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AKSA's Lender Preamp with 40Vpp Ouput GB
AKSA's Lender Preamp with 40Vpp Ouput GB
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Old 24th November 2017, 11:35 AM   #1
xrk971 is online now xrk971  United States
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AKSA's Lender Preamp with 40Vpp Ouput GB
Default AKSA's Lender Preamp with 40Vpp Ouput GB

From old thread..
It does seem that there is interest in a GB. The nice thing with this design is choice of SMD or through hole on amp core daughterboard. I have not priced those yet but they are small so probably $5 for 10. Is anyone interested in the metal core version? That would allow increased bias to use as headphone amp.

--------------- NEW GB THREAD STARTS HERE ------------------

Link to basics of this preamp starts in post 25:

AKSA's Lender Preamp with 40Vpp Ouput GB

I was asked to move the GB aspects of this preamp here. Thanks to Hugh Dean (AKSA), Keantoken, and JPS64 for making this possible.

The original thread describing this preamp is here:

AKSA's Lender Preamp with 40Vpp Output

Basic schematic of through hole prototype version:
Click the image to open in full size.

Implementation in SMT/TH prototype:
Click the image to open in full size.

Demonstration of 40vpp output into 25kohm:
Click the image to open in full size.

Measured performance 20vpp into 7kohm (with 21.6dB gain):
Click the image to open in full size.

4vpp into 7kohm gives 0.0011% THD:
Click the image to open in full size.

Layout design by JPS64 for Main PCB with CLC filter, & cap Mx PSU portion, Input selector, daughterboard sockets for amp cores, and peripheral output caps etc.

Click the image to open in full size.

TH Daughterboard:
Click the image to open in full size.

Click the image to open in full size.

SMT Daughterboard:
Click the image to open in full size.

Metal-core (IMS) Daughterboard PCB:
Click the image to open in full size.

Main PCB Data files (schematic, parts list/BOM, layout snapshots, Gerbers):
http://www.diyaudio.com/forums/attac..._all_datas-zip

Alert - error on main PCB. R141 Should be 10k not 220R.

Revised BOM for MB (8-pin connector was incorrect), file here:
http://www.diyaudio.com/forums/attac...04_01_2018-zip

Mainboard schematic looks like this:
Click the image to open in full size.

Schematic for Mainboard here:
http://www.diyaudio.com/forums/attac...ender-main-zip

Schematic for Through-Hole Daughterboard:
Click the image to open in full size.

Stuffing Guide for TH amp daughterboard:
AKSA's Lender Preamp with 40Vpp Ouput GB-th-placement-stuffing-guide-jpg

Schematic for SMT Daughterboard (updated V2 correct for silkscreen error from V1 - R102/103 were swapped, corrected now):
Click the image to open in full size.


BOM for each board can be found as Excel file in zip data files below.

TH Daughterboard Data files:
http://www.diyaudio.com/forums/attac...er-pre-tht-zip

SMT Data files:
http://www.diyaudio.com/forums/attac...er-pre-smd-zip

IMS data files:
http://www.diyaudio.com/forums/attac...er-pre-ims-zip

SMT & IMS Daughterboard Parts List/BOM:
http://www.diyaudio.com/forums/attac..._or_smd_pl-zip

TH Daughterboard Parts List/BOM:
http://www.diyaudio.com/forums/attac...er-pre-tht-zip

*****
Pricing for GB

Motherboard (155mm x 157mm) and 1 set (2 pieces ea) of your choice TH or SMT Daughterboards (ca. 30mm x 40mm) is $20.

Shipping in USA in $5, Canada is $10, everywhere else is $15.

Initial GB will be 30 sets.

Edit Dec 8, 2017 - GB1 MB and TH board test:
Click the image to open in full size.

Click the image to open in full size.

Both SMT and TH daughterboards verified to work:
Click the image to open in full size.

Playing in stereo with TH and SMT:
Click the image to open in full size.

FFT of SMT for 20Vpp into 7kohms is THD of 0.001%:
Click the image to open in full size.

Edit (Dec 2, 2018) - Latest measurements with MELF board...

4Vpp into 7kohms (45v Vcc):
Click the image to open in full size.

