AudioCircle

Audio/Video Gear and Systems => The Lab => Topic started by: happyrabbit on 4 Jul 2020, 03:25 pm

Title: Transformer Based 6db preamp.
Post by: happyrabbit on 4 Jul 2020, 03:25 pm

My latest diy preamp adventure. -/+ 24v Linear Supply. Sparkoslabs regulators. LSK489 for the jfet’s.  6 layer PCB (s/g/p/p/g/s). Startup / shutdown muting.

Balanced -> LL1676(1:2) -> jfet follower -> 10k ladder -> jfet follower ->  dc blocking cap -> RCA

I will post measurements soon..  the in/out are flipped on the case.  :duh:


(https://www.audiocircle.com/image.php?id=211337)

(https://www.audiocircle.com/image.php?id=211338)

(https://www.audiocircle.com/image.php?id=211339)

(https://www.audiocircle.com/image.php?id=211340)

Title: Re: Transformer Based 6db preamp.
Post by: happyrabbit on 16 Sep 2020, 01:36 am

Round 2..   more filtering on the linear supply.   Different output coupling caps.   Removed jfet buffer vreg’s and replaced with low pass filters.   Replaced Khozmo attenuator with the mini from Tortuga Audio. 


(https://www.audiocircle.com/image.php?id=214662)

Title: Re: Transformer Based 6db preamp.
Post by: FullRangeMan on 16 Sep 2020, 02:43 am

Nice preamp, any idea on the gain or freq range?