Post by antigua on Nov 8, 2020 15:46:04 GMT -5
I came across some more Chinese clones, and it's been fun seeing what Chinese manufactures to in order to make a pickup for bottom dollar that is at least decent enough to assure repeat business.
This two guitars in question are a Rickenbacher 325, the sort that John Lennon made famous in the early sixties, and Hofner Violin Bass, made famous by Paul McCartney in the early sixties.
The Rickenbacker 325 is a solid body short scale guitar that seems almost child sized, with three Rick "toaster" pickups. This one doesn't have an authentic vibrato, but a Bigsby style as stand in. I watched a YouTube video of a guy opening a real 325 up, and I'm really impressed by how the Chinese copy produced nearly all of the 325 hardware, very correctly. It sell for less than 1/10th the price of the real deal. It does have various shortcomings though, the finish seem very soft and scratch prone and there are numerous slight blemishes around the body and neck. No dead frets though, 100% playable.
All three pickups measure near identcal values, so I only recorded one of them:
- DC Resistance: 11.860K ohms
- Q @1khz: 0.844
- Measured L: 1.6882H
- Calculated C: 148pF
- Gauss: 550 (ceramic)
The pictures of the guts reveal that the pickups are actual humbuckers, which is pretty amazing since it's certainly not the cheapest type of construction they could have popped in there. This picture from a Reverb listing shows that actual Rick. toaster pickups are clearly a single coil with 1/4" AlNiCo pole pieces. I don't have real toaster pickups on hand, but odds are they will not sound very alike.
As far as electrical values, the defining facts are that they have very low inductance, very low Q factor, and very powerful magnets. There are two ceramic bar magnets in the coils that measure ~550 gauss at the tops, a lot stronger than most humbuckers with screws and slugs, and the low inductance means the resonant peak will be very high, while the very low Q factor . high eddy currents assures that the bass response is large relative to the treble. The low inductance paired with the low Q factor results in a thicker mid range and muted treble.
The pickups also sit pretty far from the strings, the output is very low compared to a Strat or Tele, but fortunately, the humbucking pickups help improve the signal to noise ratio, which otherwise might be a problem.
It's interesting that a pickup with ceramic bar cores would have a very low Q factor, but it probably owes to the fact that there is a conductive covers surrounding the coils, as well as a substantial metal base plate, maybe 1mm in thickness. It appears that the original Rick toaster pickups have the same thick metal plate.
As is often the case, I would guess that half of the measured capacitance is caused by the shielded lead wire, and not the pickup itself.
They even shielded the coils with copper foil tape, which I declined to remove, as that would cause it to tear. The coils are secured in the housing with hot glue.
Real toaster pickups with one wide coil and AlNiCo poles:
The next pickup are Hofner violin bass pickups. These are very similar underneath, also humbuckers, as were the originals. According to a Reverb listing, the originals measured a DC resistance around 9k, these measure around 11k.
- DC Resistance: 11.108K ohms
- Q @1khz: 1.392
- Measured L: 4.344H
- Calculated C: 137.81pF
- Gauss: 550G (ceramic)
- DC Resistance: 11.054K ohms
- Q @1khz: 1.411
- Measured L: 4.327H
- Calculated C: 150.54pF
- Gauss: 550G (ceramic)
I can't determine whether the originals used AlNiCo or ceramic magnets, but these use ceramic bars. The Q factor is not as low at 1kHz as I would have expected for a pickup with steel parts, but at at resonance, the Q factor is probably very low. The high inductance means the resonant peak will be on the lower side. They are darker sounding pickups in practice, not totally muddy, but definitely lacking treble. Since it's a bass guitar anyway, that's not a terrible thing. Also, the guitar has no tone knob, so that low resonant peak and low Q factor almost serve a functional purpose.
The base plate is soldered to the cover, like a PAF style pickup, but the bobbins are not screwed in at all, and it relies on the base plate being soldered down tight in order to keep the bobbins and bar magnet all in their proper places.
The guitar itself is full hollow body, so it's extremely light weight, and the sustain is notably shorter to a solid body bass, but that's what gives it it's signature sound. It's similar in quality to the imitation 325, no bad frets, but it has various finish defects, a lot of which could be be buffed out. The bridge saddle is unlike anything I've ever seen, it uses actual fret wire to intonate the strings. The controls were very crackly, but I blew compressed air into the pots and switches, and now they seem to work fine. The controls are PCB mounted underneath.