i bought this cuz it said SUNN

[Sledgeguitar]

i want to know more about this amp.
Sunn Sonaro
400 watt?
2 sovtek(russian made) 8550 reflector tubes and another small tube that i cannot read what it says.
4x12 Sunn cabinet.

is it really 400watt?
are those original tubes or newer ones?
when should i get new tubes and what kind?
how old is this amp?
Is the sonaro the same as the 190b?
what is the high and low switches on the amp for?
what the polarize switch for?
does it make a difference which input i plug my guitar into(1 or 2)?

that outta cover it.

[djc]

400 watts is the power consumption.  it will produce between 40 and 60-ish.  don't let that fool you, 60 watts is plenty loud.  Sonaro's I've seen are the same as a 200s, which looks to be the same as a 190B.  the small tubes will be a pre-amp 12AX7 or like and a phase inverter which I can't remember what it is.  a wierd one though, harder to find but not impossible.  there should be another larger tube a GZ34 or 5AR4 or like, or a plug kind of thingy(it's your rectifier).  it's late 60's early 70's.  hi and low are cut (or boost) switches, more accurately cut.  tubes could be original.  the ones I've seen take 6550's(probably your 8550, just read wrong) or KT-88's.  the polarity switch flips the hot and nuetral.  one way you'll get a shock(keep mouth away from microphone), the other it's fine.  unless this has been upgraded to a grounded plug and the switch disconnected.  input 1 or 2 does not matter.  and finally, there are many people with a wealth of info on Sunn amps, maybe they will chime in, add or subtract.

as for your tubes, get thee to a good amp tech.  you may need caps, tubes, various other parts and it will all be worth it.

funny you didn't ask about ohms.  most people ask about ohms...

[mckinnon audio]

  Hi there,I've got an old Sonaro with EL34's (6CA7's),the phase inverter tube is a 7199
  a triode/pentode.On the newer ones it's a 6AN8A,they're not that rare,but they are getting a little harder to find.Even though they're both triode/pentode tubes,they're not interchangeable,you have to rewire the socket,good luck Mel.

[Sledgeguitar]

well...tell me about ohms! haha!
i am picking this up today. i hope it is worth it.

[djc]

I was told the Sonaro I saw was stock (literally sat in a closet for 30+ years).  it had 6550's.  any idea if this had been changed, what was original for a Sonaro head, not the combo's.

as for impedance(ohms) match the cabinet to the jack.  you should have a 4 ohm output and a 8 ohm output.  they should be labelled at the back.  the lowest useable resistance for that head is (about) 4 ohms.  so you can use 1 4 ohm cab or 2 8 ohm cabs.  any mismatch resistance totalling 4 ohms (roughly) will work.  danger with too low a number, higher resistance is running the transformers too hot and burning them out.  make sure a cabinet of matching impedance is connected to the appropriate output before turning the amp on.  the transformer basically searches(for lack of a better term) for a resistance and this causes undue stress as well.

as far as a good buy, you will be happy with the tone this produces

[mckinnon audio]

   Hi there,my Sonaro,(and matching 1 x 15" cab),can't remember,I think it's a 68' or 69',is all orig.The 6550's were prob. a later revision to the amp,mine has a 16 ohm main spkr.and an 8 ohm ext. spkr.I run a single 16 ohm JBL D-140 and it sounds nice,not loud enough by todays standards,but beautiful tone.The output transformer taps are black,brown,green and yellow I believe,you'll find the appropriate colour/impeadance value for them on this site.You can pretty well hook up any 2 you want to the jacks,you just have to know the total imp. of the cabs you plan to use with the head.Hope this is of some help,Mel.

[djc]

thanks Mel

[EdBass]

In 1968 and 1969 Sonaro was an EL34 amp with a 15" Sunn Bass Transducer, in 1969 an "economical" version of the then new (I believe) Sonic I-40, which had 6550's and a D140F. Kind of like the Sorado was the Sunn Bass Transducer version of the D140F 200S. 
I'm not aware that the Sonaro was ever available from the factory with 6550's or the big transformers, but that certainly doesn't mean that it never happened.

[djc]

cool.  I'm gonna check with my buddies sonaro.  interesting if his is special.

[basiklybass]

Change the caps...change the caps...change the caps.

Before you burn out the power Xformer or do some other damage replace the power caps at the very least and all the electolytic caps if you can. A 40 year old amp needs a close look before using it regularly.

[Sledgeguitar]

stupid question?.....what are the caps?
i don't know anything about fixing this stuff. i want to learn but never had anyone to guide me along. anybody know of a good repair man in the pittsburgh area?

[EdBass]

There are a lot of different capacitors (caps), but the most critical ones are the big electrolytics used to filter the power supply. These guys will have all the info and parts you need;
http://store.triodestore.com/

WARNING
Based on the fact that you asked what "caps" were, I strongly suggest that you DO NOT poke around in your amp, particularly around those big filter capacitors. Take it to a pro, those caps can store potentially lethal voltages, even with the amp unplugged.

[Sledgeguitar]

glad you warned me! serves me right for trying to fix my amp while taking a bath...hahaha!

anyway thanks for the help and tips. the first nite i had it it sounded great. now its so dirty with my RAT distortion pedal on i can't distinguish notes. I accidentally left it on standby over nite and i think that may have done something to it. the tubes still glow and the amp wasn't blazing hot in morning so i don't really know.

[Sledgeguitar]

as for the tubes...
like i said i have 2 6550s but i just noticed another plug in for a larger tube. should this this have 3 6550s and maybe i am missing one?
also i popped open the cab to see the goodies and it looks like it has 4x12 original sunn transducer? speakers...at least that what the stickers say on the speakers. no other markings anywhere though. the head does say 60 watt.