Recapping A Sorado Head

[Zulubilly]

I used my newly acquired Sorado head the first time this weekend and it sounded really nice.  I was using a Fender P-bass and was pushing a Sunn 215 cabinet wth Magna 158 speakers.  The cabinet is a Sorado cabinet that I took the Sunn Guitar Transducers out of and replaced with the Magnas.  When I needed to push it a little it was starting to distort a little.  The volume was at 6.  When I turned it back to 5 most of the distortion was gone but I needed a little more headroom. 

The next night I used a new Acoustic B200H head (200 watts) with the same cabinet and had no problem distorting.  We were playing at a pretty loud volume and I was way on top.  I had the volume on about 3 and the cabinet sounded wonderful, plenty of headroom.

My question is do you think a recap would give me the extra 20% or more headroom, before distorting, that I need.  I know I am going to retube it also and I know that will help.  The head was made in 1969 and as far as I know has never been touched electronically.  Can someone give me a parts list of what I need to recap the head.

By the way it was great to hear that wonderful Sunn sound again.  I sold my Sunn gear in 1987 and I regret doing so to this day.

Thanks,
Zulu

[Soundmasterg]

Every electrolytic cap in the amp should be replaced. The would include power supply caps and cathode caps. You can measure the resistors and replace any that are drifted beyond the tolerance of the resistor value. Usually they are 5% to 20% tolerance depending on the resistor type. Carbon film and carbon comp were used in the Sunns for the most part, though some wirewounds were used for screen resistors. You can replace coupling caps if you like....pretty much any new production is better quality than what is in there, but thats up to you....it will work fine without doing so. Same for the resistors.

With today's voltages, the can cap isn't a great idea since it is often over-voltaged. If you do some searching, you can find some old threads regarding recommendations for what to do.

The Sunns tend to break up around 6 or so. You'll never get a 60 or 120 watt Sunn to have as much headroom as a 200 watt amp. You can mod the amp and increase preamp and phase inverter voltages and get a little more headroom, but its kind of fighting a losing battle. Replacing the caps will help, but only to a point.

Greg