Does this Vibro Champ sound ok to you?

When I was a kid, I had a Fender Vibro Champ, and always regretted selling it. So I just picked up a mid-70's Vibro Champ off Ebay to right that wrong. Stock speaker, and I think original tubes too.

The link is me playing my early-80's American Tele through the amp, volume at about 6. It seems to me that the sound breaks up awful early, I can even get some at about 4. I have to keep it below 4 for a clean tone. It also seems a little flappy when I hit a chord.

Any opinions on whether the speaker sounds shot? And/or would I benefit from replacing the tubes? The vibrato intensity also seems rather weak to me, even when it's maxed -- would that be impacted by a new tube?

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That doesn't sound right. My mid 70s vibro champ stays clean pretty far up the dial, certainly still clean at 6 with a Telecaster. I would start with new tubes and go from there.

Pat

I have had about 5 champs and vibro champs the last couple of years. It too was my first amp way back when. They all were a little different as far as gain goes. In fact, the last one I just traded away was the cleanest sounding of the 5 so I kept it, but it also started breaking up pretty good around 5.

I ended up replacing the cathode cap from 470 ohms to about 620 or 820 on each one to cool the bias down a bit. Recap it. Replace the filter can cap (get a CE from tube depot its a bit shorter than the stock one), and try paralleling the first cap with the unused one on the can. That may help tighten up the bass. Also, what speaker is in there? Fender seemed to use anything they could get their hands on back then.

BTW Nice smack, slappy riff you got goin there. I like. Come to my house next time your in Atlanta and we'll sit on my back porch, drink a few, eat some wings, and jam that stuff all day long.

That doesn't sound right. My mid 70s vibro champ stays clean pretty far up the dial, certainly still clean at 6 with a Telecaster. I would start with new tubes and go from there.

Pat

Still clean at 6 with stock speaker ? Maybe we don't have same definition of CLEAN.
A question for you Suproman : what are the PU on your avatar tele ? Thx.

The pickups are custom made Vintage Vibe pickups, mini-humbucker size single coil pickups with blade polepiece.

Pat

It doesn't sound like normal gain break up. My thoughts are that it could be the speaker!!

Doesnt sound right....

I'd be wanting to put a different speaker in to see why it's distorting. That sounds like a blown speaker to me.

Fresh electrolytics are needed. BEware pumping up the first stage of capacitance. That 5Y3 has a limit of 30mfds. Unti the caps are fresh, I don't expectmuch form an amp like this. Then, I start assessing tubes and such.
I also do not suport changing the bias resistor. I have gone through the exercise. Anything over mabye 550ohms or so yields a sterile amp. LEo adn WEstern Electric understood the tube and the circuit.
The best way to get cleans out of a properly functioning Champ/Vibrochamp is to control pick attack and guitar volume contorl. If you don't have a treble bypass cap circuit on that guitar's volume pot, you are missing a great opportunity. THese amps will teach a player better than any amp I know of what it means to control the input signal. I had a Champ that was dissipating over 20watts with the stock 470 ohm bias resistor...and it sounded glorious. I went all the way in steps to 820 ohms o n that bias resistor...at which point it was disspating 14.7watts...and sounded like a little bitty sterile solid state amp that I could buy for $30 at a pawn shop. AT that hot bias point with the 470ohm resistor, I could put the amp on 10 and get cleans....simply by controlling my pick attack and/or the guitar's volume.
Get the amp healthy...it is tech time....and then let it teach you how to control input signal......

