My first vintage amp

[eschertron]

Respected experts, mavins, friends: lend me your eyeballs

I received a 78 SF champ yesterday off of ebay. It does seem to be authentically vintage, tubes and all. I played it for a few minutes to confirm that it works and calibrate my sense of the amps tone and 'feel'. I'm happy with it.

Now my plan for this amp is to keep it in as pristine condition as possible. To me that means that after I play it some more with replacement tubes (old, but not vintage) and see what it sounds like driving a 2x12 cabinet. I will gut it's vintage mojo - eyelet board, sockets, pots, tubes and speaker - and store the mojo away in a safe place while I build and modify a champ clone. Yes, I'm using the original chassis, cabinet and iron (quickly looking at it I see that even the trannys can be unbolted from the chassis, so I may not be limited to a SE design).

Am I totally looney to use the exoskeleton of this amp to kick around with for the next 2 or 20 years, with the long-term aim of reconstituting the amp to its vintageness later? Feedback, wise observations, and incendiary rebuttal are all welcome.

- Alan

[bob p]

is there a picture here? if so, i can't see it.

[Bruce / Mission Amps]

Respected experts, mavins, friends: lend me your eyeballs

I received a 78 SF champ yesterday off of ebay. It does seem to be authentically vintage, tubes and all. I played it for a few minutes to confirm that it works and calibrate my sense of the amps tone and 'feel'. I'm happy with it.

Now my plan for this amp is to keep it in as pristine condition as possible. To me that means that after I play it some more with replacement tubes (old, but not vintage) and see what it sounds like driving a 2x12 cabinet. I will gut it's vintage mojo - eyelet board, sockets, pots, tubes and speaker - and store the mojo away in a safe place while I build and modify a champ clone. Yes, I'm using the original chassis, cabinet and iron (quickly looking at it I see that even the trannys can be unbolted from the chassis, so I may not be limited to a SE design).

Am I totally looney to use the exoskeleton of this amp to kick around with for the next 2 or 20 years, with the long-term aim of reconstituting the amp to its vintageness later? Feedback, wise observations, and incendiary rebuttal are all welcome.

- Alan

Well... although not a new amp, and with all due respect, now, I would not call a 1978 silverface Champ a collectable vintage amp. 20 years from now? Maybe, but probably not.
1978 SF Champ Vintage Mojo? Not hardly.

So tear into it Dr. Frankenstein... but remember, it is virtually impossible to replace all those items to it's original, untouched condition.... to fool any real collector.

[bob p]

What is Vintage?

Still can't see the picture. don't know if there's supposed to be one or not.

When it comes to "vintage", vintage is in the eye of the beholder. Fender guys used to think that BF amps were vintage and SF amps weren't, all because of the CBS thing. That belief held for a long time, but the dividing line that says BF amps are valuable while SF amps are not doesn't seem to be what it used to be.

"Vintage" is also a term that continues to evolve with time. I'm the kind of guy who doesn't think of anything from the 1970s as vintage, but the older that I get the more wrong that I become on that -- the market is placing "vintage" valuation on more and more recent gear all the time. so old farts like me need to pause and re-think where we're willing to draw the line. if we don't reassess our opinions, the market prices end up proving us wrong.

The market doesn't seem to be putting such low values on SF amps any more. SF amps have skyrocketed in price in recent years. As an example, I bought a totally original/minty SF vibro champ with a bad cathode bypass cap, and a perfectly good SF bassman head for $100 and $250 respectively. It was several years ago, but it does not seem like it was all that long ago. I thought those were OK prices.

My how the market has changed. I just looked on ebay while typing up this post, and it's common to see SFVC in nice shape routinely selling for $400 - $500 on buy-it-now auctions. I know, it's hard to believe. Now a good looking SF Bassman head can sell for $450 - $700 on ebay. What's the world coming to?

In assessing whether or not you'd be doing yourself a disservice by using an old champ as a modding platform, it would help to know how much money you've got tied up in it. If your sunk cost is low then you don't have much to lose. If you sunk cost is high then I'd skip those complicated plans to pull out parts and put them away and shove new parts into the existing cab. The cost of a small Hammond chassis is insignificant and going that route would allow you to have two amps that work at the same time, rather than one amp and a box full of "vintage" parts.

Personally, I'd just leave the old Fender as it is, and do my experimenting on a second chassis. So there you have it. Two entirely different opinions.

[bob p]

Speakers

Forgot to mention this --

One other thing that you might not have had enough time with the amp to figure out yet is that the weakest link in getting good tone out of a champ is the little 8-inch speaker. That 8-inch hole in the baffle is small enough to limit your speaker selection options to a small number of speakers, none of which IMO sound very good. When I got my first Champ I went through a speaker hunt, trying everything, even the Webers that everyone claims to really help the tone of the amp. I was even disappointed with them. The bottom line (for me at least) was that there exists no speaker that will fit into the champ cabinet that I think has good tone. To get good tone out of a champ you really need a larger speaker, and that means external cabinet.

Unfortunately, it's pretty hard to shoehorn a decent speaker into a champ, which is one reason that people prefer the slightly larger amps. Having the option to choose better speakers helps the tone of the amp a LOT, so many people end up using the champ as a head to drive a larger external cabinet.

So after a lot of trial end error, I've just decided that I could never really fall in love with the champ and any speaker that would fit in the cab. That limits it's utility for me. After reading this you might be surprised to hear me say that the SFVC is one of the amps that I use most often. Why? Because it's so small that I can keep it in the living room and tuck it away unobtrusively when I don't need it. It provides enough volume for practicing with clean tone, which does make the littlle guy very handy to have around. It's a good practice amp, even though the tonal palette is limited by the speaker. I think that as a clean tone practice amp the SFVC scores a lot of points.

