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Sonic Frontiers - A Score or a Flushing?

I may have scored or I may have flushed $50….

A couple of weeks ago I picked up a Sonic Frontiers Power 2 tube amp at a garage sale for $50.00. It was openly disclosed to me that it did not work and the seller had no idea as to why. So, my question is are there any preliminary tests with a voltage meter (or other instrument) I can use to narrow the problem down?

My hope is that the tubes are bad; my worry is the transformer is bad. But, I don’t know how to make this determination. While I am a handy guy, I am limited in my knowledge of electrical problems. If it is salvageable, I will certainly find a professional to make repairs, but I would really like to make a preliminary determination as locating and lugging it to a shop to tell me
jb8312
11 responses Add your response
johnsonwu
469 posts
 
I briefly owned a pair of Power 3s 11 years ago and all they did was heat up the room.
Too bad I didnt know any better at the time to run them as dual power 1s (YES you can pull the tubes and run them at half power)
and I didnt dare mod these things.
I am thoroughly enjoying mine that's converted to triode and fitted with 4 Vcaps.
shakeydeal
979 posts
 
>Awful sounding amp in stock form.<

I agree wholeheartedly with the above statement. I've never heard it modified in any way, so can't speak to that.

Shakey
johnsonwu
469 posts
 
Awful sounding amp in stock form.
Beautiful amp if you know how to convert it to triode.
Best of the best workmanship except for a lousy design
which necessitates sacrificial resistors when a tube starts to runaway (READ: aging 6500C tubes)
it will fry 2 resistors at a time leaving the owner scared.
It's an easy fix.
A replacement fuse, and a few resistors (10 Ohms 1Watt and 5.1 Ohms 0.25 Watt) will do the job if its the common problem most users have.
jonparkhurst
10 posts
 
I second the chris johnson idea, he always helps
jb8312 OP
247 posts
 
Thanks for the comments...I will let you all know how it works out...jtb
sibeliusfan
1 posts
 
If you haven't already checked, the first thing to look at is the fuse. I've blown a few fuses in my Power 1.
knghifi
1,668 posts
 

I would just contact Chris Johnson and ship it PCX. Their hourly rate is reasonable and probably take several hours at most to examine the amp.

If repair is inexpensive, check out the SE+ mod. Roll some NOS, GL Reissued KT88 and you got an excellent tube amp.
alpha_gt
155 posts
 
Do your surfing and find a certified service center for the amp, send it to them and get an estimate. If the estimate is high at least you will find out what the problem was and try to fix it yourself, but chances are getting them to fix it will be far cheaper than buying a working model. Be sure to check the fuses and just look for obvious problems, like burnt parts or wires if you haven't already. Plenty of times I have come out the hero for replacing a fuse.
mingles
796 posts
 
Anyone who works on your amp will want the circuit schematic so they can test voltages. You should contact Anthem (new owner of SF) and ask for a copy. It's usually standard practice to release schematics when a product is out of production. Anthem has been good about doing this in the past.

Best of luck in your efforts.
bigkidz
3,381 posts
 
yeah there is a way to see what is going on but you need to call Chris Johnson (partsconnection I think). When I had one and a tube blew he tld me to do something to identify the issue.
wizard454
51 posts
 
Might I suggest:
1) Remove tubes and take them to someone that can test them. If they test fine put them back in for now.
2) If tubes are OK, see if you can find a tech/shop that can do some electrical testing to see if they can identify the problem and if it can be fixed on the cheap.
3) Failing the above solves the problem contact Chris Johnson at www.partsconnexion.com for assitance. Great guy and he'll treat you right.
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