PeeCeeBee Preamplifier GB

[gary s]

Hi shaan, you might have missed my post #97 - any merit in HFE matching transistors for this design of yours?

 

[vizeta]

Please add me in the list:

Vizeta - 1 PCB - India

 

[shaan]

Hi again shaan, looking at getting all parts together and tested while I wait for the pcb's from India via Neal in the UK.

Can I ask if you matched any of the BC546/556 transistors for gain in your building and testing of the preamp.

No I didn't. There is an average gap of about 75 between the npn and pnp parts.

If not, do you see any merit in doing this, I have over 100 of each type, so can quite easily match some pairs for HFE if you think it would be of any advantage.

Yes I do. A better gain symmetry is always welcome for achieving a higher precision, but it is not essential for normal circuit behavior.

Hi shaan, you might have missed my post #97...

I'm sorry. I did miss the post.

 

[gary s]

Thanks for the reply shaan. I will test and match all the N and P parts I have for this - I have plenty of time and it will give me something to do for a few days.

 

[Torvbakkane]

Hi Shaan,
Want to be set up on the PreAmplifier GB list with 2 PCBs

Regards Torvbakkane - 2 pcb - Norway

 

[Vunce]

PeeCeeBee PSU example:
“+ from rectifier goes to cathode pad of D1 and - from rectifier goes to anode pad of D8. Connect the AC secondaries to anode pad of D1 and cathode of D8, both via 1Kohm 0.25W resistors. Don't forget the center tap to 0V.”

Hi Shaan,
Can we use this same method for LT4320 rectification with this preamp?
+ from rectifier goes to cathode pad of D9 and - from rectifier goes to anode pad of D12. Connect the AC secondaries to anode pad of D9 and cathode pad of D12, transformer CT to 0V. Do the AC secondaries need 1K series resistors? If so, why?

Thanks in advance

 

[SegaTomas]

Please add me with 2 PCB to Sweden- SegaTomas.
Thanks

 

[shaan]

PeeCeeBee PSU example:
“+ from rectifier goes to cathode pad of D1 and - from rectifier goes to anode pad of D8. Connect the AC secondaries to anode pad of D1 and cathode of D8, both via 1Kohm 0.25W resistors. Don't forget the center tap to 0V.”

Hi Shaan,
Can we use this same method for LT4320 rectification with this preamp?
+ from rectifier goes to cathode pad of D9 and - from rectifier goes to anode pad of D12. Connect the AC secondaries to anode pad of D9 and cathode pad of D12, transformer CT to 0V. Do the AC secondaries need 1K series resistors? If so, why?

Thanks in advance

Hi Vunce.

Yes you can use the rectifier like that.

When using an off-board rectifier, the additional AC connections to the peeceebee psu is for activating the speaker protection segments. The 1K resistors are for preventing a short-circuit when connecting the ACs to pads instead of dedicated terminals.

The preamp has no such speaker protection process! So no need to connect the ACs anywhere on the board if an off-board rectifier is used.

 

[shaan]

Updated GB list:

Sadik - 1 pcb - India
Vunce - 2 pcb - USA
Nisbeth - 2 pcb - Denmark
Blek Stena - 1 pcb - Croatia
ItsAllInMyHead - 2 pcb - USA
Deps - 1 pcb - Poland
manniraj - 1 pcb - India
MaryA - 1 pcb - USA
meanie - 1 pcb - SG
iamwhoiam - 1 pcb - UK
PinkPink - 2 pcb - Hongkong
Pistollero - 1 pcb - Portugal
helfred - 1 pcb - Denmark
woodlands - 1 pcb - Ireland
Kokanee - 1 pcb - Canada
lancer - 1 pcb - SG
redjr - 1 pcb - USA
Rajesh - 1 module - India
zebulo - 2 pcb - France
hydrovac - 1 module - India
Rick G - 1 pcb - USA
jls001 - 1 module - India
cats squirrel - 1 pcb - UK
routhun - 1 pcb - USA
Hemant07 - 1 module - India
Kana711104 - 1 pcb - India
NealJ - 2 pcb - UK
CitizenKane - 2 pcb - Germany
RobSoet - 2 pcb - Belgium
Medisinmannen - 1 pcb - Norway
bhrt - 1 pcb - India
pappu - 1 pcb - India
kbhuvi - 1 pcb - India
kartk - 1 module - India
dbwinger - 1 pcb - USA
fencki - 1 pcb - Austria
ecclesand - 1 pcb - USA
danielhk - 2 pcb - Hongkong
Faizal Mansar Alam - 1 module - India
mvictor69 - 1 pcb - Romania
vizeta - 1 pcb - India
Torvbakkane - 2 pcb - Norway
SegaTomas - 2 pcb - Sweden

