semi-urgent: Did I just kill my amp? BACK IN ACTION

[øøøøøøø]

did they say what was the culprit? 

[Regan]

Got the call back this morning. My amp has been happily repaired, and suffered no major damage. ::phew::
At this point I am beyond stoked, and plan to go pick it up and play it loudly and happily for a few hours. 

Yea!!!!!

[stevejamsecono]

bah...

so I got it home, plugged it all in.... and it sounds the same from when I last left it off.
$100 repair that was basically replacing caps and solder points or something of that nature... but it still sounds like crap.
At this point I'm thinking one of two things:
1. Perhaps one of the power tubes went and they just didn't think to check it.
2. My speakers are fucked, and that was the problem the whole time.

in either case, I'm pretty put out right now, and moreso annoyed because I won't be able to drop it off again until monday.. bah... also bah because I can't really afford to pay for another round of repairs on this thing if there's more to this. As much as I do love the thing, I'm strongly considering ejecting it and trying to cut my losses right now

meh

-Steve

[Regan]

Steve, if the place that did the repair checked it out and it was ok then it must be another problem. Or, if it they haven't repaired it properly I would take it back. Surely they would stand behind their work.

I didn't go back and re-read this thread, but like you say maybe it's a problem with the speakers. Have you checked cables, etc? It could be something simple. Irewired the '65 Jag I just refinished and everything was working great except for the rhythm circuit. COme to find out the lugs of the roller pots had gotten bent and were making contact with the housing. Maybe yours is a simple problem. I hope so.....I hate those repair costs too.

Good luck. Keep us posted.

Regan

[øøøøøøø]

Yes.  Try different guitars and different cables, and different power outlets.  If you have a digital multimeter, stick it in the wall and make sure you are getting the correct voltage (120 in the US, 220 or 240 in Europe). 

I've had amps sound like doo before only to find out the wall was only outputting ~90vac.

If the place did not even test the amp before they sent it out the door I would be leery of doing business with them. 

Whatever you do, I would advise that it's not smart to sell an amp in poorly working condition.  You will take a major hit money wise especially if it's not a prized collectable.  A '59 bassman that needs a cap job is one thing, but a silverface amp with an unknown problem is not worth much.

If it's working at the shop then that's good news and you can go from there.  Otherwise you can gripe at them for sending you out the door with a non-working amp without testing it.  Maybe they'd re-diagnose for free and only charge parts.  That would be the stand-up thing to do. 

[OffYourFace]

try your amp thru another cab in their shop?

[stevejamsecono]

Nope, she is fixed. Took her in today, explained the problem, and apparently I was just plugging it into the wrong input.

See, (and I did not know this) thing has two inputs. Speaker, and Ext. Speaker. I had been plugging it into the latter when I took it home, hence the no or minimal sound. The guy at the shop showed me this with zero condescension. So we're back up and running, happily

and in other related news, the HM-2 I picked up from there might be one of my new favorite distortion pedals. What a great sound, nice mix with my blues driver too

I'll post setup photos later, for all of you who want to see.

Thanks again everyone for your support, I learned a few important lessons here:
1. Never turn on your amp without plugging in your speaker
2. Make sure you are plugging it into the correct output
3. Offsetguitars.com folks are sympathetic nice blokes.

Cheers all

-Steve

[ohm-men]

Don't do this to often, using the ext. speaker output. I've heard it's bad for your OT.
On the other hand, the 100 Buck on repairs are well spend. New caps are a GOOD thing on old(er) tube amps. Especially the large electrolyte caps.

[øøøøøøø]

Don't do this to often, using the ext. speaker output. I've heard it's bad for your OT.
On the other hand, the 100 Buck on repairs are well spend. New caps are a GOOD thing on old(er) tube amps. Especially the large electrolyte caps.

If using the ext. speaker jack was bad for the amp, it wouldn't be on there.  In reality, it's fine as long as you use it properly.  Especially on a head, there is a way to use it in conjunction with the main output that is absolutely no different than using one speaker. 

That amp wants to see a total 4 ohm load.  The jacks are in parallel.  If you hook up 2 8 ohm cabinets, one to each jack, then you have a total of 4 ohms... an ideal load. If you use a 4 ohm cabinet and put an 8 ohm cabinet in the extension speaker jack, you will have a total load of 2.67 ohms. 

This load is actually fine, as Fender designed their output transformers to handle up to a 100% mismatch in either direction.  2.67 is above the minimum limit, which would be 2 ohms.  In the above case, however, the amount of power going to the two cabinets would be uneven. 

Incidentally, the formula for determining impedance in parallel is (R1 x R2)/(R1 + R2).  Series impedance is additive.  Most ext. speaker jacks are in parallel.

It is indeed placing a slight bit more strain on the OT to run it into a slightly mismatched load, but it is well within spec, and if Fender's design was correct, it shouldn't hurt anything.

I do agree that new electrolytic caps are good.  There is little reason to replace any other capacitor if it is working and if you like the way the amp sounds.  But the electrolytics definitely need replacing when they get older to avoid risk of damaging the amplifier from a ruptured cap.

On another note, if you ever develop a curiosity about amps and such I encourage you to follow that curiosity.  I have saved thousands of dollars by working on my own amps and avoiding the type of "operator error" described in this thread. I would guess your amp was probably fine all along, and you could've done the cap job yourself for about $20 in parts.  It's easy as long as you take the proper safety precautions.

[stevejamsecono]

I totally agree, and this has encouraged me to start looking into my new amp a bit more closely. (also helps that my upstairs neighbor/best friend has a degree in electronics engineering, so he can explain some of this stuff to me.)

Point being, is that lesson has been learned here, and I managed to get my amp back without having to pay too much, so I'm happy.

[øøøøøøø]

that's a happy ending for sure.

Enjoy your amp!

[Regan]

Glad all is well!