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Noisy mixing console Seck 122 - replace?

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August 24, 2004 1:20:46 PM

Archived from groups: rec.audio.pro (More info?)

I have a really old and worn Seck 122 mixing console (12 channels) and
it annoys me because it is so noisy. Even when nothing but the pa is
attached and every single knob and fader is turned down to zero the PA
produces hiss as soon as I open the main faders. Signals taken from
the insert points of each channel are noise-free. Signals taken from
the Aux sends (pre fader) are so noisy that they are unusable for
recording.

Recently I had the chance to temporarily replace the mixer with a
EURORACK MX602A and was completly flattened that I didn't even hear
that the PA was turned on. No mentionable hiss at all.
I know that from the technical point of view it is a completly
different beast to build a low-noise 12 channel mixers with 4 busses
compared to building a low noise 6 channel 2 busses mixer.

Do you think replacing the Seck with e.g. a Alesis 12r should improve
the noise problem?

Background:
The setup is used in 3 different situations:
1) Normal band practice sessions:
Only 2 voices and a stereo backtrack have to be amplified and
reverberated.

2) Small venue gigs, audience < 100 people
Here we need to amplify and reverberate 2 voices and maybe basedrum
and snare for the pa and provide a monitor signal for the vocalists.

3) Low budget 8 track HD recording
Here we basically want the mic preamps of the mixer to feed the DAW.
It would be nice to have a few busses to premix eg. the toms or
cymbals before tracking them down. Unfortunately the busses of the
Seck 122 are to noisy for that.

Phil
Anonymous
August 24, 2004 8:44:59 PM

Archived from groups: rec.audio.pro (More info?)

we aren't exactly talking about a million dollar console here...
August 25, 2004 4:41:24 AM

Archived from groups: rec.audio.pro (More info?)

BLCKOUT420 wrote
> we aren't exactly talking about a million dollar console here...

That's right and what I'd like to know is wether I can expect a 'more
modern' low priced console to fix my noise problems or wether I'd have
to think in different price categories. I'm prepared to pay < 400
bucks to get rid of that noise. If I had to pay > 1000 bucks I'd
prefer to live with the noise as it is.
So if anybody has experiences like "Yes, the Seck 112 console is well
known to be a 12 channel noise generator and any other console
outperforms it" please let me know. Or maybe you have experienced
something like "Whatever console with 8 mic pres and 2 busses < 400
bucks you buy - forget it, it will hiss just the same" - please share
it with me.

Phil
Related resources
August 25, 2004 10:49:19 AM

Archived from groups: rec.audio.pro (More info?)

Graham wrote
> Having heard a Behringer - what gave you the idea to buy an Alesis mixer ?
> It's hardly their speciality. Why not a 12 channel Behringer ?
>
> Graham

Thanks for replying and your opinion!

The Alesis R12 is rack mountable - an enormous advantage especially
when I consider that we use that thing on the road and that there are
3 space-units left in that amp / fx rack...

Originally I was searching for an additional rack mountable mixer with
only 4 mic inputs, a post fader aux (for external reverb) and a pre
fader aux (monitor). That would be sufficiant for our practice
sessions and small venue live performances. For 8-track recording I
still could use the mic pres of that old Seck 112.

But when I stumbled across that Alesis R12 it just had all those
features to _replace_ the Seck 112 entirely -> one bulky device less
to cause problems.
Well I'm still a bit undecided which way to go.

Phil
August 25, 2004 1:38:40 PM

Archived from groups: rec.audio.pro (More info?)

anon wrote
> what kind of cables are you using?

I must admit that the cables mixer<->amp are not quite premium mint
stuff. They are standard instrument cables. Since the Seck mixer has
only unbalanced XLR outputs I had to solder them myself and I had to
cut one of the shields to avoid humming loops. (What a pity when I
consicer that the amp has symmetrical inputs)

But even if the cables might be a problem I don't believe them to be
the weak link.
When I disconnect all cables from the board it still hisses via the
headphone jack.
Phil
Anonymous
August 25, 2004 6:08:53 PM

Archived from groups: rec.audio.pro (More info?)