GB will close on 28 August. I will start sending PMs to individual members from that date.

 

[asuslover]

Sadik - 1 pcb - India
Vunce - 2 pcb - USA
Nisbeth - 2 pcb - Denmark
Blek Stena - 1 pcb - Croatia
ItsAllInMyHead - 2 pcb - USA
Deps - 1 pcb - Poland
manniraj - 1 pcb - India
MaryA - 1 pcb - USA
meanie - 1 pcb - SG
iamwhoiam - 1 pcb - UK
PinkPink - 2 pcb - Hongkong
Pistollero - 1 pcb - Portugal
helfred - 1 pcb - Denmark
woodlands - 1 pcb - Ireland
Kokanee - 1 pcb - Canada
lancer - 1 pcb - SG
redjr - 1 pcb - USA
Rajesh - 1 module - India
zebulo - 2 pcb - France
hydrovac - 1 module - India
Rick G - 1 pcb - USA
jls001 - 1 module - India
cats squirrel - 1 pcb - UK
routhun - 1 pcb - USA
Hemant07 - 1 module - India
Kana711104 - 1 pcb - India
NealJ - 2 pcb - UK
CitizenKane - 2 pcb - Germany
RobSoet - 2 pcb - Belgium
Medisinmannen - 1 pcb - Norway
bhrt - 1 pcb - India
pappu - 1 pcb - India
kbhuvi - 1 pcb - India
kartk - 1 module - India
dbwinger - 1 pcb - USA
fencki - 1 pcb - Austria
ecclesand - 1 pcb - USA
danielhk - 2 pcb - Hongkong
Faizal Mansar Alam - 1 module - India
mvictor69 - 1 pcb - Romania
vizeta - 1 pcb - India
Torvbakkane - 2 pcb - Norway
SegaTomas - 2 pcb - Sweden
asuslover- 1pcb USA

 

[gary s]

You should be pleased with the interest shaan - 55 boards so far.

 

[The Prof]

...will it hit a century ?!!

 

[skunark]

Sadik - 1 pcb - India
Vunce - 2 pcb - USA
Nisbeth - 2 pcb - Denmark
Blek Stena - 1 pcb - Croatia
ItsAllInMyHead - 2 pcb - USA
Deps - 1 pcb - Poland
manniraj - 1 pcb - India
MaryA - 1 pcb - USA
meanie - 1 pcb - SG
iamwhoiam - 1 pcb - UK
PinkPink - 2 pcb - Hongkong
Pistollero - 1 pcb - Portugal
helfred - 1 pcb - Denmark
woodlands - 1 pcb - Ireland
Kokanee - 1 pcb - Canada
lancer - 1 pcb - SG
redjr - 1 pcb - USA
Rajesh - 1 module - India
zebulo - 2 pcb - France
hydrovac - 1 module - India
Rick G - 1 pcb - USA
jls001 - 1 module - India
cats squirrel - 1 pcb - UK
routhun - 1 pcb - USA
Hemant07 - 1 module - India
Kana711104 - 1 pcb - India
NealJ - 2 pcb - UK
CitizenKane - 2 pcb - Germany
RobSoet - 2 pcb - Belgium
Medisinmannen - 1 pcb - Norway
bhrt - 1 pcb - India
pappu - 1 pcb - India
kbhuvi - 1 pcb - India
kartk - 1 module - India
dbwinger - 1 pcb - USA
fencki - 1 pcb - Austria
ecclesand - 1 pcb - USA
danielhk - 2 pcb - Hongkong
Faizal Mansar Alam - 1 module - India
mvictor69 - 1 pcb - Romania
vizeta - 1 pcb - India
Torvbakkane - 2 pcb - Norway
SegaTomas - 2 pcb - Sweden
asuslover - 1 pcb USA
Skunark - 2 pcb USA

 

[Vunce]

Hi Vunce.