FWIW, you can 'bias' these amps by ordering a 'cold' 6V6 from distributors who grade tubes. .....order four or five of them with varying specs so that you can understand how this aspect of biasing works, maybe....you can always use spare 6V6's.

does not sound right to me either

I have had over 12 of these guys, they mostly could stay clean up to about 5 on the dial but they sounded better than this. Tell/show us your speaker. If its an Oxford, I would put in a better speaker. Jensen or Weber. Swapp the 12ax7 tubes around and see if your tremelo sounds better. Maybe time for a resistor check and a few new caps..
If you can test the tubes either on a tester or in another amp, that would tell you more.
Rob

I agree with Wally a lot of times when these old amps start breaking up folks look at the speaker or tubes and in reality it is the Electrolytic Caps that need replacing. I had gotten a Silvertone 1472 at a music shop cheap (well I traded some stuff for it) and I made a good trade because it sounded so terrible. Caps were the culprit. I learned a good lesson on that amp to suspect caps on any old amp first. If a person plans on keeping the amp it needs a cap job anyway so might as well start with that first.

Sounds like the caps.

I have a 68 SFVC, which looks just like the photo on your video. Your amp is a little sick and needs repair. Mine does not sound like that. Here is a clip of my '68 with a Weber 8A125-0 speaker. Mine starst to break up with a little hair around 5-6 on the dial. Both guitar tracks through my SFVC, no effects, just louder volume for more dirt.

http://www.soundclick.com/player/single_player.cfm?songid=11157515&q=hi&newref=1

no way, time for a trip to the tech. congrats tho, will be fine with some work.

Sounding good Keithb7

Guys,

Finally was able to spend a little more time with this amp. I'm wondering if my problem could be due to the tubes? For one, the tubes seem to be a little loose in their sockets, especially the 2nd from the left. Is that normal? I pulled them out and reseated them, and it seems to me some, maybe all, of the 'flappineness' I'd been hearing was no longer there. Does that make sense?

I also snapped a picture of the amp with the volume turned up to 10, just wondering if someone with more experience is able to say whether a tube looks healthy or not by the glow.

http://www.joegrooves.com/images/ebay/tubes.jpg

I take back what I said about pumping up the first stage filter cap (thanks to wally for the heads up). I was thinking princeton when I was typing. The more I listen, the more I'm thinking speaker, but a general servicing is in order here. Replace all the electrolytics. Ohm all the resistors. You can do this in circuit and it will take you all of about 10 minutes. I do this with every amp I have serviced. Those carbon comps tend to drift up in value. If the board is warped, poke around on the components in that area. I had an amp that had a distorted sound when cranked because a cap had a broken lead making intermittant contact right where it was warped.

All I can see glowing in your tubes is the heaters. That's a good thing. But looking at tubes doesn't mean much unless the plates are red then you have a problem.
The guys are right about getting it serviced. And part of that is tighting and cleaning the tube sockets.
Also with the drip edge and that Fender logo I think the amp is more late 60s than mid 70s. I have one of these I just haven't bothered to see what year it is.

That doesn't sound right. My mid 70s vibro champ stays clean pretty far up the dial, certainly still clean at 6 with a Telecaster. I would start with new tubes and go from there.

Pat +1 My Strat and Tele are still clean at 6 w/ my '78 VC (stock Oxford).

That is a 1968 or 1969 amp since it has the drip edge on it.

If you can connect another speaker, try that first. My first thought was the speaker is bottoming/flubbing out.

If it sounds similar, I would take the advise above and get the electronics checked out. It actually doesn't sound all that bad, just not like either of my champs.

That is a 1968 or 1969 amp since it has the drip edge on it.

That amp photo shown in the sound clip is not his amp, I don't think. The one shown is indeed a 68, not a 69. That image was taken from the Ampwares web site and used here in the video. The owner stated his amp was a mid 70's. The 69 did not have the black thin lines, blocking in sections of the face plate. Cheers...

Yes it is an early '68. They only produced the Drip Edge with black lines for a very short period. That thing sounds way off. I would first switch the tubes out, but if it hasn't been serviced in decades I would have a tech look at it just in case the caps are going bad. Here is my '68....

http://img97.imageshack.us/img97/5984/cimg0628r.jpg
By dada1952 (http://profile.imageshack.us/user/dada1952) at 2011-08-10

No sound clips but my 78 VC, with a weber classic alnico speaker, only starts to break up around 9....

