All about the Roland Jupiter-series

From: Qi [mailto:qi@...] 
Sent: Thursday, January 06, 2000 3:07 PM
To: Analogue Heaven
Subject: [AH] << Jupiter 6 Popping on Attack and Release >>


I'm still an analogue novice but have a question:  My J6 makes a slight
popping noise on the attack and sometimes the release of a note.  It's not
terribly irritating but I am having a hard time ignoring it.   Adjusting
some of the sliders (VCF and envelope) sometimes makes the popping less
prevalent but it is still there.

Is this normal or is there something physically wrong with it?

Any insight into this would be extremely helpful.

Thanks! 


[This message contained attachments]

From: Mueller, Cord MED/ATL [mailto:cord.mueller@...] 
Sent: Thursday, January 06, 2000 11:23 PM
To: 'analog heaven'
Subject: FW: [AH] << Jupiter 6 Popping on Attack and Release >>




	Subject: [AH] << Jupiter 6 Popping on Attack and Release >>

	I'm still an analogue novice but have a question:  My J6 makes a
slight
	popping noise on the attack and sometimes the release of a note.
It's not
	terribly irritating but I am having a hard time ignoring it.
Adjusting
	some of the sliders (VCF and envelope) sometimes makes the popping
less
	prevalent but it is still there.

	Mine did this too. Especially with low filter settings. Also, at the
end of a sound you will hear stepping in the VCA, like little noise. Not a
big deal but it looks like that is the price you have to pay for fast
software envelopes. 

	Cord

	


[This message contained attachments]

From: Paul Schreiber [mailto:synth1@...] 
Sent: Thursday, January 06, 2000 11:25 PM
To: Mueller, Cord MED/ATL; 'analog heaven'
Subject: Re: [AH] << Jupiter 6 Popping on Attack and Release >>


This is called Control Voltage Feedthrough. It is common on non-trimmed
CA3080-based
VCA designs. You are hearing a DC shift in the VCA output.

Paul Schreiber
Synthesis Technology

----- Original Message -----
From: Mueller, Cord MED/ATL <cord.mueller@...>
To: 'analog heaven' <analogue@...>
Sent: Thursday, January 06, 2000 4:22 PM
Subject: FW: [AH] << Jupiter 6 Popping on Attack and Release >>


>
>
> Subject: [AH] << Jupiter 6 Popping on Attack and Release >>
>
> I'm still an analogue novice but have a question:  My J6 makes a
> slight
> popping noise on the attack and sometimes the release of a note.
> It's not
> terribly irritating but I am having a hard time ignoring it.
> Adjusting
> some of the sliders (VCF and envelope) sometimes makes the popping
> less
> prevalent but it is still there.
>
> Mine did this too. Especially with low filter settings. Also, at the
> end of a sound you will hear stepping in the VCA, like little noise. Not a
> big deal but it looks like that is the price you have to pay for fast
> software envelopes.
>
> Cord
>
>
>


[This message contained attachments]

From: Paul Schreiber [mailto:synth1@...] 
Sent: Friday, January 07, 2000 6:15 AM
To: analog heaven; Qi
Subject: Re: [AH] << Jupiter 6 Popping on Attack and Release >>


According to the Service Manual, this *is a trim* on the pc board. It is
called
"DC Balance".

Now, this trimmer is VR10.

Also....on serial numbers 333000 and up, there are the following changes to
the VCA
(it is maked "For Perfect DC Balance Mod"....Ha Ha Ha)

Part    Was   Changed To

C117  22pf     150pf
R77   1.8k       47 ohms
R82   33k     6.8k
R81   100k    22k
R87   430k    140k

But the *main* thing is they added a C120, a 47uf, non-polar cap in series
with R82.

What is strange is that there is ANOTHER VCA *before this one*, a CEM3360
which is
driven by the EG. This other VCA is for Master Volume. And it messes up the
world.

In either case: adjust VR10 with a small screwdriver to minimize the pops.

Paul Schreiber:  BSEE, MSEE, EIEIO
Synthesis Technology
www.synthtech.com <<<VCAs that don't pop



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