Phil wrote:

> BLCKOUT420 wrote
> > we aren't exactly talking about a million dollar console here...
>
> That's right and what I'd like to know is wether I can expect a 'more
> modern' low priced console to fix my noise problems

In short, yes.

Seck mixers were never great when they were originally made.

Standards of noise ( amongst other parameters ) have improved greatly
since then due to improved components ( in part ) and better circuit
design.

The Behringer will do fine I'm sure. Just bear in mind that isn't built to
last like even that Seck was. When it finally goes wrong it will likely be
cheaper to throw away and buy new than attempt to repair ( practical
serviceability of stuff like that is very poor ).

Having heard a Behringer - what gave you the idea to buy an Alesis mixer ?
It's hardly their speciality. Why not a 12 channel Behringer ?

Graham
Anonymous
August 25, 2004 11:30:37 PM

Archived from groups: rec.audio.pro (More info?)

"Phil" <spam@x-phobie.de> wrote in message news:1e4e061c.0408250838.41dbef1c@posting.google.com...
> anon wrote
> > what kind of cables are you using?
>
> I must admit that the cables mixer<->amp are not quite premium mint
> stuff. They are standard instrument cables. Since the Seck mixer has
> only unbalanced XLR outputs I had to solder them myself and I had to
> cut one of the shields to avoid humming loops. (What a pity when I
> consicer that the amp has symmetrical inputs)

XLR outputs are inherently 'balanced', not unbalanced.

Where did you cut the shield? At the first device following the mixer?

Something else is awry if you had to cut the shield at all.

I found the board, even it it's aged state, to be quite usable and without
a great deal of self noise.

> But even if the cables might be a problem I don't believe them to be
> the weak link.

On the off chance your home-made cabling is out of kilter, that link
wouldn't be 'weak'. Double check the wiring... just poke a couple of
verified mic cables in there (no cuts) and go straight to an amp that's
on the same AC circuit. With just the desk and the amp, there really
shouldn't be a hum or ground problem. If it's clean, start adding things
back into the signal path and/or the peripheral interfaces one at a time
until the problem rears it's head again.

> When I disconnect all cables from the board it still hisses via the
> headphone jack.

I'm guessing old or bad capacitors, but gain structure and load impedance
of the phones could also be a factor. Most HP outputs have a higher than
expected noise floor... it's not exactly a priority circuit.

If you're a do-it-yourselfer, I have a terribly dirty old 24 channel SECK
with no power supply that you can have for $50 plus shipping. It was
used in a night club for 4 years after being purchased from a sound
company's 'no longer used' warehouse of junk stuff. It worked well
in a live situation, but some schmuck tossed the power supply after
the desk had been put in the club's attic to gather dust about 5 years
back.

Your power supply voltages may have drifted as well.


--
David Morgan (MAMS)
http://www.m-a-m-s DOT com
Morgan Audio Media Service
Dallas, Texas (214) 662-9901
_______________________________________
http://www.artisan-recordingstudio.com
August 26, 2004 4:02:48 AM

Archived from groups: rec.audio.pro (More info?)

if i recall properly the headphone amp is not a good gauge to go by. our
headphone amp was also noisy, but we got the board to work well and we cut
albums with it that sounded good.


