It's painted white.

[loopyreed]

Thought this would be a fun project:



I bought it from a friend yesterday in a fit of irresponsibility.  As you can see, it's spraypainted white.  That's a problem.  It also doesn't work.  That is also a problem.

Good thing I enjoy projects.  I'm working on getting that paint off, and soon, replacement speakers.  Can't wait. 

Inspecting the cabinet raised a question - what impedance was this cab designed to run on?  It's just a 412, not sure what year.  Guessing 70's, I doubt its a reissue.  It has two inputs just left of center close to the top of the cab. 

Any help is appreciated, impedance info, paint stripping techniques, etc. 

[Isaac]

From the looks of it, it's a 70's 412S. Does it have a plate on the back, underneath the paint? IIRC, 412S cabinets had 4 16 ohm Sunn Transducers (1216G, maybe?), and ran at 4 ohms.

[loopyreed]

I checked it again, and there isn't a plate on the back.  Doesn't look like there ever was one. And I was wrong, the two jacks are just right of center, not left.   

Is there any way to wire it at 8 ohms?  I'd really like to run this and my 612 from my Solarus.  The 612 already takes the 4 ohm output. 

[EdBass]

I checked it again, and there isn't a plate on the back.  Doesn't look like there ever was one. And I was wrong, the two jacks are just right of center, not left.   

Is there any way to wire it at 8 ohms?  I'd really like to run this and my 612 from my Solarus.  The 612 already takes the 4 ohm output. 

It all depends on what the cabinet is loaded with. Since it doesn't work, you'll need to open it up anyway.
Do you have, or can you get a multimeter?
Check back when you get it opened up, I'm sure somebody here can get you going in the right direction!

[loopyreed]

I checked it again, and there isn't a plate on the back.  Doesn't look like there ever was one. And I was wrong, the two jacks are just right of center, not left.   

Is there any way to wire it at 8 ohms?  I'd really like to run this and my 612 from my Solarus.  The 612 already takes the 4 ohm output. 

It all depends on what the cabinet is loaded with. Since it doesn't work, you'll need to open it up anyway.
Do you have, or can you get a multimeter?
Check back when you get it opened up, I'm sure somebody here can get you going in the right direction!

Well, it's opened up, unloaded, masked off, and has already had one trip to the high-pressure bay at the car wash.  It worked suprisingly well.  5 more sides, about 10 more bucks in quarters and it's done!  I was pleased to find out how good the tolex is and all the metal parts are still very shiny. 

The speakers are 4 Sunn Transducers 1216G's, 16 ohms, 60 watts each.  Believe it or not they do work - I tested it briefly with my Solarus and it sounds fine.  The guy who sold it to me (and others in his band) told me it didn't work at all.  Hmm. 

I don't have a multimeter, but I might be able to borrow one.  So, is it possible to wire the 4 1216G's at 8 ohms?  If it can only be wired to a higher impedance (more than 8?) is it safe to run out of the 8 ohm output?   

[loudthud]

It can be wired for 16 ohms. But then it will only draw as much power as one of the speakers in your 3x12.

[loopyreed]

It can be wired for 16 ohms. But then it will only draw as much power as one of the speakers in your 3x12.

Oh, hamburgers.  Well...I guess I don't really need to use both of them at the same time...

[EdBass]

Since you now know for sure what the drivers are (and they work!  ), you don't really need a multimeter.

However they can be had for dirt cheap and handy to have around, for example;
http://search.harborfreight.com/cpisearch/web/search.do?catPath=All%2BProducts%252F%252F%252F%252FUserSearch%253Dmultimeter&currentPage=2&lastPage=2&isNext=false&isPrevious=false&category=&attributeValue=&attributeName=&requestedPage=1&resultsPerPage=10&resultsPerPageBottom=0

You have a couple of options with the Solarus, one quick and dirty and one more involved but safer;
You could wire the 412 in parallel and get it to 4 ohms, and then daisy chain it in series to the 612 (I think six 8 ohm drivers, most likely actually a 5.3 ish ohm load) and probably* be safe plugging the whole mess into the 8 ohm jack, showing it a 9.3 ohm nominal load..
Or...
Rewire the 612, each set of 3 in series, and the two sets of 3 together in parallel, which will give you 12 ohms. Wire the 412 in series parallel to get 16 ohms. Switch the output transformer on your Solarus from the 8 & 4 to 16 & 8 taps (assuming your Solarus indeed has the original OT, not as hard as it sounds), and plug one cab into each jack. You would be showing the 8 ohm tap a 6.8 ohm nominal load, giving the 612 about 60% of the juice. And that's plenty close in my book. 

