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Double Bass Have I purchased a faulty Fishman Full Circle ??

T

Tallboy

Apr 23, 2002
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United Kingdom
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#1
A couple of weeks ago I got my double bass back from my luthier after deciding to invest in a Fishman Full Circle after hearing all the great reports from guys on TB.
On plugging in to various amps I was shocked to hear the smallest sound ever coming from this wonderful new pickup.
Upon investigation I noticed a visible gap (all the way round) between the top of the pickup and the leg of the bridge (about 1mm). The top of the pickup was making no contact at all with any wood.
After looking on the forum I noticed that pdbass had a similar problem that he managed to cure after "closing the gap".

.http://www.talkbass.com/forum/showthread.php?t=494476

I managed to get in to see my luthier today to rectify the situation. After looking at the bridge we realised what was causing the problem. The FC had been retro-fit in the place of my old adjusters - However, the old adjusters were not a one piece unit - each adjuster consisted of a brass sheath for the upper post (which had been fixed into the leg) and a threaded brass sheath to receive the lower threaded part of the post (which had been fixed into the foot). There was no contact with the FC as the sheath for the upper (unthreaded) post had a small lip which was preventing any of the wood touching the top of the pickup.
He very kindly filed down the metal protrusion and smoothed off the wood, which would make contact with the top of the FC. VOILA, I had volume again.
Everything was fine until I got home and started to experiment with the tone by giving the adjuster a 1/4 turn - All I could hear was the most unearthly pops and bangs and then went through a series sound then none (or very little - just as it was when no wood contact was present). Is this something that any of you have experienced or have I got a dud?
On the occasions when the volume cuts, placing a finger on top of the pickup causes a kind of feedback.
Apologies for the length of this post.
Have any of you experienced any of these pops and bangs whilst turning the wheel on your FC?
Any opinions greatly appreciated.
 
#3
Hi Jake
Thanks for your interest.
I have had a good testing session with the offending item and can confirm that gentle wiggling of the wire has no effect on the sound, I'm pretty sure that the wire is making good contact inside the wheel.
The sound that I hear on turning the wheel is reminiscent of the dreadful noise you get from a broken pot on an old amp.
Although I can't see any gaps between the leg and the top of the wheel I'm wondering if the adjuster post on the hot side is exactly at the top of the brass sheath and is impeding the necessary pressure from the top of the bridge ??? (I'm just grasping at straws now...) Surely a lack of pressure would just result in a weedy tone and not the pops, bangs and "bad earth" sound I get when I touch the wheel with my finger.:(....
 
#4
A couple of things first.

Don't turn the wheel while it's plugged in and turned on. That's bad for everything you plug into and not a sound you would be interested in hearing.

Before you turn the wheel be sure to unplug the RCA jack to the output so the wire is free to spin. Also be sure to slack the strings enough to get easy adjuster travel but not so much as to loose your soundpost. Those wheels are not strong enough to take the full weight of string tension while spinning without damaging the fragile crystals. It's the tradeoff you have to make to use that pickup.

You may have a faulty pickup or it may have sustained some damage in installation or operation. If it buzzes when you touch it that's not right. Contact Fishman's customer service and discuss it with them.
 
#7
Uncletoad said:
A couple of things first.

Don't turn the wheel while it's plugged in and turned on. That's bad for everything you plug into and not a sound you would be interested in hearing.

Before you turn the wheel be sure to unplug the RCA jack to the output so the wire is free to spin. Also be sure to slack the strings enough to get easy adjuster travel but not so much as to loose your soundpost. Those wheels are not strong enough to take the full weight of string tension while spinning without damaging the fragile crystals. It's the tradeoff you have to make to use that pickup.
Click to expand...

Thanks for your advice Phil.
When I fist plugged in the FC at the first audible pop I unplugged it from my PJB flightcase and started testing it through an old Trace Elliot combo that's on it's way to the bin.
All the turning I've talked about has been a 1/4 turn at most and done at reduced string tension.
I think I will ask the guys at Fishman - It doesn't sound too healthy does it?
My only other concern is taking the Full Circle out and replacing my original adjusters - Are there any tips you can offer to avoid the soundpost falling ? ( and a 3 hour round trip to my luthier !!!).
 
#8
standupright said:
possible that the pick up is installed upsidedown? i've got the full circle on my upright and have zero problems with it.
Click to expand...

Thanks for that standupright.
I've read the instructions about a dozen times and can confirm that the FC can be installed threads up or threads down. Mine is installed threads down (which I think is how the majority of users choose).
Thanks again for your view though - much appreciated.
 
#9
Tallboy said:
Thanks for your advice Phil.
When I fist plugged in the FC at the first audible pop I unplugged it from my PJB flightcase and started testing it through an old Trace Elliot combo that's on it's way to the bin.
All the turning I've talked about has been a 1/4 turn at most and done at reduced string tension.
I think I will ask the guys at Fishman - It doesn't sound too healthy does it?
My only other concern is taking the Full Circle out and replacing my original adjusters - Are there any tips you can offer to avoid the soundpost falling ? ( and a 3 hour round trip to my luthier !!!).
Click to expand...
Lay the bass on it's back somewhere where it will be unmolested while you have the strings slacked. Use some sort of weight that won't damage the top but will push the top down a bit and hold the soundpost in. I use a buckshot bag over top the soundpost just south of the bridge foot. As long as nothing moves you'll be fine.

1/4 turns aren't a big deal usualy although it's good to get in the habit of slacking the strings a bit when you do the turns.

I'm still not convinced of your fit either, but you'll proabably need a fresh pickup to know one way or another.

Fishman is moving their headquarters and may be difficult to reach before Jan 2009. Call and see though.
 
#14
Thank you for your reply.
I use a common amplifier and a cheap piezo pickup that sounds loud when I tap it. I touch the central connection of the 1/4 connector, in the pickup side, and it makes a loud hum sound. With the new FC there is no sound when I tap it. I connected a preamplifier in between and the old pickup sounds loud but the FC just makes a very low sound. If I press the FC with my fingers over the bridge and play the double bass, the sound from the amplifier at maximum volume is lower than the sound from the doble bass itself.
 
#17
I've never been a Fishman user myself as they were always so fiddly back in the day; and the friends I had that used them had nothing but problems. I've always been an Underwood guy - just plug and go - no hassles or weird mounting issues. Only recently have I switched to a Vic's Model C pickup, which sounds amazing.
 
#18
Without having the pickup installed, I'm not sure that you are learning much. The Full Circle is designed to perform under pressure from the bridge leg opposite the thread side of the pickup. If the unthreaded side of the adjuster is not under pressure from he bridge leg, thus compressing the piezo crystals inside, you likely won't get much output. To really test the pickup, you would need to install it on a bass as it was designed and see what happens.

I currently have the FC installed on 4 different basses and it works well on all of them.
 
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#19
I got this answer from Fishman "You should be able to plug the pickup into an amp and tap on the wheel. This should give you some output from the pickup."
Following Chris reply I used some tools to carefully press it but there is still no sound.
Thank you.
 

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