New to Sunn. Trying to get info on a Sunn Studio P.A.

[Monsta]

I just got a Sunn Studio P.A. I am just trying to find out some general info on the unit. It is not dated but lists as 400w on the back.

[loudthud]

400 watts is the rating of the convenience outlet. The Studio PA is rated at 60 watts output. Yours is probably a 69 because it has the old grill cloth and the (R) badge.

[Monsta]

Thanks so much for the info. What is the (R) badge? Also what does the polarity switch do?

[loudthud]

The Sunn badges or logo plates have gone through several changes over the years. Do a search and you can find threads where I have pictures of different examples. Hard to see in your pictures but it looks like there is a small R in a circle between the letters Sunn and the (o))) symbol. The (R) means Registered trademark. Before 1969 there was no (R).

The polarity switch is an outmoded way of establishing a ground reference for the amplifier from the days when two wire unpolarized power cords were the norm in the USA. These days, three wire power cords are used and the polarity switch is not needed. The polarity switch has actually become a safety hazzard and it's misuse will expose the amp user to possible electrical shock or, if a capacitor inside the amp fails, electrocution. Don't operate the amp or even plug it in unless you are wearing shoes. You may get a mild shock.

It is strongly suggested that you take the amp to a qualified technician for installation of a three wire power cord. Ask the tech to make a note of any date written inside the amp to date it.

[EdBass]

Thanks so much for the info. What is the (R) badge? Also what does the polarity switch do?

The polarity switch switches the polarity of the AC in the power supply, only relevent with the old two prong plugs. Sometimes switching polarity is a cure for hum and/or getting shocked by your amp when you touch something.
Usually "something" like a microphone with your lip.    

Use the search feature and do a little research, you will get answers for most of your questions, if you can't find something specific post a question. People here are very helpful but the same questions over, and over, and over can get a little annoying.  


EDIT: Sorry loudthud, I was typing when you posted!

[Monsta]

Thanks again for the info guys. I tried searching before but the way the searched worked seemed to bring up every post with a p and a in it.
It still have a 2 prong plug on the amp though. Looks like it was replaced at some point as a repair.

[loudthud]

Thanks again for the info guys. I tried searching before but the way the searched worked seemed to bring up every post with a p and a in it.
It still have a 2 prong plug on the amp though. Looks like it was replaced at some point as a repair.

You see burn marks on power cords sometimes on Sunn amps when someone stores the cord in the back of the amp before the tubes have had a chance to cool down. Also, the convenience outlets are frequently broken. These items should be corrected to keep the amp safe.

[loudthud]

Thanks again for the info guys. I tried searching before but the way the searched worked seemed to bring up every post with a p and a in it.

Use the advanced search for "studio pa" with the quote marks. The search function does have limitations so sometimes it takes several tries to find what you are looking for.

[loudthud]

Here's a thread with a picture of the early badges.

http://sunn.ampage.org/sdp/index.php/topic,4099.0.html

[pickinatit]

The polarity switch has actually become a safety hazzard and it's misuse will expose the amp user to possible electrical shock or, if a capacitor inside the amp fails, electrocution. Don't operate the amp or even plug it in unless you are wearing shoes. You may get a mild shock.

Loudthud,  I recently had the two prong power cord changed to a three prong chord on my Solarus.  When I took it in the tech. (who has been there since they were an authorized Sunn Distributor back in the 60's-70's) said there was "no need to disconnect the Polarity  switch, just no need to use it."  (I had mentioned it when I took it in as that was my understanding of the mod.).  Is he mistaken?  Am I and my Amp now at risk with a three prong power chord if the Polarity switch is still connected ?

[loudthud]

Loudthud,  I recently had the two prong power cord changed to a three prong chord on my Solarus.  When I took it in the tech. (who has been there since they were an authorized Sunn Distributor back in the 60's-70's) said there was "no need to disconnect the Polarity  switch, just no need to use it."  (I had mentioned it when I took it in as that was my understanding of the mod.).  Is he mistaken?  Am I and my Amp now at risk with a three prong power chord if the Polarity switch is still connected ?

It won't do anything as long as you plug into a properly grounded outlet. You'ld be surprised how many bars there are that have mis-wired or defective outlets. It's not a big problem but many people remove the "death cap" as it is known.

[pickinatit]

Loudthud,  I recently had the two prong power cord changed to a three prong chord on my Solarus.  When I took it in the tech. (who has been there since they were an authorized Sunn Distributor back in the 60's-70's) said there was "no need to disconnect the Polarity  switch, just no need to use it."  (I had mentioned it when I took it in as that was my understanding of the mod.).  Is he mistaken?  Am I and my Amp now at risk with a three prong power chord if the Polarity switch is still connected ?

It won't do anything as long as you plug into a properly grounded outlet. You'ld be surprised how many bars there are that have mis-wired or defective outlets. It's not a big problem but many people remove the "death cap" as it is known.

I'm relieved to hear that.  Since I don't gig out with this amp, just entertain myself in my own basement with it, I shouldn't have a problem.

thanks,
Michael