Impedance and reverb units

[Sindre]

My favourite among my amplifiers (despite its modest price) is a Laney LC-30 II. It has everything I need in terms of tone and features, but the reverb leaves something to be desired. It is a short Accutronics reverb, the two-spring 1-type, 1AB3C1B, to be exact. So I'm thinking about replacing it with a 9-type, namely the lush 3-spring 9AB2A1B. But there is a problem: 1ABs and 9ABs have almost, but not quite matching impedances; the 1AB has an input impedance of 8 Ω and output impedance of 2,250 Ω, while 9AB has 10 Ω and 2,575 Ω respectively. I guess this means that the 9AB will be quite loud in the Laney circuit (if unmodified), but is this in any way dangerous? Will it fry the reverb driver tube? I have little experience from working with tube-equipped guitar amplifiers, but I have some experience from repairing solid state hi-fi amplifiers, and that impedance mismatch would be quite unproblematic in that domain, I think.

[itchyfingers]

Sindre, there are a ton of great sounding reverbs available in pedal format these days. I wouldn't mess with the Laney tank, personally. Just add a reverb pedal to compliment the onboard reverb. If you need spring - check out the Malekko Spring Chicken or the Subdecay SPring Theory. If you want hall/plate sounds - check out the Red Panda Context or the Neunabauer WET offerings.

[Ostinato Rubato]

I understand his frustration though. I'm not a fan of the reverb on my VH100R either. I intend to also eventually have it improved on with a better tank or some kind of mod to the reverb circuit too.

But also yeah... a pedal could fix the problem easy. Unless that loop is parallel like they are on the LC50's. Then I'd probably have to break down and do something like what he's planning to do.

[itchyfingers]

I don't fault you guys for wanting to upgrade, but it seems like a serious investment with potentially dangerous consequences when there are cheaper and safe alternatives available.

Mikey, you own a Pro Reverb. Why do you even fuck with a Laney and its poverty reverb?

[clipless bumper]

cause BL80's

[Ostinato Rubato]

So, I feel compelled to make a very important clarification of facts here. 1) Pro Reverb's reverb went out a couple years ago. I'm sure it's an easy fix (tried the pre, don't even say it) but regardless of that the style I play requires more gain and better sounding gain than a pedal. I've taken the Pro reverb to a hard rock jam with some great od/distortion pedal stacks and it just doesn't work.

2) and most importantly, nobody but Billy has heard my rig in person so all'y'all hommies needs to stfu on dogging my rig, however annoying I may have been about BL80's

[itchyfingers]

So, I feel compelled to make a very important clarification of facts here. 1) Pro Reverb's reverb went out a couple years ago. I'm sure it's an easy fix (tried the pre, don't even say it) but regardless of that the style I play requires more gain and better sounding gain than a pedal. I've taken the Pro reverb to a hard rock jam with some great od/distortion pedal stacks and it just doesn't work.

2) and most importantly, nobody but Billy has heard my rig in person so all'y'all hommies needs to stfu on dogging my rig, however annoying I may have been about BL80's

1. You telling me a Fender "just doesn't work" sounds like operator error to me. Then again, I am admittedly biased...


2. You will be bringing said rig to the mapfest, yes?

[Ostinato Rubato]

No the reverb went out, that's what happened. Not sure what in the circuit happened but it wasn't the tube.

But yeah I'm still bringing the Pro Reverb and the Laney/BL80's for sure. I see this as my chance to get some, "yeah... it's legit" reactions... hopefully.

[Sindre]

ton of great sounding reverbs available in pedal format these days.

Yes, I know. But there is a problem: I really want a classic Accutronics spring reverb sound, and my effects loop is parallel, which makes time-based effects sound and feel not like the real thing.

But after some searching, I found the answer to my own question, for example here . The slight impedance mismatch is unproblematic. As long as an AB unit is replaced with another AB unit, it will work.

So I did the mod. I had an old US-built 9AB2A1B lying around, so all I had to do was drill four holes in the bottom of the cabinet. It sounds fantastic, exactly as I had hoped it would. The amount of wet signal is as predicted much larger than with the old unit, everything above 5 is excessive (but not for surf rock). But at lower levels, it blends beautifully with my tone. Happiness!

it seems like a serious investment

Well, I already had one. But a new 9XX Accutronics is only $27 here.

[itchyfingers]

^Nice! Glad you got it sorted, Sindre!