Neither is picture perfect, both would work, but IMO the second is much better/safer than the first, and...


*that's the way I would go if I had to run both of those cabs from one Solarus. 

Maybe you could try "quick and dirty" to see if you think the more involved option is worth the effort?

[loopyreed]

Since you now know for sure what the drivers are (and they work!  ), you don't really need a multimeter.

However they can be had for dirt cheap and handy to have around, for example;
http://search.harborfreight.com/cpisearch/web/search.do?catPath=All%2BProducts%252F%252F%252F%252FUserSearch%253Dmultimeter&currentPage=2&lastPage=2&isNext=false&isPrevious=false&category=&attributeValue=&attributeName=&requestedPage=1&resultsPerPage=10&resultsPerPageBottom=0

You have a couple of options with the Solarus, one quick and dirty and one more involved but safer;
You could wire the 412 in parallel and get it to 4 ohms, and then daisy chain it in series to the 612 (I think six 8 ohm drivers, most likely actually a 5.3 ish ohm load) and probably* be safe plugging the whole mess into the 8 ohm jack, showing it a 9.3 ohm nominal load..
Or...
Rewire the 612, each set of 3 in series, and the two sets of 3 together in parallel, which will give you 12 ohms. Wire the 412 in series parallel to get 16 ohms. Switch the output transformer on your Solarus from the 8 & 4 to 16 & 8 taps (assuming your Solarus indeed has the original OT, not as hard as it sounds), and plug one cab into each jack. You would be showing the 8 ohm tap a 6.8 ohm nominal load, giving the 612 about 60% of the juice. And that's plenty close in my book. 

Neither is picture perfect, both would work, but IMO the second is much better/safer than the first, and...


*that's the way I would go if I had to run both of those cabs from one Solarus. 

Maybe you could try "quick and dirty" to see if you think the more involved option is worth the effort?

I'm not opposed to quick and dirty...I'll try that first.  How do I connect the 612 and the 412 the right way?

The other, safer, more responsible way is a little more work than I'd like to do...plus, it would mean I couldn't use the just 412 or the 612 individually, right?

Honestly I'd rather replace the speakers in the 412 with some at a lower impedance...but something about replacing the original transducers seems morally wrong.  Is there another 12" driver I could use that Sunn might have used, like a d130 or d140 at a lower impedance?

[EdBass]

I'm not opposed to quick and dirty...I'll try that first.  How do I connect the 612 and the 412 the right way?

You want + to - between the two cabs. Easiest way is to switch the jack connections on one end of the speakers cable you use. MARK THE CABLE, you don't want to accidently use it for anything else.

The other, safer, more responsible way is a little more work than I'd like to do...plus, it would mean I couldn't use the just 412 or the 612 individually, right?

When you internally change which OT taps you run to the output jacks, the jacks still function the same way, just at different values. From the description of your Solarus, you currently have the 8 and 4 ohm taps wired; the output jacks are 8 ohms and 4 ohms. When you plug a cable into the 8 ohm jack, it connects directly to the 8 ohm tap on the output transformer, when you plug a cable into the 4 ohm jack, it connects directly to the 4 ohm tap. If you use both output jacks, it defaults in parallel to the 4 ohm jack only, meant for two 8 ohm cabinets to plug in. When you switch the output taps on your transformer, the jacks become 16 and 8 ohms, and operate in the same manner.
With the safer way, you could plug either of the cabinets into the "8 ohm" (now actually 16 ohm) jack by itself and be fine.

Honestly I'd rather replace the speakers in the 412 with some at a lower impedance...but something about replacing the original transducers seems morally wrong.  Is there another 12" driver I could use that Sunn might have used, like a d130 or d140 at a lower impedance?

