb_II.pdf which I believe must be the reissue model. The second jack is not an external jack but a line out jack. That would explain why it can't drive a speaker cab. An original DR would have an external speaker jack parallel with the internal jack.

[Mango Moon]

DW,

Thanks for your response.

This Line-Out business could EASILY explain what I'm experiencing here, but it is my understanding that the "Deluxe Reverb II" was an altogether different model of Deluxe Reverb manufactured by Paul Rivera (Rivera amplification), rather than the Fender Deluxe Reverb '65 Reissue.

Maybe someone more knowledgeable than I will enlighten us both a bit further, but it sure would be nice to get to the bottom of this!

Thanks again.

[Jag]

So, what did you find when you opened the amp up to look at the jacks? Can you post a picture of the jacks from inside?

I realize you're frustrated but, everyone here is doing their best to be helpful.

The DRRI '65 is not a DRII, you are quite right about that. Unless someone has modded your amp, the Ext Speaker jack is exactly that and it will be parallell with the Int Speaker jack, it is not a line out on the stock DRRI '65.

Forgive me for saying so but, if you're having this issue wtih three other combos as well, I think there could be something wrong with how you're connecting things. I can assure you that I, as well as many others on this forum I'm sure, have done this without issue many times with many different amps.

[billyz]

It is not that the amp cannot drive two 8 ohm speakers whose total impedance is 4 ohms. Each speaker if of the same impedance will share the power output.

It is possible it is miss wired or a faulty jack. But you say all your other amps do the same thing. Unless all your amps are from the same batch, I find it highly unlikely they would all share the same exact fault. I guess anything is possible.

To test plug in the internal speaker as normal. plug in a known good short speaker cable or a 1/4" phone plug with the cover off into the extension jack. Measure the resistance of the tip and shield, or + and -. it should read 6-8 ohms. If not, you have bad jack or miss wired one or a bad mechanical ground to chassis.

[billyz]

I am posting a schematic for the 65 Deluxe reverb reissue.

[Enzo]

My most humble apology for getting in your way with my attempt at assistance. The effort is sincere, if ineffective.

If I am the only one who thought impedances were not the problem, I am truly sorry.

If you think 4 ohms might be too much for the amp to produce any sound, plug a 4 ohm cab into the main speaker jack. That will answer the question one way or the other.

I will not trouble you further.

[Steve Conner]

When you plug into an extension speaker jack, it's normal to expect that sound would come out of the amp's own speaker, and also the extension speaker that you just plugged in. That's the purpose of the extension speaker jack, for goodness' sake. Plugging in another speaker to make the amp louder.

If it doesn't work, then you have a loose connection somewhere. I'm going to guess you have a dodgy speaker cable, with an intermittent connection that works only sometimes, or with some jacks but not others. Suggest you buy a good quality new cable and try again.

Alternatively, I think some Fender reissues swap the output transformer over to a different tap when you plug the extension speaker in. Maybe the jack contact that does that is dirty. But that wouldn't cause the same problem on three different amps! So we're back to the speaker cable assembly as #1 culprit again. You tried three amps and five cabs, but did you try several different cables?

PS, I know who's the ass and it isn't Enzo!