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Old 8th June 2007, 10:11 PM   #601
Theon is offline Theon  France
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Default Shielding the cores

Hi, in the photo you can see a simple but effective and save way to shield the air cores of charlize and other amps using air core inductors.
I used 0.15 mm copperfoil. Cut a stip of 2 cm wide and appr. 3 cm long. Bend it around a bar appr. 2 cm in diameter. In every tools box you can find one. Solder a piece of wire on the copper foil. Make it so that the copperfoil circle neetly fits a 19mm insulating and shrinking tube so that there is a little overlap in the copperfoil so that if shrink the tube with a little hot air the copperfoil also shrinks. The tube should be a little bit longer than the copper as not short circuit some connection on the pcb.
Every air core receives its shielding and the wires can be grounded on the board, voila.
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Old 8th June 2007, 10:20 PM   #602
Theon is offline Theon  France
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On the charlize it looks like this. Need to insulate the wires and ground them on the board.
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Old 8th June 2007, 10:54 PM   #603
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Quote:
Originally posted by robert1325
Hi,

1.The pot is mounted on a wooden board, No metal.... the hum does get louder when I touch it.

2.It's a 50k pot

3. How can I measure this? I have a DMM...


Thanks

Robert
My Charlize had a hum which got louder when I touched the pot. The pot was mounted on a perspex window in a wooden case.

Eventually I grounded the pot body (to -ve) which pretty much eliminated it.

Don't know if that helps.
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Old 10th June 2007, 01:19 PM   #604
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The new Little Dot T-150 looks interesting 150w of power! even if it is only half that it is impressive.

http://www.musical.ca/catalog/item/4377302/4639260.htm
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Old 12th June 2007, 11:11 AM   #605
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Lightbulb TA-10 Vs Krell KAV 400i and Arcam Part II

Hi All,

Well, I've learned a load about listening and my system this weekend. First off, to those who say that all amps for the same SPL are the same - I don't believe them. At least for the same "perceptible" SPL. I suppose that if you measured a musical delivery with more bottom end grip, then the SPL would be higher, even though the perceived sound level was the same. Listening was done with my Brother in Law, Dave, who built my superb IPL speaker cabinets linked below.

The system as tested was:

1. As I currently listen - Pedja 1.1b DAC, shunt pot, Oyaide PA-05 interconnects, TA-10, IPL S3TLM Ribbon IPL Speakers Nearing Completion - Wow!

We packed the women off to Bath for the morning and while I was out walking the Dog etc, Dave had a listen to the system to get his ear in. Music was a selected track from each of Jack Johnson, Eagles Hell Freezes Over, Annie Lennox Medusa, Dido Life For Rent, Dire Straits Brothers in Arms.

We found:

JJ - Intimate presentation. Polite, enjoyable and good rhythm. Not a wide soundstage, but you could almost be sat there right next to Jack himself.

Eagles - Track 4. Nice, but bass light. Bass was present, but did not drive the music. Also missing (compared with usual "Dave" system) was the width of soundstage and space between instruments.

Mid Point Comments - System strengths are realistic presentation of performers, weakeness is no 3d separation of the performers.

Annie Lennox - The system was becoming less satisfying with the more complex productions. With rock tracks, the politeness, gentleness and intimacy prevented the drive that moves the track along. There was more confusion and a lack of separation.

Dido - This very commercial mix fared the worst of all. It's a difficult mix to get inside of and unravel, and it was almost as if the system didn't bother trying to. A note would be played, but nothing more was done with it - no attack, timbre or drive. Sound effects that would in Dave's system "swirl" with a giddiness were not there and merely flattened out into a nice presentation.

Dire Straits - Money for Nothing opening minute. As the song opens up to the crescendo, many systems will smear the instruments into a blur at this point. It happened here, too.

Overall, we wanted to see what the bass would do. There was insufficient bass in the delivery to actually be gripped by the kit. It was not the foundation of the music that Dave was used to in his system and I agree. In terms of the top end, Dave was not sure if all the info was coming off the disc and he questioned whether the source was up to the job - particularly with Lennox and Dido. We coud hear parts of the songs that were present in the mix, but would never be pulled out separately from it.

To cut a long story short, we swapped the Krell into the system. Big difference. But we also took the chance to compare the ICs (the PA-02 were rolled off - as commented on by t. in a PM - we both agreed that it would be better to swap the creamy midrange presentation for the more extened top and and therefore soundstage of my StraightThru ICs). We also compare the 1.1b, the 1543 Nixon DacKit, Stock CD960 and CD80. The 1543 was good, but didn't have the fuller presentation of the 960 as a standalone. The 1.1b was the best, for sure. The CD80 sounded horrid. I'm really disappointed with the CD80 sound and wonder if it was the FMs, the BG Nx, the Clock or what that has upset it. More work needed here I reckon!!