What impedance driver would you replace them with? If you ever plan to use the cabinets together with your Solarus, or any tube amp, you need the impedances to match. With the 612 your options are limited. 16 ohm drivers in the 412 are likely the most practical drivers you could use, from an impedance aspect.

[loopyreed]

You want + to - between the two cabs. Easiest way is to switch the jack connections on one end of the speakers cable you use. MARK THE CABLE, you don't want to accidently use it for anything else.

I'm sorry, I don't think I understand this.  So it would look like this - Solarus -> 612 -> rewired speaker cable -> 412?  If that's right, where does the cable between the two cabinets connect?  I'm sorry bout all the questions, I feel like a moron.

When you internally change which OT taps you run to the output jacks, the jacks still function the same way, just at different values. From the description of your Solarus, you currently have the 8 and 4 ohm taps wired; the output jacks are 8 ohms and 4 ohms. When you plug a cable into the 8 ohm jack, it connects directly to the 8 ohm tap on the output transformer, when you plug a cable into the 4 ohm jack, it connects directly to the 4 ohm tap. If you use both output jacks, it defaults in parallel to the 4 ohm jack only, meant for two 8 ohm cabinets to plug in. When you switch the output taps on your transformer, the jacks become 16 and 8 ohms, and operate in the same manner.
With the safer way, you could plug either of the cabinets into the "8 ohm" (now actually 16 ohm) jack by itself and be fine.

Ok, so currently when I use both the 8 ohm and 4 ohm jacks at the same time, it makes the 8 ohm out a 4 ohm?  Once again, sorry, I'm just trying to understand all this.  Would that explain why the 412 worked when I tested it out?  What I did was plug it in the 8 ohm out because my 612 was already in the 4 ohm out, and it worked fine for as long as I was playing it.  Then again I've never mismatched impedance between a cab and head the bad way so I don't know what would happen as far as the sound...but the way I had it hooked up seemed to work pretty well but I don't want to do it again if it's gonna harm the 412. 

What impedance driver would you replace them with? If you ever plan to use the cabinets together with your Solarus, or any tube amp, you need the impedances to match. With the 612 your options are limited. 16 ohm drivers in the 412 are likely the most practical drivers you could use, from an impedance aspect.

I don't know, that's why I was asking about wiring possibilities before I start looking for different speakers.  Only worried about the ones in the 412, I'm happy with my 612 @ 5.3 ohms.  Right now I could just use either cabinet by itself, which would be fine, I was just curious how much work would be involved should I decide to use both cabs.  Apparently it's a lot more than I expected and I don't understand a whole lot about impedances.  I know not to mismatch them, and if you have to mismatch them with a tube amp, make sure the cab has the higher impedance.

Which leads me to another question - with the 612 at 5.3 ohms, coming from the 4 ohm output of the Solarus, is the 612 drawing as much power as it could?

Thanks for all the help so far.   

[EdBass]

You want + to - between the two cabs. Easiest way is to switch the jack connections on one end of the speakers cable you use. MARK THE CABLE, you don't want to accidently use it for anything else.

I'm sorry, I don't think I understand this.  So it would look like this - Solarus -> 612 -> rewired speaker cable -> 412?  If that's right, where does the cable between the two cabinets connect?  I'm sorry bout all the questions, I feel like a moron.

You don't sound like a moron, asking questions is the best way to learn new things. You mentioned two jacks on the 412, probably Solarus>412>reversed polarity cable>612.
Also, read this;
http://colomar.com/Shavano/spkr_wiring.html

When you internally change which OT taps you run to the output jacks, the jacks still function the same way, just at different values. From the description of your Solarus, you currently have the 8 and 4 ohm taps wired; the output jacks are 8 ohms and 4 ohms. When you plug a cable into the 8 ohm jack, it connects directly to the 8 ohm tap on the output transformer, when you plug a cable into the 4 ohm jack, it connects directly to the 4 ohm tap. If you use both output jacks, it defaults in parallel to the 4 ohm jack only, meant for two 8 ohm cabinets to plug in. When you switch the output taps on your transformer, the jacks become 16 and 8 ohms, and operate in the same manner.
With the safer way, you could plug either of the cabinets into the "8 ohm" (now actually 16 ohm) jack by itself and be fine.

