dbx 160vu clone

[envelope]

I see +/- 24V at those caps you mentioned. caps rated for 50V would be great here.  partial dbx schem. image attached

25V is okay for the caps on the +/- 15V rails, but  I'd go 35V instead.

 

[damnyankee]

I see +/- 24V at those caps.  image attached

I just looked at the schemo again and yep, you're right.  Hmmm...wonder why they put a 25V filter cap there when the voltage is +/- 24...???  

DY

 

[envelope]

Hi damnyankee, what schematic have you been using? I have the original dbx160VU drawing to work with, as I cannot get my eyes to work with the Black flourescent  schematic.


Manipulating and having to force leads is not really a minor issue, unless you have been trained by an expert. they are fragile, can take only a few flexes,  you can pull leads out of components easily, or damage the termination of the lead within the component itself, and you would not know that you just destroyed the part you soldered in. If you having to solder both sides of the transistor leads, you might consider soldering in a socket first, that way the transistor lead does not take the excessive heat stress, if you can get the socket pins to fit the pcb..that is.

 

[damnyankee]

Hi damnyankee, what schematic have you been using? I have the original dbx160VU drawing to work with, as I cannot get my eyes to work with the Black flourescent  schematic.


Manipulating and having to force leads is not really a minor issue, unless you have been trained by an expert. they are fragile, can take only a few flexes,  you can pull leads out of components easily, or damage the termination of the lead within the component itself, and you would not know that you just destroyed the part you soldered in. If you having to solder both sides of the transistor leads, you might consider soldering in a socket first, that way the transistor lead does not take the excessive heat stress, if you can get the socket pins to fit the pcb..that is.

Hi Enve,

I too, am using the original dbx schemo - and I have to give kudos to AC here - so far, he created a faithful reproduction of the original.  This power supply was designed on purpose.  From Mike Harris (who talked to Les Tyler, 160VU designer):  "Its the crappy PSU that causes the 160 to expand for 15 to 20 ms before compressing...giving that extra snap to the kick drum. (according to it's sheepish designer...Les Tyler).  Beef up the power supply and you may lose that."

This is why I want to stick as close to the schemo in regards to the power supply as possible.  But on the other hand, I want to filter out the background junk too.  If stock caps were 25V 470uF, then 25V 4700uF should work too.  But on 24V rails, I don't want to toast anything - particularly my VCA cans because I'm not up to Vbe matching transistors. 

I'm going to seat C36 and solder it in (it fits) but for C37, it won't fit so I'm going to give it some tall legs and gently bend it over Q7,Q11.  I wanted to ensure those legs sticking up didn't create any electrical fields that's going to affect performance.

 

[haima]

changing the working voltage of those power supply caps from 25 to 35v shouldn't effect the "sag" AFAIK (if someone is aware of this being incorrect i'd love to know).

it WILL stop them overheating and dying early from overvoltage though - power transformer winding/VA variations plus wall power fluctuations can create some pretty wide variations in the rectified voltage.... 1 volt of "headroom" is probably cutting it too fine.

 

[envelope]

Hi Enve,
I too, am using the original dbx schemo - and I have to give kudos to AC here - so far, he created a faithful reproduction of the original.  This power supply was designed on purpose.  From Mike Harris (who talked to Les Tyler, 160VU designer):  "Its the crappy PSU that causes the 160 to expand for 15 to 20 ms before compressing...giving that extra snap to the kick drum. (according to it's sheepish designer...Les Tyler).  Beef up the power supply and you may lose that."
This is why I want to stick as close to the schemo in regards to the power supply as possible.  But on the other hand, I want to filter out the background junk too.  If stock caps were 25V 470uF, then 25V 4700uF should work too.  But on 24V rails, I don't want to toast anything - particularly my VCA cans because I'm not up to Vbe matching transistors.  

I disagree regarding the voltage rating of 25V being the contributing factor of any 'inherent expansion'.
Haimas' point about longevity/performance is the issue being addressed.

 

[Biasrocks]

okay then, sounds like your all set. I effectively disagree regarding the voltage rating of 25V being the contributing factor of the inherent expansion, but that 'quote' is too general and encompassing, to draw any conclusion.

I agree Stuart, 25v caps in this circuit is cutting it way to close. I've not seen any evidence that putting higher voltage caps in there is going to effect the sag of the original circuit. It will effect your wallet when you're replacing those caps in a few years. Putting a 4,700uf cap instead of the 470uf will definitely affect the sag.

