synthecks wrote:Hello, first time poster here. I'm looking for some help with making my fender PA135 amp more like a guitar amp.
I would like to get this amp to sound like a old Sunn model T.
I see some similarities when comparing the schematics but dont know what changes (new power tranny, rectifier ect) would bring me closer to what I want this amp to sound like.
The fender seems to be a good amp. Though they seem very similar, to get the SUNN sound you migh have to do several things: install 6550 tubes, replace power transformer, replace output transformer, rewire for 12AX7s. Basically replace the guts with SUNN guts. But that would destroy close to a $750 amp.
To replace the silicon diodes with tube rectification, would take 2 GZ34s, because 1 can't handle the current. Maybe cheaper to get 2 X 5U4GB, plus you'll need a 5 volt 4-6 amp transformer. 4 X 6550s will use up to 280ma. They should idle at 200ma at 500 volts.
You might be able to clone one. Look around the internet. I've found a post that said the early gen one might have been built with dynaco parts and you can use a A431 output transformer for up to 120 watts. With the 2 X 6550s, the secondarys will change to 8ohms, 4ohms, and 2ohms.
http://sunn.ampage.org/sdp/index.php?ac ... pic=3796.0
http://store.triodestore.com/a4dyoutr43oh.html
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