Fender "Champ" amp clone

[BlueAngel]

Thanks for providing the help John....means I don't have to supply all teh answers anymore.

Greg

P.S. If it was up to me, I'd go with a clone unless I was interested in resale value.

So would I, unless you can get the original for close to what a clone goes for - I do honestly think the old ones sound slightly "better" (as in, more characterful and 'vibey' ) than modern clones and I'd have the original in a straight choice. But I wouldn't pay what seems to be the current market rate for one - it's just too big a difference.

I mentioned that I had a '59 5F1 a long time ago - in slightly better cosmetic condition than Sixty-Four's, although a touch less original inside, which I got cheap because it had a fault (about which more later), and a friend of mine who collects vintage Fender gear was always on to me about it. Eventually he offered me so much that I thought that no matter how much I liked it, no 3W amp was worth that! So I sold it to him. But it was a mistake really, because I do miss it and I would not even pay what I sold it for to get it back, let alone what they are now worth a few years later. I may eventually buy or build a clone - but I don't expect it to sound quite as magical as the old one. The same friend has a '61 Tweed Deluxe too, which I have compared to a Clark replica - a beautifully built amp, extremely accurate and better than the original in some ways... but it just sounds 'modern' whereas the old one sounds 'vintage'. It's not purely to do with speaker break-in either - I'm quite certain from my experience that it's the combination of ALL the old aged components in the old amp. The only way to get close to replicating that would be to try to find enough old used parts to build a new amp out of! (I do make a habit of salvaging and collecting old electronic parts, so it's not out of the question...)

What was wrong with my Champ - it was making a nasty farty distortion sound. The previous owner's tech had tried changing the tubes, and the speaker (luckily he kept the original and put it back when it wasn't the problem), and checked every joint and component inside - and couldn't find it. It didn't seem to show up on a scope either. Being an optimist and knowing it was a very simple amp, I reckoned I could cure it so I bought it for a very good price. I found it when driving the amp hard into a dummy load - the output transformer was making a huge racket, almost as loud as a small speaker. The frame had come loose and the core was rattling around inside - all it took was to re-crimp the frame tightly and soak it in varnish (as it was originally) and it was back to perfect .

[jps]

P.S. If it was up to me, I'd go with a clone unless I was interested in resale value.

So would I, unless you can get the original for close to what a clone goes for - I do honestly think the old ones sound slightly "better" (as in, more characterful and 'vibey' ) than modern clones...

I find it difficult to directly compare modern amps to their vintage equivalent as the components in the old ones have drifted, and/or failed in some way, making such comparisons invalid.

[BlueAngel]

I find it difficult to directly compare modern amps to their vintage equivalent as the components in the old ones have drifted, and/or failed in some way, making such comparisons invalid.

No it doesn't, it just means you have to be careful as to which properties of the old and new sound you're comparing. Assuming that none of the components have failed, small amounts of drift are definitely part of the 'sound' of old amps - but still, even if you measure these drifted values and replace them with the same values of modern components, you don't get the same results.

If you listen to many examples of both types you can easily hear a pattern too, regardless of the different amounts of drift in the old amps. Old amps simply sound different from new ones. Both the original construction of the components, and changes due to the way they age, mean that they don't sound the same - it isn't just down to different values.

That's why I try to use old components - both NOS and actually used, but tested of course - where appropriate when restoring vintage amps. That obviously doesn't apply to electrolytic caps and a few other parts (eg rectifier diodes), and there are some places in the circuit where reliability can be improved by using modern parts without affecting the tone, so I don't use old ones there. I don't at all believe in keeping things original for the sake of it, but I think you can get a good balance of both if you know which parts to keep the same and which to change.

[soundmasterg]

I don't at all believe in keeping things original for the sake of it, but I think you can get a good balance of both if you know which parts to keep the same and which to change

I agree and this is what I try to do also. Though I refuse to use old Astron or Bumblebee caps, even when testing good. Every one I've ever seen in an amp leak DC, and a new one on the shelf probably will eventually too. They're paper caps after all. Mallory 150's sounds quite good.

Greg

[jps]

Interesting. I had always assumed things changed enough to invalidate such comparisons, especially with regard to guitar pickups and speakers.

[BlueAngel]

Though I refuse to use old Astron or Bumblebee caps, even when testing good. Every one I've ever seen in an amp leak DC

That would not be a 'test good', to me. Test good means not only must it measure OK, it must perform correctly in circuit. The only way to find that out is to hook it up to the same sort of voltages as it will be used with.

I use the same rules for tubes, which is why I don't bother much with tube-tester results as a guarantee of anything, especially for power tubes - many tubes will pass on a tester, but fail when the much higher voltages and currents in a cranked guitar amp are applied. I test them in the amp they will be going into, under battlefield conditions . (With proper care and monitoring, so if something goes wrong I can shut it off - I have never damaged an amp doing this that wasn't faulty already.) I think the lack of proper testing under real in-use conditions is why so many new-production tubes fail straight out of the box, even from resellers who supposedly test them.

