I can't speak to the hows and the whys regarding the the electronics. I don't know much about that stuff. But the sound gets bigger, more full and cleaner with the knob pulled up. With my bass this is so with various pickups, Realist Lifeline, Wilson K4 or Underwood.
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Double Bass New Realist Active Docking Station
- Thread starter Jefenator
- Start date
Just stumbled upon this thread, and while old, I have an answer to the question posted. I've actually measured input impedance of the new device I just bought, using a signal generator and a scope. It happen to be 743 kOhm. Might be high enough to bugger a piezo pickup, but far cry from often quoted 10 MOhm value. I've used standard measurement method where one connects a variable resistor in series with the input and dials its value so that the output signal level drops in half. This means an equal resistances voltage divider was formed by these two resistances - the test variable one and input resistance (impedance) of the buffer. So all I had to do is measure the variable resistance value at that point. Like I said, it took just 743k in series to half the output signal level.
I asked David Gage in an email about the impedance. According to his tech it is 1Megohm in active mode.
I've been pretty high on the Yakahimo Dual Element Pickup lately. I'm one to try everything sooner or later. People here on Talkbass often speak of adding resistors to tame what they feel is an excessive output. I personally haven't had any issues in this regard even though I have noted that the pickup seems a bit hotter than the Realist Lifeline that I like too and have been using successfully for a number of years, with and without the Active Docking Station. I can report that the Docking Station, when engaged in active mode delivers a slight reduction in gain, as evidenced in needing to boost my amp volume very slightly to a similar volume than the pickup gives plugged directly into the amp. But.. with the Docking Station it seems a bit cleaner and clearer sounding than without. I like it!
Earl
Supporting Member
The excessive output is usually a result of using only one side of the Yamahiko. If you are using both sides bridged (the original way the pickup was developed) this should not be an issue.
This Docking Station inherently does not reduce the gain per se, but just like any preamp, it has an output voltage swing limit of around 0.7V (I've measured with 1 kHz sinewave as an input) before it starts distorting the sound (clipping the waveform). So when the button is pulled out, it works as signal follower buffering it, whatever comes in, gets out, but up to 0.7V. You can reduce the output swing to zero (very convenient), but you cannot amplify the signal per se, the max gain is 1.
When the button is pushed in (passive mode), the buffer is bypassed and the input signal is directly routed to the output, and there's no restriction of the amplitude, if 3V comes from your piezo pickup, the same 3V will be at the output jack, just un-buffered. So, in your case you likely had input signal exceeding 0.7V in active mode, so you had to reduce the gain ("volume") to avoid distortion, while in passive mode there was no limiting, thus perceived "gain reduction".
I've played EUBs for 6 years now - first Stagg and later - MK Bass, but my background is actually in electronics engineering, so I understand all this impedances, bandwidths, roll-off frequencies and all that stuff. The MHz, dBm, CMRR or THD is far more comfortable terminology for me than Ionian, Dorian, Phrygian or Lydian, which is still Greek to me. My point is - I trust my instruments, measurements and conclusions. I sure get it that ultimately what matters to a musician is what the instrument actually sounds like to his/her ear, but knowing how stuff actually built and works never hurts, and allows me to avoid wasting time and money in searching for something some people (incl. advertisers) swear by, but it makes no sense from electronics fundamentals point of view.
I did not bother to take the Docking Station apart and reverse engineer the circuit on its tiny round PCB inside, just had its cover off and inspected it visually. It's built well. It's got about $15 worth of components inside, I'd say machining the enclosure cost quite a bit more, but as with everything, the value of a unit to the musician 'course does not come from [just] part's worth+profit margin. I have clear enough idea how this unit works, so there was no need for digging into the circuit deeper. But If I ever stumble across another (even non-functional) unit, I might take it apart and reconstruct the schematic out of curiosity, just like I did with the Stagg EUB preamp - another fun project...
When the button is pushed in (passive mode), the buffer is bypassed and the input signal is directly routed to the output, and there's no restriction of the amplitude, if 3V comes from your piezo pickup, the same 3V will be at the output jack, just un-buffered. So, in your case you likely had input signal exceeding 0.7V in active mode, so you had to reduce the gain ("volume") to avoid distortion, while in passive mode there was no limiting, thus perceived "gain reduction".
I've played EUBs for 6 years now - first Stagg and later - MK Bass, but my background is actually in electronics engineering, so I understand all this impedances, bandwidths, roll-off frequencies and all that stuff. The MHz, dBm, CMRR or THD is far more comfortable terminology for me than Ionian, Dorian, Phrygian or Lydian, which is still Greek to me. My point is - I trust my instruments, measurements and conclusions. I sure get it that ultimately what matters to a musician is what the instrument actually sounds like to his/her ear, but knowing how stuff actually built and works never hurts, and allows me to avoid wasting time and money in searching for something some people (incl. advertisers) swear by, but it makes no sense from electronics fundamentals point of view.
I did not bother to take the Docking Station apart and reverse engineer the circuit on its tiny round PCB inside, just had its cover off and inspected it visually. It's built well. It's got about $15 worth of components inside, I'd say machining the enclosure cost quite a bit more, but as with everything, the value of a unit to the musician 'course does not come from [just] part's worth+profit margin. I have clear enough idea how this unit works, so there was no need for digging into the circuit deeper. But If I ever stumble across another (even non-functional) unit, I might take it apart and reconstruct the schematic out of curiosity, just like I did with the Stagg EUB preamp - another fun project...
I have the single element version, which I like quite a bit, but it absolutely needs a capacitor in the output cable. TBH, Yamahiko might want to make that standard for the single element pick up. I’d like to try a dual element at some point but for now I’m very happy with the single element.
Hi all, I just got one of these, along with a lifeline. I’ve used it twice now in performance, via a FOH supplied DI box (radial first time and I think Behringer second time) and into their mixing board. Using active mode, I’ve had to turn the volume all the way up (giving +6db) in order for them to get a decent signal. Is this need to dime the volume pretty typical? It does sound good.
As far as I can remember +6 dB is studio line level, not consumer line level.
Depends where you plug it in if you need the higher signal level.
Depends where you plug it in if you need the higher signal level.
