Author Topic: piano  (Read 3733 times)

RandomGruve

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piano
« on: December 31, 2014, 03:37:51 PM »
piano
« Last Edit: February 12, 2015, 01:27:35 PM by RandomGruve »

Offline Ledbetter

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Re: ultra quiet 1975 stage piano
« Reply #1 on: December 31, 2014, 04:29:58 PM »
Has the volume ever been normal?  Do you have an internal preamp with a dead battery?

RandomGruve

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piano
« Reply #2 on: December 31, 2014, 05:07:32 PM »
.

piano
« Last Edit: February 12, 2015, 01:28:21 PM by RandomGruve »

Offline Tim W

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Re: ultra quiet 1975 stage piano
« Reply #3 on: December 31, 2014, 06:23:50 PM »
Try going direct from the RCA jack on the harp.  If the piano now sounds at the correct volume, you may have a problem with your passive controls, cable between the harp and controls, or RCA plug.

If it is still very soft, you may have a problem with the RCA jack, your pickups, the pickup wiring, or grounding on that side of the equation.

Let us know what you find out.

Happy New Year,
Tim


RandomGruve

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piano
« Reply #4 on: January 09, 2015, 08:17:28 AM »
 piano
« Last Edit: February 12, 2015, 01:28:50 PM by RandomGruve »

Offline 4kinga

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Re: ultra quiet 1975 stage piano
« Reply #5 on: January 09, 2015, 10:23:02 AM »
[Unscientific answer]

It sounds like you have a (few?) dead pick-ups at one of the series breaks. 
I'd try tapping each pick-up with a screw driver with it plugged into an amp.  If it doesn't make a pronounced pop, its weak/dead.  Check where it is in the series.  I'd bet its right on a break.

After that,  I'd try lifting a wire off somewhere in the middle and jumper it back to the RCA jack.

Offline David Aubke

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Re: ultra quiet 1975 stage piano
« Reply #6 on: January 09, 2015, 12:57:10 PM »
The total resistance of the pickup circuit should measure around 1.3K ohms.

The screwdriver tap test suggested by 4kinga is worth doing. It's quick and easy. Of course, you'll want to replace any dead pickups you find but if you find quite a few, that would offer an explanation for your low signal strength.

Is it possible the previous owner just adjusted all of the pickups back too far from the tines?
Dave Aubke
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Offline drpepper

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Re: ultra quiet 1975 stage piano
« Reply #7 on: January 09, 2015, 02:35:49 PM »
I have just measured my resistance on my 75 suitcase harp at the RCA jack and got 1.37k ohms.
if you dont get something around that then i does seem to be pickup or wiring.
good luck
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Offline The Real MC

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Re: ultra quiet 1975 stage piano
« Reply #8 on: January 09, 2015, 11:04:57 PM »
Make sure you are using input #1 on the amp.  That is a 1Mohm input optimized for Rhodes pianos.

RandomGruve

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« Reply #9 on: January 11, 2015, 11:39:33 AM »
I
« Last Edit: February 12, 2015, 01:29:22 PM by RandomGruve »

Offline David Aubke

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Re: ultra quiet 1975 stage piano
« Reply #10 on: January 11, 2015, 11:47:41 AM »
...and you're certain you don't just need to adjust the pickups towards the tines a little bit?

On my multimeter, the proper setting for testing a pickup circuit is indicated with a Greek letter Omega ("That Girl" hairdo). This is also the correct setting for continuity testing. Touch one probe (doesn't matter which for this test) to the solder terminal at the center of the RCA and touch the other to the metal mounting bracket.
« Last Edit: January 11, 2015, 11:49:41 AM by David Aubke »
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Offline Max Brink

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Re: ultra quiet 1975 stage piano
« Reply #11 on: January 11, 2015, 12:59:58 PM »
So here's a few more puzzle pieces for everyone, since the piano left my shop last month...

Quote
The total resistance of the pickup circuit should measure around 1.3K ohms.

