Mid 70's Fender Champ

[MichYank]

In the mid 70's I picked up a Fender Champ amp.  I haven't played that rascal in decades because with the volume at 2 or 3 it breaks up quickly.  I'm almost exclusively playing jazz now and need a cleaner tone.  Can anything be done to tame this beast to get cleaner tone with more volume?  It has never been altered or messed with, perhaps I should sell it as museum piece.

Thanks for your thoughts.

 

[y2kc]

Sir,

I am a fan of this amp. Your amp is in need of some basic servicing. With the correct care and an upgraded speaker these little amps can shine for anything. 

Find someone born before 1955 to fix your amp, ask questions and expect to pay some money. Well worth it.

y2kc

 

[Gitfiddler]

It might be time for a checkup of your 40+ year old Champ by your local amp tech.  A tube update could be the main culprit.  Since Champs only have three tubes (6V6, 12AX7 and 5Y3 rectifier), consider getting the best quality or nos you can afford.  Also, check to see if your second input channel give you a tiny bit more headroom.  Finally, it might be a worn out speaker.  You didn't mention what's in your amp, but if its the original Fender branded speaker, it could be the weak link.  There are a number of modern speakers that could give more headroom. 

I'm not amp savvy enough to give you technical help, but that's where I'd start if it were my amp.  I have a 70's Silverface Vibro Champ and took the steps I recommended to you and the results were very positive.   

 

[FredZepp]

Here's a Vibro Champ.   I've got one of these, was my first amp. 

 

[MichYank]

Thank you all for your thoughts.  There's a great local amp guy, Fat Willie, but he's always in great demand and tough to get things back timely.  But, will get up to see him soon.

And, yes - it's the original speaker!  So I'll look into replacing that.

Thanks again.

Yank

[rockabilly69]

I love champs, on this recording (and on my cover of rocket man below), my '69 vibrochamp is used for the clean tremolo musicmaster part, and the dirty Oahu lap steel

 

 

 

 

 

 

 

[rockabilly69]

nice little history... 

 

[tbonesullivan]

14 hours ago, MichYank said:

Thank you all for your thoughts.  There's a great local amp guy, Fat Willie, but he's always in great demand and tough to get things back timely.  But, will get up to see him soon.

And, yes - it's the original speaker!  So I'll look into replacing that.

Thanks again.

Yank

Definitely talk to the guy when/if you bring it in. Most local guys really like talking about people who really care about their gear, and it can help you get bumped up in line a bit.

If you look for new speakers, Jensen makes some nice ones, and so does Ted Weber. Nice Vintage sound/ feel but more modern construction.

Those amps should definitely have more clean headroom than that.

[rockabilly69]

1 hour ago, tbonesullivan said:

If you look for new speakers, Jensen makes some nice ones, and so does Ted Weber. Nice Vintage sound/ feel but more modern construction.

Both good choices, and recently I put a Jupiter in my Vibro Champ, which sounds great, but took a few days to break in (I just played guitar clips of my own music through it all day).

Here's the one I put in mine...

https://jupitercondenser.com/product/8sc-8-25w-vintage-american-ceramic-guitar-speaker

 

[tbonesullivan]

I really wish I had an iso cab and a small amp I would use to play through recorded guitar music for a week or so. Some speakers take so long to break in. That's one of the reasons I like used combos/cabs: already broken in! Usually anyway.

[zguitar71]

I have a ‘76 Champ that started as a stock unit. Over the years I have modified it to suit my needs. The most important mod for volume is a new speaker and cab I have used everything from 2x10s to 4x10s to 1,2, or 4x 12s and a fifteen. They all have their good and bad sides. The more speakers to push air the more preceived volume there is and that means more headroom. The obvious problem is size with a 4x12 so that didn’t really ever get off the ground for me. In the end I settled on a 1x12 design using a Scumback M75. I like this speaker because it takes some of the icepick. 

The next thing is making sure the tubes are up to par and the caps and resistors that control the voltage for the tubes are as well. If they have drifted enough you can start to get unwanted distortion. This should be done regardless of what you want to do with the speaker for the amps health. It is important that the cathode cap on the first side of the preamp is no more than a 4uf but I would stay with the stock 2uf. The bigger the value the more low end will be let in and that will give a muddy distorted mess in this little amp. The second half of the tube can have the stock 25uf since the low end has already been filtered out.  

Next if you want to go deeper you can start to modify the amp internals. I went all the way with this and love the results. I use my amp for dinner gigs and raunchy heavy blues gigs. I changed the OT to a Classic Tone 15 watt version. It is about 2x the size of the original and helps with the headroom. I added another 6v6 to the power section for more headroom. Then I got into the tone stack. I changed it to a Marshall tonestack and this helped with the icepicky highs BUT I used a 250k mid. This allows me to get early breakup at very low volume for Kenny Burrell tone and it is killer. I can also turn the mid down and crank the volume for loud blues tone or crank both for old school tweed insanity. The 250k basically allows so much signal through it nearly bypasses the tonestack like a tweed.  With the mid cranked it requires too much amperage from the IT. I changed this too. I needed about 150 milliamperes to run the system, the stick has 75 I think. Next I added a 100k pot for the negative feed back. In reality I only need a 25k pot here but I can go from stack nfb to almost none. 

In the end it can hardly be called a champ anymore but it is the most versital amp I have every had and it lead to the decision to sell my Carr Slant 6V.  

In the end you could probably just check the health of the amps and run an efficient speaker and be amazed at the volume change.  

[zguitar71]

Also, the Classic Tone OT allows for 4,8, and 16 ohm speakers. This means you have tons of speaker options!

[Gitfiddler]

@zguitar71:  Your mods appear to have changed your original Champ almost to a Rivera era Champ II circuit. 

@Another cool Champ-esque amp with 6V6 power is the Fender Musicmaster bass amp.  It has a taller cabinet and a single 12" speaker.  Same width as a Champ.  I put a Cannabis Rex in mine and use a Boss EQ pedal to expand the frequency range.  This makes a cheap amp sound like a HUGE Champ on steroids, all in an easy to carry package.

[zguitar71]

20 minutes ago, Gitfiddler said:

@zguitar71:  Your mods appear to have changed your original Champ almost to a Rivera era Champ II circuit. 

@Another cool Champ-esque amp with 6V6 power is the Fender Musicmaster bass amp.  It has a taller cabinet and a single 12" speaker.  Same width as a Champ.  I put a Cannabis Rex in mine and use a Boss EQ pedal to expand the frequency range.  This makes a cheap amp sound like a HUGE Champ on steroids, all in an easy to carry package.

Oh man, I have not seen one of these before, I gotta check that out!

[MichYank]

Well, I picked up the little feller this week and it sounds wonderful!  I have a new 40 year amp!  I had a JBL speaker put in and the problem was an output tube cathode bias cap short, and needed a new tube. I wonder if that had always been the problem because it never sounded like this before.  Looking forward to putting some more hours on the beast!