Page 1 of 1
#1 New Luminaria Preamp
Posted: Mon Jul 11, 2022 6:46 am
by Ray P
MoFo type scenarios require a preamp with a bit of voltage gain; I'm already working on a valve preamp using 2P29L valves that'll give around 20dB of gain but as I also have a pair of Sony 2SK60 V-FETs I thought it would be interesting to use them in a preamp circuit from over on DIY Audio. The 2SK60 FETs are choke loaded (Hammond 157G).
#2 Re: New Luminaria Preamp
Posted: Mon Jul 11, 2022 6:49 am
by Ray P
As I had a bit of time over the weekend I started by assembling a volume control module using a Seiden switch and a couple of Dave Slagle's Autoformers.
#3 Re: New Luminaria Preamp
Posted: Sun Jul 17, 2022 11:56 am
by Ray P
#4 Re: New Luminaria Preamp
Posted: Sun Jul 17, 2022 12:18 pm
by JamesD
Hi Ray,
Nice design and very nice work!
I have been researching using my Sony's for a Luminaria following your recommendation and it looks very interesting!
ciao
James
#5 Re: New Luminaria Preamp
Posted: Sun Jul 17, 2022 6:50 pm
by Ray P
Cheers James. I also had some PCBs for the 'New Luminaria' section fabricated - the aim is to stack them in front of the autoformer board so I end up with quite a neat, compact preamp unit.
#6 Re: New Luminaria Preamp
Posted: Sun Jul 31, 2022 8:17 pm
by Ray P
I got the required stand-offs yesterday so here's a preview of the whole assembly. Still waiting on the trimmer pots for the buffer stage before I can wire it up and give it a try, looks like they'll be another fortnight or so before they're back in stock.
#7 Re: New Luminaria Preamp
Posted: Mon Aug 01, 2022 12:18 am
by izzy wizzy
Lovely work Ray. Your stuff looks like finished commercial stuff rather than DIYery.
#8 Re: New Luminaria Preamp
Posted: Mon Aug 01, 2022 10:02 pm
by Ray P
Cheers. I guess we all have our stengths and weaknesses - I'm not so hot on the eletronics theory stuff so I tend to follow where others have gone before in that respect but I do seem to be able to visualise ideas and I get a lot of pleasure from this hobby from creating something that looks shoddy as well as sounds good.
#9 Re: New Luminaria Preamp
Posted: Sun Aug 07, 2022 5:24 pm
by Ray P
I received the trim pots for the buffer stage and installed them this afternoon so I'll be able to test the volume control with buffer now - I've got the week off so I'll get onto it ina day or two.
I've also assembled one o Nicks (Jack's) Statistical Regulator kits to power the gain stage. Schematic calls for 120VDC, which is 21 zener diodes. I ignored the instructon sheet and installed them in groups of 10 in the outer rows and then linked the rows with zener #21 under the board. I need to put a rectifier pre-filter board together next.
#10 Re: New Luminaria Preamp
Posted: Sun Aug 07, 2022 5:42 pm
by Daniel Quinn
Quality work .
#11 Re: New Luminaria Preamp
Posted: Sun Aug 07, 2022 6:00 pm
by Ray P