Yes you can use the rectifier like that.

When using an off-board rectifier, the additional AC connections to the peeceebee psu is for activating the speaker protection segments. The 1K resistors are for preventing a short-circuit when connecting the ACs to pads instead of dedicated terminals.

The preamp has no such speaker protection process! So no need to connect the ACs anywhere on the board if an off-board rectifier is used.

Thanks Shaan for the resistor explanation.
I’ll be using a very small LT4320 ideal bridge mounted on the preamp pcb so there isn’t long leads from an off-board rectifier for this build. Should be fun

 

[shaan]

You should be pleased with the interest shaan - 55 boards so far.

I am surprised in fact! Thanks to everyone who joined.

 

[shaan]

...will it hit a century ?!!

No.

 

[shaan]

Thanks Shaan for the resistor explanation.
I’ll be using a very small LT4320 ideal bridge mounted on the preamp pcb so there isn’t long leads from an off-board rectifier for this build. Should be fun

Ah... I didn't know it would be mounted on PCB. In that case all is well.

 

[iamwhoiam]

shaan - as there is some AC coupling, please could you scope the power transients on the audio signal?

Very much appreciated! Amazing, thanks for adding these so quickly to post #1.

Given the behaviour, I'll be "MOD"ing the outputs to add a bit of turn on delay.

MOD: Mini Output Delay - a headphone / line-level audio output delay retrofit PCB

 

[zei]

Sadik - 1 pcb - India
Vunce - 2 pcb - USA
Nisbeth - 2 pcb - Denmark
Blek Stena - 1 pcb - Croatia
ItsAllInMyHead - 2 pcb - USA
Deps - 1 pcb - Poland
manniraj - 1 pcb - India
MaryA - 1 pcb - USA
meanie - 1 pcb - SG
iamwhoiam - 1 pcb - UK
PinkPink - 2 pcb - Hongkong
Pistollero - 1 pcb - Portugal
helfred - 1 pcb - Denmark
woodlands - 1 pcb - Ireland
Kokanee - 1 pcb - Canada
lancer - 1 pcb - SG
redjr - 1 pcb - USA
Rajesh - 1 module - India
zebulo - 2 pcb - France
hydrovac - 1 module - India
Rick G - 1 pcb - USA
jls001 - 1 module - India
cats squirrel - 1 pcb - UK
routhun - 1 pcb - USA
Hemant07 - 1 module - India
Kana711104 - 1 pcb - India
NealJ - 2 pcb - UK
CitizenKane - 2 pcb - Germany
RobSoet - 2 pcb - Belgium
Medisinmannen - 1 pcb - Norway
bhrt - 1 pcb - India
pappu - 1 pcb - India
kbhuvi - 1 pcb - India
kartk - 1 module - India
dbwinger - 1 pcb - USA
fencki - 1 pcb - Austria
ecclesand - 1 pcb - USA
danielhk - 2 pcb - Hongkong
Faizal Mansar Alam - 1 module - India
mvictor69 - 1 pcb - Romania
vizeta - 1 pcb - India
Torvbakkane - 2 pcb - Norway
SegaTomas - 2 pcb - Sweden
asuslover - 1 pcb USA
Skunark - 2 pcb USA
Zei - 1 pcb Sweden

 

[asuslover]

I am surprised in fact! Thanks to everyone who joined.

I am not surprised all all, in the past I got V4H and V4 from you and they are solid amps , excellent designs, thank you Shaan!