I presume that you are asking about V1 (LM337/ LM317) as compared to V2 which is an 'old school' series regulated design. Both are very good and very quiet and exceed the capabilities of my humble bench gear. I invite others to chime in, but ...
I expect that V2 might have a slight performance edge on V1.
It depends on the enclosure that you are mounting the board in. For 1U chassis I use M3 x 6mm threaded HEX standoffs.
That standoff is approximately 1/4 inch tall. I buy them on EBay.
Thanks for your help, forgot to mention that previously.
I am looking at a modushop 2U Slim Line case, but planned to have the tone controls setup like the 1U and the selector and volume with larger nobs raised and spaced outward a bit. I suppose I should lay it out before I order the standoff's. I planned to use the template as the base for the the layout and wasn't sure if they were adjusted for standoffs or not.
The schematic and basic layout has not changed since the beginning.
PCB v2x spread the front panel controls a bit per request of builders.
Please check your private messages. I just sent you a link to the latest DOCs.
I would per default replace the 3.3k resistors by 1k to set overall gain to unity. But in the end this depends on your needs.
Doug Self Pre Amp
Hi Carl. I built the original precision pre amp in 1996. It was featured in Wireless World as a series of articles. Loved the tone controls, very good at controlling a booming base. Is it still possible to order the set of boards plus any other components that come with them.
Many thanks.
Hi Carl. I built the original precision pre amp in 1996. It was featured in Wireless World as a series of articles. Loved the tone controls, very good at controlling a booming base. Is it still possible to order the set of boards plus any other components that come with them.
Many thanks.
This project is based upon the Doug Self article entitled, "A low-noise preamplifier with variable-frequency tone controls" that was published in Vol 5 of Jan Didden's excellent Linear Audio magazine. The important details of the project are all contained in that article.
I still have a few kits available. Please send me a personal message if you are interested if you are interested in acquiring one or more of them.
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Alright! Enough lurking and indecision. After reading Doug's "Self on Audio" and "Electronics for Vinyl" books, spending many hours on breadboards, and finally realizing that there is no way I can even come close to duplicating the Elector or Linear Audio circuits without spending way too much time and money, I've now officially joined the club, having ordered some PCBs from Carl today. Tonight I go through the BOMs and see what parts I'm going to need to buy. This thread (actually this whole site) is fantastic. Thanks everyone! -Bob
Reviving an old question asked back in Feb of this year. I think I saw that the input impedance is 50k. But I didn't see any replies regarding the output impedance.
Hi Carl! I just looked at the pictures of your build in post #1111.
It seems the panels are anodized black aluminum and I assume you ordered them from front panel express. According to the front design software the edges of anodized panels should turn out silver (natural). The same goes for the inside edges of the rack mount holes. Yet your edges seem to be black. How did you do that?
It seems the panels are anodized black aluminum and I assume you ordered them from front panel express. According to the front design software the edges of anodized panels should turn out silver (natural). The same goes for the inside edges of the rack mount holes. Yet your edges seem to be black. How did you do that?
That's because I am in the habit of buying chassis and sending the front panel to Panel Express for engraving. That is, I use their 'user supplied' option.
The chassis sold in the DiyAudio store are good examples.
Happy Holidays!
Happy Holidays to everyone that has participated in this thread.
And a special thanks to Doug Self and Jan Didden for their help and allowing me to share this project with all of you.
I only hope that those of you that have built this project enjoy it as much as I did bringing it to you.
Happy Holidays to everyone that has participated in this thread.
And a special thanks to Doug Self and Jan Didden for their help and allowing me to share this project with all of you.
I only hope that those of you that have built this project enjoy it as much as I did bringing it to you.
Basic question on gain structure. With the default gain of 10 db, how does this translate to input sensitivity? What is the max input signal that leaves enough headroom to avoid clipping with the 17v power supply? Is this dependent on the crest factor of the source signal?
If the source is unbalanced 2Vrms / 5db, the default 10db gain structure would increase this to unbalanced 6Vrms / 16db at the output. Do I have the math correct?
If the source is unbalanced 2Vrms / 5db, the default 10db gain structure would increase this to unbalanced 6Vrms / 16db at the output. Do I have the math correct?