"David Morgan (MAMS)" <mams@NOSPAm-a-m-s.com> wroyte in message
news:xN5Xc.2676$2F.1437@trnddc05...
>
> "Phil" <spam@x-phobie.de> wrote in message
news:1e4e061c.0408250838.41dbef1c@posting.google.com...
> > anon wrote
> > > what kind of cables are you using?
> >
> > I must admit that the cables mixer<->amp are not quite premium mint
> > stuff. They are standard instrument cables. Since the Seck mixer has
> > only unbalanced XLR outputs I had to solder them myself and I had to
> > cut one of the shields to avoid humming loops. (What a pity when I
> > consicer that the amp has symmetrical inputs)
>
> XLR outputs are inherently 'balanced', not unbalanced.
>
> Where did you cut the shield? At the first device following the mixer?
>
> Something else is awry if you had to cut the shield at all.
>
> I found the board, even it it's aged state, to be quite usable and without
> a great deal of self noise.
>
> > But even if the cables might be a problem I don't believe them to be
> > the weak link.
>
> On the off chance your home-made cabling is out of kilter, that link
> wouldn't be 'weak'. Double check the wiring... just poke a couple of
> verified mic cables in there (no cuts) and go straight to an amp that's
> on the same AC circuit. With just the desk and the amp, there really
> shouldn't be a hum or ground problem. If it's clean, start adding things
> back into the signal path and/or the peripheral interfaces one at a time
> until the problem rears it's head again.
>
> > When I disconnect all cables from the board it still hisses via the
> > headphone jack.
>
> I'm guessing old or bad capacitors, but gain structure and load impedance
> of the phones could also be a factor. Most HP outputs have a higher than
> expected noise floor... it's not exactly a priority circuit.
>
> If you're a do-it-yourselfer, I have a terribly dirty old 24 channel SECK
> with no power supply that you can have for $50 plus shipping. It was
> used in a night club for 4 years after being purchased from a sound
> company's 'no longer used' warehouse of junk stuff. It worked well
> in a live situation, but some schmuck tossed the power supply after
> the desk had been put in the club's attic to gather dust about 5 years
> back.
>
> Your power supply voltages may have drifted as well.
>
>
> --
> David Morgan (MAMS)
> http://www.m-a-m-s DOT com
> Morgan Audio Media Service
> Dallas, Texas (214) 662-9901
> _______________________________________
> http://www.artisan-recordingstudio.com
>
>
>
Anonymous
August 26, 2004 5:59:48 AM

Archived from groups: rec.audio.pro (More info?)

Phil wrote:

> Graham wrote
> > Having heard a Behringer - what gave you the idea to buy an Alesis mixer ?
> > It's hardly their speciality. Why not a 12 channel Behringer ?
> >
> > Graham
>
> Thanks for replying and your opinion!
>
> The Alesis R12 is rack mountable - an enormous advantage especially
> when I consider that we use that thing on the road and that there are
> 3 space-units left in that amp / fx rack...
>
> Originally I was searching for an additional rack mountable mixer with
> only 4 mic inputs, a post fader aux (for external reverb) and a pre
> fader aux (monitor). That would be sufficiant for our practice
> sessions and small venue live performances. For 8-track recording I
> still could use the mic pres of that old Seck 112.
>
> But when I stumbled across that Alesis R12 it just had all those
> features to _replace_ the Seck 112 entirely -> one bulky device less
> to cause problems.
> Well I'm still a bit undecided which way to go.

Given that you're keen on rack mount, then I understand your preferences.

That Seck is hardly rack mount though !

If you're looking for a quick fix to assess suitability and can live with
non-rack mount, why not get a Behringer UB series mixer. There are loads of
configurations with various numbers of channels and your needs are simple. It
won't cost a bomb and you can check it out for usability.

Allen and Heath make a really excellent rack mount mixer btw - it has 16
chaneels and rather more facilities than you need it seems. It's also rather
more than 3 rack units !.

I'm actually just signing off on a 1 rack unit mixer that conceivably might meet
your needs. It won't be in production for a few months though.

I'll run this by you though for interest value.

It has 4 mic inputs. Mic 1 has fully independent gain and 3 band EQ.

Mics 2, 3 and 4 have individual level controls and shared 3 band EQ.

Phantom power ( 17V ) is available for the mic inputs.

There are 4 stereo inputs ( for CD, sampler, whatever etc ) with individual
level control and overall 2 band EQ.

A multi-effect 20 bit DSP reverb is included with sends from each 'group' of
inputs as shown above.

Each 'group' of inputs also has a 'monitor send'.

In 1u - the controls are a bit cramped - but it's cute.


Graham
Anonymous
August 26, 2004 6:06:18 AM

Archived from groups: rec.audio.pro (More info?)

"David Morgan (MAMS)" wrote:

> XLR outputs are inherently 'balanced', not unbalanced.

NO !

You can wire an XLR unbalanced. This has been done by many mixer makers back in the 70s and 80s.

Just tie pin 3 low.

