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Search: Posts Made By: ian_r
Forum: WD Amplifiers 31st July 2012, 12:08 PM
Replies: 8
Views: 2,334
Posted By ian_r
Re: Help out there for a KEL80

John,

Does this thread help?

http://www.world-designs.co.uk/forum/showthread.php?t=343&highlight=transformers
Forum: General 9th November 2011, 03:34 PM
Replies: 14
Views: 3,493
Posted By ian_r
Re: Replacement valves for icon stereo 25mk1

Do you a circuit diagram?

Blurb on Icon Audio website (albeit for the mk2)says "Our simplified bias circuit means that valve replacement of the same type requires no bias adjustment" so sounds...
Forum: WD Amplifiers 12th October 2011, 12:54 PM
Replies: 2
Views: 1,652
Posted By ian_r
Re: Wd88 ecc83s

Richard,

Thanks. Sound is I think pretty much unchanged with the EH 12 AX7, I may look for a 5751 to try.

Ian
Forum: WD Amplifiers 11th October 2011, 05:56 PM
Replies: 2
Views: 1,652
Posted By ian_r
Wd88 ecc83s

Hi All,

My WD88 has performed without problems from first switch on until now.... lost one channel (only noise from speaker). Some swapping of valves showed that one side of the ECC83S first stage...
Forum: Amplifiers 23rd February 2010, 05:38 PM
Replies: 7
Views: 4,177
Posted By ian_r
Re: Valve buffer for NOS DAC

Thanks for the input guys. I have already started down the path of this circuit:

http://users.podolsk.ru/boga/Images/DAC_Buffer.gif

but only by ordering a couple of 6C45P's so might change my...
Forum: Amplifiers 7th February 2010, 04:28 PM
Replies: 5
Views: 3,338
Posted By ian_r
Re: Driving an EM84 'Magic Eye'

Isn't the 6C45PI a single triode? - datasheetsheet

http://lib.store.yahoo.net/lib/thetubestore/RU-6C45P.pdf :)
Forum: Amplifiers 4th February 2010, 09:19 PM
Replies: 7
Views: 4,177
Posted By ian_r
Re: Valve buffer for NOS DAC

Made my own using press-n-peel film. Its a bit of a faff (esp on the double sided board), but if it goes wrong you can clean it off and start again.
Forum: Amplifiers 4th February 2010, 05:50 PM
Replies: 7
Views: 4,177
Posted By ian_r
Valve buffer for NOS DAC

Hi All,

I've just completed the spdif and dac bits for a dual TDA1541 NOS dac, using the PCB layouts from here ( http://bygselvhifi.dk/dualdactubefacelift.htm ). Got it all working surprisingly...
Forum: Amplifiers 13th February 2009, 03:55 PM
Replies: 33
Views: 7,591
Posted By ian_r
Re: new maplins 4/20

Go to duncanamps.com and download the free PSU designer software. Easy to use, you can experiment with each configuration and answer your question. :)
Forum: Amplifiers 18th January 2009, 06:44 PM
Replies: 33
Views: 7,591
Posted By ian_r
Re: new maplins 4/20

If V1/6 volts are OK, and since its unlikely to be the same (random) fault on both PCB's, I suggest you check the values of R9, R10, R11 and R12.
Forum: Amplifiers 15th January 2009, 06:46 PM
Replies: 33
Views: 7,591
Posted By ian_r
Re: new maplins 4/20

What does V1 pin 6 measure? Do both channels measure the same on V2 1/6? Is the amp working, if so how does it sound? :)
Forum: Amplifiers 29th December 2008, 07:19 PM
Replies: 33
Views: 7,591
Posted By ian_r
Re: new maplins 4/20

The resistance you measure from p4 to p5 will be around 500K - eventually. You are measuring R1 (470K) through two diodes, plus the charging current for C1. The charging current will gradually drop...
Forum: Amplifiers 28th December 2008, 09:58 PM
Replies: 33
Views: 7,591
Posted By ian_r
Re: new maplins 4/20

"new tx" - I assume this is the mains tx, and "powered up psu only" means that the heaters and B+ were not connected to amplifiers. The fuse may have blown for a reason, so before powering up again...
Forum: General 22nd November 2008, 11:10 PM
Replies: 12
Views: 3,594
Posted By ian_r
Re: would no mains transformer be a bad idea?

