Supergreen Thread

[josh]

You know, this has been bugging me all day, and here's why. How is it fair for you to come at me like that? I don't have to apologize for what I dont know and I'm never going to. To you or anyone else. Unless you came out of the womb knowing what all those damn symbols and scribbles mean, then you have no right...

EVERYONE was in my place at one time. I've said many times I don't really know what I'm doing, but I am trying, and if you feel my questions are below you, then feel free to ignore them. All you're going to do with smart-assed quips is start a fight.

When someone takes a ***, then follows it with the winky eye :wink: it means they were KIDDING But one day I will know what I'm doing, and I'll guarantee you now that I won't look down on the guy who has 1.5 successful builds outside of stompboxes that were all so well documented that he didn't *have* to understand the schematic. No way.

 

[antiguru]

ps- i figured it out, snooty comments aside.

 

[okgb]

I think anyone should have an idea of reading a schematic , so you can understand what you are doing , if not , then accept this will be a learning curve , not exactly a great first project .


So maybe i didn't make it clear when i was ordering boards , but even
not being a kit , means somehow anyone will have to figure out what
they want to use , i just liked the schematic in princple and wanted a pair
so went ahead made a group order .

I still haven't ordred all the parts as i think i'll deviate from the bom ,
Which another member made up on his own time [ thank you ], but it gives you a great place to start , i'm going to sub a few caps and where
i am lazy just order the parts he speced , if there is a problem i'll deal with , cause no one told me there were any guarantees .

I remember when i first start buying parts , if i couldn't tell them exactly what i wanted , i'd end up with whatever and find out when i got home
and started to build it , then i learned to look a little harder ,

So even though this may not be fun , you'll get smarter
[ and you may finish your preamp before me ! ]

Happy d.i.y.ing regards Greg

 

[josh]

moved from the other thread per G's request

FYI:
I just noticed a small error on the boards and I dont think its been mentioned. C102 & 103 are on the board twice. If you look at the component pdf, in the lower left hand corner are C112 & C113, but the board lables them incorrectly as C102 & C103.

I was wondering why I had extra WIMA's laying around

Also, C15 right next to IC1 on your board is not listed in anyone's BOM should be 22pF but I cant tell what type though?

 

[okgb]

The schematic has two R 20 s , where the circuit board has
R20 & R22
LOOKING at the schematic it would appear both are 100K to ground after the last opamp , so no worry , just a tiny bit of tracing

For c15 in the pf range there is not too much choice ,
ceramic would be common , anything better as in a poly-type
considering it is feedback may be better
bom omission noted [ really ? both versions ? i'll check tomorrow when
i'm not working ]

Hey Olaff is it o.k. to photo bucket your schematic to this thread ?
[ i'll do it if you say it is o.k. , i think it would help some ]

regards Greg

 

[StefanAC]

Dunno if it's an error but to me D6 and D7 are drawn in the wrong direction as I compare Olaf's overlay file with my boards.
I put them in as Olaf suggested and hope everything will be alright, cause the tracing is the same, only the diode direction differs... :?:

 

[okgb]

I know Olafmatt & Salsa weren't starting this up and just making the info
available for others but if you guys know better and have the time ,
we'd be gratefull ,

Hey Salsa , did you finish your proto types ? if so any issues ?


I'll try to combine issues into one post , i only have resisters in mine
i usually get the case & power supply ready first , but again despite the overlay [ is it all reverse ? ] double check the schematic against it as well
, does it matter ? or make sense which direction the diodes are ,
meant to be back to back ?


O.k. which the relay power info is not on the schematic
.... d6 & d7 are for the relays , so despite what the screen says they should be oriented correctly for the voltage , no ?
Which looks different than the d5 relay diode , hmmmm


Who will be the first to finnish their Super Green ! ?

regards Greg

 

[delaymix]

Hello,

This it is a project that in addition to not being indeed easy, brings with himself some that another "surprise". :?

The diodes D1, D2, D3 and D4 in the scheme are oriented opposite to each. In pcb the marks are inverted the other way around.

