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Messages - Jenzz

Pages: [1] 2 3 ... 5
1
The Fender Rhodes Electric Piano / Re: New Vintage Vibe Electric Pianos
« on: November 15, 2021, 02:36:47 AM »
Hi .-)

This red VV was once owned by board member 'Nitrofunk'... Looks like it is in good shape since 2013 :-)

Jenzz

2
The Wurlitzer Electric Piano / Re: Action Question
« on: November 10, 2021, 02:14:49 PM »
Hi .-)

These are 2 different things:

There is nothing said about these damper arm / lever springs in the manual, so i came up with my own solution: I use a spring-balance to pull the damper arms up and bend these spings slightly so that the damper arms will not move up before reaching 40-50 gramms force / weight.

Refer to Fig. 2 from the manual... The damper regulating srew is the one that goes through to grommet. With key at rest, there should be an minimal play of 0,8mm between the top of the grommet and the bottom of the screw head.

To keep this measure is important esp. on the bass side. If the gap is to wide, the dampers will come down too close to the reed when the pedal is pressed. (Play and hold low A, then press the pedal and watch the damper arm moving, then you will understand...)

If you press a key, the whip pulls down the damper actuating rod / regulating screw combo. Therefore, the tension of the damper lever spring will alter key resistance.

If the lever spring is loose, the key will play light, if the lever spring is tight, the keys will play stiffer.

Jenzz


3
The Wurlitzer Electric Piano / Re: Action Question
« on: November 08, 2021, 02:02:11 AM »
Hi .-)

Maybe the damper arm springs are too loose. The tension of these will add to the key resistance.
Also check for propper adjusment of the damper regulating screws. The gap to the grommet should be around 1mm max.

Jenzz

4
The Fender Rhodes Electric Piano / Re: The Rhodes Mark 8
« on: November 05, 2021, 01:56:54 PM »
Hi :-)

What about the Rhodes-direct-to-Amp lovers? Do you consider an all-passive version?

regards, Jens :-)

5
Hi .-)

The 2 jacks on the front panel are the effects loop (top = send, bottom = return), not the outputs.

The 'external amp' jacks located on the cabinet can be used as outputs.

Jenzz

6
Hi .-)

Regarding hiss: The voltage regulator chip (723) is often noisy, because this chip was intended for industrial use, not esp. for audio. In most cases a 100nF film cap across R54 will reduce hiss audibly.

How is your audio measurement setup? It seems there is a ground loop between the piano and your setup, because you have some values even when the piano is off... This can only happen if a ground loop is present.

Jenzz

7
Hi .-)

In most cases, shielding is an issue... There are internal ground loops... The conductive paint inside the case bottom can loose connection to ground... Allways use shielded power cables inside the piano.

When the hood is open, the speakers see no air volumina to work on. If you close the hood, the air volimina inside the piano acts as in a closed speaker box. This will increase volume and bass, so the hum gets louder when the hood ist closed.

Jenzz 

8
Hi .-)

Yes, ols vactrols are prone to failiure when getting older... In most cases, the LDR element will drift out of spec.

The original vactrol seems to be not available anymore... I've used the VTL5C3 with good results.


Jenzz

9
Hi .-)

Allways use a Line-iso box to connect a Wurlitzer to an Amp, regardless of using the AUX or the Phones jack, otherwise grounding problems can occur. It is essential to have Amp ground an Piano ground separated (via the transformer inside the Line-iso box)

Palmer PLI-01 is a good example

Please note that the ground / sleeve contact of the Phones jack is not identical to the piano ground !
There is a 470 ohm resistor between ground and the sleeve contact for current limiting.
When using a line-iso box, this resistror doesn't matter.

Jenzz

10
Hi .-)

Just plug a plain TS plug into the Phones jack. This cuts off the internal speakers and automatically connects an internal load resistor to the amp's output (see schematic or open the piano, the resistor is located on a small soldering post directly at the Phones jack).

Jenzz

11
Hi .-)

14,5V is ok !

What about the value of the Tremolo Pot (50k) ? Is it wired correctly? What happens when you diconnect the wiper wire from TP5?

If TP5 is disconnected, the Tremolo pot should do nothing....

Jenzz

12
Hi .-)

This is not normal.... Did you check the 15V comimg from the regulator (TP 19 on the PCB)? There should be from 13,5 to roundabout 15,5 volts. If this voltage is low due to a bad regulator chip, signal headroom is decreased and distortion occurs...

Jenzz

13
Hi .-)

There are two trimpots on the 200A PCB...

One locatetd on the left front edge (max. volume adjustment), this one can be left as-is.

The second one (red dial mostly) on the left side in the back, right before the heat sink.  This is to adjust the average volume change / gain when tremolo is dialed in.

Jenzz

14
Hi .-)

The cap mod was published in german music magazine 'Fachblatt' back in the 70s (attachment)...

Adding the cap forms a resonant circuit, which enhances a certain frequency. If the cap value is propperly chosen, it can enhance the 'bell' attack tone or add some bite to the mids.

