Vintage Synth Repair

Sorry if this post is a bit vague...
I've just got an ARP Odyssey from the US brought over to uk and purchased a power coverter. 
When powered up and plugged it displays the following symptoms
 - Produces a really loud earth hum
 - Sounds high pass filtered - no bass at all (the actual hpf is off of course!)
 - VCF doesn't work at all and neither does the mixer section

 If anyone has any ideas on the above i'd be really grateful.

Thanks,

Matt.

Hi, Can you give a few more details.
What should the input supply be into the Odyssey?
What converter are you using?
JohnB (Somerset UK)

----- Original Message -----
From: "mcharrigan" <mcharrigan@...>
To: <vintagesynthrepair@yahoogroups.com>
Sent: Thursday, October 12, 2006 8:53 AM
Subject: [vintagesynthrepair] My new Odyssey Doesn't Work


> Sorry if this post is a bit vague...
> I've just got an ARP Odyssey from the US brought over to uk and purchased
a power coverter.
> When powered up and plugged it displays the following symptoms
>  - Produces a really loud earth hum
>  - Sounds high pass filtered - no bass at all (the actual hpf is off of
course!)

>  - VCF doesn't work at all and neither does the mixer section
>
>  If anyone has any ideas on the above i'd be really grateful.
>
> Thanks,
>
> Matt.
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.408 / Virus Database: 268.13.2/472 - Release Date: 11/10/06
>
>

Hi Matt.
That should be fine.  Is it a standard step up transformer or an inverter
you are using.  The hum sounds like an earth loop.    Can you e-mail a
simple wiring diagram of the set up you have showing any earth connections.
If you are only using a small power amp, try using the same 240V for it as
you are using for the ARP.
John.
----- Original Message -----
From: "mcharrigan" <mcharrigan@...>
To: <vintagesynthrepair@yahoogroups.com>
Sent: Friday, October 13, 2006 6:57 AM
Subject: [vintagesynthrepair] Re: My new Odyssey Doesn't Work


> Hi John,
> The ARP's input supply is is 100-130v, 20W, 50-60Hz.
> The coverter's output is 100-120v with maxium load of 100w.
> Thanks,
> Matt (Nottingham UK)
>
>
> --- In vintagesynthrepair@yahoogroups.com, "John Brewer" <john@...> wrote:
> >
> > Hi, Can you give a few more details.
> > What should the input supply be into the Odyssey?
> > What converter are you using?
> > JohnB (Somerset UK)
> >
> > ----- Original Message -----
> > From: "mcharrigan" <mcharrigan@...>
> > To: <vintagesynthrepair@yahoogroups.com>
> > Sent: Thursday, October 12, 2006 8:53 AM
> > Subject: [vintagesynthrepair] My new Odyssey Doesn't Work
> >
> >
> > > Sorry if this post is a bit vague...
> > > I've just got an ARP Odyssey from the US brought over to uk and
purchased
> > a power coverter.
> > > When powered up and plugged it displays the following symptoms
> > >  - Produces a really loud earth hum
> > >  - Sounds high pass filtered - no bass at all (the actual hpf is off
of
> > course!)
> > >  - VCF doesn't work at all and neither does the mixer section
> > >
> > >  If anyone has any ideas on the above i'd be really grateful.
> > >
> > > Thanks,
> > >
> > > Matt.
> > >
> > >
> > >
> > >
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > --
> > > No virus found in this incoming message.
> > > Checked by AVG Free Edition.
> > > Version: 7.1.408 / Virus Database: 268.13.2/472 - Release Date:
11/10/06

> > >
> > >
> >
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.408 / Virus Database: 268.13.2/472 - Release Date: 11/10/06
>
>

Hi John,
The ARP's input supply is is 100-130v, 20W, 50-60Hz.
The coverter's output is 100-120v with maxium load of 100w.
Thanks,
Matt (Nottingham UK)


--- In vintagesynthrepair@yahoogroups.com, "John Brewer" <john@...> wrote:

>
> Hi, Can you give a few more details.
> What should the input supply be into the Odyssey?
> What converter are you using?
> JohnB (Somerset UK)
> 
> ----- Original Message -----
> From: "mcharrigan" <mcharrigan@...>
> To: <vintagesynthrepair@yahoogroups.com>
> Sent: Thursday, October 12, 2006 8:53 AM
> Subject: [vintagesynthrepair] My new Odyssey Doesn't Work
> 
> 
> > Sorry if this post is a bit vague...
> > I've just got an ARP Odyssey from the US brought over to uk and purchased
> a power coverter.
> > When powered up and plugged it displays the following symptoms
> >  - Produces a really loud earth hum
> >  - Sounds high pass filtered - no bass at all (the actual hpf is off of
> course!)
> >  - VCF doesn't work at all and neither does the mixer section
> >
> >  If anyone has any ideas on the above i'd be really grateful.
> >
> > Thanks,
> >
> > Matt.
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> > --
> > No virus found in this incoming message.
> > Checked by AVG Free Edition.
> > Version: 7.1.408 / Virus Database: 268.13.2/472 - Release Date: 11/10/06
> >
> >
>

