Search found 4206 matches

by Andrew
Wed Feb 22, 2023 7:12 pm
Forum: Everyones Projects
Topic: It's time I built a D3a -> 5687 phonostage
Replies: 78
Views: 51890

Re: It's time I built a D3a -> 5687 phonostage

IslandPink wrote: Wed Feb 22, 2023 7:04 pm Ha !
How about £25 each nowadays ?
I should have bought more :roll:
by Andrew
Wed Feb 22, 2023 7:03 pm
Forum: Everyones Projects
Topic: It's time I built a D3a -> 5687 phonostage
Replies: 78
Views: 51890

Re: It's time I built a D3a -> 5687 phonostage

IslandPink wrote: Wed Feb 22, 2023 6:52 pm Re. D3a ,They are a lot more expensive than they used to be, as well.
Haven't looked recently, usually paid above a fiver for mine.
by Andrew
Wed Feb 22, 2023 7:02 pm
Forum: Everyones Projects
Topic: It's time I built a D3a -> 5687 phonostage
Replies: 78
Views: 51890

Re: It's time I built a D3a -> 5687 phonostage

I guess you could use a interstage, but again I think you are assuming the problem exists that needs a solution. I guess you could use a small cap into a high impedance buffer such as a op amp with voltage protection clamps on its inputs. A lot of the Japanese "DIY" designs of yesteryear ...
by Andrew
Wed Feb 22, 2023 6:31 pm
Forum: Everyones Projects
Topic: It's time I built a D3a -> 5687 phonostage
Replies: 78
Views: 51890

Re: It's time I built a D3a -> 5687 phonostage

I used two of these https://uk.farnell.com/vishay/f339mx263031mym2t0/cap-30-f-20-pp/dp/1902188 Use spice to decide what value you want to use, or follow Andrews path and send yourself mad trying to find a way to avoid the caps. If you drive it with matching Z you can terminate with a high Z, I thin...
by Andrew
Thu Feb 16, 2023 9:25 am
Forum: News
Topic: Nicola Sturgeon...
Replies: 13
Views: 7230

Re: Nicola Sturgeon...

Neal wrote: Wed Feb 15, 2023 6:55 pm There was little harmony inside the SNP of NS dogged approach to independence, it seemed to be an obsession clouding her approach she was getting heavy push back from her own party
I am not certain it wasn't the other way around, she wasn't dogged enough :?:

Better the devil you know....
by Andrew
Wed Feb 15, 2023 2:29 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81195

Re: C3g Aikido Phono

They look great, Simon!

I also found it useful to increase the size of the default pads on some of the resistor and capacitor models, making the diameters as large as the width's of the tracks they sat upon.
by Andrew
Sat Feb 11, 2023 5:56 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81195

Re: C3g Aikido Phono

I would increase the gaps a bit now between the tracks and the fill ins.
by Andrew
Sat Feb 11, 2023 1:54 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81195

Re: C3g Aikido Phono

No, reason not to make the tracks thicker too, or even create blocks of voltage.
by Andrew
Fri Feb 10, 2023 1:49 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81195

Re: C3g Aikido Phono

The hot air gun is a good idea, tho' in practical terms, if you have a paint stripper sized gun, then a small nozzle adapter would give more precise and controlled results, sort of a low tech rework station.
by Andrew
Fri Feb 10, 2023 1:14 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81195

Re: C3g Aikido Phono

Thanks Andrew. I've tried to keep connections as short as practicable, the physical size of some of the caps makes this a bit tricky though, particularly the 10uF on the C3g and the 47nF teflon in the RIAA. Interesting you mention the thermal reliefs. I've left them switched on - I struggled to get...
by Andrew
Fri Feb 10, 2023 12:22 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81195

Re: C3g Aikido Phono

The other bit of advice I would give is that you shouldn't assume caps are evil, or any other component, I think I was of that opinion, it's coloured thinking, it's all about a balances of compromises. All components have inherent weaknesses and strengths, the evil bit is not recognizing that and ma...
by Andrew
Fri Feb 10, 2023 12:15 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81195

Re: C3g Aikido Phono

The trick I was taught was to try and keep as much of the copper as possible, take a look at one of the DC heater boards, oh, and keep the connections as short as you can, tho' I appreciate some compromises are often required. I also tend to switch of the thermal reliefs for thru hole components. Ro...
by Andrew
Mon Feb 06, 2023 4:28 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81195

Re: C3g Aikido Phono

If you are feeling a tad masochistic, Simon, then this is probably worth a read re: pentode's capacitance.

http://www.r-type.org/articles/art-004c.htm
by Andrew
Fri Feb 03, 2023 3:01 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81195

Re: C3g Aikido Phono

Nick wrote: Fri Feb 03, 2023 1:05 pm Try inserting a 1R series resistor and measure the current through that against frequency, then set the signal level to represent what actually happens and see what current is being pulled.
Real or imaginary, or both?
by Andrew
Fri Feb 03, 2023 2:53 pm
Forum: Everyones Projects
Topic: C3g Aikido Phono
Replies: 319
Views: 81195

Re: C3g Aikido Phono

Next sim is with a 15k series resistor before the RIAA, and the RIAA values changed as discussed previously. RIAA new 1.png Now there appears to be 1.6dB difference, but it looks nicer above 1kHz By adding the series resistance you have made it an easier load but the bass now rolls off, doesn't it?