Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: MWaldorf on August 26, 2020, 06:41:17 pm
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Cooped up minds go strange places. My mind decided to hyper-focus on reverb pans and why vintage and modern pans sound different (with the vintage pans sounding better). So I conjured up a test - a modern MOD 4AB3C1B pan (the standard for Fender applications: long, two spring, long decay pan), a modern MOD 4AB1C1B pan (same as above, but short decay), a modern MOD 4AB3C1B with springs from a vintage Gibbs pan installed, and a vintage 4AB3C1B.
Video is below. Lots of blathering at the beginning, playing commences around 3:20 in.
My feeling is that the vintage pan sounds best (duh) but the 4AB1C1B and the 4AB3C1B with vintage springs, while still a bit too enveloping, are strong contenders and have a decay length much closer to a vintage unit. I think the difference is in the damping materials on the transducer ring magnet mounts used to control decay - the modern ones seem to have much less damping than the vintage ones, though I'm not sure how much of that is the age of the materials in the vintage pans. That being said, the vintage pan sound is right in line with 60s recordings of surf bands, so I don't think that age is the only factor.
If you can find a vintage pan with the correct impedances, that'll always be the best bet, but if you can't find that, and you're not the tinkering type to swap springs, you'll still get much closer to vintage tone with a new short decay pan than a new long decay one.
Anyway, thought I'd post this here in case there are any other reverb kooks around.
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I can’t help but wonder if you adjusted the dwell, tone and mix, would you reduce the amount of reverb washing out the dry signal.
Thanks for posting. I think I am not a fan of long decay reverb... but, then again, if it’s too short it sounds funny.
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Ha! The demo was targeting cork sniffing surk-niks like myself. ;)
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So using a vintage tank matters a lot to me with vintage Fender amps with reverb, as the reverb alters the overall amp-EQ even if there's not a lot of apparent reverb in the resulting sound. I imagine the onboard reverb exhibits more sonic difference than even which tank is used in the outboard reverb (I've got a 1965 Reverb Unit, but never bothered swapping tanks to listen).
To my ear, the modern tanks are all bright & metallic, while the old tanks are midrangey. I discovered that buying a vintage Fender amp, and finding out after-the-fact that the tank was replaced with a MOD tank. Buying an original Gibbs tank immediately changed the EQ of the reverb, and the amp by extension when the reverb was on.
I'm no good at spotting any differences when the outboard reverb is played surf-style. It's not what I usually play, and the standalone reverb imposes its own sonic changes to even the Dry signal.