Go with a minimum 35v cap there, better yet a 50v, stick with the original uf values if you want the sponge.

Mark

 

[damnyankee]

You guys ROCK!  Thanks for sharing your expertise.

DY

 

[abechap024]

Anyone making any progress on this? I'm still waiting on parts and been crazy busy.

Cheers,

AC

 

[damnyankee]

Anyone making any progress on this? I'm still waiting on parts and been crazy busy.

Cheers,

AC

I'll try to finish up the component/board after next weekend (I'm out of town this week).  If anyone has any recommendations for Wire to wire the switches and the VU meter, I'd be most grateful.  All I have is crappy, stiff, plastic coated Radio Shack wire works great for geetar pedals.

Thanks in advance,

DY

 

[Rybow]

Whew! I was able to snag the last proto board. Sent out today. Thanks AC! Nice work on the BOM as well. I am going to be in compression heaven soon!

damnyankee- which geetar pedals have you built so far? Thats how I got addicted to this DIY business. Started with the good ole TS9. I have added a Rat and a sansamp, and I have a Marshall Guvnor and MXR noise gate in the works. Get the projects from tonepad for now, but I would love to find something a little crazier. Where do you get yours from?

When I built my LA 4's, I just used your good old stranded 24 gauge wire. Nothing special. Worked really well! You'll just want to make sure to twist wires together really tightly that are going to the same place to help with noise.

 

[haima]

If anyone has any recommendations for Wire to wire the switches and the VU meter, I'd be most grateful.  All I have is crappy, stiff, plastic coated Radio Shack wire works great for geetar pedals.

i find 26 AWG is a good standard gauge for internal hook up wire - for the general low voltage/low current stuff like this - signal, switches and meters etc.

i've always just recycled wire for internal hookup - in decades of DIY i don't think i've ever bought wire for the internal hookup (mic/patchbay cabling definitely, but for inside the boxes no).

just look around for old computers, tape machines, VCRs etc on the side of the road or in skips. i've found some amazing decommissioned science lab units full of knobs, meters, wire etc in skips out the front of universities, but even just in suburban streets there's always something lying around.

carry a pair of sidecutters/screwdrivers and cut out anything useful and leave the rest. keep your eye out, it'll take a little while but soon enough you'll build up a good collection of colors, gauges etc. i've got a big plastic tub under my desk.

old tape machines can be a good source of shielded cable when you need shielded cable for internal runs...

it seems crazy and wasteful to me to buy something that is being thrown out all around us every day. i know some people wouldn't trust 2nd hand wire, but i have NEVER had a single problem working this way.

** i loved the wombles as a kid: http://www.youtube.com/watch?v=qFsL_wKdlMo

 

[damnyankee]

Whew! I was able to snag the last proto board. Sent out today. Thanks AC! Nice work on the BOM as well. I am going to be in compression heaven soon!

damnyankee- which geetar pedals have you built so far? Thats how I got addicted to this DIY business. Started with the good ole TS9. I have added a Rat and a sansamp, and I have a Marshall Guvnor and MXR noise gate in the works. Get the projects from tonepad for now, but I would love to find something a little crazier. Where do you get yours from?

When I built my LA 4's, I just used your good old stranded 24 gauge wire. Nothing special. Worked really well! You'll just want to make sure to twist wires together really tightly that are going to the same place to help with noise.

Ha!  So that was YOU who bought the last board...GRRR!!! *hahaha!*

Not to vary from the this thread but the pedals were runoffgroove (Thor, Prof Tweed, Mockman) and moosapotamus' ADA flanger clone. 

I would LOVE to build an LA-4A (or LA-3A)...I love UREI stuff.  I have (4) UREI 537 eqs and a 565T Filter set (LOVE that telephone sound).  Is there a build for the LA-4A?  I want to build 2 of those.  For comps, all I have is (4) dbx 903 gold cans, (1) dbx 166, (4) dbx 163x, (2) aphex compellors, (1) aphex dominator, and a valley people dyna-mic/dyna-mite combo (the silver railed version).

And thanks Clown & haima for the wire recommendation!!!

