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Old 16th August 2003, 10:29 PM   #21
Tor M is offline Tor M  Norway
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Sorry!

Maybe this one works:

http://www.farnell.com/datasheets/2511.pdf


Tor Martin
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Old 16th August 2003, 11:00 PM   #22
Previously: Kuei Yang Wang
 
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Konnichiwa,

Quote:
Originally posted by Tor M
Sorry!

http://www.farnell.com/datasheets/2511.pdf

Works and indeed, P11 it is.

Sayonara
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Old 17th August 2003, 12:02 AM   #23
Tor M is offline Tor M  Norway
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Thanks!

Then I have something to add to my next order.

This evening, listening to music with my 2 years old daughter, one channel of my cd-player went dead!! And my first attemt to fix did not work! So now I`m frustrated

So I have something to do tomorrow.

Enjoy the weekend!

Tor Martin
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Old 17th August 2003, 01:56 AM   #24
hacknet is offline hacknet  Singapore
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thanks guys... i think i`ve got almost every thing sorted out.... i`ll report back when i`m done building...


couldn`t have done it without you guyZ!
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Old 24th August 2003, 04:35 PM   #25
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Default Re: Re: Re: Re: Silver Mica de-coupling caps

Quote:
Originally posted by Kuei Yang Wang

No pot. The 18k+15k arrangement is for use as Power Amplifier (without Volume control). As integrated Amp (with Volume Control) use a 100k linear law Pot and a 10k Input resistor as directed.

Sayonara
I'm confused.. can somebody attach a diagram with the latest values ?

I've attached my implementation.

Here's some quick review of the sound by the current owner:
- rather dry, without detail, sometimes a bit harsh
- no power, weak bass

my impression is, it sounds like a loud (not very loud) boombox.

the amp was left to burn in for up to 8hrs a couple of times but never for up to 24hrs unattended. In total the amp has been playing for a long time now since May 2003.
Unfortunately, due to Farnell erasing my parts list, I don't have the original pot but it's probably the cheapest from the catalog - probably a cermet type.

Currently using a single toroid for both channels, I guess 225-300VA.
I can't remember if it's 2 or 4 diode bridges but can check.

Can anyone guess what I've done wrong/how to improve ?

LS cables are single CAT5 strands, hardwired, which replaced some Mogami or Monster LS cables (can't remember which).

One last thing, dunno if its important, heatshrink and flame resistant sleeving were used alternately to cover leads and prevent shorts. The fr sleeving is very common type you often see for eg. inside cookers etc.

regards

Stelios

PS: are these the stacked film type caps that KYW recomends ?
I couldn't get the Wima ones. Would Wima MKS4 be an improvement ?
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Old 24th August 2003, 04:43 PM   #26
hacknet is offline hacknet  Singapore
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this looks very much like what mine is going to look like except for the input cap being a 4.7uf bipolar BG.

i`m planning to use 18-0-18 @ 225va toroidals to do a dual mono....

is 18-0-18 advisable for a 5 ohm load?
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Old 24th August 2003, 06:49 PM   #27
Nuuk is offline Nuuk  United Kingdom
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The sound that you describe from your Gainclone is not what most of us have experienced and I'm not quite sure why that should be.

I would recommend replacing the 18K/22K resistors to ground with a plain wire from non-inverting input to ground with no connection to ground from the inverting input. See what that sounds like.

You will find that you have more DC offset on the speaker terminals (do measure it before reconnecting the speakers) but many of us prefer the sound with that arrangement.
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Old 24th August 2003, 07:13 PM   #28
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Hi

a correction:

the 1uF cap across the +/-V is an EPCOS Stacked film polyester capacitor 1.0UF 63V.

There are only two diode bridges for both amps.

Would wiring the mains TX the wrong way significantly affect the sound ? I would suppose that since there 2 bridges, there's dc through the TX and if these two dc's are not opposing each other then that might lead to saturation of the core. What would that sound like ?

Nuuk, thanks for the suggestion : I can't try it right now though as the amp is not in my hands so any changes would have to be quite simple for a non-tec person to carry out safely... :|
It's definitely sth I'll try in the future though..

I'm thinking about removing the output resistor or perhaps replacing it with sth better.

Btw what are better resistors to use ?
Also is sticking to the exact values really important ?
Ie. mine didn't measure exactly 18k but closer to 17k.
I thought of using a vishay or sth in that league but they were far too expensive for me.. (7 each) I'd rather get a separate transformer if I was to spend this kind of money.

regards

Stelios

PS: I'm about to build my own set to be able to experiment more with them. Do you know which resistors are the ones that Thorsten suggests changing to the new values ?
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Old 24th August 2003, 07:57 PM   #29
Nuuk is offline Nuuk  United Kingdom
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Quote:
I'm thinking about removing the output resistor or perhaps replacing it with sth better.
I like the Welwyn RC55s which are not too expensive. The RC55Cs are even cheaper and I can't hear any difference. I prefer to double up for the feedback resistor.

Thorsten recommends changing the original 220K feedback resistor to 330K. The input resistor remains at 10K. I still prefer to use a wire on the non-inverting input to ground and no connection to ground from the inverting input.

All this and more information on the Decibel Dungeon Gainclone pages .
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Old 24th August 2003, 08:02 PM   #30
Nuuk is offline Nuuk  United Kingdom
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Just another thought Stelios. One strand of Cat 5 may not be enough. Have you tried other speaker cables? Or even two strands of Cat 5?

I am using a speaker cable that I 'wrote off' years ago but which seems to work very well with the IGC. It is a flat type braided cable but there is no name on it to identify exactly what it is!
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