Even now - some 'quasi - balanced' outputs have pin 3 tied low via a resistor.

Don't ever confuse an XLR with a balanced signal - it's what the manufacturer choose to connect to it
that counts.


Graham
Anonymous
August 26, 2004 6:07:44 AM

Archived from groups: rec.audio.pro (More info?)

Phil wrote:

> anon wrote
> > what kind of cables are you using?
>
> I must admit that the cables mixer<->amp are not quite premium mint
> stuff. They are standard instrument cables. Since the Seck mixer has
> only unbalanced XLR outputs I had to solder them myself and I had to
> cut one of the shields to avoid humming loops. (What a pity when I
> consicer that the amp has symmetrical inputs)
>
> But even if the cables might be a problem I don't believe them to be
> the weak link.
> When I disconnect all cables from the board it still hisses via the
> headphone jack.

Cables *will not* be a source of noise ( hiss ).

Anyone suggesting so shouldn't be posting in a pro group.


Graham
Anonymous
August 26, 2004 6:59:52 AM

Archived from groups: rec.audio.pro (More info?)

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message news:412D378A.A70C6248@hotmail.com...
>
> "David Morgan (MAMS)" wrote:
>
> > XLR outputs are inherently 'balanced', not unbalanced.
>
> NO !

Oh ?

> You can wire an XLR unbalanced. This has been done by many mixer
> makers back in the 70s and 80s.

Yes, but I don't believe that SECK 'shipped' product that was unbalanced
at the XLR main outputs. On larger mixers there was an additional set of
1/4" jacks for main outputs, but I can't see a reason to intentionally
unbalance the XLR outs from the factory.

> Just tie pin 3 low.

Unless I'm sadly mistaken, the SECK has balanced outs... but maybe
there's something the original poster mentioned on that, that I missed.

> Even now - some 'quasi - balanced' outputs have pin 3 tied low via a resistor.

.... And some desks convert XLR inputs to the line inputs by dropping a pin
and doing almost the same.

> Don't ever confuse an XLR with a balanced signal -

Wouldn't dream of it... <g>

> it's what the manufacturer choose to connect to it that counts.

If SECKs were shipped with unbalanced XLRs I apologize for my haste.


--
David Morgan (MAMS)
http://www.m-a-m-s DOT com
Morgan Audio Media Service
Dallas, Texas (214) 662-9901
_______________________________________
http://www.artisan-recordingstudio.com
August 26, 2004 6:59:53 AM

Archived from groups: rec.audio.pro (More info?)

"David Morgan \(MAMS\)" <mams@NOSPAm-a-m-s.com> wrote in message >
> Yes, but I don't believe that SECK 'shipped' product that was unbalanced
> at the XLR main outputs.

It surprised me too, but there are even little diagrams printed next
to the jacks to make sure anyone who plugs something in notices that
pin 1 and 3 are ground. To make things even clearer they labelled the
outputs "unbalanced".


(concerning source of hiss)
> I'm guessing old or bad capacitors,

Is that true that old (leaked ?) capacitors can cause hiss? If so I
should try to replace some. I haven't tried to measure the frequency
spectrum of the hiss yet but to me it sounds quite like white noise.


> > I had to cut one of the shields to avoid humming loops
> Where did you cut the shield? At the first device following the mixer?
> Something else is awry if you had to cut the shield at all.

I was talking about the wires connecting the outputs of the mixer with
the inputs of the power amp. There are no other devices in between. As
the power amp has both 1/4" jacks for unbalanced input and xlr jacks
for balanced input I used instrument cables, kept the plug on one end
and replaced the other plug with a xlr plug. I connected the hot end
to pin 2 and grounded pin 1 and 3. When I connected only one cable
there was no hum. As soon as I inserted the other channel there was
humm. Thus I cut the ground of one cable - I think on the amp side.
The hum was gone and I was satisfied.

Thank you for your insights

Phil
Anonymous
August 26, 2004 8:27:41 AM

Archived from groups: rec.audio.pro (More info?)