I don't think so but you need to get rid of the hum before you can really
hear what else is happening.  Temporarily disconnect the earth from the
mains plug feeding the ARP then, if that does not improve the hum, reconnect
it and remove the earth wire from the plug feeding the mixer.  Note any
changes in the volume of the hum.  Have you tried the phones straight into
the ARP.
JohnB
----- Original Message -----
From: "mcharrigan" <mcharrigan@...>
To: <vintagesynthrepair@yahoogroups.com>
Sent: Sunday, October 15, 2006 1:48 AM
Subject: [vintagesynthrepair] Re: My new Odyssey Doesn't Work


> My set is very simple, just the ARP and a mixer with headphones, both
connected to the
> same power socket, both earthed. Silly question, but would an earth loop
stop the VCF

> from working?
>
> --- In vintagesynthrepair@yahoogroups.com, "John Brewer" <john@...> wrote:
> >

My set is very simple, just the ARP and a mixer with headphones, both connected to the 
same power socket, both earthed. Silly question, but would an earth loop stop the VCF 
from working?

--- In vintagesynthrepair@yahoogroups.com, "John Brewer" <john@...> wrote:

>
> Hi Matt.
> That should be fine.  Is it a standard step up transformer or an inverter
> you are using.  The hum sounds like an earth loop.    Can you e-mail a
> simple wiring diagram of the set up you have showing any earth connections.
> If you are only using a small power amp, try using the same 240V for it as
> you are using for the ARP.
> John.
> ----- Original Message -----
> From: "mcharrigan" <mcharrigan@...>
> To: <vintagesynthrepair@yahoogroups.com>
> Sent: Friday, October 13, 2006 6:57 AM
> Subject: [vintagesynthrepair] Re: My new Odyssey Doesn't Work
> 
> 
> > Hi John,
> > The ARP's input supply is is 100-130v, 20W, 50-60Hz.
> > The coverter's output is 100-120v with maxium load of 100w.
> > Thanks,
> > Matt (Nottingham UK)
> >
> >
> > --- In vintagesynthrepair@yahoogroups.com, "John Brewer" <john@> wrote:
> > >
> > > Hi, Can you give a few more details.
> > > What should the input supply be into the Odyssey?
> > > What converter are you using?
> > > JohnB (Somerset UK)
> > >
> > > ----- Original Message -----
> > > From: "mcharrigan" <mcharrigan@>
> > > To: <vintagesynthrepair@yahoogroups.com>
> > > Sent: Thursday, October 12, 2006 8:53 AM
> > > Subject: [vintagesynthrepair] My new Odyssey Doesn't Work
> > >
> > >
> > > > Sorry if this post is a bit vague...
> > > > I've just got an ARP Odyssey from the US brought over to uk and
> purchased
> > > a power coverter.
> > > > When powered up and plugged it displays the following symptoms
> > > >  - Produces a really loud earth hum
> > > >  - Sounds high pass filtered - no bass at all (the actual hpf is off
> of
> > > course!)
> > > >  - VCF doesn't work at all and neither does the mixer section
> > > >
> > > >  If anyone has any ideas on the above i'd be really grateful.
> > > >
> > > > Thanks,
> > > >
> > > > Matt.
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Yahoo! Groups Links
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > --
> > > > No virus found in this incoming message.
> > > > Checked by AVG Free Edition.
> > > > Version: 7.1.408 / Virus Database: 268.13.2/472 - Release Date:
> 11/10/06
> > > >
> > > >
> > >
> >
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> > --
> > No virus found in this incoming message.
> > Checked by AVG Free Edition.
> > Version: 7.1.408 / Virus Database: 268.13.2/472 - Release Date: 11/10/06
> >
> >
>

It mat be that the ground or even the hot conncetion has broken off 
at the VCF outpout or one of the main outputs.  The power supply 
should be +15v on the red wire and -15v on the purple wire with black 
being ground.
JohnK

--- In vintagesynthrepair@yahoogroups.com, "John Brewer" <john@...> 
wrote:
>
> I don't think so but you need to get rid of the hum before you can 
really
> hear what else is happening.  Temporarily disconnect the earth from 
the
> mains plug feeding the ARP then, if that does not improve the hum, 
reconnect
> it and remove the earth wire from the plug feeding the mixer.  Note 
any
> changes in the volume of the hum.  Have you tried the phones 
straight into
> the ARP.
> JohnB
> ----- Original Message -----
> From: "mcharrigan" <mcharrigan@...>
> To: <vintagesynthrepair@yahoogroups.com>
> Sent: Sunday, October 15, 2006 1:48 AM
> Subject: [vintagesynthrepair] Re: My new Odyssey Doesn't Work
> 
> 
> > My set is very simple, just the ARP and a mixer with headphones, 
both
> connected to the
> > same power socket, both earthed. Silly question, but would an 
earth loop
> stop the VCF
> > from working?
> >
> > --- In vintagesynthrepair@yahoogroups.com, "John Brewer" <john@> 
wrote:
> > >
>