S800 Support Thread

Hi guys,
i tried to study harder,
i'm guessing that for HF ,
changing the Q could be done by replacing R9 by a trimpot
FOR LF ,it might be R12
HMF R14 and LMF R16
Please can anybody help me for this ?
best regards,
Francois

Still nobody ?
please EQ guru's help us,
i think a lot of people would like to put trimpot or pots
to change the Q on this wonderfull EQ,
best regards,
francois

Hi All,
      Only got to page 18 so far, but haven't seen the info I'm looking for yet, so here goes ...  ;D

  In this pic, is what I have labeled  A = Link/jumper/ zero Ohm R
                                                B = 47kR
                                                C  = 47kR

  ... Also, are all the Lk / LK1 / LK1LK / LK2 / LK2LK / LK3LK  - are they all Link/jumper / zero Ohm R ?

  sorry if I've missed it or haven't read it yet

  many thanks as always 

Yes to all. I remember that part of the board was really confusing. All of those lk parts are jumpers

Thanks !   

LK = link

couls somebody come and shine with a way to change the Q
on this wonderfull EQ ?

Hi All,
        Will be putting four of these in a 2U rack case, was wondering about PSU.... I have the one that came with Collins kits, ( the Green Pre PSU )  but also have a couple SSL9k PSU PCBs left over,  is one better suited for this than the other ?

  Also would like to know about different OpAmp options...  ;D

  any info would be great, Thanks

O.K.  --  I'm going to used the the Green Pre PSU , and would like to know if I can use a W04 bridge rectifier instead of the big square one

  Thanks,
            Chip

Chip

W04 should be fine.

Peter

Thanks Peter !

  should be ready to flip the switch in a couple of days, waiting on some parts, ...  and Thanks for building and making this project available.

    Chip

Hi All,
      Just re-read this thread , but didn't see the problem I'm having. Just fired up a quad of these in a 2U case, three work fine, one the LF and HF dont work, audio passes fine and LMF and HMF work fine, bypass works too.

  Any Idea's ?

  with the PCBs upside down makes it very difficult to test, was thinking of swapping out ICs with a working channel, if not the problem will have to remove and run leads from PSU to test 

  any suggestions greatly appreciated.

  Thanks  !

Check all your soldering & component values (I'm sure you have already). The fact that 2 bands work & 2 dont point to an error there in.

Check pot wiring as well.

Peter

Thanks Peter 

.. well... I swapped in  ICs from a working channel and its all good now ! 

  so gotta place an order for for some TL071s, I think I have a couple 5532s left over from  GSSL builds - will post some pics soon.
 

Hi All,
        Got the new ICs in and all is well 

      I've been doing some testing with a frequency analyzer and found some things a little odd.
Running Pink Noise through it I found the that the Low frequency seems to be centered around 80Hz with toggle on the lower frequency position, when toggle in higher frequency position, frequency doesn't seem to change, what does seem to change is the Q or bell curve gets wider but still centered around 80Hz  ???

  Same thing with the High Frequency, seems to be centered around 10k with toggle in lower frequency position, when switch to higher frequency position the Q gets wider, but still centered around 10k  ???

  I hope I havent wired something wrong or placed wrong components, I used Collins Kits, and it all sound s good.

  Any Thoughts ?  Anyone ? 

  Pix to follow soon 

I apologies if this has been covered or if this is too much of a Newbee question, but would like to know if this is the way this EQ works, or did I mess up the build ?

audiophreak said:

I apologies if this has been covered or if this is too much of a Newbee question, but would like to know if this is the way this EQ works, or did I mess up the build ?

Click to expand...

No question is too newb. Sometimes pink noise with a spectrum analyzer can be tough to see smoothly and clearly. Check out the sweeps I made of my unit:
http://blog.benlindell.com/?p=75

You may want to try out something like RMAA or fuzzmeasure as well.

Thanks Ben !
    .. so I guess I need to invest in proper testing gear  ;D  from your description my method doesn't  seem to have a fine enough  " resolution "  .
    after posting last night, i remembered your blog - ( awesome information , and I used your pannel layout too ) I think everything sounds like your sweeps in my unit, but the LF doesnt " sound " like your LF sweeps, - will need to figue out better testing methods.
  Thanks again,
                      Chip

Hi All,
      Setting for unity gain ( Duh )  :  seams to have fixed what I was hearing and the units sound great ! 

  Thanks to Peterc , benlindell  - ( used your panel graphic ) , and All who posted, and to this Great Forum Community.

here are some pix - https://goo.gl/photos/5K71Xuvt7iaKfbWD9