"David Morgan (MAMS)" wrote:

> "Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message news:412D378A.A70C6248@hotmail.com...
> >
> > "David Morgan (MAMS)" wrote:
> >
> > > XLR outputs are inherently 'balanced', not unbalanced.
> >
> > NO !
>
> Oh ?

Uhuh !


> > You can wire an XLR unbalanced. This has been done by many mixer
> > makers back in the 70s and 80s.
>
> Yes, but I don't believe that SECK 'shipped' product that was unbalanced
> at the XLR main outputs. On larger mixers there was an additional set of
> 1/4" jacks for main outputs, but I can't see a reason to intentionally
> unbalance the XLR outs from the factory.

The reason would be an absence of internally balanced circuitry.

Common in mixers of that era. Even *good* ones.


> > Just tie pin 3 low.
>
> Unless I'm sadly mistaken, the SECK has balanced outs... but maybe
> there's something the original poster mentioned on that, that I missed.
>
> > Even now - some 'quasi - balanced' outputs have pin 3 tied low via a resistor.
>
> ... And some desks convert XLR inputs to the line inputs by dropping a pin
> and doing almost the same.
>
> > Don't ever confuse an XLR with a balanced signal -
>
> Wouldn't dream of it... <g>
>
> > it's what the manufacturer choose to connect to it that counts.
>
> If SECKs were shipped with unbalanced XLRs I apologize for my haste.

I couldn't say for sure now - but I doubt they are likely to be balanced.


Graham
Anonymous
August 26, 2004 8:08:00 PM

Archived from groups: rec.audio.pro (More info?)

At some point in this discussion, Phil mentioned that the mixer still hisses
way too much when there's nothing plugged into the inputs. I skipped a day,
so I don't know if this was covered, but...

That's not an important data point; you won't be using the mixer with
nothing plugged in. And if nothing's plugged in, the source impedance is
equal to the terminating resistance at the input, which is typically a good
deal higher than the source impedance would be if there was a source, if you
get my drift. So the real question is not how much hiss there is when
nothing's plugged in; the real question is how much hiss there is with a
dummy source plugged in. (Good dummy source: a 150-ohm metal film resistor
mounted between pins 2 & 3 of an XLR plug.

Peace,
Paul
Anonymous
August 27, 2004 5:03:32 AM

Archived from groups: rec.audio.pro (More info?)

Phil wrote:

> Is that true that old (leaked ?) capacitors can cause hiss? If so I
> should try to replace some. I haven't tried to measure the frequency
> spectrum of the hiss yet but to me it sounds quite like white noise.

Capacitors ( specifically electrolytic types ) can cause noise ( depending on
their location in the circuitry ) if they go 'leaky'. If left unused for some
time - you may have some leaky electrolytics. If you leave the desk powered on
for a long time - the caps may 're-form' and such noise may disappear.

The noise produced is likely to have a fairly obvious low frequency bias to
it. Like 'flicker noise' if you're familiar. If it isn't like that - chances
are it's not due to caps. With an op-amp based design there are likely to be
few candidates in the signal path that might go noisy anyway.

It's possible that the mixer isn't that quiet anyway. TL072s aren't the
quietest op-amps, especially for certain configurations such as summing amps.


Graham
August 27, 2004 7:28:16 AM

Archived from groups: rec.audio.pro (More info?)

"Paul Stamler" <pstamlerhell@pobox.com> wrote in message news:<AVnXc.252491$OB3.194649@bgtnsc05-news.ops.worldnet.att.net>...
> Phil mentioned that the mixer still hisses
> way too much when there's nothing plugged into the inputs.
>
> That's not an important data point; you won't be using the mixer with
> nothing plugged in. And if nothing's plugged in, the source impedance is
> equal to the terminating resistance at the input, which is typically a good
> deal higher than the source impedance would be if there was a source, if you
> get my drift.

Never thought about that. But I also mentioned that I turned all gains
and faders down. That should take care of the hisses. That nothing was
connected to the inputs was only an info to show that the noise comes
from the mixer itself and not from an external device.

But thank you for the inspiration. Maybe there is a market for
150-ohms-XLR-terminator-plugs to dehiss open mic inputs? :) 

Phil
August 27, 2004 7:57:22 AM

Archived from groups: rec.audio.pro (More info?)

