All things Green Pre

[dissonantstring]

hi mike,
either xicon (i use them all the time) or panasonic (which i sometimes use in fx pedals) will be fine as long as they are metal film 1%. just use 1/4 watt (unless 1/2 watt is stated) for ease of mounting on the green pcb. no benefit to using 1/2 watt as there isn't enough current draw in the greens which require 1/2 watt IIRC. the panasonics at DK have smaller casings than the standard sized 1/4 and 1/2 watt resistors so you'll be exposing more lead when mounting (just something to be aware of). xicon (at mouser) and yeago (at DK) are the same in my experience, i order either brand (whichever is closest to the required value). hope this helps.
regards,
grant

 

[Phrazemaster]

Hey grant, excellent info my man! thanks!

 

[kato]

[quote author="Phrazemaster"]you rock kato! thank-you!!!![/quote]

You're welcome. (Re: molex connectors)
If you haven't ordered them already - they arrived today and I think I prefer the more expensive "friction lock" ones from the same catalog page.

I've ordered those before and liked them. But then I took someone else's advice to get the cheaper ones that don't lock. (that I mentioned in my post)

It's a really minor distinction - and both will work fine - but if you're picky like me - it might be worth the extra expense to get the locking headers.

I edited my previous post with with more expensive connectors.

 

[Phrazemaster]

cool beans, nice distinction! I have not yet ordered, but I will update!!!

 

[Phrazemaster]

Hi, perhaps a stupid question, but I'm looking for high quality caps for the green. I have seen references to "non polar" and "bipolar" capacitors, and I'm wondering what this means? Can I use them in the green, and if so where? Are they compatible with electrolytics, or what? Or should I just avoid these? I guess I'm under the impression that the circuit has to be designed for these in particular, but I'm confused as to nonpolar vs. bipolar vs. "no polar" (ie nothing stated).

Also, I thought I read somewhere that it is OK to use higher voltage versions of capacitors in the circuit. Is this true of the green (and any place it's not?). For example, if the green BOM says to use a 35v cap, can I use a 50v instead? If so, how much higher is it ok to go, any advantage or not? And would increasing the actual capacitance of any components have any value (ie use a 2000mf instead of a 1000mf (I have read this is cool, but there seemed to be some stipulation that this could tire the regulator too quickly, but in another place someone was saying how great it was, gee I'm corn-fused!)). <--Please note correct closing of parentheses; that dog will hunt!

I'm sorry if these are obvious or covered elsewhere, but I have been reading my eyeballs out and I'm just going to ask the direct questions; I hope you don't mind. I have been reading quite a bit on this forum (like, HOURS!!!).

Thanks any help in advance.

Mikey

 

[Phrazemaster]

bump

anyone help a brutha out?

 

[peterc]

99% of caps fall into 2 categories: polar & non-polar.

Polar: Electrolytic & tantalum (mostly), the pos terminal shown with a + and a square solder pad on my PCB's. There are other types of polar caps, but are very few & far between. (Panasonic, Nichicon, Rubycon, Elma are some of the good brands here).

Non-polar: ceramic, polyester, polycarb & polyprop, polystyrene, paper in oil, these are generally non-polarised & are shown with no polarising marks on the PCB. Wima are popular for the poly types.

DONT GET TOO HUNG UP on the brand of component. If you choose from the above list, you're going in the right direction. The circuit design will have FAR MORE bearing on the sound than the types of caps used.

You can use a higher voltage cap than specced, but dont go too high as the polarising voltage will not be enough to keep the caps properly formed & there moght be a difference very long term - in 10 or 15 years time. But todays components are such high quality, it might not even be an issue.

You could change the cap values if you wished, but be aware that the current values are way over-rated anyway where possible.

My advice is to just get on & build the pre, get to know the sound, & THEN try different options for components. I have built them with really odd types of caps, mixtures of carbon & mo resistors, 1% & 5%, & they still sound great. Hard to tell the sound difference between the old one & my "standard" build.

Peter

 

[matta]

Hi Mikey,

Hi, perhaps a stupid question, but I'm looking for high quality caps for the green. I have seen references to "non polar" and "bipolar" capacitors, and I'm wondering what this means? Can I use them in the green, and if so where? Are they compatible with electrolytics, or what? Or should I just avoid these? I guess I'm under the impression that the circuit has to be designed for these in particular, but I'm confused as to nonpolar vs. bipolar vs. "no polar" (ie nothing stated)

.

Non polar caps are normally referring to Poly and Ceramic capacitors, Electrolytics are typical polarized, though one does get NON or rather BI-POLAR lytic caps. I don't think those can be used in place of any of the lytics speced out for the Green, you are safer using polarized caps, and RE good brands, Nichicon, Panansonic and Rubycon all make good quality caps.

Also, I thought I read somewhere that it is OK to use higher voltage versions of capacitors in the circuit. Is this true of the green (and any place it's not?). For example, if the green BOM says to use a 35v cap, can I use a 50v instead? If so, how much higher is it ok to go, any advantage or not? And would increasing the actual capacitance of any components have any value (ie use a 2000mf instead of a 1000mf (I have read this is cool, but there seemed to be some stipulation that this could tire the regulator too quickly, but in another place someone was saying how great it was, gee I'm corn-fused!)). <--Please note correct closing of parentheses; that dog will hunt!

