Doug Self Preamp from Linear Audio #5

[Carl_Huff]

"Where else does anyone make circuit boards for this preamplifier ? "

To the best of my knowledge I am the only source. Please check your messages.

 

[Btsblues]

Hello everyone,
got the circuit boards from Carl. And a question came up. Are there different versions of the preamp ? His preamp was first published in Elektor in 2012. Are we talking about this version ??

 

[Carl_Huff]

Version of this Preamplifier

BtsBlues,

The Preamplifier kit that you bought is based on an article that Doug Self published in Linear Audio magazine #5 in 2013.

The Doug Self 2012 Preamplifier was published in Elector magazine and is quite different.

 

[tcpip]

BtsBlues,



The Preamplifier kit that you bought is based on an article that Doug Self published in Linear Audio magazine #5 in 2013.



The Doug Self 2012 Preamplifier was published in Elector magazine and is quite different.

Can you point out the broad differences please? At a gross level, I see that both have the awesome variable turnover frequency tone controls, right?

 

[Carl_Huff]

Differences between Doug Self's 2012 and 2013 preamplifiers

Sure,

I am sure to forget something but here goes ...

#1) The 2012 preamp includes a phono stage, 2013 does not.

#2) The tone controls in the 2013 preamplifier are improved over those in the 2012 elector project.

#3) The 2013 preamp has an improved layout, split between the main and IO PCBs. Or perhaps I am biased as I crafted the 2013 PCBs! Ha, ha ...

Beyond these few items, the differences are of little consequence. Both the 2012 and 2013 designs are great performers.

 

[tcpip]

Sure,



I am sure to forget something but here goes ...



#1) The 2012 preamp includes a phono stage, 2013 does not.



#2) The tone controls in the 2013 preamplifier are improved over those in the 2012 elector project.



#3) The 2013 preamp has an improved layout, split between the main and IO PCBs. Or perhaps I am biased as I crafted the 2013 PCBs! Ha, ha ...



Beyond these few items, the differences are of little consequence. Both the 2012 and 2013 designs are great performers.

Ah, I had not noticed the phono stage difference. Thanks a lot. And yes, it's great to get the other improvements.

And a separate board for the IO is totally necessary for most of us. Grateful that we have this mod.

 

[hadihf]

Sure,

I am sure to forget something but here goes ...

#1) The 2012 preamp includes a phono stage, 2013 does not.

#2) The tone controls in the 2013 preamplifier are improved over those in the 2012 elector project.

#3) The 2013 preamp has an improved layout, split between the main and IO PCBs. Or perhaps I am biased as I crafted the 2013 PCBs! Ha, ha ...

Beyond these few items, the differences are of little consequence. Both the 2012 and 2013 designs are great performers.

The 2012 also specifies hard to find, very expansive, 1k 'power' pots, specially for the volume control.

 

[khurrum]

Hi Carl, are boards still available please

Hi Carl
I wondered if the kit is still available as I would definitely like to build one
thanks
khurrum

 

[Carl_Huff]

"I wondered if the kit is still available as I would definitely like to build one ..."

Got'em! Please check your personal messages

 

[kouiky]

Thank you Carl for your taking the time to answer questions.

The BD139 and BD140 devices that are available from distributors are BD139G, BD13910S, etc. Does this matter in the power supply circuit?

Do we have a few named substitutes for the discontinued BC560C in the power supply? The NPN complement, the 550C, seems easier to buy than it's mate the 560C.

 

[Carl_Huff]

I don't know about the BD13910S but the BD139G and BC560C are good to go.

 

[kouiky]

I've had trouble finding genuine BC560C. Digi and Mouser are out.

In the case of the TL431CLP (VR1 and VR2 positions of the power supply), the TL431BCLP is more plentiful from Mouser. Any hazard if I use these 0.5% versions instead of the 2% version?

 

[Carl_Huff]

I find it amazing how low vendor parts stocks are these days. I never expected to see them get this low.

BC556/ 557/ or 559 can substituted for the BC560 called out in the drawing.

And since the voltage is adjustable using a pot, substituting the described TL431CLP should not be a problem.

 

[diyralf]

I wouldn't use this power supply. A good voltage regulator is more economical and also has less noise and better ripple rejection.

 

[Carl_Huff]

I wouldn't use this power supply. A good voltage regulator is more economical and also has less noise and better ripple rejection.

Not to pick a fight as that is not my nature, but simply put ...

What you describe is not my experience and not the experience of the 500 plus people that I have shipped kits to.

 

[Hicoco]

Replaced R5/R6 with 100ohm and R9/R10 with 1kohm....see this post from Jan.didden

 

[Carl_Huff]

Jan's comments are appreciated. I'll make the change to the power supply drawing.

 

[comicrcc]

Carl;
The PCB for this is still available? I have read a lot about this pre. I have wanted to build it. Have parts need PCB. Please let me know
Thanks
Bob Craig

 

[Carl_Huff]

Yes, PCBs are available. Please check your personal messages.

 

[itsikhefez]

Would it be possible to integrate the AMB LCDuino as a remote volume control and display such as in the alpha10 preamp?
It could be used with or without a physical pot. https://www.amb.org/audio/alpha10/