MPP

[FdW]

Hi Quick one before I get ready for flight to Venice.

Yes got R2 Boards
The noise is hiss, white noise.
There is no hum boards are realy good even with open box and fluereshent tube inches awayor moving things around there is none whatsoever the board design is absolutley brilant.

As Albert say it is strange and I think it's My fault seting up V at tp1 tp2
I have both a 25 25 Trafo and 30 30 trafo with 25 X 1.471 and diodedrops I got around 35 + - going in to the boards.

Once again I can change the V at the TP1 and TP2 (+17.5 - 17.5 at present) with the 2 k pots WHAT shuld it be set at please?

I am going to try to take it up to + - 25 at TP1 TP2



On regards to ofset I got 1.36 mV I tried the mod and it fit nice and easy on botom of boards.
It can be set to nothink and desapear with small loading resistor.
I like the space and the 2 set of pads round the imput pins Ideal for small caps and load resistor as needed by MC

Do not change the voltage above 18V on the R2 board. The 17.5V for the R2 board is just fine.

 

[RCruz]

The 5.1V will work, but given the high input voltage I would prefer something higher. The 5.1V is the minimum value to be used; it just allows the CCS to work properly. The voltage at TP202 should be the same as at TP203 minus Vbe(Q202). The next thing to do is check the value of R203 and replace Q201 and Q202.

Thank you Frans... I will work on that tonight

 

[Bksabath]

Tanks Frans
will live as is then and re visit suply some what quiter with small 100NF on soket from umbilical.

Well I am off now see you next week.

Live well and prosper.

 

[Joachim Gerhard]

My R2 is very low in hiss, even lower then R1, so i can not explain the problem with hiss that Bksabath has.
Thanks Hesener, to include the offset cancelation. This may not normally be needed, only with higher impedance cartridges and for the total perfectionist.
It works like Bksabath found and good to have it.

 

[Benedetto]

Another question from the Fool;
because i've got most of the R values in 1/4W.
Are they useable ?

 

[Joachim Gerhard]

Yes, but not the bigger resistors that program the current sources ( 10 Ohm ) and the ones that supply in input stage ( 120 Ohm ). Those have to be 2W minimum. I use Metal Oxide from Reichelt, other like Frans prefer Metal Film because of lower voltage coefficient, hence lower noise. It does not make an audible difference though. The impedances are just too low.

 

[Benedetto]

This is fine to me.
Because i've already bought the bigger ones @ "B".

 

[RCruz]

Hi Frans

I found TIP31C is shorted... I allready ordered a spare

Regarding the new paradise, Can I use TIP31 (NPN) and TIP32(PNP) instead of D44H11 and D45H11 ?

 

[Joachim Gerhard]

Good that a REAL problem was found.
I think you can use the TIPs but i will look up the spec sheet first.

 

[Joachim Gerhard]

They are a bit weaker then the DHs but standing 3A collector is more then enough.

 

[RCruz]

Thank you Joachim.

Maybe the malfunctioning shunt is responsible for the absence of sound... strangely the shunts output the correct +-24V but maybe there is not enough current.

 

[FdW]

Thank you Joachim.

Maybe the malfunctioning shunt is responsible for the absence of sound... strangely the shunts output the correct +-24V but maybe there is not enough current.

Good that you have found the problem, as the output voltage was 24V this problem should not have any problems (other than sub-optimal regulation). P.s. Be shure to check the driver transistor.

 

[RCruz]

Which is the driver transistor ?

 

[Joachim Gerhard]

That must be a BC near and connected to the TIP31C.

 

[RCruz]

Perfect, I was planning to replace it as well..... Now let´s see if curing the ccs part of the shunt solves the problem.... I wonder..... I miss my scope.

In the mean time I am collecting parts for the R2

 

[RCruz]

In total the values are :
11nF
33.3nF
9.1k
73.5k

Reading the boom that Hesener sent I have the same values but in the schematic, the values are different.... Is there a final schematic with the correct values for paradise r2 ?

 

[Joachim Gerhard]

I used the values in post 6296 and got results that i posted. That are my official values.
0.75dB plus in the bass and 0.25dB plus in the treble. That was a deliberate choice by MiiB and me. Getting away the 0.75dB gain at 20Hz is easy. Just make the 73.5kOhm resistor a bit smaller.

 

[RCruz]

Reading the boom that Hesener sent I have the same values but in the schematic, the values are different.... Is there a final schematic with the correct values for paradise r2 ?

Sorry... just found it hidden in hesenner´s box

 

[Joachim Gerhard]

No problem, this is a complex project and got even me confused at times. The R2 on the other hand is a very good stage where all contributors can be proud of.

 

[RCruz]

I am working on it now...

As for the non working original paradise, I have bad news.. removing the power transistor from the shunt was a disaster.. the pads lifted making it impossible to replace.. I will leave it as is for now.