Supergreen Thread

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Josh - Maybe if you have a few minutes to summarize the screening errors / corrections and put them in the first post of this thread it might be a good idea for people searching in the future =]

Just a thought!
 
[quote author="antiguru"]Josh - Maybe if you have a few minutes to summarize the screening errors / corrections and put them in the first post of this thread it might be a good idea for people searching in the future =]

Just a thought![/quote]

Certainly. I'll put that together.

My boards are completely stuffed now. I'm going to use a green psu from Ptownkid. It seems the modifications are minimal to make it work.
Has anyone purchased a power toroid yet, if so which one?
 
I lied, I have 1 more question while I wait for my rear panel to be machined.

I have 10 OPA604 opamps, which are pricier than ne5534's.
Would you recomment the NE5534's over these or not? Is it a matter of taste or is one better. I would like to use the 604's because I have 10 sitting here doing nothing.
 
Usually i'd say the ones that do more gain may notice a bigger difference
but there only is the buffer and output drivers , not sure if the impedences [ or range ]
are the same on the chips , but with only three
it isn't many sockets , which is what i've done on mine
but haven't got the transistors yet .

Regards Greg
 
Electrolytics C9, C10 are recomended Low ESR.
But what about C13 to C115? They are also 100u, so just the same as above?
The BOM posted on this thread choose "low Z" instead of "low ESR". Just for price or what one are better?


More, C20,C21,c27C28 10uf (FKP2 or silver Mica), FKp2 better?
C31 to C113 100n (MKT or ceramic) , better the MKT?

Not easy to find those FKP2 on 10uf here in Spain, as well as the Mkt on 100n, but I would like to put the best components posible.
 
[quote author="olafmatt"][quote author="lagoausente"]Not easy to find those FKP2 on 10uf here in Spain, as well as the Mkt on 100n, but I would like to put the best components posible.[/quote]

I used Wima MKP4 for the 10uF and silver mica for the small ones in pF range.
Concerning the Wimas, if I would build one again I'd probably try something else. These Wimas are so large that they pick up quite a strong hum field from the power transfromer. So I ended up putting a shield in front of the caps on the channel that was closes to the power transformer.

Olaf[/quote]

I want to supply the Supergreen with batteries. Probably will use 4X9V batteries for +/- 18V. I´ll have to measure the batteries Z to find if there is no drop on voltage. But till now have to say that on a test with my Presonus Mp20, using those 4x 9V batteries, I realized a quite noticecable improvement with the Batteries. Simply much more "clean". The AC PSU adds a important noise, also on high frequencies, maybe from Diodes? maybe from the regulator? don´t know.
I concected the batteries after the regulators, and with just that, it sounded better than with the AC PSU.

Concerning the caps, I had a missprint. My doubt is not about the 10uF. I already have them.
My doubt is about the 47p (fkp2, or silver Mica) (C20,C21,C27,C28
and 100n (MKT or ceramic).
Having in account that offer the two posibilities, I want to know what diference maybe be betwenn FKp2/silver Mica, and MKT/ceramic, or if it´s totally the same performance?

More doubts; about relays, what are Single and double winding? and what latching and non latching?
I´m checking those G6h-2 relays. I´m thinking on use 9V instead 5V, so could take the voltage from one of the two 9V batteries that I will use to get the +18V.
 
Any hint with my doubt about type of caps?

FKP2 Vs Silver Mica
MKT Vs Ceramic ?

And also a question, can be used the 990 opamps with the supergreen?
 
Why brass? I bought (well my work did anyway :wink: ) 1/4 of a sheet of 16 ga. aluminum for making shields and whatnot. Do you suppose this would work also? I know nothing about shielding, only that EM fields are very touchy about being present or not, and that Jaako enclosed his Sontec modules in aluminum
http://www.thediypill.phx.com.br/diy_sontec.htm
so I am too

Thoughts?
 
Thanks Olaf.

And about the Electrolytics, on the part list only specifies C9,C10 to be "low ESR", but on the notes at the end of the list tells about "low Esr" in general. So maybe better take them all low ESR?

And about the Hypergreen.., I suppose DOAs, means Dicrete opamps, isn´t? About the Space, that 990 capsule it´s a little big fot the PCB, but maybe could fit in it in some way. The question is if it´s worth having in acount the Supergreen topology. I have not knowledge enough to valuate the pros and cons of this design, so I´m not sure where the bottle neck could be.
Would the 990 replace the dual Ne5532AN on the first stage? or would need two 990 for replacing the dual?

I had already listened the Jens samples. Nice. I liked the TI NE5532 best.
 
Thanks Jenssenmann. I apreciate this replies. It´s my first DIY, and even I have basic electronics knowledge, I´m still lost about preamp desings, and all this infinite world of reading and reading. At this learning point have to ask sometimes things that I know are very basic for the guys on the forum, and even it sounds absurd, I´m still trying to find out, what really I´m building. I mean, what are the advantages and limits of this preamp.
As you tell, this design allow a very neutral-pre at affordable cost.
This suggest me more doubts.
Well, this is a trafo-less design. What limit the performance of this designs, the thing that have no trafo? Seems that Trafo based preamps, look for a specific color, but seems that also some designs using trafo try to use it to get things up, or I´m wrong?
For the Supergreen, I could finally get the original 2SC3329 transistors, the big Wimas, etc.
I guess what more can get, moreover the neutral sound, what is very fine. I mean, low distorsion, low noise... I´m still not sure if this parameters give better sound, because have reading several times about pres with higher dist, and noise sounding better then other with better specs... so get me more confused.

The DOA seems atractive, although complicate things, if can open a new door for the preamp sound, if really can clear things up.
I have read some suggestion from Jim Williams from Audio Upgrades, recomended trying the LT1357 opamp, what is designed for video. This one is a 8 pin compatible, so no problem to try it, and found about.


The 990 is an atractive thing to try, but I think would need some help for the isolation issue.
Do you think the 990 would worth the try on this preamp, or do you think would need other design to get the best of the DOA?
 
there are a lot other DOA based designes out there where the designer had the advantages of an DOA in mind, hence they are optimized for a particular DOA. I´d prefer this for an DOA pre

I listened to your samples. I find TI NE5532 sound clearer then the other three. I found more details on the voice, and natural, even others didn´t ear the same. Anyway diferences are not very high.
I guess what diference may be between a Monolithic and a discreete. Have you compared that anytime?
 
A question about "low ESR". Is important the get all electrolytics low ESR or only the specified in the part list?
At the end notes tells: "electrolytic cap must have temp rating 105 and low ESR...

So, them all, or not?
 

Latest posts

Back
Top