1) I cannot recall the exact resistance of this Rhodes but it was definitely within an acceptable range. It was the lowest resistance of four open Rhodes pianos at my workshop, but all pianos were within about 5% of one another. It was noticeably the lowest output but at the same time I wouldn't say that it was outside of normal variance for a Rhodes piano.



Quote
Is it possible the previous owner just adjusted all of the pickups back too far from the tines?

2) The piano received a full setup with all new cubed hammer tips. It was setup "identically" to the other four pianos that I had open at the time. The pickups are very well balanced from bass to treble and are as close as I would recommend without getting too hot.



Quote
Try going direct from the RCA jack on the harp.  If the piano now sounds at the correct volume, you may have a problem with your passive controls, cable between the harp and controls, or RCA plug.

3) With the open pianos on my workbenches we swapped rails between a 1971, 1982, and 1979 piano. Same results with all the other rails.



My personal conclusion is that the piano is within normal variance in it's output but is on the lower side of things. I would be very curious to know if there is something that I overlooked and if there is anything that can be done to increase the output without swapping out all of the pickups with a set from another piano with higher output.


I'm not an expert when it comes to pickup design, but I believe that in addition to the impedance/resistance measurement that the tightness of the winds on the pickup coils also have an affect. I think this could possibly be an explanation. The other speculation that I would offer for review is that when you have 73 pickups with a variance of around 10 ohms each and then wire up 73 of them together then the output from one harp to the next is going to vary as well...
« Last Edit: January 11, 2015, 01:01:38 PM by Max Brink »
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RandomGruve

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Re: ultra quiet 1975 stage piano
« Reply #12 on: January 11, 2015, 03:53:29 PM »
piano
« Last Edit: February 12, 2015, 01:29:48 PM by RandomGruve »

RandomGruve

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piano
« Reply #13 on: January 11, 2015, 04:20:50 PM »
next
« Last Edit: February 12, 2015, 01:30:20 PM by RandomGruve »

RandomGruve

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piano
« Reply #14 on: January 12, 2015, 06:29:42 PM »
 low.

« Last Edit: February 12, 2015, 01:30:37 PM by RandomGruve »

RandomGruve

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« Reply #15 on: January 13, 2015, 08:02:31 AM »
 setup.
« Last Edit: February 12, 2015, 01:30:58 PM by RandomGruve »

Offline drpepper

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Re: ultra quiet 1975 stage piano
« Reply #16 on: January 13, 2015, 08:57:57 AM »
Moving pick ups does not sound like the right answer, a couple of millimetres will not solve such s large volume drop.  Your harp seems to have the correct impedance/resistance and your amp is checked. My bet would be that 40 year old rca cable. A break in connection in that would give the drop in output you talk about. Measure the resistance on you lead to your  amp while plugged in and on full volume, it should be very close to what is measured at the harp.
Rhodes Suitcase 75
gibson 335

Offline David Aubke

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Re: ultra quiet 1975 stage piano
« Reply #17 on: January 13, 2015, 09:00:22 AM »
Perhaps I will try moving a few pickups and see what I think. I will mark the existing pickup position before I start so I can easily return it. I don't want to mess up the setup.

It's worth trying.

The pickups are very well balanced from bass to treble and are as close as I would recommend without getting too hot.

They're probably already positioned appropriately but maybe your opinion of the correct distance differs from Max's.


It's an interesting case. The Rhodes pickup circuit is so simple. If you're getting 1.3K ohm across the circuit and going directly from the RCA doesn't help, I don't know what else you could check. I'd consider the possibility that maybe Rhodes chose an oddball alloy for its pickup slugs for some period of time.

How does it sound when you turn up the amplifier? It's my view that, in a very general sense, lower output pickups and circuits produce better tone. Usually the trade-off for hotter pickups is a more muddy tone. That holds for higher numbers of windings but I don't know about different magnet slug metals.
Dave Aubke
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