I got lucky though. Mine was freshly serviced right before i purchased it.

get the amp to a tech, it is time.

nice playing, though. Get that amp healthy and do us another clip, please.

It definitely doesn't sound right. Could be speaker, could be tubes, could be caps, could be a lot of different things, but without investigating further, you can't find the problem. Also keep in mind what knowledge you already have about tube amps to see what you could actually do, and what you need a tech for.

First thing to do would be to hook it up to a different speaker (you can get away with hooking it up to a mismatched impedance). Second would be tp drain the filter caps, and then clean out all of the tube sockets and pots. Third would be to swap out the 2 preamp tubes (V1 would be more likely causing the distortion). Fourth would be checking the bias and the power tube.

If none of those change the distorting sound in that video, then you would want to go through and check the measurements of the different caps (starting with the filter caps and bias cap), as well as the resistors and replacing if necessary.

Do what you feel comfortable doing on your own, and if you don't have the proper tools or knowledge, its better to take it to a tech before you break something or electrocute yourself.

No sound clips but my 78 VC, with a weber classic alnico speaker, only starts to break up around 9....

I got lucky though. Mine was freshly serviced right before i purchased it.

What ppickup do you use ?

Ok, I'm going to get the amp to a tech. My lack of knowledge of electricity is rivaled only by my incompetence with a soldering iron.

Ok, I'm going to get the amp to a tech. My lack of knowledge of electricity is rivaled only by my incompetence with a soldering iron.

Good choice, it should'nt cost that much and you will have an excellent sounding amp afterwards

Ok, I'm going to get the amp to a tech. My lack of knowledge of electricity is rivaled only by my incompetence with a soldering iron.

Hey, no worries man. I'm right there with you. I've never really done any soldering and can't read a schematic, haha. But it's great if you can start learning basic maintenance and troubleshooting.

If I were you, go get a pair of alligator clips with rubber sleeves (so you don't touch the metal), some non-flammable control/contact cleaner/lubricant from Radioshack (64-4315 is the product number I believe), drain the filter caps and then clean out the tube sockets, jacks and pots.

Sometimes the problem is just some dirt in the tube sockets, but its a good thing to clean your amp regularly (its like changing oil in a car).

Let me know if you need instructions for draining the caps and cleaning the parts.

What ppickup do you use ?

Single coils into input 1 and humbuckers into input 2.

ex - MW Tele and a jazzmaster with WRHB's

I mentioned before about the speaker being blown and I still think that's the problem. Really, I'd try a different speaker before going through the caps, sockets and pots.

Hello, I just signed on to the Tele forum as yesterday my 76’ Vibro champ just started distorting at low volumes in a very unmusical and unhappy way. When warmed up the amp still sounds strong, but breaks up easily if the string attack is pushed even a little bit at near minimum volumes (3-5). It has previously not broken up much at all until at least “5-6”. It’s sounded great for several years up until yesterday, and now I’m a bit concerned. Pretty sure it’s not the speaker or the tubes as I have tried swapping all.

Saw these posts (couldn't watch the clip as it's labeled "private") but think I have a similar sounding problem as the original post and I was hoping to get instructions for draining the caps and cleaning the parts? Hoping I can solder and use a meter well to try to do the work myself if I have clear instructions and references.

Hoping it’s not the transformers as I have been running it through a 12” Jensen P12q rated at 8 ohms?

Very much obliged for any responses.

You need a multi-meter, some wire, a 100K ohm 1/2 W resistor and 2 alligator clips to safely drain the caps. Take 1 wire but it in half, and solder a 100K ohm resistor in the middle of the two wires, rejoining them. Connect alligator clips, one on each end now of the wire. You now have a safe way to clip one end on the chassis, the other on the end of the caps to drain them to ground. The resistor suppresses any arcing. Check that the caps are each drained with your digital multi meter. Triple check your voltages in DC current before you touch anything. You could very well shock yourself real bad, possible death. So if you are not sure and defy safety, don't go ahead with this.

Cleaning which parts? The caps are to be drained for removal and new replacements are usually installed.