RuudNL

Re: 500 series Level-Loc project
« Reply #20 on: February 07, 2014, 12:04:55 PM »
How many 2N5457's do you need? I've got loads of them...
There is a solution for every problem!

http://www.vansteenisaudio.nl


Re: 500 series Level-Loc project
« Reply #21 on: February 07, 2014, 12:11:17 PM »
How many 2N5457's do you need? I've got loads of them...

Thanks for the offer - I've got plenty myself but I'm thinking about longevity and ease of availability.

I've got a J112 here I can whack in to see if the circuit still functions sounds better/worse/same so at least those without 2n5457s can source alternatives.

Thanks again,
Ian
 :)

RuudNL

Re: 500 series Level-Loc project
« Reply #22 on: February 07, 2014, 12:43:03 PM »
IMHO the 'sound' isn't in the FET...
They all distort and attenuate!
There is a solution for every problem!

http://www.vansteenisaudio.nl

Re: 500 series Level-Loc project
« Reply #23 on: February 07, 2014, 12:48:24 PM »
That's good news, it shouldn't be a problem substituting then.  :)

Not sure when I'll get chance to work on this again - hence the stolen lunch hours - hopefully though I should be able to confirm everything and get sharing!

 ;D

 

Re: 500 series Level-Loc project
« Reply #24 on: February 10, 2014, 10:22:20 AM »
This project has been on my mind, IM glad someone far more competent then I am has started and completed it!!

thanks for the great posts.

dkm



Re: 500 series Level-Loc project
« Reply #25 on: February 12, 2014, 09:10:58 AM »
Update!

So I got the prototype front panel through in the post, despite the laminate being really tough to break it came delivered in two pieces.  You can see that it broke along the weakest part (where the dial indicators and labelling material had been removed).



Well, waste not want not.  A bit of glue and we're back in business.  I got a couple of dimensions a little tight but I guess that's the point of testing it.  :)

Anyway, the panel in place:



So I'm about to build up the v1.12 board (bottom of page 1) - if there are any suggestions to improve things I'm happy to give them a go .

I've attached the schematic below - I suppose my biggest blind spot is the impedance between elements of the board.  It sounds great to me as is but if any unnecessary noise/losses can be minimised I'll happily implement the tweaks.

I've also been thinking that it might be a good way to test the circuit if people would like me to process some audio for them and post it here for reference?  Let me know - I guess only 2 or 3 examples would do?

Cheers,
Ian
 ;)

Dr Gris

Re: 500 series Level-Loc project
« Reply #26 on: February 12, 2014, 02:59:51 PM »
Sorry about your front panel. It looks good in the rack though.
Have you done any measurements like sweeps or THD or what not, blah blah...?

I think this is really a cool project, and sure could use some myself.
If you need some audio files let me know what you want.

Keep it up!
Best
Magnus

Re: 500 series Level-Loc project
« Reply #27 on: February 13, 2014, 11:53:50 AM »
Thanks for the encouragement!  It seems to be these last stages that are the hardest work!

I'll pm you for contact details and I'll grab a couple of samples - I'm supposing it'll be more representative with some 'random' recordings rather than just those I choose.

I'll do some sweeps and some level checking - I have a feeling I may need to add a bit of gain to the 'receiver' amp of the mixing section - but make sure the physical level matches the perceived level of DRY and BYPASS.

I've reordered the panel in a thicker laminate and made a couple of changes to the layout/labelling/drilling and will report back on that too - for those interested in getting a panel too I've spoken to the gent doing the CNCing for me and he's happy to pass on his contact details once this is all ironed out so that's another box ticked!

Typically I am really busy at work at the moment so it may take a few days to turn around, but we'll get there.

Ian
 :)

Dr Gris

Re: 500 series Level-Loc project
« Reply #28 on: February 16, 2014, 01:01:26 PM »
Sent you some files. Happy leveling :)

Cheers
Magnus

Re: 500 series Level-Loc project
« Reply #29 on: February 17, 2014, 02:00:50 PM »
KindaBump...

I'm away with work at the moment so haven't had chance to get the final-final-final revision checked.  I've asked for the front panel to be remade with my suggested 'improvements' and also to try the panel in a thicker laminate (this time 3mm as per the normal 500 panel thickness I've used).


Magnus,

Cheers for the files.  I've managed to have a quick play/listen before heading out to work and they seem to confirm findings from my own recordings... I'll do some deliberate tests and output/share the results.