Pooh Bear wrote
> That Seck is hardly rack mount though !

For my intended use that is one more reason to replace it :) 

> If you're looking for a quick fix to assess suitability and can live with
> non-rack mount, why not get a Behringer UB series mixer.

Well now that I consider buying a mixer I need a good reason why I
should buy one that isn't rack mount.

> Allen and Heath make a really excellent rack mount mixer btw - it has 16
> chaneels and rather more facilities than you need it seems. It's also rather
> more than 3 rack units !.

What I saw there is beyond my budget :( 

> I'm actually just signing off on a 1 rack unit mixer that conceivably might
> meet your needs. It won't be in production for a few months though.
> I'll run this by you though for interest value.

Sorry for my lack of english but I don't understand that sentence.
The description of your device sounds interesting though. About what
dimensions of budget are we talking here?

Phil
Anonymous
August 31, 2004 1:58:49 AM

Archived from groups: rec.audio.pro (More info?)

Phil wrote:

> Pooh Bear wrote
> > That Seck is hardly rack mount though !
>
> For my intended use that is one more reason to replace it :) 
>
> > If you're looking for a quick fix to assess suitability and can live with
> > non-rack mount, why not get a Behringer UB series mixer.
>
> Well now that I consider buying a mixer I need a good reason why I
> should buy one that isn't rack mount.
>
> > Allen and Heath make a really excellent rack mount mixer btw - it has 16
> > chaneels and rather more facilities than you need it seems. It's also rather
> > more than 3 rack units !.
>
> What I saw there is beyond my budget :( 
>
> > I'm actually just signing off on a 1 rack unit mixer that conceivably might
> > meet your needs. It won't be in production for a few months though.
> > I'll run this by you though for interest value.
>
> Sorry for my lack of english but I don't understand that sentence.
> The description of your device sounds interesting though. About what
> dimensions of budget are we talking here?

Hmmm - I forgot the recommended retail price now - maybe around 320 Euros or
thereabouts.

Graham
Anonymous
August 21, 2010 8:51:52 PM

I have a SECK1882 model console...it was made originally for 8 track studio recording...all the busses, including the channel outputs and main L+R are quiet and sound quite good...i use it as a mic pre-mixer to DAW...works great. I wonder if the output section on yours is faulty...noise to signal ratio could be affected. Unfortunately parts for these old boards are not in abundance...there are however some British parts warehouses...happy hunting!
August 29, 2010 9:36:23 AM

I've used various Seck mixers, of different frame sizes, for recording, and never had a problem with noise. OK, they probably aern't going to as quiet as a modern mixer, but it should be more than usable. Maybe there is a problem with it ? I know the PSU's on those mixers were particularly prone to breakdown, maybe yours in on the edge, which could explain an increase in noise, capacitors drying out etc. The actual sound quality from a Seck is good, with a warm well rounded sound, I would definitely think twice before replacing it with a Behringer, which in my opinion, "are" unusable, terrible sound, they may be quiet, but the overall tonal quality is disgusting. I owned a Behringer for two weeks, that was enough for me. If you really are convinced you want to buy something new, then the only mixers I can recommend from every aspect, noise, overall sound etc, are by Mackie, they have great mic-amps, and a great sound, and are built to last, they cost a bit more, but you get what you pay for.
August 29, 2010 9:41:26 AM

Quote:
I have a SECK1882 model console...it was made originally for 8 track studio recording...all the busses, including the channel outputs and main L+R are quiet and sound quite good...i use it as a mic pre-mixer to DAW...works great. I wonder if the output section on yours is faulty...noise to signal ratio could be affected. Unfortunately parts for these old boards are not in abundance...there are however some British parts warehouses...happy hunting!



These mixers are so cheap to buy secondhand, that repairing them is a last resort, great if you can do it yourself, but it's not worth paying anyone, you should be able to pick up Seck's of various sizes for silly money these days.
September 26, 2010 11:31:08 PM

anyone have any leads on a power supply for a Seck 1882?
October 14, 2010 7:23:32 AM

This topic has been closed by Buwish
!