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Messages - ilcaccillo

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1
Other Keyboards & Software Synths / Re: Clavinet D-6 power supply specs
« on: January 12, 2020, 06:50:04 PM »
Take a look onto the schematics (and the 'real thing', too):
Clavinet C, D6, E7, Pianet Duo have center negative.
Jenzz

You're totally right, thanks

2
Hi .-)

BC550C and MPSA18 differ only 1 dB regarding noise, but sometimes it is worth a try.

The additional caps reduce the hiss, but also cut treble, so this mod is a matter of personal taste.

I allways change the 1 meg resistor to a metalfilm type, the 8,2.pF ceramic to a 10pF Mica and the 100uF across the supply to an low ESR type.

Replaced all the tantalum for a Panasonic low ESR Electrolytic and the Ceramic in the tone circuit for a COG of the same value.



Hi Jenzz,
thank you so much for the reply.

I replaced all the resistors in the audio signal path for Metal Film, the 1 Mega was included

The 8,2.pF ceramic I replaced it for a COG capacitor of the same value

The 100uf filter cap, I replaced it for a 330uf Panasonic 105 degrees low ESR.

I guess I will have to do a sound test with or without the additional caps to check if the treble reduction impacts a positive or negative outcome for our taste.

Thank you so much

3
I already replaced low-noise transistor substitutes might be worth experimenting with.

I already replaced the BC550C input transistor for a MPSA18 selected for higher gain.
But anyway the BC550C is already a low noise transistor

4
Other Keyboards & Software Synths / Clavinet E7 "Hiss Mods" - Opinions
« on: January 11, 2020, 05:53:07 PM »
Hello,
I'm servicing a Clavinet E7 at the moment.

I would like to ask you opinions on the Hiss mods described in this video from Vintagevibe:

https://www.youtube.com/watch?v=47ZnyzLW2Hk

It recommends soldering 2 extra capacitors.
One 100pf between Base and collector of the input transistor and one 470pf between base and collector of the output transistor.

Here is a schematic with the mods in red:



It removes the Hiss and some people like it, but there's also opinions that it kills the tone of the clavinet since it forms a Low Pass Filter.

What are your opinions on this?

Thank you so much


5
Other Keyboards & Software Synths / Re: Clavinet D-6 power supply specs
« on: January 11, 2020, 06:04:16 AM »
Center positive 9V 300mA min or 6V 600 mA min.  Voltage isn't a huge issue with D.C., just make sure the adapter has the mA rating or more. Dunno on the size. Have some calipers?

Beware !  Power connector on the D6 is center negative !!  Use a linear supply, not a switching supply, which will probably cause annoying ripple and other artifacts. Any regulated 9V / 100mA supply will do. (...remember, the circuit only needs some mA's...)

Jenzz


Just to clear things up,
so it's center Positive or Center Negative?

there's 2 different informations here


6
Other Keyboards & Software Synths / Re: Foamy clavinet?
« on: January 11, 2020, 05:45:22 AM »
the entire insides were not only foil-lined but also completely filled with Poly-Fil, basically cotton. 

Well at some point he found the need to dampen the reflections inside the box, probably to have a more controlled sound with less resonance live.

Don't know how well it will work for that, but it will dampen reflections for sure even if by a marginal percentage

7
Hello Everyone,
I have been advised to replace the caps to reduce noise, I have made a list of the parts but there are lots of different types of capacitors, made of different materials. I have contacted Hifi Collective but they haven't got back to me. I know theirs will be expensive but probably good quality. What does good quality mean? Expensive? But what type? I

For Future reference:

- For electrolytics use Panasonic rated at 105 degrees and low ESR (all Panasonic series are really good)

- For Film caps, use Wima, Panasonic, Vishay, Sprague, Phillips, Mundorf or Nichicon, all of them are high quality

- For filter circuits in the picofarads range use Polystyrene capacitors sometimes called Styroflex

- Tantalum capacitors I always replace them with high quality electrolytics, maybe not everyone agrees but Tantalum caps hava a tendency to when they fail they fail short, do a short circuit, and sometimes the end result is devastating.
Some people say the tantalum caps should not be replace with electrolytics because it has impact on the sound, I never noticed any sound impact but if you are worried, replace the old tantalum's with new high quality tantalum from a good well know brand.

Avoid at all costs Chinese brands, unknown brands, unbranded capacitors, and in the case of Electrolytics avoid NOS caps (you want as new production as possible on the Electrolytic).
For Film caps NOS is fine

8
old thread, but maybe this link is relevant for future readers.

Maybe it's possible to adapt any of these rocker switches:

https://www.banzaimusic.com/Rocker-Switches/

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