I don't think option (1) would work - well not if you connect the 0V to earth. Earth and neutral are already connected together (usually at the nearest substation). So there will (at least) be a fuse...
Forum: DIY Pictures 20th November 2008, 03:01 PM
Replies: 160
Views: 67,402
Posted By ian_r
Re: Millenium 4-20 (Maplin Electronics)

I have already traced them in PowerPoint format (including modification to latest circuit). Print onto PressnPeel and your ready to go! PM me if you want the files.
Forum: Loudspeakers 18th November 2008, 04:21 PM
Replies: 6
Views: 2,565
Posted By ian_r
Re: small speakers for unusual room shape?

Shane - interesting idea but probably a bit too intrusive (the bulkhead is structural so I don't want to cut into it)

Grog - I looked at the thread you referenced; not sure what drivers you are...
Forum: Loudspeakers 17th November 2008, 07:05 PM
Replies: 6
Views: 2,565
Posted By ian_r
Re: small speakers for unusual room shape?

Hi Jerry,

This will be a new installation (at present I use a car stereo). I was indeed thinking along the lines of a T amp; battery power (12v) is always at a bit of a premium hence I'd prefer to...
Forum: Loudspeakers 16th November 2008, 10:56 PM
Replies: 6
Views: 2,565
Posted By ian_r
small speakers for unusual room shape?

Any suggestions for the attached? As I spend my weekends afloat in the summer its time the audio was upgraded :). Space is very limited (about 10" by 12", and the thinner the better); I was thinking...
Forum: DIY Pictures 12th November 2008, 11:18 AM
Replies: 160
Views: 67,402
Posted By ian_r
Re: Millenium 4-20 (Maplin Electronics)

I have scans of the relevant pages (including the follow up) + powerpoint slides of the PCB layouts (with the error corrected) - if anyone wants them pm me and I'll dig them out.

Ian
Forum: Amplifiers 29th October 2008, 05:00 PM
Replies: 9
Views: 3,369
Posted By ian_r
Re: Prototype OPT

You can still get a DIY mains xformer kit from Mike: http://livinginthepast-audioweb.co.uk/xformer.html

I think hand winding an OPT would not be so easy :rolleyes:
Forum: General 22nd August 2008, 07:27 PM
Replies: 0
Views: 1,558
Posted By ian_r
if you've 160 pounds to spare

Apparently ...

On Saturday 4 October 2008 Menno van der Veen, MSc., leading designer of valve amplifiers and output transformers will be presenting his Masterclass on high-end valve amplifiers at...
Forum: General 19th June 2008, 01:13 PM
Replies: 3
Views: 2,115
Posted By ian_r
Re: Pioneer SX-535 receiver - loud hum

Transistor amp so no o/p transformer. Spark might indicate DC voltage at speaker terminal - worth checking before speaker is damaged. PM me if you want the a copy of the service manual.

Ian
Forum: WAD Problems 17th January 2008, 12:08 AM
Replies: 10
Views: 3,995
Posted By ian_r
Re: Kat34 component replacement

I'm sure you could spend much more, but you might also consider starting with (for a similar price to Maplin)
...
Forum: WD Amplifiers 16th January 2008, 07:29 PM
Replies: 6
Views: 2,460
Posted By ian_r
Forum: WD Amplifiers 16th January 2008, 01:14 PM
Replies: 6
Views: 2,460
Posted By ian_r
Re: Looking for a second hand KEL84 - how much should I expect to pay?

I might be pursuaded to sell mine; haven't finally decided. Whereabouts in the UK are you? I'd prefer to sell locally (I'm in the west of Scotland) so that buyer can see/hear it first.
Showing results 1 to 25 of 47

 
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