Ok, so currently when I use both the 8 ohm and 4 ohm jacks at the same time, it makes the 8 ohm out a 4 ohm?  Once again, sorry, I'm just trying to understand all this.  Would that explain why the 412 worked when I tested it out?  What I did was plug it in the 8 ohm out because my 612 was already in the 4 ohm out, and it worked fine for as long as I was playing it.  Then again I've never mismatched impedance between a cab and head the bad way so I don't know what would happen as far as the sound...but the way I had it hooked up seemed to work pretty well but I don't want to do it again if it's gonna harm the 412.

The two output jacks on the back of your Solarus are in parallel (did you read the link yet? ), so when you plug your cabinets (assuming the 16 ohm drivers in the 412 are wired for 4 ohms) in you are presenting a 2.3 ohm load to the 4 ohm transformer tap. Maybe OK, maybe not, depends on who you ask. I wouldn't do it personally, not for very long anyway.
If the 412 is wired for 16 ohms, you'll be Okey Dokey from an impedance standpoint, but be sending less than 25% of your amps power to the 412, and over 75% of the power to the 612.
It won't harm your 412 or the 612 at all, the damage potential with an impedance mismatch is to the amp, not the speakers.

What impedance driver would you replace them with? If you ever plan to use the cabinets together with your Solarus, or any tube amp, you need the impedances to match. With the 612 your options are limited. 16 ohm drivers in the 412 are likely the most practical drivers you could use, from an impedance aspect.

I don't know, that's why I was asking about wiring possibilities before I start looking for different speakers.  Only worried about the ones in the 412, I'm happy with my 612 @ 5.3 ohms.  Right now I could just use either cabinet by itself, which would be fine, I was just curious how much work would be involved should I decide to use both cabs.  Apparently it's a lot more than I expected and I don't understand a whole lot about impedances.  I know not to mismatch them, and if you have to mismatch them with a tube amp, make sure the cab has the higher impedance.

It's my opinion that if a mismatch is unavoidable with a tube amp you are actually safer to have a load mismatch down, not up. Speaker impedance is not an exact science. Keep in mind we are dealing with a nominal impedance, the actual resistance varies with frequency, amp potential, SPL level, etc., a "4 ohm" speaker cabinet may show actual resistance from near zero to 6-7 ohms  for brief periods during use.
With a transistor amp, too low of a load will cause issues.

Which leads me to another question - with the 612 at 5.3 ohms, coming from the 4 ohm output of the Solarus, is the 612 drawing as much power as it could?

I think you are only dealing with about 40 watts with the Solarus, it's a 2 X EL34 amp if I'm not mistaken, but you are getting as much as you can out of it by using the 4 ohm output for your 612.

  

[loopyreed]

It's my opinion that if a mismatch is unavoidable with a tube amp you are actually safer to have a load mismatch down, not up. Speaker impedance is not an exact science. Keep in mind we are dealing with a nominal impedance, the actual resistance varies with frequency, amp potential, SPL level, etc., a "4 ohm" speaker cabinet may show actual resistance from near zero to 6-7 ohms  for brief periods during use.
With a transistor amp, too low of a load will cause issues.

Which leads me to another question - with the 612 at 5.3 ohms, coming from the 4 ohm output of the Solarus, is the 612 drawing as much power as it could?

I think you are only dealing with about 40 watts with the Solarus, it's a 2 X EL34 amp if I'm not mistaken, but you are getting as much as you can out of it by using the 4 ohm output for your 612.

So you're saying it might be better to have the amp's load at a higher rating than the amp?  I guess that makes sense...that way the only damage will be to the speakers...those are easier to replace than, well...whatever breaks in the amp because of running into a higher impedance.

My Solarus is early 70's, larger transistors, 6550's, 60 watts (i've seen ratings between 60 and 80 watts)? 
 
