Harrison Ford Filter Feeler

[dandeurloo]

I finally had time to price stuff out.

Kit (case purchased separate): $475 + shipping
Kits include parts for 8 channels: Knobs, Push botton caps, switches, pots, PCB's, resistors, caps (Wima's for the filters), IC's, IC sockets, IEC inlet, DB25 connectors and Molex headers, crimps pins.  You need the case and front panel seprataley, the PSU and power lamp.

The PSU and power lamp are things that can easily be sourced.  I left them out so I didn't have to worry about what part of the world everyone lives in.  A number of other guys in the White Market have good options for these.

Kit & Case Comb Sell:  $600 + Shipping

I hope this helps. 

Thanks

 

[manulaudic]

Oua great post !

Are the pcbs still available?
I would love to build one into 500 format or something

Manu

 

[tsv]

I just got my PCB's and parts from Dan. Great stuff!

I intrigued by the 'Bump' control on Harrison's version. I'm guessing it's some resonance in the HP circuit? Anybody know?

Thanks!

 

[skal1]

yes they're  a self etch version , or schematic



cheers

skal1

 

[Marcocet]

I find myself intrigued by this circuit - I reckon i'll be building it unbalanced too, and I'm going to try and use that fourth Opamp stage (which is, I think, unused, right?) for a little variable all-pass filter... might combine two channels' worth for a two-stage all-pass that can work on one of the channels rather like the ibp... is that nuts? all my filters in one basket....

How's that coming mute? If you sort that out I'd love to see it! I could use a simple, variable allpass, and I do have one or two spare boards floating around...

 

[skizotom]

Hi I'm planning on attempting this awesome project, but I have no idea about power.

With regards to racking up 8, am I right in thinking that the boards draw 20mA each so I'd need a PSU that can supply 160mA?
Then I'll need something to convert the power to dual rail +/-15 v.
I'm based in Europe, so would something like this combination work?
http://www.audiomaintenance.com/acatalog/Power_Transformers_and_Chokes.html
With
http://diypartssupply.com/index.php?main_page=product_info&cPath=2&products_id=34

Or am I totally off track and need something completely different?

 

[shot]

You need a power transformer that has two secondary windings with 15VAC or 18VAC. You'll connect that to the input rails of the PSU board like the one you linked. That board has to convert AC to DC, regulate the voltage and filter it a bit to provide you with two DC power rails - plus and minus rail.
Maybe you can score the power transformer locally, most of the electronic shops have some. Look for dual secondary (15+15 or 18+18) with at least 15VA (volt-amperes). That's the power rating of your transformer. Someone smarter than me can calculate minimum VA to supply at least 160mA...

 

[skizotom]

Thanks Shot!
Ok figured out what I need now, and thought I'd share for other Europe based people.
Pretty damned cheap too
http://www.ebay.com/itm/AC-220V-Dual-AC-15V-Output-Transformer-5W-for-NE5532-AD82-Amplifier-Amp-Circuit-/371159747402?pt=BI_Circuit_Breakers_Transformers&hash=item566ad84b4a
&
http://www.ebay.com/itm/Power-Supply-Board-Kit-PCB-Based-on-LM317-LM337-IC-/260484989112?pt=US_Amplifier_Parts_Components&hash=item3ca61d80b8

 

[kante1603]

China/Hongkong is not in europe...... :

 

[skizotom]

well with free postage it might as well be. And really I was refering to the Voltage  :

 

[kante1603]

Hello,


where are you located?
Updating your profile helps.
For the psu,there are tons of infos here to find.For a smart lmxxx-based psu or just the pcb you might want to ask e.g. Volker(silent:arts) in Berlin or Cemal (sahib) in Glasgow.Tell them what you need and I'm sure they can help you.
For the transformer I'd personally prefer a torroid.Causes way less trouble when it comes to magnetic fields ("...why does ch.8 have a hum that is louder than on the first channel...." ).
Don't know the specs for this build (where do the 20mAs come from,has anybody measured it?) but 5w for the transformer seems to be on the lowish side (at least I don't have a good feeling).
If you want to learn more a fool around with numbers I highly recommend Joe Malone's ac/dc calculator:


http://www.jlmaudio.com/ACDC%20Calculator.htm


As always be careful with mains voltages!


Have fun,


Udo.

 

[skizotom]

Thanks for the suggestions Udu  It's always good to know where one can get hold of parts. I'm in Norway, so customs are slapped on everything from everywhere!
Earlier in the thread Jensemannen said the draw was only 20mA per board. It's a pretty simple circuit with no hefty transformers so that doesnt seem so strange.
Interesting about the magnetic fields. I'll have a good listen to see how it pans out, and see if the power needs to be rethinked  8)

 

[kante1603]

yep,


just in case hum occurs on the channel(s) closest to the transformer you can move or turn it a bit while listening to it.
Again,be careful with the mains voltages,they can kill you!
If moving doesn't help enough you might want to give it some shielding.
If your case is deep enough simply mount it at the most far away spot from all audio pcbs.Same for all audio wiring,e.g. don't run audio wires close or even across the transformer.
Strong twisting the wires or shielded caples are always helpful.


Have fun,


Udo.


P.S.idn't read the whole thread,but if Jens says 20mAs it is then trust him (Hi Jens!) 
Anyway I'd still give the psu some headroom,maybe you're better off with a higher va transformer,just a thought.
Maybe something like TALEMA torroids (I use them often in my smaller builds),available in 10va and higher.

 

[kante1603]

Oh,and if you want to go safe:
Build the circuits,but temporarily just attach one filterboard to the psu.
Measure the current,best under load and some hot signals running through it.
This way you'll have a "real world" condition.
Then multiply by 8,then again by say 1,5 or so to have some headroom.
Or use Joe's calculator.It tells you the estimated va value in the down left corner.
Or both,hahaha......


Udo.

 

[skizotom]

So Iv'e had some trouble working out how to power 8 of these boards. However I've managed to come up with what I think might work. Could anyone who's built a rack of these or got general nohow check over my drawing to see if it's ok?
Thanks

 

[skizotom]

bump 

 

[12afael]

the chassis should be conected as close as posible of the IEC switch.
daisy chain the ground is not a good idea, star ground is a better option. I would do the same with the power rails but the benefit could be debatible.

I would put the led near the  power supply.

 

[skizotom]

Thanks for your input 12afael
So you would suggest something more like this for the grounding?

Or have I misunderstood 'Starground'?
Thanks
Tom

 

[skizotom]

anyone?  ???

 

[12afael]

yep the ground wiring is ok for me.  as I said  I would do the same for the V+ and V- one wire from each pcb to the power supply. any noise should be filtered in every pcb but better if there is not noise to be filtered.  provably is not necesary but I feel better doing it that way.