Search found 718 matches

by RhythMick
Fri Oct 22, 2021 8:56 am
Forum: Everyones Projects
Topic: Poundland 45
Replies: 104
Views: 6255

Re: Poundland 45

Is it worth adding fuses to each transformer secondary?

You could also off board the power supply into a separate chassis with an umbilical if the chassis is tight, though it sounds like you don't need it now. I usually find the power supply dominates the space requirements.
by RhythMick
Wed Sep 08, 2021 8:33 am
Forum: Everyones Projects
Topic: Poundland 45
Replies: 104
Views: 6255

Re: Poundland 45

So yesterday I did a resistor/glow tube stack shunt reg feed to the input stage and was pleased with the results. Today I decided it was time to take a leaf out of Mark's phono stage book and feed the glow tube stack from a constant current source. 'Sod it! Just do it!' I thought. I've got a load o...
by RhythMick
Wed Sep 08, 2021 8:27 am
Forum: Everyones Projects
Topic: Poundland 45
Replies: 104
Views: 6255

Re: Poundland 45

So yesterday I did a resistor/glow tube stack shunt reg feed to the input stage and was pleased with the results. Today I decided it was time to take a leaf out of Mark's phono stage book and feed the glow tube stack from a constant current source. 'Sod it! Just do it!' I thought. I've got a load o...
by RhythMick
Sun Sep 05, 2021 10:50 pm
Forum: Everyones Projects
Topic: Poundland 45
Replies: 104
Views: 6255

Re: Poundland 45

I have a good handful of BG caps I will never use if you want them Steve.

Several are doubles (220+220, 50+50, 100+100 maybe) and a few singles.
by RhythMick
Sun Sep 05, 2021 10:43 pm
Forum: Everyones Projects
Topic: ‘bout time I listened to 46
Replies: 19
Views: 836

Re: ‘bout time I listened to 46

Plenty of options in the bases. At present I’ll just make a 2.5v power supply and mirror the relevant pins including heater supply from 46 use to 45 use. Same b+ and heater. The ht transformer is 170mA so the increased current of the 45 from 22mA (46) to 50mA (45). The “Neptune” potted transformer ...
by RhythMick
Tue Aug 31, 2021 9:25 pm
Forum: Everyones Projects
Topic: Question re Izzy Wizzy phono stage
Replies: 18
Views: 1453

Re: Question re Izzy Wizzy phono stage

Thanks for confirming.

In true Mick style I've departed from the safe path and gone off-piste. I'll draw up what I'm building and post for general merriment and laughter if nothing else.

It'll all end in tears...
by RhythMick
Tue Aug 31, 2021 2:56 pm
Forum: Everyones Projects
Topic: Question re Izzy Wizzy phono stage
Replies: 18
Views: 1453

Re: Question re Izzy Wizzy phono stage

Capture.PNG Apologies for the dumb question. Working my way through my design and the DC coupling values to the next stage. I think I know the answer but really just want to check. Output taken from D3a anode is an AC signal riding on a DC offset. That will present at the grids of the valves on the...
by RhythMick
Mon Aug 30, 2021 8:35 am
Forum: Everyones Projects
Topic: ‘bout time I listened to 46
Replies: 19
Views: 836

Re: ‘bout time I listened to 46

I'll have a look through my boxes. I have a nagging thought that I may have a pair of Cunningham globe 46.
by RhythMick
Sun Aug 29, 2021 12:38 pm
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 66
Views: 3419

Re: 801a amplifier

The major and sometimes insurmountable problem for anxiety sufferers is something that I would term as thought crowding. When thought crowding occurs it becomes difficult to function properly. The sufferer has tremendous difficulty sorting through what is important and what is not, as everything in...
by RhythMick
Sun Aug 29, 2021 8:22 am
Forum: Everyones Projects
Topic: 801a amplifier
Replies: 66
Views: 3419

Re: 801a amplifier

I look forward to reading that.

My view, it's perfectly fine to have a head full of ideas and not act on them. Problems occur when you try to act on them all...
by RhythMick
Thu Aug 26, 2021 7:50 am
Forum: Everyones Projects
Topic: Born Again Vinylista Phono Stage
Replies: 177
Views: 25241

Re: Born Again Vinylista Phono Stage

There are arguments for both ways. The ideal is to keep a constant g2 voltage, but what constant means to the valve is the voltage between its cathode and g2. Its knows nothing about gnd. However in theory the cap across the cathode resistor means that the cathode and gnd are at the point for AC at...
by RhythMick
Wed Aug 25, 2021 10:59 pm
Forum: Everyones Projects
Topic: Born Again Vinylista Phono Stage
Replies: 177
Views: 25241

Re: Born Again Vinylista Phono Stage

Question - should the 22uF from D3a g2 go to ground rather than cathode ?
by RhythMick
Wed Aug 25, 2021 8:31 pm
Forum: Everyones Projects
Topic: Born Again Vinylista Phono Stage
Replies: 177
Views: 25241

Re: Born Again Vinylista Phono Stage

400v caps not expensive. I'd keep it there and avoid raising the value.
by RhythMick
Tue Aug 24, 2021 8:43 pm
Forum: Everyones Projects
Topic: Born Again Vinylista Phono Stage
Replies: 177
Views: 25241

Re: Born Again Vinylista Phono Stage

Going out on a limb, possible someone will correct me. I believe R1 is the series total of the output resistance of the previous stage and the actual resistor. So if the calculators show R1 as 24K and the output resistance is 3K then you need a 21K series resistor. Zout of previous stage calculated ...
by RhythMick
Mon Aug 23, 2021 11:09 pm
Forum: Everyones Projects
Topic: Born Again Vinylista Phono Stage
Replies: 177
Views: 25241

Re: Born Again Vinylista Phono Stage

Most MCs are very low impedance, low volts, high current (relatively) and have a rising top end so capacitance is not usually a problem. MM is the opposite. Some higher Z MC carts maybe not so much but that's another story and not so sure of my calcs on that front. From a personal POV, anything to ...