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Search: Posts Made By: NickG
Forum: Amplifiers 17th June 2012, 01:25 PM
Replies: 12
Views: 5,349
Posted By NickG
Re: James JS-6123H output TX Spec Help

Try both, use what you prefer.
Forum: Amplifiers 17th June 2012, 12:21 PM
Replies: 12
Views: 5,349
Posted By NickG
Re: James JS-6123H output TX Spec Help

Cant see why not. Thats not far off a typical 300b op point.
Forum: Amplifiers 17th June 2012, 12:56 AM
Replies: 12
Views: 5,349
Posted By NickG
Re: James JS-6123H output TX Spec Help

The power rating refers to the max power that can be transferred through the transformers, probably at 1kHz, normally less at 20Hz. Its limited mainly by the size of the core, which governs the max...
Forum: General 31st March 2012, 09:33 PM
Replies: 7
Views: 1,464
Posted By NickG
Re: Radford Ownership

Join the Yahoo Radford group and look at the posting archive.
Forum: General 31st March 2012, 03:42 PM
Replies: 7
Views: 1,464
Posted By NickG
Re: Radford Ownership

I wont post the full body of Peters post, but the important points were that yes, he still has the name, but that he is giving his blessing to what the Radford Revival folk are doing and wishes them...
Forum: WD Amplifiers 29th November 2011, 08:14 AM
Replies: 14
Views: 3,323
Posted By NickG
Re: Remote volume for the Kel84

Just run a couple of wires from the heater supply to one of the valves to the board. Or maybe I don't understand your question.

I would pick an el34 socket and solder a wire to pin 4 and another...
Forum: The Coffee Bar 8th August 2011, 01:22 PM
Replies: 37
Views: 4,328
Posted By NickG
Re: Computer Problems Windows 7

http://support.microsoft.com/lifecycle/?LN=en-gb&C2=1173
Forum: Amplifiers 24th April 2011, 03:13 AM
Replies: 62
Views: 16,520
Posted By NickG
Re: Help switching out Zener for 0b2 regulator tube

When the voltage across the VR tube is higher than its regulating voltage, then the tube passes more current. if you connect the vr tube to a higher than its striking voltage through a load resistor...
Forum: Amplifiers 23rd April 2011, 01:53 AM
Replies: 62
Views: 16,520
Posted By NickG
Re: Help switching out Zener for 0b2 regulator tube

the 17ma was a mistake, it should have been 1,7ma (392-102)/168000. With the 0b2 you will need the extra resistor, 16k or whatever. the 2ma or so would be ok for the 85A2 though.

The VR connection...
Forum: Amplifiers 22nd April 2011, 08:01 PM
Replies: 62
Views: 16,520
Posted By NickG
Re: Help switching out Zener for 0b2 regulator tube

Almost. The 0ba anode (1,5) goes to the triodes cathode, an its cathode (2,4,7) to ground.
Forum: Amplifiers 22nd April 2011, 10:14 AM
Replies: 62
Views: 16,520
Posted By NickG
Re: Help switching out Zener for 0b2 regulator tube

Looking at the new diag, you already have 17ma going top the cathode via r9 and r10, so the 0b2 VR would just work I think. Just remove the cap across the zener and replace with a 100nf one.
Forum: Amplifiers 21st April 2011, 11:41 PM
Replies: 62
Views: 16,520
Posted By NickG
Re: Help switching out Zener for 0b2 regulator tube

Nothing from dropping the voltage, but the valve is a voltage reference instead of a voltage regulator, so its lower noise, more stable, and needs far less current to strike.
Forum: Amplifiers 21st April 2011, 08:44 AM
Replies: 62
Views: 16,520
Posted By NickG
Re: Help switching out Zener for 0b2 regulator tube