DY

 

[Rybow]

Ha!  So that was YOU who bought the last board...GRRR!!! *hahaha!*

Not to vary from the this thread but the pedals were runoffgroove (Thor, Prof Tweed, Mockman) and moosapotamus' ADA flanger clone. 

I would LOVE to build an LA-4A (or LA-3A)...I love UREI stuff.  I have (4) UREI 537 eqs and a 565T Filter set (LOVE that telephone sound).  Is there a build for the LA-4A?  I want to build 2 of those.  For comps, all I have is (4) dbx 903 gold cans, (1) dbx 166, (4) dbx 163x, (2) aphex compellors, (1) aphex dominator, and a valley people dyna-mic/dyna-mite combo (the silver railed version).

And thanks Clown & haima for the wire recommendation!!!

DY

Dang right! I swooped in there and nabbed it. I am pretty excited about this one. Fairly inexpensive build too, and lots of great info in this thread.

Thanks for those links damnyankee. Checked out the pedals on runoffgroove, and there is some great stuff on there! I am going to have to build me some of those.

My LA 4's are awesome! They are actually the only outboard compressors that I have right now. Great for cleanly slamming a signal into oblivion. I have always wanted a valley people dynamite. How did you get one of those?

On topic- I was thinking about this power supply issue. Is anyone going to implement a sag switch? I was thinking about moutning the 470uF and 4700uF off board, and then hooking up a switch to flip between them. Mainly just to easily see if there is some mojo that gets lost with the cap upgrade. Could be interesting if it's workable.

 

[abechap024]

...and then hooking up a switch to flip between them. Mainly just to easily see if there is some mojo that gets lost with the cap upgrade. Could be interesting if it's workable.

That would be a great experiment!

Cheers,
AC

 

[damnyankee]

Dang right! I swooped in there and nabbed it. I am pretty excited about this one. Fairly inexpensive build too, and lots of great info in this thread.

Thanks for those links damnyankee. Checked out the pedals on runoffgroove, and there is some great stuff on there! I am going to have to build me some of those.

My LA 4's are awesome! They are actually the only outboard compressors that I have right now. Great for cleanly slamming a signal into oblivion. I have always wanted a valley people dynamite. How did you get one of those?

On topic- I was thinking about this power supply issue. Is anyone going to implement a sag switch? I was thinking about moutning the 470uF and 4700uF off board, and then hooking up a switch to flip between them. Mainly just to easily see if there is some mojo that gets lost with the cap upgrade. Could be interesting if it's workable.

You're welcome for the links.  It is amazing how they take those amplifier preamp circuits and create a similar circuit using J201's and other opamps.  They sound pretty darn good!

I REALLY want to do a pair of LA-3A's or LA-4A's as well as a couple of 1176LN's.  First thing's first: knock out 4 of these dbx 160VU's.

And IC: that's a great suggestion about hooking up a switch between the filter caps to see how they impart the sound. 

DY

DY

 

[Tekay]

On topic- I was thinking about this power supply issue. Is anyone going to implement a sag switch? I was thinking about moutning the 470uF and 4700uF off board, and then hooking up a switch to flip between them. Mainly just to easily see if there is some mojo that gets lost with the cap upgrade. Could be interesting if it's workable.

Don't switch between them, use the switch to add the extra 4700u, otherwice your voltage will be unfiltered between the positions and put a resistor betwen the positions so you don't switch in an uncharged 4700u. Don't think you want the pops and hum when you change between the caps.

Just a thought!

 

[haima]

good point TK!  ;D

 

[Rybow]

That is a good point. Thanks Tekay!

 

[damnyankee]

Hi Guys,

While I'm awaiting the rest of my parts from Mouser & Digikey, I thought I'd fiddle around with Front Panel Designer.  I have a few questions:

1.  19" 1U or 2U rack?  (as cheap as this build is: <$120 or so, I'm assuming everyone will be building two units)

2.  Which VU/DC meter from Hairball did we decide on?  http://hairballaudio.com/shop/index.php?cPath=25

3.  I assume we're going to use the 4 button 1176 switches from Hairball Audio, correct (3 for meters, 1 for power off)? 
http://hairballaudio.com/shop/product_info.php?cPath=28&products_id=55

4.  What size holes should I use for the Threshold, Gain, & Output Gain pots?  (Come to think of it, I don't recall any pots being on the BOM list...so what type should they be?)

Thanks in advance,

DY