[Tom Phillips]

...Am I totally looney to use the exoskeleton of this amp to kick around with for the next 2 or 20 years, with the long-term aim of reconstituting the amp to its vintageness later? Feedback, wise observations, and incendiary rebuttal are all welcome...

IMO Yes!
If this is a joke then there is no more to say.
However, if you are just reacting to various internet discussions then my recommendation is to use the amp as is. Make whatever repairs that are necessary and feel free to make reasonable modifications if they increase your enjoyment of the amp. Avoid the trap of changing out perfectly good parts because some internet lore says that changing some component will elevate the amp to tone heaven via some internal mojo juice. As already mentioned, hooking up to a larger speaker cabinet is a fun experience with a champ.
Cheers,
Tom

[The Dude]

I'll +1 with the others here.

My view is that it would be a waste of time to "gut" the chassis when you could just construct or buy a chassis for a build. The other reason to just start fresh is that you could buy or build a new chassis and cabinet that would be large enough for a 12" speaker.
(A little off subject but) I'm not one for messing too much with amps. Slight mods maybe, but I've had guys come into the shop and say things like "Can you mod my black faced Fender to sound more like a Marshall?". There's somebody out there who wants that amp as is. If you don't like it, sell it and go buy the amp you want.
Again, I know the subject of this thread is not so much about mods, but the point is this. If you really are intent on owning/preserving a "vintage" amp, then I'd start by not messing with it other than to repair any defects.

[eschertron]

Well said!

Bob P said:
"Vintage" is also a term that continues to evolve with time.

The Dude said:
Again, I know the subject of this thread is not so much about mods, but the point is this. If you really are intent on owning/preserving a "vintage" amp, then I'd start by not messing with it other than to repair any defects.

Bruce said:
So tear into it Dr. Frankenstein... but remember, it is virtually impossible to replace all those items to it's original, untouched condition.... to fool any real collector.

---------------------

I confess I really don't know what constitutes 'vintage', and my allusion to it was perhaps somewhat tongue in cheek, since my amp is - after all - just a champ. I certainly harbor no intent to fool any collectors, since I am not one, and cannot attest to the actual 'originality' of the unit. The grillcloth may have been replaced (it's quite clean), and one of the tubes is not Fender branded. Also the date stamp on the speaker indicates 1978, but the sticker inside the chassis correlates with what I've been able to determine is 1976. Is it likely that early in its life the amp got a new speaker? And more to the point, since I don't know what constitutes vintage, does a replacement speaker (albeit a Fender-authorized Oxford R8EV) kill the vintage-ness? Also, from what I've heard, ANY replacement, even a much-needed cap job, reduces the collector's value of the amp. Does playability count for something to the collector?

Tom said:
Make whatever repairs that are necessary and feel free to make reasonable modifications if they increase your enjoyment of the amp.

Bob P said:
Unfortunately, it's pretty hard to shoehorn a decent speaker into a champ.

------------------------------------

One of the things that drew me to the amp is the 'small, light, combo' aspect of it. My regular church gig is done with a 50+ lbm Vox digital modeler, which except for occasional forays outside, stays put. I've also got a Champion 600 (reissue... I didn't know until yesterday that there was an early Fender 'champion' amp) that I've modded a little, and play mostly through an open-back 2x12 cab. Yes, the SF champ also sounds good through the bigger speakers! I'd like to put a sturdier speaker in the cab. Other than a few models by Weber, I see only an Eminence 820H as a possible swap. I'm looking for something that won't break up (or burn up?!) even when pushed to the limits with massively clipped signal. I have my doubts that the Oxford was engineered within that operating envelope.

So I bought it to use it, knowing that there are 'weak links' that need to be addressed as mentioned in the above posts. I will say that one of the rubriks I used when making the purchase was to add up what I see as the cost of cabinet (my woodworking skills are for snot), chassis and trannys; and to balance that against ready-made. Sure, I'm forced into the engineered constraints of the champ speaker size, power, etc. but I take that as a set of specs to work with, and not ignore.

I value all the opinions expressed and, as a newbie lurking on these boards, have developed a recognition and appreciation of each of you. Thanks for your time!

[eschertron]

The FrankenAmp is Alive and living in...

18 months and several incarnations later...

I have listened well to the prevailing wisdom and have refrained from trying to make a Fender (champ) into something it's not. That said, this amp seemed very dark to me. I couldn't turn the bass up up beyond about three, and the treble was always above seven. So I knew I wanted to do something with the tone controls (replace? repair?). Also I never had the volume knob anywhere but 'twelve' (or is it 10 on this amp?). So that had to go.

I replaced the tone control with a slightly less lossy tilt circuit, and gave it a variable NFB for a different kind of volume control. Lastly, I have added a switchable cathode bias on the second stage to go from a very cold bias (think woody, or almost acoustic tones) to a very hot bias. Schematic and sound samples attached.

...Oh, and I cheated on the recordings: amp is hooked up to an open-back 2x12 cab.


Schematic:
SF_Champ.pdf

The bias switch selects 'bark' (a woody sound, geddit?) or 'bite' (for some snarl)
PRS SE singlecut with dual humbuckers
LP BARK.mp3
LP BITE.mp3

Fender Highway One strat (in desperate need of more renovation!)
Strat BARK.mp3
Strat BITE.mp3

[The Dude]

Nice work and great sounding clips!