Just noticed you had removed the adjustment pot from the diagram. You would just alter the voltage dropper to give about 84v at the grid with the required output voltage. If you want I will work out...
Forum: Amplifiers 20th April 2011, 05:15 PM
Replies: 62
Views: 16,520
Posted By NickG
Re: Help switching out Zener for 0b2 regulator tube

Actually, my choice would be to use a 85A2 and a 33k resistor. That will only pull 5ma or so from the supply.
Forum: Amplifiers 19th April 2011, 05:25 PM
Replies: 62
Views: 16,520
Posted By NickG
Re: Help switching out Zener for 0b2 regulator tube

Well, I can only say John, that firstly having built several regulators using VR tubes, and assuming one of the goals of the circuit is reducing ripple, the effect of introducting any ripple into the...
Forum: Amplifiers 19th April 2011, 02:26 PM
Replies: 62
Views: 16,520
Posted By NickG
Re: Help switching out Zener for 0b2 regulator tube

No, because you are taking it from the regulated output. If the supply can't provide a extra 10ma its broken anyway IMHO.

Though, I still dont see what wouldbe gained by using the gas tube in this...
Forum: Amplifiers 19th April 2011, 11:45 AM
Replies: 62
Views: 16,520
Posted By NickG
Re: Help switching out Zener for 0b2 regulator tube

If it helps, I would use a 16k 5W resistor to the VR tube, and I would take it from the 260v out from the regulator, otherwise you are feeding it unsmoothed AC and your regulators hum rejection will...
Forum: WAD Problems 20th March 2011, 05:32 PM
Replies: 18
Views: 3,346
Posted By NickG
Re: Help wanted please

You have to look at what happened before the fuse went. The rectifiers overloaded. They will do that if they are passing too much current, they will pass too much current if there is a short after...
Forum: WAD Problems 20th March 2011, 10:58 AM
Replies: 18
Views: 3,346
Posted By NickG
Re: Help wanted please

Assuming it was working when it was shipped, which you have every reason to believe. The chance of transport damaging a transformer is zero. Much more likely is that a component has become dislodged...
Forum: WD Other Parts and Projects 14th March 2011, 03:53 PM
Replies: 17
Views: 6,572
Posted By NickG
Re: The WD Phonostage is cleared for take off!

Though it might look similar, there is one huge difference. The WD phono uses passive EQ, the EAR uses the EQ in a feedback lopk.
Forum: Useful Links 12th March 2011, 07:25 PM
Replies: 9
Views: 4,894
Posted By NickG
Re: Software Oscilloscope

The input is the input of your sound car, so only you can answer those questions.

My only problem with using a sound card for setting up the phono, is you need to be able to see the square wave...
Forum: Membership Issues 9th March 2011, 02:33 AM
Replies: 27
Views: 6,245
Posted By NickG
Re: How private are PM's

Cant say for this site, I don't use vBulletin, I can't read them using phpbb that I use. In reality, if I wanted to read them I could, but that would be by querying the database behind the board. I...
Forum: News 8th March 2011, 12:10 PM
Replies: 21
Views: 10,107
Posted By NickG
Re: A great new owner for World Designs

I am not saying its not possible to set up a company in the UK to design, sell and support DIY hifi, and I agree there is a customer base out there that would buy such a service. What I am saying is...
Forum: News 8th March 2011, 10:26 AM
Replies: 21
Views: 10,107
Posted By NickG
Re: A great new owner for World Designs

I would look at this sort of thing instead of 12 worth

http://www.rapidonline.com/sku/Cables-Connectors/Connectors-Mains-Power/IEC-Connectors/Polyflange-vertical-IEC-inlet/66201/23-3238

All...
Forum: General 7th March 2011, 05:43 PM
Replies: 5
Views: 1,431
Posted By NickG
Re: Rule 34

RoHS applies to new electrical goods and components. So MV Rectifiers not being new would be outside the scope. But I think if they were sold as part of a complete amplifier it may be a different...
Showing results 1 to 25 of 1810

 
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