I've heard people use the CRC in tube amps. And tube amps are
simple designs that is prone to PS problems. I only try the CRC
in preamp's supply. I guess it is needed there because preamps
are sensitive to power supply. In (SS) amps, may be the RC should
be used for the front end section only??
From Pavel and Johan explanations above I think it is clear
(to me) that we should not use it unless necessary?? And we
should choose minimum R to not "kill" the supply impedance?
I have tried to use CRC but is not satisfied with the results,
or I cannot hear the difference. But in my opamp-based preamp'
power supply, I used a 10 Ohm resistor and I was surprised by
the good result. But this R is right behind a TIP31/32 regulator
so may be that is the explanation?
simple designs that is prone to PS problems. I only try the CRC
in preamp's supply. I guess it is needed there because preamps
are sensitive to power supply. In (SS) amps, may be the RC should
be used for the front end section only??
From Pavel and Johan explanations above I think it is clear
(to me) that we should not use it unless necessary?? And we
should choose minimum R to not "kill" the supply impedance?
I have tried to use CRC but is not satisfied with the results,
or I cannot hear the difference. But in my opamp-based preamp'
power supply, I used a 10 Ohm resistor and I was surprised by
the good result. But this R is right behind a TIP31/32 regulator
so may be that is the explanation?
Upupa,
the original articles can be found on Geoffs excellent website:
http://www.tcaas.btinternet.co.uk/hiraga.htm
Johan
the original articles can be found on Geoffs excellent website:
http://www.tcaas.btinternet.co.uk/hiraga.htm
Johan
Johan, Hiraga 30 W ( if have the same PCB as 20 W ) ) probably huming. Mr. Hiraga is trying to solve it with gigantic batery of capacitors, but reason is wrong designed PCB. From amp module MUST lead TWO ground wires. On FIRST must be connected ouput Boucherot and zener diodes with capacitors, which must have much more bigger value ( 100 - 470 microfarad ). On SECOND connect input and feedback groud. Fault on Hiraga's PCB is , that ground is here common, so spikes on rails come thrue zener diodes to the ground and groud wire ( which have not zero resistance ) is by this spike modulated and this modulation ( hum ) come thrue input resistor ( 10 kOhm ) to the input. Is that clear now ? Similar mistakes have Monster's PCB, maybe worse 
. Here is the same problems as at first and one in addition. Although is idea schematic is rails voltage separated, on PCB is connected together and 'cos Z rails is very low, value of this connected capacitor is only for joke and DC voltage for VAS is not enough smoothed and thrue voltagge divider ( 22 k + 22 k ) come to to top base of cascode. Solution is ( except grounding ) again lead two separate wires to the PS, one for VAS and second for output stage. Is that clear too ?
. Here is the same problems as at first and one in addition. Although is idea schematic is rails voltage separated, on PCB is connected together and 'cos Z rails is very low, value of this connected capacitor is only for joke and DC voltage for VAS is not enough smoothed and thrue voltagge divider ( 22 k + 22 k ) come to to top base of cascode. Solution is ( except grounding ) again lead two separate wires to the PS, one for VAS and second for output stage. Is that clear too ?Yes, Upupa, good point. I think that amp should sound much better with separated grounds.
As I saw, you like dual mono design, and you place filter caps and diode brigdes on same board with amp. What is your favorite way connecting both ground in a dual mono amp? Or maybe you live them disconnected?
Regards
As I saw, you like dual mono design, and you place filter caps and diode brigdes on same board with amp. What is your favorite way connecting both ground in a dual mono amp? Or maybe you live them disconnected?
Regards
Upupa, I see I was not clear. Sorry.
When we do dual mono construction (two transformers, two bridges and two banks of capacitors) there are two separated grounds: each for one psu (each for one channel). If these PS are on others PCBs than no way to connect grounds together at one central ground point. What is best solution: live them floating from each other or connect together at inputs? And what we should do with chassis ground than?
When we do dual mono construction (two transformers, two bridges and two banks of capacitors) there are two separated grounds: each for one psu (each for one channel). If these PS are on others PCBs than no way to connect grounds together at one central ground point. What is best solution: live them floating from each other or connect together at inputs? And what we should do with chassis ground than?
Final Monstre?
It's been a while but today I hooked up my latest Monstre and compared it with the current one.
The one that's going to stay is my latest version. It betters the other one in that it seems to have an even more natural sound with clearer groundtones; several solo instruments sound more lifelike. Depth of image and imaging have also improved. Another improvement I hadn't expected was a small reduction in sibilance.
So how does it differ from the "lesser" one?
First of all: it is built dual mono.
Second: all resistors are tantalum (the other has Beyschlag)
and third: the output emitter resistors are MOX instead of wirewound.
I feel that this Monstre will stay put for a fairly long time.
Johan
It's been a while but today I hooked up my latest Monstre and compared it with the current one.
The one that's going to stay is my latest version. It betters the other one in that it seems to have an even more natural sound with clearer groundtones; several solo instruments sound more lifelike. Depth of image and imaging have also improved. Another improvement I hadn't expected was a small reduction in sibilance.
So how does it differ from the "lesser" one?
First of all: it is built dual mono.
Second: all resistors are tantalum (the other has Beyschlag)
and third: the output emitter resistors are MOX instead of wirewound.
I feel that this Monstre will stay put for a fairly long time.
Johan
Hi all,
I just build the Hiraga Le Monstre with new components as in Kristjan website http://web.vip.hr/pcb-design.vip/hiraga.html. Transistors are MJ15003/4 instead of 3055/2955. I draw my own PCB.
The problem is when I power up the amplifier. The volume is too soft. I have to lean my ears towards the speaker cone to barely hear the music, even though the sound is fine ( I mean no cracking sound or other nasties). The bias current per rail measured at 1ohm resistor is 165mA. I thought the bias is too small and I change the bias resistor from 390R to 1K, the bias increases to 1.3A. Still the sound is too soft.
Pls help.
Thanks,
Ipanema
I just build the Hiraga Le Monstre with new components as in Kristjan website http://web.vip.hr/pcb-design.vip/hiraga.html. Transistors are MJ15003/4 instead of 3055/2955. I draw my own PCB.
The problem is when I power up the amplifier. The volume is too soft. I have to lean my ears towards the speaker cone to barely hear the music, even though the sound is fine ( I mean no cracking sound or other nasties). The bias current per rail measured at 1ohm resistor is 165mA. I thought the bias is too small and I change the bias resistor from 390R to 1K, the bias increases to 1.3A. Still the sound is too soft.
Pls help.
Thanks,
Ipanema
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