SX74 woes

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dietrich10
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SX74 woes

Post: # 14068Unread post dietrich10
Thu Apr 07, 2011 4:08 pm

Afternoon troubleshooting. Isolated to the right channel of the sx74.

Getting distortion in the 150-350hz range when pushed beyond certain dB.
I swapped every card in the rack as well as all inputs coming in.

Its almost like it was dropped and inside a part is loose that rattles when this freq range threshold is reached. the real lows do not seem to affect..

luckily spare head arrives tomorrow and then mine off to see AG
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concretecowboy71
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Post: # 14070Unread post concretecowboy71
Thu Apr 07, 2011 4:26 pm

Sorry to hear that.

Always a bummer when something doesn't work right...
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mossboss
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Post: # 14071Unread post mossboss
Thu Apr 07, 2011 9:21 pm

Sx 74 ++ whatever dB = visits to AG = negative bank balance, Happy days Cheers
Chris

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dietrich10
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Post: # 14080Unread post dietrich10
Fri Apr 08, 2011 11:01 am

Its not the head...its something else. which is still not determined.....
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JayDC
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Post: # 14083Unread post JayDC
Fri Apr 08, 2011 3:11 pm

same problem after mounting the backup head?

are you using the original rack, maybe you need new caps or something..
generally its for reproduction.. but i like to play wif it sometimes.. :P

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dietrich10
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Post: # 14088Unread post dietrich10
Fri Apr 08, 2011 3:41 pm

its nothing in the rack. it always stays right channel no matter what. something near end of signal path near head..
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JayDC
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Post: # 14089Unread post JayDC
Fri Apr 08, 2011 4:05 pm

well i don't know much about your system, I use something far simpler.. Maybe its a bad wire? or if there is a connector, a pin is going bad..

i dunno, I'm just taking shots in the dark, but I wanna help you figure this out..
generally its for reproduction.. but i like to play wif it sometimes.. :P

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opcode66
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Post: # 14090Unread post opcode66
Fri Apr 08, 2011 4:27 pm

Remove the four screws for the depth/heating control panel. Gently pull the panel off. Behind the panel is where the audio signal, feedback signal and command signals for suspension box all come together. I looked inside of mine and noticed a HUGE drip of oil that was about to fall on the wiring harness in there. Maybe you had some oil drip and it is casuing a small short of something??? Working having a look.
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dietrich10
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Post: # 14091Unread post dietrich10
Fri Apr 08, 2011 5:01 pm

thanks O66 as been in there too already. the good thing is every connection has been cleaned. one mind thinks i am being hypercritical with my cuts as I check everything on 3 turntables with such light weight on the cartridge that any issue is detected.

'normal' weight on the playback and there is not any issue. i am trying to discover why not on both sides when it appears.

after all the cleanup/reconnects cut a decent length dance record very loud and fit great
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jtransition
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Distortion

Post: # 14109Unread post jtransition
Sat Apr 09, 2011 7:52 am

Hello D,
Can you hear this noise on the feedback monitor whilst cutting?
Are you using Concord playback stylus?
Jason

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dietrich10
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Re: Distortion

Post: # 14110Unread post dietrich10
Sat Apr 09, 2011 7:59 am

jtransition wrote:Hello D,
Can you hear this noise on the feedback monitor whilst cutting?
Are you using Concord playback stylus?
Jason
You cannot hear this on feedback monitor.

I have three different playback stylus and stations.
SME are with shure head+stylus on the vms+ 2x 1200 in the other room , 1 with concord and one with another orotofon.
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jtransition
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Murphy

Post: # 14111Unread post jtransition
Sat Apr 09, 2011 8:03 am

Is it worse on the concord?

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dietrich10
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Re: Murphy

Post: # 14112Unread post dietrich10
Sat Apr 09, 2011 8:23 am

jtransition wrote:Is it worse on the concord?
a bit
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jtransition
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Post: # 14114Unread post jtransition
Sat Apr 09, 2011 1:43 pm

D
I would do some more test cuts at different levels but with old masters that you know were ok,It sounds to me (if you pardon the pun)That what you are hearing is the resonant frequency of the playback cartidges with the Concord being the worst offender (in my opinion).
Jason

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dietrich10
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Post: # 14148Unread post dietrich10
Tue Apr 12, 2011 9:26 am

Its nothing on the VMS. loud deep cuts on my light playback systems=issue

hyper critical here

the system running great all lubed up and calibrated like new!
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mossboss
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Post: # 14155Unread post mossboss
Tue Apr 12, 2011 10:56 am

dietrich10 wrote:
hyper critical here
Yes D I know :wink:
Chris

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GROOVE-GUARD
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Re: SX74 woes

Post: # 14164Unread post GROOVE-GUARD
Tue Apr 12, 2011 5:57 pm

Hi ,

first > if the same distortion with your backup head ???

no > listen the fb monitorlevel without the 9 db feedback and with max +8db , push the level in carefully steps (around 100 - 200 hz)
when you listen bad harmonics it´s a head problem in the mechanical parts > fb glue, ceramic broken, damping bad and so on ...

second > if your styli hole perfekt ???


pray for the head ... :roll:

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dietrich10
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Re: SX74 woes

Post: # 14165Unread post dietrich10
Tue Apr 12, 2011 6:05 pm

GROOVE-GUARD wrote:Hi ,

first > if the same distortion with your backup head ???
yes

no > listen the fb monitorlevel without the 9 db feedback and with max +8db , push the level in carefully steps (around 100 - 200 hz)
when you listen bad harmonics it´s a head problem in the mechanical parts > fb glue, ceramic broken, damping bad and so on ...
no issue fb monitor. with those settings or others.

second > if your styli hole perfekt ???
yes

problem solved


pray for the head ... :roll:
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jtransition
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Murphy

Post: # 14456Unread post jtransition
Thu Apr 21, 2011 4:38 pm

D,
Did you solve this and what was the issue?
Jason

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Nickou
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Post: # 14458Unread post Nickou
Thu Apr 21, 2011 5:29 pm

Yes , I am curious too ...
did you find somthing?

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