The 1.1b was the only source that REALLY managed to get into the Dire Straits crescendo. At the very end, before the song starts for real, the audio frenzy finishes with an upward roll of tom toms that you can really make out.

We tried the Arcam D290P (not biamped though) and although they had a load of power and a refined pesesntation, they seemed a little too rolled off in this system by comparison.

The Krell - ahhhhh. What I found was very interesting. A sound similar to Dave's system at home. Power, soundstage, grip, clarity etc etc. I loved it. But, for the JJ, the intimacy was GONE - no doubt. That little magic, the sparkle was missing. Replaced by an altogether more direct presentation. Velvet glove and iron fist stuff here. I could listen to it for hours. The next day, I tried some Nu Soul discs and they sounded just as alive with that genre. Some Faure classical was beautifully presented.

I like the Krell very much - but what we both found really amazing was that with the right music, the TA-10 was a gem; an absolute little belter! Intimate, excellent - within certain limits. I would certainly like to cross the two amps to get a powerhouse that has the same delicacy and imtimate presentation the TA-10 has. For me, that'd be the one!! What's the biggest T-Amp out there - 100WPC? Or maye the UcD 400s are the way to go - bang for
buck?

What I learned about my system, that is even more telling, is that the source and speakers were not once embarrased by the day's listening. My CD960 transport pulled sufficient data off the discs for the 1.1b to get working on, and the IPLs, I believe, have even more to give quality-wise, even when paired with what is, to me , a high end amp. Dave's advice was that I get the soldering iron onto those AX boards and get some Class A love going myself. Can't say I disagree, but I'm still looking towards a higher powered T-Amp or the UcDs as a solution.

We had a great time!! The next instalment will be his source in my system - that'll show just what sort of level the 1.1b is comparable to, and how the TA-10 (by then with some Platinum Sonicap bypasses and a mass of others trialled) works with a decent source. I'm currently delighted as I know that just by sorting out the right amplification, I can be most of the way to excellent sound quality.

Dontcha just love it??? :0)

Jon
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Old 12th June 2007, 11:51 AM   #606
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Did anyone try Dynamicaps ?

/Erling
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Old 12th June 2007, 12:31 PM   #607
dweekie is offline dweekie  United States
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Hi Jon, have you considered the tripath kits from 41hz? The new 2x300W truepath model should be of interest to you. I actually purchased one of the Audiosource 200W T-Amps posted in an earlier thread, and the power it provides makes a large difference to some speakers. Also, have you read through the ucd vs t-amp thread? UcD180ad Vs 41Hz Audio AMP5 (Tripath TA2022)
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Old 12th June 2007, 12:41 PM   #608
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I haven't, but I will!!

Thanks very much for the pointers and link - appreciate that!!

Jon
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Old 21st June 2007, 10:40 PM   #609
Stanco is offline Stanco  Italy
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I have big problem....
Before a left channel was not felt.
Then the checked the channel and found that bias setting to were within to +/- 6V range. What has happened? i don't now.
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Old 25th June 2007, 08:49 AM   #610
Sjef is offline Sjef  Netherlands
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Finally I have found a new smps supply. I bought a Delta Elektronika SX-150-15-15 wich is an industrial power supply. The build quality is very impressive, much better an solid than any high-end audio equipment I have seen in my life. The estimated time before failure of this unit is 500.000 to 1 million hours !!!!, that's 30 to 60 years, 24/7 duty.

But how does it sound. To be honest, only slightly better than the stock supply. I have also tried to add some extra buffer caps between the supply and the amp but that doesn't make any audible difference, I mean completely inaudible. I have tried 2200uF up 100.000uF of caps but in either case I can't hear any difference. Maybe because the power supply is allready stabilized. I measure an output voltage of 12.07 V at zero load and a voltage of 12.05V at 5A load, with only 5mV of rubbish, that's quite impressive

I was hoping for a bit more low/mid "drive" from the amp but this is still the area where it completely fails against my other amps. Higher mids and highs have become quite nice after intensive modding though. Yesterday I have compared it against my other still unmodded TA10 and that one...... well guess you all know allready what I think of them.

Maybe the difference is so small in my case because I'm driving 97dB efficient loudspeakers with them so it doesn't have to deliver any power anyway.
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