MPP

RCruz · 2012-08-12 1:01 pm

FdW said:
So the big disasters is in fact not so big at all

Cool

RCruz · 2012-08-12 1:03 pm

Back to Paradise.... Why the super filtering (2 x 4700uF) over the first mirror ?

Can I use lower values ?

jacco vermeulen · 2012-08-12 1:17 pm

R27 (29) is 120 ohm.

RCruz · 2012-08-12 1:29 pm

jacco vermeulen said:
R27 (29) is 120 ohm.

Ok and Fc = 1/ 2 pi RC

Using only one 4700, we get 0.28Hz... not so bad right ?

jacco vermeulen · 2012-08-12 1:35 pm

1mA variation across 120R makes 120mV
1mA variation over 2 x 4700uF makes ?

Joachim Gerhard · 2012-08-12 1:47 pm

Ricardo, you can use 2200uF.

RCruz · 2012-08-12 5:09 pm

Joachim Gerhard said:
Ricardo, you can use 2200uF.

Thank you Joachim

Why the choice of 2 x 4700uF ?

Joachim Gerhard · 2012-08-12 5:32 pm

It is over dimensioned in the spirit of High End.

RCruz · 2012-08-12 6:36 pm

You are joking I presume.... Anyway, my experiences with shunts gave me de impression decoupling / filtering caps do not need to be too big... and I have some good caps but not in 4700uf so these are good news.

Joachim Gerhard · 2012-08-12 8:39 pm

Passive RC filtering has it´s merits. One is very good transient response or should i say slow response.

RCruz · 2012-08-12 10:33 pm

Joachim Gerhard said:
Passive RC filtering has it´s merits. One is very good transient response or should i say slow response.

??

Very good transient response.... not slow right ?

Joachim Gerhard · 2012-08-12 11:31 pm

No, passive filtering is slow. Thats the name of the gave.

Bksabath · 2012-08-13 12:27 am

Joachim Gerhard said:
No, passive filtering is slow. Thats the name of the gave.

I have noticed quite a big improvment in using a second comon mode coke after the pre regulator

For the beta I had just one trafo and 1 board as drafted a while ago
this won't be the case for the V3 build

Joachim Gerhard · 2012-08-13 12:32 am

Joachim Gerhard said:
No, passive filtering is slow. Thats the name of the game.

hesener · 2012-08-13 10:38 am

RCruz said:
Thank you again

I do not see placement for C91 and C92 on the board... Guess these filtering/decoupling caps for the opamp psu lines proved irrelevant right ?

yes, I ran out of space, and since there is one cap there and the PSU caps quite close I took that risk. proved to be fine.

Bksabath · 2012-08-13 12:43 pm

Big $1M question

I am really happy with my V2 Paradise. (Not big secret is it?)

Now waiting for the V3boards I am thinking about really pushing the boat out and use the best components I can get without getting over the top. I think the FM type caps are fine for the job as an example

Now my tanking is V2 sound pretty good as it is and is going to be difficult to make a big difference.

So, considering the law of diminishing returns, where is the best place to throw money at it?

Apart from supply and pre regulator (I am thinking R cores Trafos and big multiple common mode chokes) would it be worth paying attention to the 120 Homs resistors on the mirrors?

Any thoughts?

hesener · 2012-08-13 1:16 pm

In my humble opinion, using the best RIAA components and spend a lot of time matching them between the channels, and also the transistors of the input stage, should give the biggest gains....
glad you like it - we are at 265 sets (!!!!!) right now..... group buy will be closed today....

Joachim Gerhard · 2012-08-13 1:26 pm

That is an enormous number. I am very happy that so many trust our work.

Bksabath, I use Dale RS60 or RS65 resistors in the RIAA and in some points in the signal chain.

Stefanoo · 2012-08-13 2:53 pm

Bksabath said:
Big $1M question

I am really happy with my V2 Paradise. (Not big secret is it?)

Now waiting for the V3boards I am thinking about really pushing the boat out and use the best components I can get without getting over the top. I think the FM type caps are fine for the job as an example

Now my tanking is V2 sound pretty good as it is and is going to be difficult to make a big difference.

So, considering the law of diminishing returns, where is the best place to throw money at it?

Apart from supply and pre regulator (I am thinking R cores Trafos and big multiple common mode chokes) would it be worth paying attention to the 120 Homs resistors on the mirrors?

Any thoughts?

RIAA parts and matching (caps and resistors) also matching of the input stage and film bypass capacitors and bulk capacitors on the PSU.
If you are powering it with battery, good quality there will make a significant difference (same as Transformer if you are using one).
Also quality on the OPAMP should make a difference. I would recommend it to replace the OP AMP with a discrete module.

jacco vermeulen · 2012-08-13 3:26 pm

You don't happen to have an example of a discrete opamp for servo use ?

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