73 vibro champ restoration

[GotA]

Ok, so Im not one to drive in the slow lane so let's kick it up a notch. Now while the amp was sounding good again, an 8" speaker will always sound small and boxy. The true sound of the amp was being masked by the speaker. I have various 10" speakers that I had from my old Princeton reverb reissue I sold some years back. Only problem is they are 8ohm speakers and the champ is setup up for 4ohm. Time to change the output transformer

Here is the original. I'll keep this safely set aside so it can be returned to original spec should I ever decide to sell it, but I think my kids are likely to get this amp when I die so that's their problem

Here is the new output transformer. It's a direct replacement but has additional taps on the the primary and secondary. On the primary I'll keep the 8kohm connected like stock and the secondary I'll be using the 8ohm. This means I can easily hook up any of my many 8ohm speakers, 10 and 12 inch as well as use my captor and cabm+ setup for the ultimate versatility. The unused wires are heat shrunk on the ends and cleanly rolled up and tucked out of the way. While I'm at it let's remove that annoying RCA jack for the speaker.

I wired up a proper switchcraft shunted tip 1/4" jack. Here's everything all done.

Next post we will address the cab issue and address the 10" speaker.

[GotA]

Here we are at the end of the journey. I couldn't just put a new baffle in the original cab for a larger speaker without destroying the cab. But I do have a frontman25R solid state amp that isn't the best sounding thing ever. Turns out that it's the same width as the vibro champ so I have to start taking it apart and measuring for holes to drill for the chassis straps of the champ.

After lots of measuring and remeasuring and widening of holes I had the chassis in place and it's starting to take shape. But, there are holes on the top of the cab where the old solid state amp mounted. I can't leave that like that so it's time to get to work on that.

I plugged the holes with some dowels. Then I drilled out for threaded inserts of the original screws. I'll have to trim the screws with my Dremel so they don't go through the cab


And here it is all put together. No janky open holes

For the speaker, I have a couple nicer 10" 8 ohm speakers but I decided on my WGS ET10. It's the 10 inch version of my favorite ET-65 speaker in my larger blackface amp. Plus it workers better than my Weber Jensen voiced speaker with dirt pedals. I wired up a new 1/4" speaker cable and got it all together. Now with the deeper cab and larger speaker the amp reveals it's true nature. There is more depth the the sound and the knobs respond vs being restricted by the 8" speaker. I now have a 5watt home pedal platform amp that I can actually turn up mic instead of only using the captor and cabm+. Having the option to do both has truly made this amp versatile and will be my daily driver from here on out.


***Post edit***
While the amp was finished I had the epiphany that I hated the black panel grill cloth and needed to change it to a more accurate silverface aesthetic. So here it with the new grill cloth that I put on a few days ago.

[hulakatt]

Now while the amp was sounding good again, an 8" speaker will always sound small and boxy. The true sound of the amp was being masked by the speaker.

That may have been true when the amp was built and may have held true for a long time after but I would argue it no longer holds true today. Wether a speaker sounds small and boxy has little to do with it's size and everything to do with it's quality and you know they never put the best into these "practice" amps, even the Fender ones which were far better and more professional than the rest. No, these days there are options for 8" speakers that sound every bit as full range and open as other sized speakers of high quality.

The difference is real. I have the Jupiter 8sc in both my Champs and neither could be confused for small or boxy, both are now their larger siblings in miniature instead of caricature. The Jupiter is not the only 8" punching in this class these days either.

[JSett]

Excellent work! It's looking tip-top now! Bravo.

Now while the amp was sounding good again, an 8" speaker will always sound small and boxy. The true sound of the amp was being masked by the speaker.

That may have been true when the amp was built and may have held true for a long time after but I would argue it no longer holds true today. Wether a speaker sounds small and boxy has little to do with it's size and everything to do with it's quality and you know they never put the best into these "practice" amps, even the Fender ones which were far better and more professional than the rest. No, these days there are options for 8" speakers that sound every bit as full range and open as other sized speakers of high quality.

The difference is real. I have the Jupiter 8sc in both my Champs and neither could be confused for small or boxy, both are now their larger siblings in miniature instead of caricature. The Jupiter is not the only 8" punching in this class these days either.

I concurr with Hulakatt, 8" of old we're often not that great but modern ones destroy them on quality and fullness. I had a Weber Classic AlNiCo 8" and now a Jupiter 8SC in mine and both sounded HUGE compared to old 60's/70's/80's 8" speakers. Everyone that's been round and played it would agree.

BUT, you have the 10" in there now, and that does open up a world of possibilities to you in the future and no doubt sounds great. Enjoy

[GotA]

Excellent work! It's looking tip-top now! Bravo.

Now while the amp was sounding good again, an 8" speaker will always sound small and boxy. The true sound of the amp was being masked by the speaker.

That may have been true when the amp was built and may have held true for a long time after but I would argue it no longer holds true today. Wether a speaker sounds small and boxy has little to do with it's size and everything to do with it's quality and you know they never put the best into these "practice" amps, even the Fender ones which were far better and more professional than the rest. No, these days there are options for 8" speakers that sound every bit as full range and open as other sized speakers of high quality.

The difference is real. I have the Jupiter 8sc in both my Champs and neither could be confused for small or boxy, both are now their larger siblings in miniature instead of caricature. The Jupiter is not the only 8" punching in this class these days either.

I concurr with Hulakatt, 8" of old we're often not that great but modern ones destroy them on quality and fullness. I had a Weber Classic AlNiCo 8" and now a Jupiter 8SC in mine and both sounded HUGE compared to old 60's/70's/80's 8" speakers. Everyone that's been round and played it would agree.

BUT, you have the 10" in there now, and that does open up a world of possibilities to you in the future and no doubt sounds great. Enjoy

Ok, I get what you are saying, and I may have not elaborated enough lol. Yes, 8 inch speakers sound much better today and I've played some like a Weber, this celestion, a Jensen and a wgs. But, they still sound like a small speaker to me. The size of the magnet and the size of the cone will only give so much depth. The other part of the equation is the cab size. Having more depth in the cab offers more projection and depth. The really sound of the amp comes alive with a slightly bigger cab and speaker. I think that's what I was trying to say but didn't fully articulate. Nothing wrong with the way the 8" sounds, it just doesn't fill the room the same way, much more directional than a larger speaker. Playing this through a 12 in speaker is🥵🥵

[hulakatt]

2 12" Celestion Golds in the Bassman cab
1 Jupiter 8sc in the Champ

The difference in the size of the speaker is the least of the differences in sound between these two and they're probably the two amps I play the most. Oddly, the Gold and the 8sc are my two favorite speakers but not really very similar in any way, on paper at least.

[GotA]

2 12" Celestion Golds in the Bassman cab
1 Jupiter 8sc in the Champ

The difference in the size of the speaker is the least of the differences in sound between these two and they're probably the two amps I play the most. Oddly, the Gold and the 8sc are my two favorite speakers but not really very similar in any way, on paper at least.

That drip edge

[hulakatt]