Valve vs. solid state buffered fx loops

acceptance

acceptance

Well-known member
I have two Metro fx loops and don't know any better. I often see amp designers going for valve buffered. So are valve buffered loops better, and if so, why?
 
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Buffered loops won't be loaded by whatever you put in the loop. They'll handle things without changing the overall sound of your amplifier. From an electronics perspective, there's no reason (outside cost/space) not to use buffers. Of course, there will be players who like how things sound when they're loaded, as that's a taste issue.

A poorly designed buffer can alter tone, but a well designed one (which isn't that difficult) shouldn't. Valve buffers are there mostly because the rest of the amp is valve, the designers know them better, and guitar players desire them and will pay for them. In reality, a good transistor buffer for sends/returns is smaller, takes less power, and won't affect the sound at all.
 
rstites said:
A poorly designed buffer can alter tone, but a well designed one (which isn't that difficult) shouldn't.
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So if a well designed buffered loop won't affect tone (I assume also when bypassed) does that mean that there is no advantage to true bypass?
 
acceptance said:
So if a well designed buffered loop won't affect tone (I assume also when bypassed) does that mean that there is no advantage to true bypas
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True bypass is more a pedal thing and it's due to pedals sucking tone when they're switched off. Really, this isn't even in response to poor buffers, but more about not bypassing the entire electronics when switched off. Those electronics load the signal and introduce noise. They are largely due to pedals being designed to a budge. Switching everything in/out is far more expensive when mass-manufactured and was even more of an issue in the 70's and 80's. When people started buffering pedals, they frequently built buffers that ended up sucking tone, but it's much easier to build a good buffer and properly switch things now. It's always worth remembering that engineering is primarily about building something that mostly works to a budget so that a profit can be made, not to do things the best.

FWIW, one of the issues I see lots of guys run into is getting their first time on stage, going for longer cable runs, and suddenly their all-true-bypass rig sucks because they lack buffers to push current through the longer cables. (An advantage of wireless is you get buffering naturally at the unit.)
 
rstites said:
It won't matter. Redundant buffering won't hurt anything.

All buffers do is offer a power supply to push some more current down the line, if needed. If not, no big deal.
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Thanks for clarifying that, I had always wondered.
rstites said:
Switching everything in/out is far more expensive when mass-manufactured and was even more of an issue in the 70's and 80's. When people started buffering pedals, they frequently built buffers that ended up sucking tone, but it's much easier to build a good buffer and properly switch things now. It's always worth remembering that engineering is primarily about building something that mostly works to a budget so that a profit can be made, not to do things the best.
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That's really interesting, never considered it. So do you have an opinion about the quality of the ubiquitous Boss buffers?
 
acceptance said:
Thanks for clarifying that, I had always wondered.

That's really interesting, never considered it. So do you have an opinion about the quality of the ubiquitous Boss buffers?
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I don't. I've used my old Boss SD-1 forever, but it and a wah were all I used "back in the day" and the Boss most certainly wasn't the tone issue there. Now, I do switch everything in/out with a switcher, so never really listened to one. I went wireless pretty early on too, so never had everything running through pedals.

The wireless was mostly safety, after playing in one too many clubs that had the backline and PA wired out of phase with each other. lol
 
griff10672 said:
your metro loops are buffered .... just not with tubes ....
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I think I confused "Zero loss" with "True bypass" and valve buffers. Maybe there isn't even such a thing as a true bypass loop? For that matter why can't we have buffered and true bypass for when not in use?
 
acceptance said:
I think I confused "Zero loss" with "True bypass" and valve buffers. Maybe there isn't even such a thing as a true bypass loop? For that matter why can't we have buffered and true bypass for when not in use?
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Some amps (like Mesa dual rectifier) have the option of bypassing the FX loop circuitry entirely via the rotary switch on the back. That’s about as ‘true bypass’ as you can get as it’s is effectively a loopless amp with it hard bypassed like that.

Most amps don’t and whatever signal padding, buffering, and boosting back up to line level for the power amp is always on.
 
I enjoyed all of the info on this thread. As an anecdotal experience; I have been swapping out tubes in my buffered FX loop and the type that is in there affects the sound the pedals produce. Some changes are hard to hear, others, not so much!

As far as running buffers into the front end on my board - nothing has affected the tone is a way that was positive as of yet, so I leave them off.

I have also A/B my fx loop pedals with and without buffers and have not found a buffer I like there either.

Maybe the tube buffered effects loop eliminates my need for another buffer in the mix(?)

I just hate how every buffer I have used takes something out of the frequency spectrum, even if it would add top end.
 
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