Audere's Blend vs. Passive

Note: I prefer Vol/blend to vol/vol

I can't say that the difference between the Audere's blend and things I've had before is very striking, but it is more usable in this respect: Previous preamps I've owned/played were very finicky.. most of the tone changed happened very close to one extreme of turning the knob. In baad cases, this essentially just made the blend knob a glorified neck/both/bridge pickup switch.

The blend on the Audere preamp that I have now is much more what I expect a blend ought to be.. there's a consistent blend between the two sounds across the travel of the knob.

So, put me down as a fan of the buffered blend as implemented by Audere.

This isn't to say that other preamps don't do the blend thing right, of course... just that I haven't found another one that does. While I love the Audere preamp that I've got, it's only one of a number of outstanding bass preamps out there.

 

Yes the buffered blend of the Audere is very very good. It make a HUGE difference, especially if your going from stock passive electronics to the audere preamp.

 

the blend on the Audere is OK for my application, the blended 50-50 sound was much lower than expected, even when taking into account frequency cancellation etc. The blend on my ACG preamp is much much better, there is buffered and buffered I guess. But I would still take any buffered blending over passive mixing....

 

Agreed, buffered mixing is almost always better than passive mixing. In fact the only exception I can think of is where the mutual loading between the two pickups (blended passively) causes a pleasing tone. Some people like the tone of the classic J bass and part of that tone is the loading.

For almost all other cases though, you just want the best quality buffered blend you can get.

 

Can't happen. In passive, the two pickup's inductances are summed in parallel, giving half the inductance if both pickups are wound the same. This reduces the gradual attenuation of the highs, and raises the resonant peak up. In a buffered setup, the pickups don't interact - that's the entire point.

In the buffered setup, the resonance will be very high with each pickup if there's no capacitance in the circuit besides the pickup's own, and the inductance remains the same. Since the circuit drops off response rather quickly above the resonance in the passive circuit, you're effectively extending your highs by buffering the pickups, but you won't have the reduction in attenuation before the peak from the reduced inductance. You could go with lower wind pickups if you wanted to do that with the preamp and adjust with onboard gain. Half the windings is a quarter of the inductance. That would be over half the voltage output in the active setup (lower resonances can raise voltage output passively). Easy to do!

 

With a passive blend system, not only is the combined value of the blend pot loading down your pickup (a 500K blend equals a 250K load, a 250K blend equals 125K... then add your volume and tone controls), but one pickup also loads the other. Besides the impedance dropping to half, they also cause you to loose some high end from the loading.

A well executed active blend will give you the buffered tone of each pickup, and they will not interact like passive pickups do.

When I was making my low Z pickups, each pickup had its own preamp, and the mixing came after the preamps, so you really heard the tone of each pickup combined, and not a third tone. But that can be cool too.

 

hey, look at that! emg now makes an an active summing pot!
although looking at the data sheet, 200k input impedance per pickup is a bit low, isn't it?

 

That looks useful! I was recently telling one of the Creation Audio guys that they should make something like that.

 

Yeah, I recently saw that. 200K? Must be for their active pickups. Unless they are trying to simulate the load of a pot.

 

The site says they make a version for active and a version for passive, yet the data sheet only provides one spec. So my hope is that the data sheet is missing some data.

 

Oh yeah... they have the P and A version. The spec has to be for the active version.

 

nope, the "active" version has 25k inputs.

too bad, as a little active summing pot with 500k or even 1m inputs could be a real useful item.

 

25k? That seems odd. Some EMG pickups have an output impedance of 10k. The input impedance should be 10 times higher. I guess because they use 25K pots. I told them that the pickups with the higher output impedance, like the J model, sound much better with 100k volume controls, but they didn't believe me.

I made an A/B switching box back in the early 90's and ran the pickups right to the box so I could listen to the different pot values. 100k had a more open top end then the 25k pots, so that's what I was using in my basses at the time.

Yeah, I had been wanting to check one of these things out.

If would be easy enough to run each pickup through a jfet buffer and then to the active blend.

I guess I have to make my own version. I'm including an active blend on the preamp I'm designing... No reason I can split that part off on its own.

 

Count me as a likely customer for that item. As I said above, I was trying to talk the Creation Audio guys into it already, and they were curious but not exactly falling out of their chairs to do it.