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Search: Posts Made By: John Caswell
Forum: WAD General Today, 10:47 AM
Replies: 1
Views: 43
Posted By John Caswell
Re: Heater wiring for twin rectifiers

Hi Greg,
Whilst there is some evidence this helps when used in output stages, be it PP or SE I cannot see it making any real difference on power supplies. I suppose the best I can answer is it's...
Forum: WD Amplifiers Today, 10:42 AM
Replies: 23
Views: 418
Posted By John Caswell
Re: WD88VA didn't survive move

Wiggers you have a PM

John
Forum: WD Amplifiers 17th October 2018, 03:01 PM
Replies: 23
Views: 418
Posted By John Caswell
Re: WD88VA didn't survive move

Hi Wiggers,
Yes that's the correct address etc.
Let me know what you want to do.

John
Forum: WD Amplifiers 17th October 2018, 02:14 PM
Replies: 23
Views: 418
Posted By John Caswell
Re: WD88VA didn't survive move

Hi Wiggers,
Yes still am, do you wish me to have look at it?
Was the flash and pop from the same valve position or the other one on that side.
If so you may have had another faulty valve, not...
Forum: WD Amplifiers 14th October 2018, 09:23 PM
Replies: 23
Views: 418
Posted By John Caswell
Re: WD88VA didn't survive move

Hi Wiggers et al,
Oh I haven't left the forum, I just keep a slightly lower profile now as others are more than capable of answering the questions that pop up.

John
Forum: WD Amplifiers 14th October 2018, 02:12 PM
Replies: 23
Views: 418
Posted By John Caswell
Re: WD88VA didn't survive move

Hi Wiggers ,
Don't panic Mr Mainwaring it is most likely to be a valve shaken up by the move and possibly a bit of cathode material worked loose.
If you have a spare valve stick it in, but not...
Forum: WAD General 5th October 2018, 06:04 PM
Replies: 9
Views: 159
Posted By John Caswell
Re: KT5881 valve change

Hi all,
Yes, apologies, I did not make my intention clear that it was heater current I was discussing.
Gary, Yes the Quad amplifier will accept KT66, 5881, 6L6 and 6P3P because its heater current...
Forum: WAD General 5th October 2018, 03:12 PM
Replies: 9
Views: 159
Posted By John Caswell
Talking Re: KT5881 valve change

Phil et al,
Built my first amp when I was 9 albeit with a bit of help, I'm now 77 and still learning, but apparently still "don't know nuffin" as I am constantly contradicted by self professed...
Forum: WAD General 5th October 2018, 02:08 PM
Replies: 9
Views: 159
Posted By John Caswell
Re: KT5881 valve change

Hi Gary,
This is not a substitution I would recommend, purely on the grounds of heater current consumption.
The 5881 is rated at 6.3v 900ma whereas the KT66 is rated at 6.3v 1.3A. This is well...
Forum: WD Amplifiers 11th September 2018, 10:35 AM
Replies: 2
Views: 175
Posted By John Caswell
Re: WD phono load

Hi Phil,
The output impedance of the Phono 2/3 is approx 4K, so I would not run it into less than 10X as much ie 40K.

John
Forum: General 18th August 2018, 09:53 PM
Replies: 19
Views: 1,413
Posted By John Caswell
Re: A gun, wax and hearing problems.

Hi Bob et al,
This of course is the main problem with all hearing aids, you go from something that can differentiate sounds around, to basically a point receiver (the microphone) so it takes some...
Forum: WD Amplifiers 18th August 2018, 04:21 PM
Replies: 9
Views: 354
Posted By John Caswell
Re: Where to buy valves

Hi Mel,
I see you r point they do not do 6P14P and I am not sure who you would be able to get a matched set/pairs of those from as I don't know of anyone who imports the Russian variety.
You may...
Forum: WD Amplifiers 18th August 2018, 10:19 AM
Replies: 9
Views: 354
Posted By John Caswell
Re: Where to buy valves

Hello Mel,
Don't waste money on buying matched ECF80/E80CF/6BL* or their CV equivalent CV5215 they are so variable - see my comments and FAQ.
I suggest Hotrox in Nottingham for EL84/6BQ5/6P14P....
Forum: General 18th August 2018, 09:22 AM
Replies: 19
Views: 1,413
Posted By John Caswell
Re: A gun, wax and hearing problems.