I had an idea.  Mismatches really freak me out.  I read the link you sent me and it said that a 5.33 ohm works well with a 4 ohm amp, but I don't want anything to go wrong with my Solarus no matter what sort of time frame that would take.  My 612 has six Eminence red coats, I guess they're 16 ohms since it's at 5.33 ohms together.  It has two inputs, so what I was thinking was wire the top two speakers parallel at 8 ohms on the top jack, the bottom four in parallel as well at 4 ohms on the bottom jack.  So it would go 8 ohm out -> top jack (2 12's), 4 ohm out -> bottom jack (4 12's) Would that work without risking damage to either the amp or the speakers?  I may have this completely wrong...

I'm not even worried about using the 412 and the 612 at the same time anymore.  Besides, that gives me an excuse to buy another head for the unclaimed 412 cab. 

Thanks again for all the help.  Best forum ever. 

[EdBass]

It's my opinion that if a mismatch is unavoidable with a tube amp you are actually safer to have a load mismatch down, not up. Speaker impedance is not an exact science. Keep in mind we are dealing with a nominal impedance, the actual resistance varies with frequency, amp potential, SPL level, etc., a "4 ohm" speaker cabinet may show actual resistance from near zero to 6-7 ohms  for brief periods during use.
With a transistor amp, too low of a load will cause issues.

Which leads me to another question - with the 612 at 5.3 ohms, coming from the 4 ohm output of the Solarus, is the 612 drawing as much power as it could?

I think you are only dealing with about 40 watts with the Solarus, it's a 2 X EL34 amp if I'm not mistaken, but you are getting as much as you can out of it by using the 4 ohm output for your 612.

So you're saying it might be better to have the amp's load at a higher rating than the amp?  I guess that makes sense...that way the only damage will be to the speakers...those are easier to replace than, well...whatever breaks in the amp because of running into a higher impedance.

Actually, I think it's best to have the speaker load a little less than the output tap you are using on the amp. The speaker(s) don't really care what tap you are using on the amp, they will be fine regardless. The only true potential for damage is to the amp itself.

My Solarus is early 70's, larger transistors, 6550's, 60 watts (i've seen ratings between 60 and 80 watts)?

I'm not familiar with the 6550 Solarus, but I think it's safe to assume that it's the same amp as all of the other 2 X 6550 Sunns. The difference between 60 and 80 watts is whether it has a tube or SS rectifier.
I think you mean "larger transformers". 
 

I had an idea.  Mismatches really freak me out.  I read the link you sent me and it said that a 5.33 ohm works well with a 4 ohm amp, but I don't want anything to go wrong with my Solarus no matter what sort of time frame that would take.  My 612 has six Eminence red coats, I guess they're 16 ohms since it's at 5.33 ohms together.  It has two inputs, so what I was thinking was wire the top two speakers parallel at 8 ohms on the top jack, the bottom four in parallel as well at 4 ohms on the bottom jack.  So it would go 8 ohm out -> top jack (2 12's), 4 ohm out -> bottom jack (4 12's) Would that work without risking damage to either the amp or the speakers?  I may have this completely wrong...

The speakers could be 8 ohm in parallel/series to get 5.33 also. Have you had a chance to actually measure the cabinets DC resistance, or pulled the speakers to see if they are marked?
If they are 16 ohm your plan would work, but only if you only used one of the jacks at a time, either the 8 ohm to the top two or the 4 ohm to the bottom four.
Your amp only has one true output at a time, the impedance is determined by which tap from the output transformer is being used. If used together the two jacks in the back of your amp will connect in parallel to this single output tap. In the case of your amp, plugging two cabinets in at once will provide two parallel connections to the single 4 ohm tap. This means the amp will be set up to look for two 8 ohm cabinets in parallel for a total impedance of 4 ohms.
You can use the jacks for one 8 ohm cab in the 8 ohm jack, OR one 4 ohm cab in the 4 ohm jack, OR two 8 ohm cabs, one in each jack, no mix 'n match allowed!
Clear as mud? 

I'm not even worried about using the 412 and the 612 at the same time anymore.  Besides, that gives me an excuse to buy another head for the unclaimed 412 cab.

 
I think the only limit to the number of amps you use should be how big your transport vehicle is and how strong your back is!