Correct, you can use a higher voltage cap, the only issue you will have will of course be the space the bigger cap may take up compared to a lower voltage, also it is generally accepted to use as mid range voltage cap, i.e use a 50V in place of a 35V, but don't use 200V, not only will it probably not fit, but it will impact on the sound of the unit, negatively. 35V for the Greens for most caps is ample since the operation voltage is only 15V, except on the phantom rail and phantom blocking caps where these should be 63V for safe keeping.

RE using the value of the caps, rule of thumb is go up not down, so use a 220uF on place of a 100uF, not a 50uF in place of a 100uF, you dig? I would try where possible to stick to the original values for this project, built it like that and mod/play later, it may make it easier to troubleshoot if you run into any issues.

I'm sorry if these are obvious or covered elsewhere, but I have been reading my eyeballs out and I'm just going to ask the direct questions; I hope you don't mind. I have been reading quite a bit on this forum (like, HOURS!!!).

It is only obvious once you know it. Now you do, retain the info, move on :thumb:

Cheers

Matt


EDIT: Peter C beat me to it! South African's win again! LOL

 

[Phrazemaster]

Thanks Peter and Matt,

I do tend to overthink and analyze stuff, and I hear to just get decent quality caps and the design itself has more impact than the quality of the components per se, and playing with the specific caps and things will make more sense down the line. Understood, thanks. Sorry, I don't mean to be too nosy, but I do like to know as much as possible. When I get into a subject I tend to get into waay to much detail sometimes.

Thanks both very much for the info and advice; that helped a lot!!!

I will be posting pix and build progress as things go on. It will be a while before I get the boards and parts, but just trying to build a good foundation for all this stuff. I like to know as much as possible, but maybe its like the kid at the top of the slide trying to calculate wind shear factor and friction values for specific sun angles on a certain day, and how it might affect the quality of the experience. Get off your *** and slide already, lol!

Thanks again, and what a great board and people you all are.

Cheers,

Mike

 

[Phrazemaster]

OK can you stand one more cap question?

I have noticed that some caps are called "DC" caps, and some rated for AC/DC. And some don't seem to say either way. Any thoughts on this? Whats the diff betw them, and what would happen if a DC was used for an AC, etc.

Thx

 

[matta]

OK can you stand one more cap question?

No I can't, Hah hah!!!!

I have noticed that some caps are called "DC" caps, and some rated for AC/DC. And some don't seem to say either way. Any thoughts on this? Whats the diff betw them, and what would happen if a DC was used for an AC, etc.

Thx

Inmost cases your primary concern is the DC voltage the cap can handle, since the voltages across it are regulated DC, so check out the caps DC voltage limitations as first port of call.

Hope that helps

Matt

 

[Phrazemaster]

thanks Matt, that helps.

So I don't need to worry about AC/DC unless the Voltage value (AC or DC) is not high enough, if I understand you correctly. That means "DC" caps are fine, if high enough.

I guess I just have a fear of burning the house down lol. Thanks

 

[Phrazemaster]

Nichicon HEs or Panasonic FMs?

For the PSU caps...

 

[Phrazemaster]

Capacitor info

:thumb:

 

[peterc]

DONT GET TOO HUNG UP on the brand of component. If you choose from the above list, you're going in the right direction. The circuit design will have FAR MORE bearing on the sound than the types of caps used.

No difference

 

[Phrazemaster]

So noted, thanks.

 

[Phrazemaster]

Hi, just a question, would there be a way to effectively mute a mic channel, other than turning off the green pre? Perhaps an extra stop on the Lorlin switch or the gain pot, with an open circuit or something? Sorry if this is obvious, just trying to learn and grow.

Thanks,

 

[Phrazemaster]

Bump, anyone? Plus another question...

Some folks claim using a linear pot with a law-faking resistor can make a better overall pot than a log pot, which as I understand it often fakes itself anyway via using different sets of resistive material, so there is more of a jump in values. The law faking resistor with a linear pot supposedly can make a better result.

Would this work for the green pre 10k log pot, and any thoughts how to wire it? My understanding, flawed as it may be, would be to put a 1k6 resistor between cw position and wiper. Or is this just a bad idea?

Thanks. I'm trying here! But its a cruel world for the stupid!

 

[peterc]

would there be a way to effectively mute a mic channel,

You could use a switch to ground the wiper of the ouptut level pot.

I dont understand why you would want to change the law? The log pot is the right part for this application, besides I think your description is to make an ANTI-log pot. What are your references?

There has been some discussion for this process on this board, genrally does not work very well was the general concensus AFAIK.

Peter

 

[Phrazemaster]

thanks Peter, not trying to change your design, I just found a lot more linear taper pots than audio, and wanted to see if I could get a clarostat or an alps. yeah i know, just build it, but i like to find out as much as possible.

thanks very much,

Mike