SWR California Blonde acting odd...

[southpaw pete]

I recently bought a used SWR California Blonde amp. It isn't the II model, pre-Fender I think, made in Mexico, with the Celestion Speaker and Super-Tweeter. I think the manufacture date is 2003. The guy I bought it from used it performing back in the day, but it sounds like it has been sitting unused for a number of years. Anyhow, it sounds amazing... most of the time... and here is where I could use some help...

It will be sounding crisp and clear and full and punchy, and then on occasion, after playing for maybe 30 minutes or so, the sound will kind of deteriorate - dropping a little in volume, getting a little fizzy and distorted, on all inputs. That also happens to the sound coming through the DI out, as well as the headphones out - but interestingly enough, the sound in the headphones cleans up when I turn the "Speaker" switch on the back of the amp off.

I am not overloading/clipping the input at all. In fact I've only been using it at home right now, so I've been keeping the volume quite low on it. I've wondered if it could be something over-heating, except it isn't always after 30 minutes, there has been a time or two when I just turn it on and it is fizzy and weird from the start. Oh, and when I turn it off, sometimes just for a minute or so, and back on, it can come back to it's normal punchy sound. Sometimes it takes a few tries, or a little longer. But it always comes back eventually.

The pots are all clean - well, the effects blend knobs were a little scratchy, but I cleaned them up. And I pulled the chassis out to see if there were any obvious signs of something going wrong. The capacitors all look healthy - at least not bulging or leaking, but I don't have the gear on hand to check beyond visually.

I will probably be bringing it in to a tech to have it checked out, but I thought I would post about it here and see if you fine folk have any insights for me.

Thanks!!!

[lschwart]

What happens when you turn down the "Tweeter Attenuator Control?" The fact that the headphone out isn't affected suggests that something is going wrong with the speaker or the power amp itself. If the problem decreases when you turn down the tweeter that at least might suggest that the tweeter is the problem.

If there's a way to do it, you might also try unhooking the internal speaker and hooking up a passive extension speaker to see if that's affected in the same way as the internal speaker. If it's not, you'll know it's one or both of your speakers that need attention.

Louis

[southpaw pete]

Originally Posted by lschwart

What happens when you turn down the "Tweeter Attenuator Control?" The fact that the headphone out isn't affected suggests that something is going wrong with the speaker or the power amp itself. If the problem decreases when you turn down the tweeter that at least might suggest that the tweeter is the problem.

If there's a way to do it, you might also try unhooking the internal speaker and hooking up a passive extension speaker to see if that's affected in the same way as the internal speaker. If it's not, you'll know it's one or both of your speakers that need attention.

Louis

Thanks, Louis!
Well, the Tweeter Attenuator control works as it should. I can't recall if I tried turning the tweeter all the way off while it was acting odd or not though. I will try that next time, as well as running an external speaker instead to see if the distortion is there as well. There is a jack on the back where the onboard speaker/tweeter combo connects... I imagine I should be able to just unplug that and plug another passive cabinet into there to see. It also has a second external speaker output for powering a second additional cabinet. I haven't tried that one at all yet, but I will give that a shot while I'm at it. Good ideas.

Regarding the headphone out, the signal does get fizzy and distorted through the headphones when this happens. The odd thing is that when I turn off the switch for the main speaker out, then the headphones' signal cleans up.

Oh yeah, and as I mentioned, when it gets all weird, the signal from the DI out of the back of the chassis is also fizzy and distorted. So it seems that it must be happening before the signal gets to the speaker/tweeter. But I will try the external speaker ideas anyways.

Thanks again!
Pete

[sdelsolray]

Sounds like a power supply problem, but that's just a guess.

[lschwart]

I hope it turns out to be an easy and inexpensive fix!

Louis

[southpaw pete]

Originally Posted by sdelsolray

Sounds like a power supply problem, but that's just a guess.

Hmmm... quite possibly.

Originally Posted by lschwart

I hope it turns out to be an easy and inexpensive fix!

Louis

I hope so too. Thanks!

[southpaw pete]

I had posted elsewhere in response to someone's thread, but thought I would update this thread as well.

I finally brought the amp in to my local tech. He was a bit puzzled by my description of the problem, but apparently once he started checking it out, and noticed how extremely hot (temperature) that it was running, he started looking in to the heat sink and such. I don't know what all he did, but the main thing he mentioned was adjusting the bias. He did a few other little minor things - cleaning the pots, replacing the master volume pot, which was pretty scratchy...

That evening I brought it home and gave it a good long workout. And the whole time the amp was running cool and clean. Sounds great!!!

It has such a unique sound, and the nice thing is, if I want the big punchy sound with the Aural Exciter on, I can run direct into the top channel, and I'm sure it would cut through any mix. But I can also opt to run through my TC Play Acoustic (with the BodyRez technology) into the mic channel for a much more natural sound when preferred. I'm really looking forward to trying it out live, now that I can trust it to not start acting up mid-set.

[ljguitar]

Hi SP

Thanks for the update, and glad it's working again!!

[southpaw pete]

Originally Posted by ljguitar

Hi SP

Thanks for the update, and glad it's working again!!

[southpaw pete]

So, I wanted to post another update, as last night was the Cali's debut performance with me...

My wife and I host a very cool and eclectic open mic called Cafe Absinthe at a local pub about once a month. Normally only about 1/3 of the presenters are musical acts. We often have a wide variety of other presenters, including scientists (who could be talking about geology, the environment, astrophysics, biology...), authors, poets, historians, fashion designers, photographers, inventors, comic or video game enthusiasts... and many of the people come in Steampunk attire (top hats, goggles, bustle skirts...). Think open mic meets Ted Talks meets show and tell. It has to be one of my favourite nights of the month.

Anyways, I set up our normal rig - a couple of mics, Mackie mixer, a pair of Mackie SRM350 speakers... But this time I also brought the California Blonde, set it up kind of centre stage and ran Aux One out from the mixer to one of the inputs. That way I could blend in whichever instrument I wanted into the amp as well as the mains, and it worked really well!

Last night we ended up having a LOT of new bands come out, and the evening was about 80% music, which involved acoustic guitars, flute, an acoustic bass, backing tracks, drum loops, and some intense industrial synth stuff. Being able to run a lot of that through the amp really made a HUGE difference. Most I ran through the mixer/aux setup, but the bass I just ran direct into the other channel of the amp. I really like the Mackie speakers for vocals and acoustic, but when it comes to bass and drum loops, they just don't seem to have enough oomph for what I'm looking for. The Cali really delivered through it all. It looks like we'll be bringing that as a regular part of our setup, especially for this event, in the future.