XVR1 active crossover, discrete active stage

That´s about what I also had in mind, I was trying to find the correct resistor values today in simulation. Have you simulated or built thic circuit yet ?

Mr. Pass does this circuit have anything to do with the new active crossover that will be posted soon, or will that one be totaly different ?


2000-11-24 12:02 am
As I mentioned before I have not build it. Yet.

Just simulation. Load was 100 Ohm and up. The "simetrix" phase margin shows around 50 deg. -3db down at aprox. 900khz.
Not to bad, I think.

Let's put some better transistors in, and this could become a real circuit.

I am trying to make a dicrete opamp like this for an analog output for a new DAC I am building. It has 4 opamps int original design and I dont want to use them. I prefer to put a discrete stage instead.
I saw the simplified circuit in the Pass active crossover. I think it is what I want. I also like the Borbeley FET cascode line stages but are not quite my taste.
What you designed is really really good.
the 2SK389 is one of the best around and the BC550C are also low noise very good transistors. Do you mean to change the output transistors ?
The BC337 and BC327 are also very good high current BJTs.
The specs you say are very good. I will try to simulate it and tell you what I got. How do you simulate the 2sk389 btw?


2000-11-24 12:02 am
model for 2sk389

.model J2sk389 NJF(Beta=51.76m Rs=8.008 Rd=8.008 Betatce=-.5 Lambda=11.22m
+ Vto=-.5275 Vtotc=-2.5m Cgd=18.28p M=.3367 Pb=.3905 Fc=.5
+ Cgs=20.07p Isr=112.8p Nr=2 Is=11.28p N=1 Xti=3 Alpha=10u Vk=100
+ Kf=92.85E-18 Af=1)

Drop two of these in, after you have added this model to your simulator, or one of its library's.

Hope this helps.
Found this the other day, from l'Audiophie magazine and uses the input stage fom the Le Monstre power amp.

<font color=#808040>Fig 17: Filtre actif 2 voies utilisant deux filtres passifs RC en cassade. Caracteristiques des composants: resistance a 1% tantale, condensateurs cuivre, potentiometres a film plastique, trim 100<FONT FACE="Symbol">W</FONT> <<COSMOS >>, La frequence de compure est aisement determinee a partir de F<sub>c</sub> = 1 / 2 <FONT FACE="Symbol">p</FONT> RC Ainsi pour une coupre de 590Hz C= 10nF R = 27k<FONT FACE="Symbol">W</FONT>.</font>


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Found it posted at <a href="http://forums.delphiforums.com/n/main.asp?webtag=haute_fidelite&nav=start">le Forum de HAUTE-FIDELITE.net</a>, can't find the thread now.

The original poster said;
<i>"I do not know if it is Kaneda, it is the active filter of the audiophile N°7, new series. With the PSU of Kaneda 50W and the input stage of the Monster 8W for each of 4 cells"</i>

Tanslated the caption for the schematic using <a href="http://trans.voila.fr/?getting_web">Viola
</a><i>Fig 17: active Filter 2 ways using two passive filters RC there cassade. Caracteristiques constituents(component): copper resistance is 1 % tantale, condensers, potentiometres has plastic film, trim 100<FONT FACE="Symbol">W</FONT> < < COSMOS > >, The frequence of compure is aisement determinee has to leave Fc = 1 /(2 <FONT FACE="Symbol">p</FONT> RC) So for a coupre of 590Hz C = 10nF R = 27k<FONT FACE="Symbol">W</FONT></i>.

Thought someone might find it of interest?