Building a symmetrical psu B1 buffer - Page 259

Erlend Sæterdal · 30th December 2012, 08:09 PM

Are you sure the electrolyts is mounted correct ?

ncc · 31st December 2012, 12:26 PM

Quote:

Originally Posted by Erlend Sæterdal

Are you sure the electrolyts is mounted correct ?

Yes, I've checked again and all electrolytics are mounted correctly

noSmoking · 5th February 2013, 11:56 PM

hi ncc,
I checked google for bc517 and it's a high Hfe darlington,I am not sure bc550 will do it ,might try MPSW45A and 2N6426 are similar to BC517, both are good.Pinout is different.
Regards,
NS

noSmoking · 6th February 2013, 12:26 AM

Hi Salas,
My Mezmerize is working great ! It went right together and played fine ,Sounds Great!
THANKS!
NS

Erlend Sæterdal · 6th February 2013, 01:24 AM

MPSA 13 ?

Salas · 6th February 2013, 03:16 AM

Sounds like a candidate. Should reverse its orientation and check that the 7812 is good.

Salas · 6th February 2013, 03:31 AM

Quote:

Originally Posted by noSmoking

Hi Salas,
My Mezmerize is working great ! It went right together and played fine ,Sounds Great!
THANKS!
NS

That layout is vintage of what later sprung to Mez and Hypno in their popular forms. Nice to see it done again and playing well. Watch turn off cycle mainly if to ever drive a DC coupled amp since there is no relay. Enjoy.

ckwong99 · 25th February 2013, 03:55 PM

Hello there,

These is my questions :

1) Can anyone know how to arrange my B1 buffer + Shunt type attenuator + tube pre-amp order for the best deliver the source from CD player or Phono ?

2) What is the optimal value of the signal in series resistor for the shunt attenuator with B1 buffer interpose ?

Thanks for your answer in advance

AndrewT · 26th February 2013, 09:50 AM

The B1 has two switchable inputs. That's where the two sources connect.
Then the switches should feed the selected signal to the attenuator.
Finally the output of the attenuator is fed to the buffer since the attenuator cannot alone drive the cables to the power amplifier and/or the pre-amp.

Do you really need a pre-amp?
Which signal needs more amplification?
Do that before you send the signal to the attenuator.

ckwong99 · 28th February 2013, 05:04 AM

Hello Andrew,

Tube preamp was my DIY project finished in few years ago but last year I added B1 buffer on it. All the sound and presentation is slightly better than before. Right now I am replacing my Preamp's 24 steps attenuator by shunt type attenuator (with remote control and has 80 steps). Actually, I want the phono signal can get a better presentation.

My concern is the order arrangement for the shunt type attenuator and B1 buffer. You know the shunt type attenuator drawback is vary of impedance to its next stage. Base on my situation, how following option is better deployment ?

Option 1) Source signal -> Shunt type attenuator -> B1 buffer -> Tube Preamp
Option 2) Source signal -> B1 buffer -> Shunt type attenuator -> Tube Preamp

Another question is how to selection the value of series resistor inside the attenuator ?

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30th December 2012, 08:09 PM	#2581
Erlend Sæterdal diyAudio Member Join Date: Mar 2007	Are you sure the electrolyts is mounted correct ?

5th February 2013, 11:56 PM	#2583
noSmoking diyAudio Member Join Date: May 2010 Location: Texas	hi ncc, I checked google for bc517 and it's a high Hfe darlington,I am not sure bc550 will do it ,might try MPSW45A and 2N6426 are similar to BC517, both are good.Pinout is different. Regards, NS

6th February 2013, 12:26 AM	#2584
noSmoking diyAudio Member Join Date: May 2010 Location: Texas	Hi Salas, My Mezmerize is working great ! It went right together and played fine ,Sounds Great! THANKS! NS

6th February 2013, 01:24 AM	#2585
Erlend Sæterdal diyAudio Member Join Date: Mar 2007	MPSA 13 ?

6th February 2013, 03:16 AM	#2586
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Sounds like a candidate. Should reverse its orientation and check that the 7812 is good.

26th February 2013, 09:50 AM	#2589
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	The B1 has two switchable inputs. That's where the two sources connect. Then the switches should feed the selected signal to the attenuator. Finally the output of the attenuator is fed to the buffer since the attenuator cannot alone drive the cables to the power amplifier and/or the pre-amp. Do you really need a pre-amp? Which signal needs more amplification? Do that before you send the signal to the attenuator.

28th February 2013, 05:04 AM	#2590
ckwong99 diyAudio Member Join Date: May 2005 Location: HK	Hello Andrew, Tube preamp was my DIY project finished in few years ago but last year I added B1 buffer on it. All the sound and presentation is slightly better than before. Right now I am replacing my Preamp's 24 steps attenuator by shunt type attenuator (with remote control and has 80 steps). Actually, I want the phono signal can get a better presentation. My concern is the order arrangement for the shunt type attenuator and B1 buffer. You know the shunt type attenuator drawback is vary of impedance to its next stage. Base on my situation, how following option is better deployment ? Option 1) Source signal -> Shunt type attenuator -> B1 buffer -> Tube Preamp Option 2) Source signal -> B1 buffer -> Shunt type attenuator -> Tube Preamp Another question is how to selection the value of series resistor inside the attenuator ?