Hi all,
Had mine checked a couple of years ago, usual problem about 6dB down at 8KHz, possibly more.
Went to Royal Berks Audiology Dept. in Bracknell which is apparently the best locally and was...
Forum: For Sale 30th July 2018, 11:46 AM
Replies: 25
Views: 1,161
Posted By John Caswell
Re: FS WAD 300b with mods

Hi Adrian,
Yes I agree with what you say, from the picture is was not easy to see whether the 15R were in parallel or not.
As the "cathode bias" R is 1K5 this will reduce the current allowed so the...
Forum: For Sale 30th July 2018, 08:55 AM
Replies: 25
Views: 1,161
Posted By John Caswell
Re: FS WAD 300b with mods

Hi all,
As I see it, according to the colour code on the green resistors, it appears to be a 1K5 paralleled with a 15R (Brown, Green, Black) which is definitely wrong.
Adrian I think your sums are...
Forum: For Sale 29th July 2018, 12:26 PM
Replies: 25
Views: 1,161
Posted By John Caswell
Re: FS WAD 300b with mods

Gentlemen,
This thread is drifting off topic.

John
Forum: WD Amplifiers 26th June 2018, 08:36 AM
Replies: 7
Views: 422
Posted By John Caswell
Re: WAD CF Pre relayboard not working Help

Hi Colin et al,
Although I am not normally into violence I have to admit a good slap often helps gel the brain:D
Nicely done Colin

John
Forum: WD Amplifiers 25th June 2018, 05:41 PM
Replies: 7
Views: 422
Posted By John Caswell
Re: WAD CF Pre relayboard not working Help

Hi Colin,
1) Did it work originally?
2) Is the 6.3 v supply the correct way round, because the LED is not lit up, which could mean that the heaters supply is the wrong way round.

John
Forum: WAD Problems 16th June 2018, 11:19 PM
Replies: 2
Views: 250
Posted By John Caswell
Re: KiT/KaT6550 and fuse blowing inrush current

Hi Greg,
Yes this item is fine and as Farnell says a suitable replacement for the original.
Just remember to mount it on longish leads as it gets pretty hot and contrary to my general...
Forum: WD Amplifiers 7th May 2018, 10:09 AM
Replies: 5
Views: 417
Posted By John Caswell
Re: Converting WD KT88 to XLR

Converting the WD88 to balanced inputs is a relatively simple job.
There are two ways of doing it either electronically using a dedicated unbalanced to balanced IC, or using a 1:1 transformer...
Forum: The Coffee Bar 6th May 2018, 03:58 PM
Replies: 32
Views: 1,369
Posted By John Caswell
Re: SME & Garrard

Baggy,
Don't worry about it.

John
Forum: The Coffee Bar 5th May 2018, 10:48 AM
Replies: 32
Views: 1,369
Posted By John Caswell
Re: SME & Garrard

Gentlemen,
Don't let this thread degenerate into a polite but nevertheless "slanging match" re belt/idler/direct drive turntables. I has all been done to death elsewhere. Everyone has their own...
Forum: Amplifiers 3rd May 2018, 10:34 PM
Replies: 3
Views: 457
Posted By John Caswell
Re: 5881 Amp building instructions

Hi Snodge,
There were some layouts in the supplements, which I will have a look for, but I suggest that you try Matthew at World Designs first.
Bear in mind that there were three variations on a...
Forum: WAD General 15th April 2018, 09:12 AM
Replies: 8
Views: 542
Posted By John Caswell
Re: Kat6550 vibration/hum

Hi all,
The 6550 was a WAD design and as such had steel chassis, so of course things are a bit different.
A bolt to stress the base between the top of the chassis and the base may help or even some...
Showing results 1 to 25 of 1449

 
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