Totally lost need help. I have a DSL100H amp and 1960a and cabinets.

[Dan Robinette]

How do i connect both cabinets to the amp? I've been reading the threads on this but am getting lost on using the two 8ohm and one 16ohm jacks on how to exactly connect them. Sorry for this question. Any help is much appreciated. I have both 1960 cabinets A and B sorry about that.

 

[Leonard Neemoil]

Welcome to the forum Dan.

The cabinets are 16 ohm, correct?

 

[Ray Baker]

Amp selector needs to be @8ohms. Assuming the cabs are 16ohms each. Cabinets have the selector switch similar to the image below?

 

[Dan Robinette]

Thank you i will double check that.

 

[GIBSON67]

deleted post, thanks for correcting me...and i have a DSL100H, doh!

 

[RLW59]

2x 16 ohm cabs, so plug both cabs into both jacks in the middle in this picture.

View attachment 154340

That's a DSL100HR, the newer version with 5 output jacks.

The older DSL100H just has 3 very poorly labeled jacks:


The 2 jacks labeled 8 ohms are connected together in parallel to the output transformer's 8 ohm output.

When using the 8 ohm jacks, the amp wants to see 8 ohms total. That's one 8 ohm cab, or two 16 ohm cabs.

So you plug your two 16 ohm cabs into the two 8 ohm jacks.

 

[Leonard Neemoil]

That's a DSL100HR, the newer version with 5 output jacks.

The older DSL100H just has 3 very poorly labeled jacks:
View attachment 154343

The 2 jacks labeled 8 ohms are connected together in parallel to the output transformer's 8 ohm output.

When using the 8 ohm jacks, the amp wants to see 8 ohms total. That's one 8 ohm cab, or two 16 ohm cabs.

So you plug your two 16 ohm cabs into the two 8 ohm jacks.

This is correct. ^^^

 

[Dan Robinette]

Amp selector needs to be @8ohms. Assuming the cabs are 16ohms each. Cabinets have the selector switch similar to the image below?

Ok, well I checked the cabinets plugged into the 8ohm input and get 7.6ohm so i went to the 16ohm and get 7.6ohm. You were talking about the 1960a and 1960b cabinets being 16ohm from what i put here are these cabinets wired wrong or am I checking them wrong ? Thanks

 

[Matthews Guitars]

Ohm ratings on cabinets are nominal impedance, not DC resistance. An "8 ohm" speaker that's perfectly good will typically read between 6 and 10 ohms to an ohmmeter, and a 4 ohm speaker will read from 2 to 6 ohms, more or less, and a 16 ohm speaker might read as low as 10 ohms and as much as 20. Although it's not common to find speakers that read HIGHER in their resistance than their nominal rating, it can happen.

A 1960 cabinet with two jacks and an impedance switch works as it says on the data plate:

With the switch in one, the stereo. position, both jacks are 8 ohms nominal.

With the switch in the mono position, one jack is 4 ohms nominal (the left jack) and the other is 16 ohms nominal. (the right jack)

If it's wired properly this is how it will work. If all four speakers are 16 ohms and wired in the factory configuration.

 

[Kendall124]

Do this….
Plug your quality speaker cables into each one of these.



Plug one into each cabinet at this location.


Make sure this switch is on mono.


Turn it on.
Crank it up.
Attract women.
Piss off the neighbors.
Rock it!!!

 

[solarburn]

Ohm ratings on cabinets are nominal impedance, not DC resistance. An "8 ohm" speaker that's perfectly good will typically read between 6 and 10 ohms to an ohmmeter, and a 4 ohm speaker will read from 2 to 6 ohms, more or less, and a 16 ohm speaker might read as low as 10 ohms and as much as 20. Although it's not common to find speakers that read HIGHER in their resistance than their nominal rating, it can happen.

A 1960 cabinet with two jacks and an impedance switch works as it says on the data plate:

With the switch in one, the stereo. position, both jacks are 8 ohms nominal.

With the switch in the mono position, one jack is 4 ohms nominal (the left jack) and the other is 16 ohms nominal. (the right jack)

If it's wired properly this is how it will work. If all four speakers are 16 ohms and wired in the factory configuration.

Yep. I use the same multimeter checking ohms on speakers and cabs. The 16/15 ohms on it run 12.7 to 13.9 and the 8 ohms at 6.4/6.8. Consistently. I roll a lot of speakers with cabs.

 

[RLW59]

plugged into the 8ohm input and get 7.6ohm...
the 16ohm and get 7.6ohm...

With the slide switch set to mono, the 16 ohm jack should give you 12~14 ohms (approximately -- anything from 10 to 16 would be ok). But it shouldn't read the same as when the switch is in the stereo position (the only time either jack is nominally 8 ohms is with the switch in stereo).

The switching jackplates are known to fail sometimes and cause impedance problems. Be sure to figure out exactly what's going on before cranking your amp.
------------------------
Switch in mono: one jack should read a little under 4 ohms, the other jack should read a bit under 16 ohms.

Switch in stereo: both jacks should read a bit under 8 ohms. In stereo, each jack is connected to only 2 speakers instead of all 4 in mono. (That way you can run 2 amps into a single cab -- one amp is connected to the left 2 speakers, the other amp is connected to the right 2 speakers.)