Diodes disposition, part of amek 9098-a original scheme

Diodes disposition, Olaf scheme

Diodes disposition, Supergreen board v1.6

Diodes disposition, Supergreen board Olaf prototype

 

[okgb]

On Olafmatt's site he does say not to follow the picture as it was
a prototype .
Here's a question that shows my ignorance , but is it critical when
diodes are back to back , which direction they are ?
That's how you make a bipolar cap right , i'll dig into it

but maybe that we have to ignore the screen and follow the schematic

regards Greg

 

[delaymix]

[quote author="okgb"]On Olafmatt's site he does say not to follow the picture as it was a prototype .[/quote]

Certain, it is truth.

I believe that exists certain controversy between pcb version 1.6 and theoretical schemes.

regards delaymix.

 

[okgb]

It would seem they are more correct as in the schematic ,
that is the way i have seen it any other place so far
Easy fix for the board , hopefully no other Oops's in there

They seem to be for input protection , and as such shouldn't come into play until their voltage is reached , so if they were backwards would take
the negative part of the waveform ? or still come into play at that voltage?

Nice catch though , Anyone have a finished Sgreen they'd like to comment on ? Time to search the old threads for a build

 

[jensenmann]

-

 

[lagoausente]

I used 2SC2240s. Way easier to get and a low noise type, too. This one has been suggested in different places for the obsolete original transistor.

2SC2240 Vs 2SC3329

Since seems avaible to get any of them, is any advantage on getting any of them over the other?

 

[Rossi]

If you can't get the 2SC3329 (which is the lowest Rbb transistor known to mankind) get the 2SC2546.

I tested various low Rbb transistors in a ribbon mic input stage (which is probably as critically as it gets regarding noise). I think I tested the 2SC2240 as well, and while it is better than usual "low noise" transistors such as the BC550, it isn't as low noise as the 2SC3329 or 2SC2546.

 

[Samuel Groner]

Which is the lowest Rbb transistor known to mankind.

You might check the 2SB737. Most power divices will have much lower Rbb as well.

Samuel

 

[Rossi]

The 2SD737 (Rbb =2 ohms) is a PNP device. The NPN counterpart is the 2SD786 (Rbb = 4 ohms). Unfortunately both are obsolete.

Believe it or not, Behringer used the 2SC737 quite extensively. I found them in my old Ultragain 2000 and also in my MX8000 (the older grey model). Later they used the 2SA1316 for a while. Behringer now use a transistor with the unusual number 2SV888. I've long tried to find information on that transistor, and finally found it here (no datasheet, though, and there doesn't seem to be a NPN complementary ): http://www.coolaudio.com/products.html

For all I know, Coolaudio belongs to Behringer. So apparently they now build their own semiconductors. :shock:

 

[Gus]

Think about the zener clamps

.6 or so volts one way and about 20V the other

so a 20VDC + .6 VDC diode clamp

 

[josh]

3 more questions and my boards are stuffed. This time I looked at the schematic until the numbers were running together, I swear!

-D5 D6 and D7 are not listed on the schematic, nor on anyones BOM. You all are talking about them above, but how do you know *what* value they are? There is no reference to them anywhere?.

-I used a 4 pole switch instead of the 1 pole. Is that going to matter? I have some 1 poles in stock if it does.

-not a question. See here for the orientation of the relays toward the bottom of the page: http://oeiwcsnts1.omron.com/pdfcatal.nsf/PDFLookupByUniqueID/D6757D14AF00758C86256D350051C3D2/$File/D20G6H0503.pdf?OpenElement

-I decided to use the 2N4410 transistors since Mouser recommended them. I am going to socket them in case they need to be swapped. Maybe later on when this thing is up and running I'll do an A/B with different transistors for y'all.

 

[okgb]

d5 ,d6 , d7 are for the relays , i'd think most any diode would do ,
but most often see a small signal glass one like a 4148 , or 914 ?

The power part of the relay was not on the schematic , perhaps to keep
it cleaner to read .

You may be the first to finnish your S.G. Pre !

If you have only need one pole and your switch has 4 , but you don't use them , no problem , it would be a waste if you bought it , but if you had
it or got a good deal , won't hurt anything , which switch ?

socketss a good idea , we should get it into the bom

regards Greg

 

[lagoausente]

I would like not to use special supply for 5 volt for relays. Any suggestion for relays that acept any other variable voltage, like 9V, 18...v to can get directly from batteries?

Any suggestion for a portable case for a pretty stereo SG? I looked at the Hammon cases, but I´m not sure how will I can make the holes for the XLR`s :?