Buffers

[mingsta]

I've read a bit about the potential benefits of buffers if you're running lots of cable/true-bypass effects.

In general is this less of an issue for active basses?

I've done a quick A/B of plugging in direct and going through my pedal board with ~4-5 effects in series and couldn't hear too much of a difference.

[dannybuoy]

Passive pickups don't drive a signal too well down long cables, resulting in a loss of the high frequencies. Once the signal passes through a transistor gain stage, it is 'buffered' and can be driven down a long cable without much degradation. This is the basic premise. So, active basses have a built in buffer. Some effect pedals are true bypass, meaning they are effectively out of the chain when bypassed, but some pedals (most older pedals, plus all current Boss and Tech21 pedals for example) are buffered bypass. So if you have an active bass, or a pedal with buffered bypass early on in the chain (e.g. a Boss tuner) then you can add loads more pedals without hearing much of an effect. However, not all buffers are well designed, and some can noticeably colour the signal. So a good rule of thumb is to have one good quality buffer as close to the pickups as possible, then use true bypass pedals for the rest of the signal chain!

Edited October 22, 2014 by dannybuoy

[thisnameistaken]

Totally agree with Danny's entire post. You'll notice some degradation if you have some average-quality-buffered-bypass pedals in your signal path. The best setup is to have some sort of pedal which will bypass all your buffered bypass pedals, and contains a high quality buffer itself. For me it's an SFX Loop Logic.

[elephantgrey]

From what i understand its all about impedance, which naturally drops by simply passing through a cable. An active bass already buffers the signal, increasing the impedance so that it can drop furtherer before the effects are noticeable. adding a buffer at the start and the end of a pedal board will also help. Something to note would be that some fuzz's (fuzzfaces come to mind) incorporate your bass's pickups into their circuitry, and having a buffer in between them will prevent this (also why some fuzz pedals sont work well with active bass's)

Edit: Ive just reminded my self that pantherairsoft's pedalboard company does a buffer interface. I must look into it, I was thinking of geting one but by the time life stopped getting in the way i had forgotten about it…

Edited October 22, 2014 by elephantgrey

[dannybuoy]

Not quite - this is how I see it, although electronics gurus please correct me if I'm wrong!

Think of impedance as resistance. Pickups have a lot of resistance due to all that thin tightly wound wire, whereas the output of a transistor amplifier has much less.

When you combine resistance with capacitance, you make a low pass filter. This is how the basic passive tone control works to roll off top end.

Your guitar cable is like one big capacitor. So when driven by a high impedance source like pickups, there is a loss of high frequencies. When driven by a low impedance source such as a preamp in an active bass, the capacitance stays constant, but as the resistance is less, the frequency cutoff of the filter is moved higher, letting more treble through.

[rmorris]

[quote name='elephantgrey' timestamp='1414013019' post='2584941']
. An active bass already buffers the signal, increasing the impedance so that it can drop furtherer before the effects are noticeable. .[/quote]

Not quite. The active circuit lowers the output impedance of the signal.
This does mean that more level is delivered to the next stage in the signal path (rather than being dropped over the impedance of the pickup itself ).
Then it gets a bit more complicated due to reactive impedances ( Inductance / Capacitance ) which give frequency and phase effects.

[elephantgrey]

Well, this is why my electrical knowledge remains theoretical…

[Bassnut62]

Well I don't understand any of that science either; but I have just discovered that putting my Tech 21 Boost DLA after bypass loop (with about 8 TBP pedals in it) and before the amp, balances the signal to the amp very nicely between the bypassed signal and the signal from the loop. I am very pleased about this discovery.

Now I am wondering if I should put a buffer at front of loop too. Would that improve signal in the loop?

Ps. I am running a passive MIJ 54 Strat through pedal board into assorted old valve amps.

Edited April 12, 2015 by Bassnut62

[Sibob]

Let's assume that your pedal board is fully true bypass (so no Boss pedals etc).
If you run your passive instrument via a long cable into your pedalboard, then I'd put a buffer at the start. If you run 3-4 pedals, you're probably not going to need a buffer really unless you're using the aforementioned long instrument cable. If you're running a short cable from your instrument into 12 pedals, I'd pop a buffer in the middle or the end.
If you're running a long cable into a pedalboard of lots of pedals, I'd have one at the start and one at the end.
Bear in mind that some pedals (most notably Fuzz Face based fuzz pedals HATE a buffered signal fed to them (hence why they don't work well with active instruments).

Also have in mind that if you use any Boss pedals (there are others, DOD, some EHX, some boutique, B7K), basically buffered pedals, these work as your buffer, you don't need a little boutique buffer taking up extra space. A Boss tuner at the start (or wherever you need it as above) will usually do the trick.

Si

[ahpook]

Dannybuoy and Sibob have nailed it.

I think the thing to bear in mind is that there are guitarists/bassists out there who [i]don't use any effects[/i] (yes, i know......weird isn't it ? ) so they may have just a cable between their amp and instrument. In this situation you're going to notice the effect of a long cable a lot more than if (as Sibob said) you have a buffered tuner in there, which I think most bass/guitar-ists do.

So some people put a buffer in to get round the tone suck of long cables.

[Bassnut62]

Thanks chaps, short cable into TK electronics micro Polytune, then Kelley Compressor, then loop with about 8 pedals (all TBP, no Boss, etc), then into buffered Tech 21 Boost DLA, then short cable to amp (occasionally long cable here)......seems all sorted in sound to me. Good to finally understand buffers.

[Sibob]

You're probably fine as you have a short cable into your board, but with 8 pedals, if you add up those patch cables, you might have another 3ft of cabling perhaps, you you at consider trying a buffer at the start of the 8 chain.
But then again, if it sounds good to you, it is good

Si