Spectrum II cab

[Newtosunn]

Hello everyone!  I?m new to this forum.  I recently acquired this cabinet.   From what I understand it had been sitting in a garage for 30 + years unused.  I cleaned it up the best I could.  Looks like the tolex was removed and replaced with white vinyl wrapping.  Grill cloth looks replaced as well.  Casters were removed and covered with the vinyl.  Dimensions are 36 x 24x 11.5.  Not sure if the speakers work. 

I have Fender Hot Rod Deluxe 40w which has an extension speaker jack.  I?ve read many different things about ohms/impedance and I?m hesitant to hook anything up.  I know very little about circuits and ohms.  Any suggestions for testing the speakers?  I don?t have electrical readers or circuit testers.  Also, are these normally played through a amp head?  Are the speakers wired in parallel?

Last question, would it be hard or worth putting tolex back on to restore to a more vintage look?  Just curious on the forums thoughts.  Thanks and I?m looking forward to playing this. 

[loudthud]

Hard to say what the impedance of the cabinet might be. It would be best to take the back off and inspect the speakers, or just measure the resistance with a meter. In general, a tube guitar amp can withstand a mismatched load for as much as an hour, especially if you are not playing loudly with lots of distortion. That will tell you if the speakers work or not.

Recovering the cabinet can be an involved process. The first problem will be finding the exact type of  original covering (called Tolex) to use (if that is important to you). Do some research to see what you are getting into.

[Newtosunn]

Thanks for your reply.  I was having trouble uploading the pictures.   Here they are.   Thanks for your input

[Isaac]

So many things to say!

I think the white vinyl is ugly, but it's not my cabinet.

Yes, the grill cloth has been replaced. That's Fender grill cloth. It's very similar, but, IIRC, Sunn never had the blue lines that your cloth has.

The drivers have also been replaced. AFAIK, Sunn never used Altec drivers. But the Altec 418B is a superb driver, every bit as good as the JBLs of the era.

As for the cabinet impedance, it would appear to be 4 ohms. The Altecs are 8 ohm drivers (at least, that's what it says on the back), and the pictures show that they are wired in parallel. That gives you a 4 ohm load. I don't know how that would work with your Fender.

A quick and dirty way to find out if the drivers work is to take a 9V battery and touch it to the terminals. If you hear a pop, then the driver works, at least somewhat. There could still be problems, but it will make sound. Easy way to do this with what you have is to plug a speaker cord into the jack and touch the battery to the other end of the cord. Try to see that both cones move when you do, and that they move in the same direction. These are efficient drivers, so the pop should be pretty loud.

[Newtosunn]

I agree about the white vinyl lol.  Not complaining as it was a gift.  I wouldn?t mind trying to replace the grill and tolex.  Both would be a first for me.  Just really focusing in how I can use it with what I already have or getting another piece of gear.  1st step is making sure it works.   Thank you so much for your input!

[Isaac]

What I'd try, after testing the drivers with the 9V, would be disconnecting the internal speaker in the Fender and connecting the Sunn. I'm as sure as I can be that the amp wold be fine with a 4 ohm load, and the Altecs can easily handle everything the Fender can put out.  I have a feeling that it would sound great.

[Soundmasterg]

Did Ampeg ever use Altec drivers for their larger cabinets? Reason I ask is a friend had an Ampeg cabinet and amp that were stolen maybe 7 years ago locally and they were both re-covered with white tolex of some sort. It isn't a common color to see on amps or speakers since it gets dirty so easily. I wonder if that might be an Ampeg cabinet and someone put a Sunn logo on it to hide the identity and sell it?

Greg

[Newtosunn]

What I'd try, after testing the drivers with the 9V, would be disconnecting the internal speaker in the Fender and connecting the Sunn. I'm as sure as I can be that the amp wold be fine with a 4 ohm load, and the Altecs can easily handle everything the Fender can put out.  I have a feeling that it would sound great.

I forgot that I have a little Fender Champion 600 with the following specs:
- Output: 5 Watts
- Ohms: 4 Ohms
- Speaker: One 6 Inch, 4 Ohm Special Design Driver With Ceramic Magnet

As you said I could just disconnect the internal speaker and run the cabinet directly through the amp speaker jack and get a matching 4 ohm load.  Does that sound good or should I still go with the battery test first?  Either way I?ll give it a try tonight.  Thank you for the suggestion!

[Newtosunn]

Did Ampeg ever use Altec drivers for their larger cabinets? Reason I ask is a friend had an Ampeg cabinet and amp that were stolen maybe 7 years ago locally and they were both re-covered with white tolex of some sort. It isn't a common color to see on amps or speakers since it gets dirty so easily. I wonder if that might be an Ampeg cabinet and someone put a Sunn logo on it to hide the identity and sell it?

Greg

That?s a possibility.  The first odd thing I noticed was that the Sunn logo was in the lower right corner of the cab.  Every picture I saw on the internet had the logo in the upper left corner. After hours of searching this forum of models and designs I narrowed it down to a possible Sentura II based on the dimensions, port location and offset speakers.  The front of the cab had been put on upside down (attached are the before pics).   I removed the front, cleaned everything up and put it back on so that from the front view the port is on the lower right area, and the logo is in the upper left corner.   