Even though I did study electronics properly, I take a much more empirical approach to repairing guitar amps - basically there are only two important questions: 1 - does it work reliably? 2 - does it sound good? Your ears and a determination to find out why something broke and not to let it happen again are your most important tools .

Interesting. I had always assumed things changed enough to invalidate such comparisons, especially with regard to guitar pickups and speakers.

I agree totally if you mean things like noticing that an old amp with drifted plate resistors seems to have more gain and earlier breakup than a new one - it does, purely because of the higher values. But it isn't just that - there's a difference in the character of the sound too. I think it becomes obvious when you average it over many, many amps - you can tell a pattern, even if individual amps (old ones especially) vary quite a lot. It can't be only to do with speakers and pickups since it applies equally to amp heads played through the same cabinet, and with the same guitar.

Of course, the speakers and the pickups make a bigger difference, but I do think the amp does as well - and it isn't just the transformers, even though they're also important. I have several times come across an old amp that a well-meaning 'by the book' tech has replaced just about every component in bar the transformers, and they don't really sound like old amps any more - they sound more like a new clone.

You may be amused to learn that actually I personally play modern amps! I like the sound of the old ones and I can definitely hear the difference but it doesn't really bother me, and the new ones have cool features that the old ones don't...

[soundmasterg]

That would not be a 'test good', to me. Test good means not only must it measure OK, it must perform correctly in circuit. The only way to find that out is to hook it up to the same sort of voltages as it will be used with

Yah, what I mean by "test good" is a cap that tests out to not leak any DC when in circuit or in simulated circuit with the same voltages. I just won't use Astrons or Bumblebees even when they test good like I mentioned because every one I've ever seen in use inside an amp is leaking DC and one that is NOS and sat on a shelf for who knows how long will eventually leak too. I prefer something that will hold up for more than a year. Now the old Mallory Fender "molded" ones, even though they are paper/polyester, work for a long, long time even when used or NOS, and sound great, so I have put those in when people request them and when I have them.

I play a 1993 Korg/Marshall AC30TBX, and a 1993 Mesa Dual Rectifier. Both circuit board amps and both sound great. I don't much like working on the Mesa but I don't have to very often. I have some of my own amps in progress but have so many other things to do I'm not done with them yet.

Greg

[BlueAngel]

I play a 1993 Korg/Marshall AC30TBX, and a 1993 Mesa Dual Rectifier. Both circuit board amps and both sound great. I don't much like working on the Mesa but I don't have to very often.

Same here, I have a Mesa Blue Angel (surprise surprise ) and a '94 (I think) Trem-o-verb. I got the T-verb cheap because a couple of the opto switches had gone down - this is unfortunately going to get common on earlier Dual Rectifiers as they have a limited life expectancy, and they are not much fun to change, as they are mounted in stacks and you can bet it won't be the top one which has gone! On the whole I don't mind working on PCB amps at all though (unlike many techs) - they really aren't difficult, you just often have to do more dismantling to get at the problem, but it's usually nowhere near as time-consuming as you expect when you first look inside. In some ways I even prefer them.

It's interesting to note that Mesa still use carbon-comp resistors, too - including in places I think they probably shouldn't (eg power tube screen resistors). Like you I don't actually think the method of construction makes a real difference to the tone quality as long as the amp is well designed and laid out, and both the board and the components are high quality. Sadly this doesn't apply to most cheaper PCB amps which is why the method has a bad reputation.

I also think the AC30TBX is the best modern AC30-type amp made by the way - it's the only one that I know of which is a proper AC30 with all three channels of the classic AC30/6TB - including the Vib/Trem - replicated correctly, and to me sounds closer to an old one than either the CC or the HW, or any of the Vox-derived 'clones' (none of which are). The main thing I really don't like about it is that tube access is a complete pain - possibly worse even than the CC, although it's a very close call.

That's one reason I went for the Blue Angel as my cathode-bias EL84 amp, even though it doesn't really sound much like an AC30...

[ken_j]

That's one reason I went for the Blue Angel as my cathode-bias EL84 amp, even though it doesn't really sound much like an AC30...

How do you use your Blue Angel most, EL84 mode, 6V6 mode, or in Simul Link mode (both together)?

[BlueAngel]

How do you use your Blue Angel most, EL84 mode, 6V6 mode, or in Simul Link mode (both together)?

Most commonly the 6V6 mode when I want it to break up - I run it at the 'normal' impedance match of the 8 ohm output with the 8 ohm speaker, rather than reseting it to 4 ohms as Mesa recommend, since it lowers the power and makes it overdrive sooner and in a thicker, softer way which I prefer - and usually the Simul-Link mode when I want it to stay clean. I don't dislike the EL84 mode, it's just the least useful for the sounds I want - it's just a little too focused and takes away some of the bottom end.

(I'm obviously a frustrated bass player because I rarely run the bass control on any guitar amp anywhere other than full up .)

[ken_j]

Thanks. I have played Boogies for over ten years now. I started with a DC-5 but sold it last year as it was getting too heavy for me and I don't need nowhere near that much power. I have since picked up a Subway Blues that I have been playing with tube combinations and different speaker cabs to get the sound I want. I am going to try a pentode/triode switch in the near future for a lower power setting.