Doug Self Preamp from Linear Audio #5

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Hi Carl

I don't understand your figure of 650 mA. The original design had 14 LM4562s. The max quiescent current from the rails is 12 mA per dual package.
I make that 168 mA.

You have 15 LM4562s which is only 180 mA total

Am I missing something here ??? ...

I get your point! I have been accepting the meter readings on the face of my 30 year old lab bench supply. Maybe the old girl is lying to me! I will look deeper into it this weekend and report back.
 
Hi Carl

I don't understand your figure of 650 mA. The original design had 14 LM4562s. The max quiescent current from the rails is 12 mA per dual package.
I make that 168 mA.

You have 15 LM4562s which is only 180 mA total

Am I missing something here ??? ...

Doug you are absolutely correct!

My previous remarks were in error. This time I took the time to actually measure the current with a trusted meter. Current measured to be 160mA.

My error would have been obvious if I'd taken the time to think about it, my bad for having not done that ...
 
PS

Doug you are absolutely correct!

My previous remarks were in error. This time I took the time to actually measure the current with a trusted meter. Current measured to be 160mA.

My error would have been obvious if I'd taken the time to think about it, my bad for having not done that ...

Well, that reduces the size of the PS somewhat. In some countries I think a battery and solar power should be enough. Sadly, not here though.

George
 
Great!

Let's start a group buy list. I'll leave it up until November 1st. Expect delivery to be mid to late November

georgebrooke - 1kit - PAID
Halauhula - 1 kit - PAID
jan.didden - 1 kit - PAID
hfxrzw - 2 kits - PAID
PJN - 1 kit
kiroje - 1 kit
still4given - 1kit - PAID
GlennW - 1kit
erik777 - 1 kit
arthur - 1 kit
zrxshack - 1 kit
rock12 - 1 kit
canute - 1 kit
Somakmaitra - 1 kit - PAID
MosfetDemon - 1 kit
mik000000 - 1 kit
AMV8 - 2 kits
arthur - 2 kits - PAID
Badge - 1 kit
AMPMAN - 1 kit
orjan - 1 kit
OZAM - 2 kits
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If you have asked to be added to the list but don't see your name be sure to let me know!
 
Last edited:
Great!

Let's start a group buy list. I'll leave it up until November 1st. Expect delivery to be mid to late November

georgebrooke - 1kit - PAID
Halauhula - 1 kit - PAID
jan.didden - 1 kit - PAID
hfxrzw - 2 kits - PAID
PJN - 1 kit
kiroje - 1 kit
still4given - 1kit - PAID
GlennW - 1kit
erik777 - 1 kit
arthur - 1 kit
zrxshack - 1 kit
rock12 - 1 kit
canute - 1 kit
Somakmaitra - 1 kit - PAID
MosfetDemon - 1 kit
mik000000 - 1 kit
AMV8 - 2 kits
arthur - 2 kits - PAID
Badge - 1 kit
AMPMAN - 1 kit
orjan - 1 kit
OZAM - 2 kits
emyeuoi - 1 kit - PAID

If you have asked to be added to the list but don't see your name be sure to let me know!
 
Hi Carl, a rough cost of component parts reqd. might get me on the list.

Many thanks for your work.

Paul

Well ...

Much depends on what goodies & parts you have on hand. A quick count of parts says there are (approximately) ...

Qty 90 1% resistors that cost $0.05 each lots of 10 = less than ... $5.00
Qty 80 various small caps that cost (roughly) $0.25 each ........... $20.00
Qty 30 electrolytic caps that cost (roughly) $1.00 each .............. $30.00
Qty 15 NJM4562 opamps that cost $1.00 each .......................... $15.00
Misc XLR connectors, panel switch, knobs, standoffs, etc ............ $30.00

That means total on board parts amount to $85 to $100

Plus a power supply ($80 to $100) and of course the enclosure of your choice.
 
Great!

Let's start a group buy list. I'll leave it up until November 1st. Expect delivery to be mid to late November

georgebrooke - 1kit - PAID
Halauhula - 1 kit - PAID
jan.didden - 1 kit - PAID
hfxrzw - 2 kits - PAID
PJN - 1 kit
kiroje - 1 kit
still4given - 1kit - PAID
GlennW - 1kit
erik777 - 1 kit
arthur - 1 kit
zrxshack - 1 kit
rock12 - 1 kit
canute - 1 kit
Somakmaitra - 1 kit - PAID
MosfetDemon - 1 kit
mik000000 - 1 kit - PAID
AMV8 - 2 kits
arthur - 2 kits - PAID
Badge - 1 kit
AMPMAN - 1 kit
orjan - 1 kit
OZAM - 2 kits
emyeuoi - 1 kit - PAID

If you have asked to be added to the list but don't see your name be sure to let me know!
 
Great!

Let's start a group buy list. I'll leave it up until November 1st. Expect delivery to be mid to late November

georgebrooke - 1kit - PAID
Halauhula - 1 kit - PAID
jan.didden - 1 kit - PAID
hfxrzw - 2 kits - PAID
PJN - 1 kit
kiroje - 1 kit
still4given - 1kit - PAID
GlennW - 1kit
erik777 - 1 kit
arthur - 1 kit
zrxshack - 1 kit
rock12 - 1 kit
canute - 1 kit
Somakmaitra - 1 kit - PAID
MosfetDemon - 1 kit
mik000000 - 1 kit - PAID
AMV8 - 2 kits
arthur - 2 kits - PAID
Badge - 1 kit
AMPMAN - 1 kit
orjan - 1 kit
OZAM - 2 kits
emyeuoi - 1 kit - PAID
misterdog - 1 kit

If you have asked to be added to the list but don't see your name be sure to let me know!
 
NJM4562 opamps? I am sure you are aware that they are not the same as LM4562? the NJM4562 cost certainly is a bargain.
From the article

Hello rsavas,

It is nice to see you contributing here.

Yea, I am aware that they are not the same, but they are an audiophile favorite and do represent a lesser expensive path than the recently obsolete LM4562 part. I for one am really annoyed that TI has decided to kill off so many of the old National parts.
 
Great!

Let's start a group buy list. I'll leave it up until November 1st. Expect delivery to be mid to late November

georgebrooke - 1kit - PAID
Halauhula - 1 kit - PAID
jan.didden - 1 kit - PAID
hfxrzw - 2 kits - PAID
PJN - 1 kit
kiroje - 1 kit
still4given - 1kit - PAID
GlennW - 1kit
erik777 - 1 kit
arthur - 1 kit
zrxshack - 1 kit
rock12 - 1 kit
canute - 1 kit
Somakmaitra - 1 kit - PAID
MosfetDemon - 1 kit
mik000000 - 1 kit - PAID
AMV8 - 2 kits
arthur - 2 kits - PAID
Badge - 1 kit - PAID
AMPMAN - 1 kit
orjan - 1 kit
OZAM - 2 kits
emyeuoi - 1 kit - PAID
misterdog - 1 kit

If you have asked to be added to the list but don't see your name be sure to let me know!