Search found 11819 matches

by Nick
Fri Sep 20, 2019 9:21 am
Forum: Everyones Projects
Topic: Valve DAC
Replies: 22
Views: 385

Re: Valve DAC

Read it last night, Ray's interpretation is the one I think the author means. He sets himself a (possibly intellectual rather than performance) goal of doing all the non DSP parts with valves, so those mentioned parts have to be implemented using valves to meet that goal. Its an impressive body of w...
by Nick
Thu Sep 19, 2019 8:06 pm
Forum: Everyones Projects
Topic: Valve DAC
Replies: 22
Views: 385

Re: Valve DAC

Yes, that gives a different context than Wolfgang's post did. I will try and find time to read the article again tonight.
by Nick
Thu Sep 19, 2019 9:03 am
Forum: Everyones Projects
Topic: Valve DAC
Replies: 22
Views: 385

Re: Valve DAC

Ignoring the more contentious parts, what possible reason could there be for suggesting that valves are better in the "time reference and a voltage or current reference". Not saying there isn't a reason, but if there is one, its not one I know off.
by Nick
Mon Sep 16, 2019 8:21 pm
Forum: Computer Audio
Topic: Digital.
Replies: 55
Views: 5065

Re: Digital.

While we're in the general vicinity of delta-sigma processing its maybe worth thinking about how a mainstream delta-sigma DAC chip functions with PCM data. That's sort of my point, DSD and DS DAC's convert the PCM into a bit stream that allows simple conversion to analogue. In your case, you are do...
by Nick
Mon Sep 16, 2019 3:03 pm
Forum: Computer Audio
Topic: Digital.
Replies: 55
Views: 5065

Re: Digital.

I have read that article in Linear Audio and its impressive. But call me cynical that any design that includes a FPGA could really be called a valve dac, more of a dac with valves. Semantics to some extent but the FPGA operates solely in the digital domain and you could choose to send the data from...
by Nick
Sun Sep 15, 2019 11:31 pm
Forum: Everyones Projects
Topic: Valve DAC
Replies: 22
Views: 385

Re: Valve DAC

Here is another one

by Nick
Sun Sep 15, 2019 10:49 am
Forum: Computer Audio
Topic: Digital.
Replies: 55
Views: 5065

Re: Digital.

I have read that article in Linear Audio and its impressive. But call me cynical that any design that includes a FPGA could really be called a valve dac, more of a dac with valves.
by Nick
Tue Sep 10, 2019 11:43 pm
Forum: Valves
Topic: Recommendations needed for high quality valve bases
Replies: 3
Views: 414

Re: Recommendations needed for high quality valve bases

I use ceramic with gold platerd contacts normally. CMC Teflon for best (both from HFC). Not sure low capacitance is any issue at audio frequencies we are working with.
by Nick
Fri Aug 30, 2019 7:42 pm
Forum: Everyones Projects
Topic: Inverted OTL with 6SN7/6AS7
Replies: 116
Views: 7069

Re: Inverted OTL with 6SN7/6AS7

The diodes on the input will stop the voltage going above or below 0.6v the supply rails, the resistor will limit the current at those times. Though I agree 250v may be problematic, depends on the power supply for the logic, a zener 1v above the normal supply voltage across the rails would provide a...
by Nick
Fri Aug 30, 2019 2:32 pm
Forum: General Vinyl
Topic: Technics Sp10 Woes
Replies: 120
Views: 14033

Re: Technics Sp10 Woes

And to answer Simons point, I too have thought of doing something similar to get a LED to flash at 50Hz. I do have one of these somewhere (actually I know where it is, its got a MEMS's device connected to it via i2c as I was playing at making a electronic turntable level). https://www.mattairtech.co...
by Nick
Fri Aug 30, 2019 2:22 pm
Forum: General Vinyl
Topic: Technics Sp10 Woes
Replies: 120
Views: 14033

Re: Technics Sp10 Woes

Something like 1. Take F3 out in the power supply to disconnect the 140v supply 2. Remove neon from strobe housing 3. Connect led in series with 330R (or so) resistor between 0v and IC15 Pin 3 on the logic board. 4. Position the LED where the neon bulb was Or something like that, it was some time ag...
by Nick
Fri Aug 30, 2019 8:58 am
Forum: Everyones Projects
Topic: Inverted OTL with 6SN7/6AS7
Replies: 116
Views: 7069

Re: Inverted OTL with 6SN7/6AS7

and at the same time with the correct voltage for the input of the CD4093.
I assumed the diodes on the input would protect the CMOS from over voltage. And at worst, socket the IC and buy a bag of them and include a test button to bleed voltage to the output.
by Nick
Thu Aug 29, 2019 5:35 pm
Forum: Everyones Projects
Topic: Inverted OTL with 6SN7/6AS7
Replies: 116
Views: 7069

Re: Inverted OTL with 6SN7/6AS7

I don't understand, if you have a trigger at +- 40v, then that will also trigger at +250v? If the problem is the voltage limit of the solid state relay, why not use a mechanical one, and or a relay in the supply lines to remove the source of the voltage. Or a crowbar circuit maybe?
by Nick
Thu Aug 29, 2019 4:08 pm
Forum: General Vinyl
Topic: Technics Sp10 Woes
Replies: 120
Views: 14033

Re: Technics Sp10 Woes

Well, with mine, the neon would go out all together some times. I think partly due to age of the lamp, and maybe the 140v (or whatever it was) voltage dropping as caps age. I eventually removed the neon altogether and replaced it with a pair of blue LED's driven by the logic signal and not using the...
by Nick
Tue Aug 27, 2019 9:11 pm
Forum: Everyones Projects
Topic: Question re grounding
Replies: 4
Views: 195

Re: Question re grounding

three separate power trafos for galvanic isolation
Three separate secondaries will do the same thing.