I believe I need to increase the gain of the WET section so will implement that before the above tests - hopefully then the bypass/engaged process will make a bit more sense!  8) :P ;D

Right - awful food awaits me in the pub next door to this hotel - at least it IS still food though.  ;D

Ian


Re: 500 series Level-Loc project
« Reply #30 on: February 19, 2014, 06:11:29 AM »
Had a quick chance to test a couple of things:

1) Sweeps



As you can see (or not) the bypass signal (passes through INA/DRV) is flat, the 100% WET is as good as flat.  The 100% WET signal has an obvious roll off but not too bad - plus given the typical signal coming out of the unit I'm not sure you'd want that much down there anyway?

In any case the WET signal is deliberately below unity due to the perceived level of compressed audio being higher... In all honesty I would consider using a trimmer here if you're really fussy about this (1k in-line with 5k pot maybe?) but given the variation of level you'll be dealing with it is unlikely that a single level will be a magic bullet.  Having said that -  I settled on a value of 3K3.  ;D

Dr.Gris kindly forwarded through a few files to process - one of which has been through the mill and is uploaded here:

https://soundcloud.com/minoian/lvl-lok-500-drgris-drums

The file was a drum pattern so I have done this in 4 repeats:

  • BYPASS
  • 100% WET
  • 60/40 DRY/WET balance
  • as above with toggled BYPASS

There are so many different ways to make this thing mangle audio it's hard to do it justice!  :D

Hope this is useful.  I'll try and get the others processed and uploaded but so far I can see why this thing is seen as a one trick pony!

Cheers,
Ian.

 :)

mjrippe

Re: 500 series Level-Loc project
« Reply #31 on: February 19, 2014, 11:37:23 AM »
Pretty awesome!  Were the comp and release settings "most" and "fast"?

Re: 500 series Level-Loc project
« Reply #32 on: February 19, 2014, 12:17:26 PM »
Hmm, that's a seemingly simple question but has a bit of a weird answer!

The release was on fastest, the comp was on the middle position (least compression) but the input was at max with the pad at -30dB. so was acting more like the -40dB pad/More combo.

There are loads of different ways to approach the signal input level - e.g. use the -40dB pad and leave input at max, or use -30dB and roll back the input pot.  The COMP settings are fixed values and playing with the pad/input pot you can get a blend of distortion and/or compression levels.  Most of them beautifully ugly!  ;D  The -30db pad is the most flexible as it is a strong but manageable signal that the input pot can work with nicely... Definitely where I'd recommend starting...

The release setting is quite cool and may be useful - on the uploaded example the 'normal' release time was resulting in a really noticeable pumping - thinking about it I should really upload that as an example.  ::)

I'm going to try the circuit with transistor substitutes just to see how it copes, and hopefully very the LAST layout revision!

Cheers,
Ian

 :)


Dr Gris

Re: 500 series Level-Loc project
« Reply #33 on: February 19, 2014, 03:54:41 PM »
Finally got the soundcloud to work with me. Sounds really cool!!!!
Damn it, now I want a couple....

Interesting with all those options you've given it, I'm really impressed!

Give us more!!

Best regards
Magnus

KasperNyhus

Re: 500 series Level-Loc project
« Reply #34 on: March 01, 2014, 08:30:58 PM »
Really nice project!! Will you make a layout available for home etch?  :)

Best
Kasper

Re: 500 series Level-Loc project
« Reply #35 on: March 05, 2014, 04:44:53 AM »
Morning all.  Sorry for the continuing delays - responsible are a heady mix of too much work and far too much flu.  >:(



Really nice project!! Will you make a layout available for home etch?  :)

Best
Kasper

Thanks - I'm definitely intending to release the layout etc for home-etching and I've spoken to a gent who is happy to CNC them upon request too if people aren't able to etch at home.

Speaking of that gentleman - he has also made up a front panel at my request using 3mm laminate (instead of the 1.6mm used before):



An awful picture to be sure, but the panel has worked out nicely...  :)

All that is left is for me to verify the last PCB layout I faffed with, plus a couple of transistor substitutions and we'll be good to go.


Cheers,
Ian
 :D


mylesgm

Re: 500 series Level-Loc project
« Reply #36 on: March 05, 2014, 05:37:55 AM »
Look forward to it!
Check my work at www.mylesmumford.com

Indecline

Re: 500 series Level-Loc project
« Reply #37 on: March 06, 2014, 06:30:50 PM »
Wow, great work! I saw the Sherlock project and was bummed it was no longer available.

I would love to get your gent to knock me up a board and faceplate when available 8)

Re: 500 series Level-Loc project
« Reply #38 on: March 07, 2014, 12:12:56 PM »
I've finally had a bit of time - so I hope we are on the home stretch.







Having said that - I'm going to be busy again for the next few days but I'm keen to get this out for criticism!  ;)


Ian.
 :)

shot

Re: 500 series Level-Loc project
« Reply #39 on: March 07, 2014, 02:26:58 PM »
Fantastic! I love etching boards!

Can't wait for you to release etch layout!
 :D