Search found 15706 matches

by Nick
Fri Feb 16, 2024 2:26 pm
Forum: Assorted Stuff
Topic: Nothing In Particular
Replies: 16439
Views: 4649354

Re: Nothing In Particular

Seems like this is known and expected (and not only the case for smart meters) All gas meters (Smart and traditional) have an internal battery that power them. This is designed to last for up to 20 years, with a meter recertification (exchanging the meter to replace it with a new one) scheduled ever...
by Nick
Fri Feb 16, 2024 1:59 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81380

Re: C3g Aikido Phono

Yep, you maybe need to compensate for any gain change. Its the S/N ratio that matters in this case. Also, you tend to get that sort of noise/f curve depending on the type of noise source (thermal, shot, partition etc ). Generally paralleling devices will reduce noise proportionally to square root of...
by Nick
Thu Feb 15, 2024 11:11 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81380

Re: C3g Aikido Phono

Yep the noise will reduce for every doubling of the FETs. I think there is a error though. The 40r source resistor is shorted out
by Nick
Thu Feb 15, 2024 9:28 am
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81380

Re: C3g Aikido Phono

The gate resistor will be needed for each one. in case you don't know, its job is to protect the fet if the input is sent too +ve. The gate/source junction will become a forward biased diode (as shown in the symbol) and its to prevent excess current in that case. This is one of these bits of informa...
by Nick
Wed Feb 14, 2024 9:49 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81380

Re: C3g Aikido Phono

You can play with the source resistor in the case of the jfet to alter the gain, and also try paralleling up 2 or more.
by Nick
Wed Feb 14, 2024 5:11 pm
Forum: Everyones Projects
Topic: 6550 SE Amplifier
Replies: 110
Views: 9410

Re: 6550 SE Amplifier

I normally use 100R on ecc88, I would have thought 10k would be more than enough.
by Nick
Tue Feb 13, 2024 7:54 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81380

Re: C3g Aikido Phono

The small signal section is for AC analysis of fr and phase. It may be you need to set that depending on the analysis you are showing. The left hand side is for voltage/current against time.
by Nick
Tue Feb 13, 2024 11:22 am
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81380

Re: C3g Aikido Phono

Are you using AC on the input? if so, whats the 1.4V
by Nick
Mon Feb 12, 2024 10:08 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81380

Re: C3g Aikido Phono

Q2 is upside down.
by Nick
Sun Feb 11, 2024 10:18 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81380

Re: C3g Aikido Phono

You should be able to ground the stepup metalwork, while leaving the windings floating. It may be ok to ground the primary if needed, but try and leave the secondary grounded via the phono stage.
by Nick
Sun Feb 11, 2024 6:35 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81380

Re: C3g Aikido Phono

Yes, and also, because the input is now floating (assuming the cartridge is wired as is normal so the output is not connected to earth), any voltage generated in the 0v line down to the ground point at the output RCA's is not seen by the input valve as its common mode WRT the input.
by Nick
Sat Feb 10, 2024 12:55 am
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81380

Re: C3g Aikido Phono

Maybe.
by Nick
Fri Feb 09, 2024 11:34 pm
Forum: Valves
Topic: Valve amplifier service
Replies: 176
Views: 84308

Re: Valve amplifier service

Is the single cap C14 to allow ripple currents in the bridge to have an easy path to mains supply earth? Maybe, sounds like could be correct. Not ripple though, its 10nf, so will be to pass switching noise from the diodes I would have thought. HF signals will see the wire to the other end of the 0v...
by Nick
Fri Feb 09, 2024 11:30 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81380

Re: C3g Aikido Phono

Looks like fun, but going from *4 to *10 is not that trivial.