Jenzz


15
Yesss man! .-)

Jenzz

16
The Fender Rhodes Electric Piano / Re: New Rhodes?
« on: May 22, 2021, 06:11:41 AM »
Maybe JD73 can tell us more about that? ;-)

Jenzz

17
Hi .-)

Janus / Haigler (5-Pin XLR connector cabinet): 4 Ohms (2x 8 ohms parallel) per channel

Peterson (4-Pin DIN / or Chinch-Jones connector cabinet): 16 Ohms (2x 32 ohms parallel or 2x 8 ohms in series) per channel


Jenzz


18
The Wurlitzer Electric Piano / Re: 200a cheap amp replacement
« on: February 26, 2021, 05:53:55 AM »
Current amp has some nasty crossover distortion, my tech couldn’t find the problem so it’s still there.

Hi .-)

Always check for proper bias. If its too low, you will get this crossover distortion.

Jenzz

19
Hi :-)

Ulf is always fiddling around with tremolo and sound ‘per se’, so he came up with some ideas and had some of the mods done himself.

3 jacks on the far left:

top: insert point between Vol pot and EQ
mid + bottom: preamp outputs

XLR: power supply only

Acc 1 + 2: Effects loop as usual

Ulf has the second version of the preamp (with the ‘faint tremolo’). We corrected this by changing the switch to a DPDT… Cutting the depth pot + stopping the Vactrol LEDs (like on the 1st version).

Things near right of the panel:

Push/push switch for adding an additional set of caps to C8 and C20 for slower/smoother ramp curves.

Pot below the swich: This one is wired as an expression pedal / remote and connected to the jack on the far right of the panel. This is used to have the speed control of the Moog Phaser ‘at hand’ while playing.

Pot with the curve / line marking: Additional possibility of altering the tremolo curve: This is R17 of the schematics ‘as a pot’ (C11 cut out), so the curve can be altered from slice-type square to near triangle.

Jenzz

20
Hi .-)

TODAY !!

Ulf live with HR BigBand !

https://www.youtube.com/watch?v=t8fM4LG51G4


Jenzz

21
ThX a lot ;-)

Yes, Ulf is one of my log-term Rhodes buddies and a good friend. He is always in for technical minded stuff, like building his own approach of the Dyno Percussion pedal and the like....

Jenzz

22
Hi .-)

We are working on Pianet T's but due to Covid we don't take any work in. We are more than a year (untill Feb. 2022) delayed on our ongoing projects.

Jenzz

23
Hi .-)

The VTL5C3s will work, too, but give a different character of the tremolo wave. They have an overall lower resistance, so with intensity at full, there will be a little bit of signal left.

See the PerkinElmer datasheets:

www.tasteundtechnik.de/bilder/perkinelmer.pdf

Jenzz

24
Hi .-)

Couplers should be VTL5C1... The /2 types have a dual LDR element (hence the 3 wires instead of 2) and are only used by Rhodes in the latest Mk2 Suitcase Preamp circuit ('Blackface' with all rotary knobs)...

Jenzz

25
Hi .-)

If you have a bunch, i would replace them both.

BTW: Did you measure the + / - 15 voltages for the preamp coming from the cabinet? If one or both are siginficantly lower, the LEDs will be darker, too.

Jenzz

26
Hi :-)

Seems that one of the Vactrol Optocouplers is bad. If the intensity pot alters the volume, the LDR in the defective channel goes not down enough in resistance when its LED is lit... Or the LED becomes not bright enough.

Did it work correct before the recab job?

Jenzz

27
The Wurlitzer Electric Piano / Re: Shaking Power Transformer?
« on: October 11, 2020, 12:25:08 PM »
Hi .-)

Do you have the 200 schematic?

42V is ok.

The 1600uF is a 'fake' measurement, but makes kind of sense, because there is another 470 /500 uF filter cap after a 10 Ohms resistor... So nothing wrong here :-)

Jenzz

28
The Wurlitzer Electric Piano / Re: Shaking Power Transformer?
« on: October 10, 2020, 02:53:35 PM »
Hi .-)

You should measure the voltage across the 1000uF filter cap... If you are at roundabout 44 to 46 volts, it's allright.

The '220' stamp only indicates that this is a 4-wire primary EU-Transformer which can be wired for 115V or 230V. The US models have a '115V only' 2-wire primary.

Jenzz

29
The Fender Rhodes Electric Piano / Re: What's Wrong With My Rhodes?
« on: September 02, 2020, 05:52:04 AM »
Hi .-)

It should NOT look like this: (see pic)


If it does, the best way to dust off is using compressed air...

Jenzz

30
The Fender Rhodes Electric Piano / Re: What's Wrong With My Rhodes?
« on: August 31, 2020, 07:37:00 AM »
Hi .-)

Check for metallic debris around the pickup's magnets... This will often cause strange and distortion-like artifacts...

Jenzz

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