While waiting for the admin to approve my forum registration request I read a post that mentioned it would be ok to email Conrad directly.   Took a chance and sent him an email with exterior/interior pics post correcting the front.  He responded that ?it looks like an early Sunn Spectrum II cabinet.  Some of our customers preferred the brighter tone of the Altec speaker over the JBL D130F.?  I thought is was very kind and awesome of him to respond!  What a cool dude  .    Anyhow, I haven?t gotten around to testing the speakers yet but I plan on doing that tonight.  Like I said, the previous owner said that it has sat in her garage for at least 30+ years untouched.   Should be interesting.

Just to confirm I did correct the front panel.   Now when facing the front the handle is on the left side, and the rubber feet are on the right.   The square caster indents that I could see through the white vinyl are now on the bottom.

[Isaac]

I forgot that I have a little Fender Champion 600 with the following specs:
- Output: 5 Watts
- Ohms: 4 Ohms
- Speaker: One 6 Inch, 4 Ohm Special Design Driver With Ceramic Magnet

As you said I could just disconnect the internal speaker and run the cabinet directly through the amp speaker jack and get a matching 4 ohm load.  Does that sound good or should I still go with the battery test first?  Either way I?ll give it a try tonight.  Thank you for the suggestion!

The battery test should take only a moment. Might as well go ahead.  The reason I'd do it is because you don't know the condition of the drivers. If one were to be shorted, it could conceivably damage the amp. I think that's highly unlikely, but, if it doesn't cost you anything to test it, then why not?

[Newtosunn]

I forgot that I have a little Fender Champion 600 with the following specs:
- Output: 5 Watts
- Ohms: 4 Ohms
- Speaker: One 6 Inch, 4 Ohm Special Design Driver With Ceramic Magnet

As you said I could just disconnect the internal speaker and run the cabinet directly through the amp speaker jack and get a matching 4 ohm load.  Does that sound good or should I still go with the battery test first?  Either way I?ll give it a try tonight.  Thank you for the suggestion!

The battery test should take only a moment. Might as well go ahead.  The reason I'd do it is because you don't know the condition of the drivers. If one were to be shorted, it could conceivably damage the amp. I think that's highly unlikely, but, if it doesn't cost you anything to test it, then why not?

Will do.  Thank you Isaac!

[Soundmasterg]

Did Ampeg ever use Altec drivers for their larger cabinets? Reason I ask is a friend had an Ampeg cabinet and amp that were stolen maybe 7 years ago locally and they were both re-covered with white tolex of some sort. It isn't a common color to see on amps or speakers since it gets dirty so easily. I wonder if that might be an Ampeg cabinet and someone put a Sunn logo on it to hide the identity and sell it?

Greg

That?s a possibility.  The first odd thing I noticed was that the Sunn logo was in the lower right corner of the cab.  Every picture I saw on the internet had the logo in the upper left corner. After hours of searching this forum of models and designs I narrowed it down to a possible Sentura II based on the dimensions, port location and offset speakers.  The front of the cab had been put on upside down (attached are the before pics).   I removed the front, cleaned everything up and put it back on so that from the front view the port is on the lower right area, and the logo is in the upper left corner.   

While waiting for the admin to approve my forum registration request I read a post that mentioned it would be ok to email Conrad directly.   Took a chance and sent him an email with exterior/interior pics post correcting the front.  He responded that ?it looks like an early Sunn Spectrum II cabinet.  Some of our customers preferred the brighter tone of the Altec speaker over the JBL D130F.?  I thought is was very kind and awesome of him to respond!  What a cool dude  .    Anyhow, I haven?t gotten around to testing the speakers yet but I plan on doing that tonight.  Like I said, the previous owner said that it has sat in her garage for at least 30+ years untouched.   Should be interesting.

Just to confirm I did correct the front panel.   Now when facing the front the handle is on the left side, and the rubber feet are on the right.   The square caster indents that I could see through the white vinyl are now on the bottom.

Conrad would certainly know better than me. What reminded me of my friend's Ampeg cabinet was the white color in yours, and I know that Ampeg used a lot of the Altecs in the 70's in their B15's.

Greg

[Newtosunn]

I forgot that I have a little Fender Champion 600 with the following specs:
- Output: 5 Watts
- Ohms: 4 Ohms
- Speaker: One 6 Inch, 4 Ohm Special Design Driver With Ceramic Magnet

As you said I could just disconnect the internal speaker and run the cabinet directly through the amp speaker jack and get a matching 4 ohm load.  Does that sound good or should I still go with the battery test first?  Either way I?ll give it a try tonight.  Thank you for the suggestion!

The battery test should take only a moment. Might as well go ahead.  The reason I'd do it is because you don't know the condition of the drivers. If one were to be shorted, it could conceivably damage the amp. I think that's highly unlikely, but, if it doesn't cost you anything to test it, then why not?

I tested the drivers individually with a 9v battery short new wires to the terminals.  Both cones popped.  I put the original wiring back and connected the cab directly to the speaker jack on my 4 ohm (5 watt) amp and got 0 output.  The input jack on the back panel looks pretty crusty.   I?ll try replacing the wiring and jack.  Any other suggestions?

[Isaac]

Crusty jack sounds like a definite problem area. Before that, though, I'd plug in a speaker cord to it, then take the 9V to the other end of the cord. Put one terminal of the battery on the tip, then touch the other to the sleeve. Again, you should get a pop. If so, then the problem is in the amp. If not, then it's between the plug where you touched the battery and the drivers. Crusty jack is, I think, the most likely place in that case.