20Vpp into 7kohms (45v Vcc):
Click the image to open in full size.

40Vpp into 7kohms (50v Vcc):
Click the image to open in full size.

51.4Vpp into 7kohms (59v Vcc):
Click the image to open in full size.

Maybe thread title should be renamed to 51v?

Edit Jan 16, 2018: Aksa Lender as very nice HPA:

Click the image to open in full size.

2.0Vpp into 50ohms with HPA (title is a typo):
Click the image to open in full size.

Click the image to open in full size.
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Last edited by xrk971; 17th January 2018 at 04:49 PM.
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Old 24th November 2017, 12:32 PM   #2
xrk971 is online now xrk971  United States
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AKSA's Lender Preamp with 40Vpp Ouput GB
Default GB interest

So far we have the following interested members, please quote message and edit with your name and qnty and type if interested.

JPS64 - 2 sets w/ SMT daughterboards
Algar Emi - 1 set, SMT or TH?
Redarc12 - 1 set, SMT or TH?
Jacques Antoine - 1 set TH
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Old 24th November 2017, 02:26 PM   #3
silasmellor is offline silasmellor  Denmark
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So far we have the following interested members, please quote message and edit with your name and qnty and type if interested.

JPS64 - 2 sets w/ SMT daughterboards
Algar Emi - 1 set, SMT or TH?
Redarc12 - 1 set, SMT or TH?
CFT - 1 set, SMT or TH?
Jacques Antoine - 1 set TH
Silasmellor - 1 set THT
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Old 24th November 2017, 03:33 PM   #4
bvtrinh is offline bvtrinh  United States
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Join Date: Sep 2014
Default GB

JPS64 - 2 sets w/ SMT daughterboards
Algar Emi - 1 set, SMT or TH?
Redarc12 - 1 set, SMT or TH?
CFT - 1 set, SMT or TH?
Jacques Antoine - 1 set TH
Silasmellor - 1 set THT
Bvtrinh- 1 set TH
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Old 24th November 2017, 05:40 PM   #5
ggetzoff is offline ggetzoff  United States
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X,

Put me on list for a TH. Thanks for all you do for the forum.

Cheers,

Greg
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Old 24th November 2017, 05:48 PM   #6
Aatto is offline Aatto  United States
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count me in for a set as well, SMT.

Last edited by Aatto; 24th November 2017 at 05:51 PM.
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Old 24th November 2017, 05:48 PM   #7
tubesguy is offline tubesguy  United States
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Join Date: May 2002
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JPS64 - 2 sets w/ SMT daughterboards
Algar Emi - 1 set, SMT or TH?
Redarc12 - 1 set, SMT or TH?
CFT - 1 set, SMT or TH?
Jacques Antoine - 1 set TH
Silasmellor - 1 set THT
Bvtrinh- 1 set TH
ggetzoff - 1 set TH
tubesguy - 1 set TH
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Old 24th November 2017, 05:53 PM   #8
tubesguy is offline tubesguy  United States
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"please quote message and edit with your name and qnty and type if interested"

Under "Quick Reply":
Copy and paste.
Hit enter for new line.
Type your username and what you want.
Hit "post quick reply"
Boom! You're done.
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Old 24th November 2017, 07:13 PM   #9
Johnny2Bad is offline Johnny2Bad  Canada
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Join Date: May 2010
JPS64 - 2 sets w/ SMT daughterboards
Algar Emi - 1 set, SMT or TH?
Redarc12 - 1 set, SMT or TH?
CFT - 1 set, SMT or TH?
Jacques Antoine - 1 set TH
Silasmellor - 1 set THT
Bvtrinh- 1 set TH
ggetzoff - 1 set TH
tubesguy - 1 set TH
Aatto - 1 set SMT
Mordikai - 1 set TH
Johnny2Bad 1 set TH; 1 set SMT
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Old 24th November 2017, 07:38 PM   #10
xrk971 is online now xrk971  United States
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AKSA's Lender Preamp with 40Vpp Ouput GB
Johnny2Bad, do you mean 2 separate motherboards one each with SMT and other with TH? Or 1 motherboard and 1 set ea of SMT and TH daughterboards?
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