Ross comp/Dynacomp as a possible first project?

[powerplayj]

I am thinking of undertaking my first project and I need a compressor.  I am comfortable soldering and have modded several pedals and do my own pickup/switch/pots wiring.  I like the idea of doing the Ross/Dynacomp dual pedal but, is this a bit too ambitious for a newbie?  I hear the Orange Squeezer is more for a beginner but, I like the versatility that the Ross/Dyna would offer.  What makes the Ross more complicated? (I assume the 5 transistors and dealing with their orientation would be one obstacle)

[Mark Hammer]

There are two FETs in the OS and 5 transistors in the Dynacomp, with a trimpot in each.  So, there is possibility for error in each when you factor transistor pinouts in each.  Francisco Pena has been gracious enough to provide decent PCB layouts for each.

In terms of screw-ups, I can't see one being a bigger deal than the other unless your soldering technique is shoddy (more pads/joints in the Dynacomp so more chances to mess up signal continuity), but yu've indicated it isn't.

If you were planning on going the PCB route, then attempt the Dyna/Ross.  If you don't like, but you still turn out something relatively competent, you can always sell it.  If you are going to go the perfboard route, however, I would strongly recommend the OS.

As many many comments on this forum will attest, they each have their strong and weak points.  For me the only way to flip this hypothetical coin is to go by convenience.  The OS may be a bit more convenient in terms of acquiring parts and assembly.

[brett]

Another point worth noting is that the Ross takes out LOTS of treble, so maybe the straight Dyna build would be a good option.

[petemoore]

It took me a while to develop my debugging skills, had I tried a Ross as a first...I would have surely been stoked if everything went right the first time and it didn't require any debugging and I found that I'd made exactly 0 x 0 mistakes.
 I'm having trouble computing the odds.
 THe Ross with PCB is 'color by number' *Pretty much, findiing the problem was easy: It didn't work right.
 Finding the solution was another matter tho.

[PB Wilson]

I started out my foray into DIY pedals with a Big Cheese clone (RG Keen's Great Cheddar). Most people suggest a booster pedal or an A/B box because of simplicity, but if you are careful, you shouldn't have too many problems. If you are using a ready-to-solder PCB, your chances of success are greater as well.

I've had a few pedals that didn't work immediately (I forgot to put the IC in my Great Cheddar when I first fired it up  :oops: and for my Scrambler, I had to bend the transistor pins to achieve the correct pinout, and my PT-80 delay, well let's just say that one of my next projects is an audio probe :roll: . I say go for it!

[BDuguay]

If only I could figure the quoting thingy. Say Brett, I've built the Dynacomp from tonepad and later, changed it to a Ross without any noticeable treble loss. Please explain.
B.

[Mark Hammer]

The discrepancy between Brian's and Brett's experience with the Ross/Dynacomp build may stem from a typo on one of the issues of the PDF file.  A cap to ground on the input, for rolling off problematic highs/hiss, etc., is accidentally shown as 2200pf when really it should be 220pf.   That tenfold difference in value in that particular location will drastically affect treble response.

[Kleber AG]

Most peoole say the Ross has less highs than the Dyna, but I believe this is due to the first wrong believed 0,0022uF at input, that now it's sure to be just a 0,00022uf(220pF).

Then I   wonder if the Ross lack of highs reputation wasn't due to that wrong cap value at first, but now with the right cap vaulue it's reputation remains the same....

I hope I wrote that right, hope it makes sense...

Can someone confirm, and help the Ross reputatiion??? :lol:

Kleber AG
Note: Nope I only have an "script logo" DynaComp... not a Ross...

[Kleber AG]

oooopsss... I guess I'm too slow trying to type in english, sorry Mark, I was writing while you posted your response... :oops:

[petemoore]

With all the Ross talk, and crossRoss talk :wink:
 I've been using the Ross Dyna and have an answer preceded by this question:
 Fransisco made the board for me, and it is completely filled with parts...Do I have a Dynacomp, or a Ross Compressor?
 Answer...in the form of typed feeling, my unfettered impression[till the lack of highs post] was that the highs, [though not excessively omnipresent], are bountiful and well defined on my Ross/Dyna build.

[powerplayj]

Anyone got a roundabout cost on this project before I go to itemizing it myself at Small Bear? (yeah, I'm lazy)  Since it will be an "always on" pedal for me I plan to go hi-fi as possible (metal film resistors, Panasonic poly film caps, etc.).

[Fret Wire]

It would be easy to go "hi-fi" on this project. Use Panasonic ECQ-V metal film for the caps, and metal film for the resistors. For the 10uf electro, you could use a Panasonic 10uf @25 or 35v tantalum.

For cap values over 1uf, I try to use tantalum. Depending where and what it does in the ckt, when you sub metal film or tants for electro's, sometimes you will get what sounds like slightly less, tighter bass. It's really just the effect of some muddiness removed.  This has been my experience, but remember, sometimes it does nothing you can hear. As long as the tants don't recieve any reverse voltage. And tants cost more than electro's.

As far as the 220pf cap, I doubt a silver mica will fit on Tonepad's  board. It's pretty tight. You could try a monolithic ceramic 220pf, they look like little tan resistors. I haven't A/B'd those against disc ceramics to say for sure if they are worth the bother, though. Maybe someone else will know. Being that it's not a distortion, ceramic disc's would have no value (extra dirt) to offer if there was something cleaner or quieter.

[brett]

Thanks Mark and others for explaining my lack of treble in my Ross.  I'll swap that cap soon.

You could try a monolithic ceramic 220pf

As far as I am aware, the audio qualities of monos are similar or inferior to ceramic disc, and their tolerances are wider, so they aren't much good in the <1000pF range.  From 1000pF to 1uF greencaps and *especially* MKTs rule IMO.  Above 1uF you could argue about tants and electros, but in the Dyna/Ross and other circuits, they aren't in the audio path anyway, so there's not going to be a noticeable effect if they were made from hen's teeth.

I'm no expert, but that's my 2c worth anyway.

cheers

[Fret Wire]

Brett, have you actually tried the mono ceramics? I haven't. Above 1uf? You can hear the difference when you sub tants for electro's depending on where in the ckt it is. That's from experience.
Sometimes, they defy the rules, and the opposite of what you think will happen does. From .001 to 1uf, I like the Panasonic ECQ-V series, but that's another story.