 

[Dan Robinette]

Well I took the back off one of the cabinets and found this 4 speakers 16ohm each but the wiring looks to be in parallel. input from the switch on the back of the cabinet left side was wired to two speakers from back + to + top speaker and - wired to top speaker and then it goes to the bottom speaker + from the top and - to bottom speaker. And the other 2 speakers are wired the same except they are coming in from the side of the input jack that says 16ohms but I'm getting 8ohms from the two sets of four speakers. I think this is wired wrong.. The speakers Celestion GT 12T -75watts 16ohm speakers white label. I don't want kill my amp. Thanks any help

 

[RLW59]

Well I took the back off one of the cabinets and found this 4 speakers 16ohm each but the wiring looks to be in parallel. input from the switch on the back of the cabinet left side was wired to two speakers from back + to + top speaker and - wired to top speaker and then it goes to the bottom speaker + from the top and - to bottom speaker. And the other 2 speakers are wired the same except they are coming in from the side of the input jack that says 16ohms but I'm getting 8ohms from the two sets of four speakers. I think this is wired wrong.. The speakers Celestion GT 12T -75watts 16ohm speakers white label. I don't want kill my amp. Thanks any help

Saturday night and I'm more stoned than usual. So I'm sorry but I'm utterly confused by "back + to top +" and such.

A picture would be a huge help. I think this forum may require new members to have a certain number of posts before they can upload pics or post links. But we'll get there.

In the meantime, does your wiring match this?:

 

[RLW59]

With correct wiring, the left pair of speakers are connected together in parallel for 8 ohms. And the right pair are connected together in parallel for 8 ohms.

The slide switch and switching contacts in the jacks then connect the two parallel pairs together in series (16 ohms total) or in parallel (4 ohms total).

With the switch in stereo, the two pairs aren't connected together at all. The left pair is connected to the left jack, and the right pair is connected to the right jack.

If you measure at the 16 ohm jack and get 7.6 in both mono and stereo, the problem is almost certainly in the switching circuit itself.

 

[Dan Robinette]

Ok I think I get it. This is a picture of one of the cabinets. I think it's right. Here's a picture. The picture is to large to send to the server. I'll try to compress it down

 

[Dan Robinette]

I compressed it hope this works. Might be a little blurry. But I think there might be a problem with the switch in Mono it reads 7.6ohms and on the 16ohm side it reads 7.6ohms. So what I should do is leave both cabinets in mono mode and plug each cabinet into each 8ohm input on the amp. ?

 

[RLW59]

So what I should do is leave both cabinets in mono mode and plug each cabinet into each 8ohm input on the amp. ?

Two 8 ohm cabinets is a 4 ohm total load and your amp doesn't support 4 ohms. (The two 8 ohm output jacks are for one 8 ohm cab or two 16 ohm cabs.).

If the cab jack reads 7.6 in both mono and stereo, that strongly suggests it's stuck in stereo and only two speakers are actually running. 412's can fool you into thinking all the speakers are working even when only running two speakers, because the changes in air pressure inside the cab makes the cones of the non-functioning pair move and contribute a little bit of sound.

Are both your cabs giving you weird readings, or does the other one read normally?

 

[Dan Robinette]

Two 8 ohm cabinets is a 4 ohm total load and your amp doesn't support 4 ohms. (The two 8 ohm output jacks are for one 8 ohm cab or two 16 ohm cabs.).

If the cab jack reads 7.6 in both mono and stereo, that strongly suggests it's stuck in stereo and only two speakers are actually running. 412's can fool you into thinking all the speakers are working even when only running two speakers, because the changes in air pressure inside the cab makes the cones of the non-functioning pair move and contribute a little bit of sound.

Are both your cabs giving you weird readings, or does the other one read normally?

Well 1960B cabinet reads 7.6 in mono and when im in mono on the 16ohm output i get 14.6ohm

 

[PelliX]

Well 1960B cabinet reads 7.6 in mono and when im in mono on the 16ohm output i get 14.6ohm

So that's correct as per design. 8 Ohms mono, 16 Ohms stereo.

I compressed it hope this works. Might be a little blurry. But I think there might be a problem with the switch in Mono it reads 7.6ohms and on the 16ohm side it reads 7.6ohms.

I'm a little confused by the way you worded that; On the 16 Ohm jack you should read roughly 16 Ohms when the switch is in the Mono position and all the speakers are connected inside. That's not what's happening?

So what I should do is leave both cabinets in mono mode and plug each cabinet into each 8ohm input on the amp. ?

No! The 8 Ohm jacks are basically just two physical jacks on the same 8 Ohm tap. That tap must witness a load of ~8 Ohms, in simple terms. If you attach two 8 Ohm cabs, the impedence is divided by the number of cabs (2) and thus the tap sees a 4 Ohm load. That's not good. In this setup you *need* both cabs to present a ~16 Ohm load. The 1960B is doing that. The only part you need to sort out now is the 1960A.

Could you check the resistance of a single speaker in that cab (so make sure it's disconnected from the rest, else your measurement isn't accurate)?