Lepai T-Amp with TA2020 - Page 128 - diyAudio
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Old 26th October 2012, 05:22 PM   #1271
Bare is offline Bare  Canada
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Quote:
Originally Posted by hozepipe View Post
Still don't understand why Tripath went bust...

Realise I'm taking a bit of a risk with the Mk1 board: if it blows up so will my speakers! I take it the YJ has speaker protection?
Read 'somewhere there were horrendous legal battles that caused the disappearance rather than Market ones.
Good product though.
Stereophile once reviewed/measured/published it as as having 'cleaner' output than the Gainclones... all in the wayy above human hearing ranges though :-)
Speaker protection? perhaps?
More of a turn on/off thump protection is my understanding.
DC output is what kills drivers (tweeters) quickly
The DC offset controlling variable resistors ..alone... make it worth the price of admission IMO.
When you get a chance, do try the 2.2 (?) uf caps from the inputs to a volume pot to the chip 'mod'. Only 2 caps and a decent pot required.
Deleting the tone nonsense completely, gives pretty nice (best possible imo) results.
Yess these are fun to fiddle with.. Just trying to point out what does work.
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Old 26th October 2012, 06:10 PM   #1272
Trileru is offline Trileru  Romania
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Quote:
Originally Posted by Redshift187 View Post
I found a huge improvement when upgrading the volume control op-amp, but I found the sound quality slightly better yet, with a wider sound stage, when I removed that and set up the volume pot as a simple attenuator. I was using the trusty OPA2132. In the blue and red boards, the volume op-amp is set up as a variable gain amp, with volume settings below about half on the knob being attenuated, and settings above amplified. As I could never ever see wanting a pre-amp gain over 1, I saw no reason to have extra amplifiers in the signal path, no matter how good.
I have a variant of this amp that doesn't have any opamp but I was thinking at a small valve preamp.
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Old 28th October 2012, 02:27 PM   #1273
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That for the info Bare. Will try the 2.2 uf caps soon. Just pulled the trigger on a pair of Helder 2050 based 100w amp boards off flea bay along with a meanwell 24V 14A supply.

I am selling my high-end american valve power amp
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Old 28th October 2012, 04:52 PM   #1274
Bare is offline Bare  Canada
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Quote:
Originally Posted by Trileru View Post
I have a variant of this amp that doesn't have any opamp but I was thinking at a small valve preamp.
Simple curiosity: Why.. for phono preamp/LP use?
Have tried mine with a hi spec tube pre I've had for years.
When running off of a CD player it added nothing, (also lost nothing :-) to the sound. Consequently inserting mine into the circuit proved pointless.
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Old 29th October 2012, 12:53 PM   #1275
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Just received the YJ TA2020 board. Connected it up (after checking the DC offset which was very low) but it sounds awful.

There is a distinct distortion somewhere making it sound harsh and nasty, especially on vocals. Its nowhere near the open, easy, silky, valve-like sound of the Lepai. Very disappointing.

It arrived wrapped in bubble wrap in a jiffy bag, plopped through my letterbox onto a tiled floor Could it be damaged? I don't see any obvious damage to any of the components and apart from one dry-looking joint on the RCA sockets everything looks OK (I resoldered it just in case).
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Old 30th October 2012, 09:32 AM   #1276
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Just noticed that there is a HF whine when the volume control is either down low or up high. In the middle position the noise is almost gone. Are the tripath chips themselves fragile or do they vary in quality?
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Old 30th October 2012, 05:03 PM   #1277
Bare is offline Bare  Canada
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Shame.. that World Famous Chinee Quality surfacing.. yet again.
Dunno what to say.
Still 'experimenting' with mine. Sounds quite good, but oddly still not quite as good as My stripped/modded Lepai (took my soldering iron and literally wiped off all the SMD bits of the worthless tone setup).
YJ Bass, mids are still a bit thinner, highs are similar.
Likely down to the YJ oem Inductors.. as a guess..which I have not replaced in the YJ.. Yet!
Was looking at the removed Lepai inductors and realised that I can unwind the rascals and rewind these with thicker Magnet wire (same # of Winds) and have 4/6 amp capable coils :-) without buying or waiting endlessly for arrival.
Strangely the Lepai follows the Tripath spec sheet 'suggested' circuit much more so than the YJ.. which largely doesn't. Bit concerning that.
I did use the same output caps as on the lepai mods, yes.. pulled the 'wima' (copies?) with apparent improvement.
Ta chip is of decent quality, either of US mfg or Korean, should not be any inherent issues IMO.
Can't imagine cloned/fake ones when these are so inexpensive, but apparently many chips and power output devices ..are.. **** poor copies...even pharmaceuticals appearing in pharmacies are being discovered as imposters these days. unbelievable and genuinely frightening.
Have a couple of Ta chips in US mfg packages.. presumably real
So will build my Own DIY copy of the Tripath data sheet circuit.
Only way to achieve a quality assembly, beyond buying a quickly disappearing 41hz.com kit,also involving being forced to pay his Usurious 'up charges' to ship.
The Helder ones are again; Fabrique en Chine.. no thanks.
Not a helluvalot of worthwhile choices IMO.

Last edited by Bare; 30th October 2012 at 05:07 PM.
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Old 31st October 2012, 12:47 PM   #1278
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Nothing to say Bare. Just the luck of the draw with chifi I guess.

They've offered to replace it, but waiting for their return address (said it was from the UK on fleabay, but...). I will insist they pay any shipping of course.

Good info on the inductors and glad the chips seem robust.

On another note, I can't find decent quality chassis mount binding posts (for use on a metal box). I thought this would be easy, but I can only find cheapo 4mm insulated sockets for chassis mounting. Any ideas (UK preferably)?
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Old 31st October 2012, 01:51 PM   #1279
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Just search gold speaker binding posts on fleabay, hozepipe

They are a bit big, not sure they would fit on the back of an LP-2020 case. I certainly wouldn't want to use the bare wire connection to them because of how difficult it would be to turn them in such tight quarters. For banana plugs they would work fine though.
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Last edited by Redshift187; 31st October 2012 at 02:16 PM.
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Old 31st October 2012, 02:34 PM   #1280
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They would be ideal (and yes of course I searched on ebay ) but aren't these going to short on a metal case? I'm building a new enclosure and wanted to use steel or aluminium. Is it a case of using some insulating collars/grommets or shrinkwrap over the metal sections that pass through the metal case?

The cost starts to add up quickly when you need to buy all the extra bits and bobs (in packs of 10 or 100!) so I just wanted a set of posts that would be ready-insulated. Have I misunderstood something?

Last edited by hozepipe; 31st October 2012 at 02:38 PM.
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