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Old 1st September 2011, 08:22 PM   #901
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What's the difference, sound quality-wise between this new TA2020(A+) model without modification and the previous Lepai TA2020 with the blue LED, also without modification?

I own the previous version and I've been really happy with it, but after two and a half years, it's starting to die. I get static if I touch the thing, and today, the volume knob fell off. I'm thinking about replacing it with the new version, but I want to make sure I'm not wasting money if it's not at least as good sounding as the previous generation was.

I'm not going to mod mine. And since I'm replacing my previous Lepai, I already have a power source for it.

How does the new one compare, sound quality wise, to the previous generation?
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Old 2nd September 2011, 01:11 AM   #902
nige838 is offline nige838  United States
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Quote:
Originally Posted by xoaphexox View Post
Received my TA2020(A+) from Parts Express a few days ago.

Recapped using Panasonic FM/FR for the power supply electrolytics and Elna Silmic II for most signal path electrolytics. Also replacing the output film caps with polypropylene caps.

I am not comfortable with removing the SMDs but I was thinking about replacing the stock 10uH inductors.

Has anyone tried this on the new model yet? I think it sounds better in tone bypass mode than with tone controls in circuit - things sound a bit muddy and veiled - thinking this may be the stock 1.75uF electrolytics I left in circuit - I was going to try a pair of Nichicon Muse ES Bipolars here, 2.2uF - or 1uF depending on what sounds best.

Anyone try that either?

Thanks!

I replaced the SMT input caps with MKP 2.2uf caps. Sounds beautiful...
I'm only using one channel though. I used two 10k resistors from the input side tied together to the cap tied to the right channel.

I have a question. The new amps appear to have 2 preamps. why?
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Old 2nd September 2011, 01:23 AM   #903
nige838 is offline nige838  United States
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Originally Posted by dealerpriest View Post
Have a 2011 model but without tone switch (relay and one JRC op-amp)
My brother accidently switched a power supply so that ground was in middle and positive in ring. There was some smoke, then he was real sad. Does anybody know if it could be fixed?
With correct power supply I get the blue led light and I can just about hear the input music if I keep my ear very close to the board and all knobs are turned to max.
Any ideas?
I have been looking for this model for some time, where did you find yours?

Thanks
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Old 2nd September 2011, 01:24 AM   #904
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Quote:
Originally Posted by xoaphexox View Post
I am not comfortable with removing the SMDs but I was thinking about replacing the stock 10uH inductors.
Desoldering SMDs is actually way easier than desoldering through-hole!

The method I use is to add as much molten solder to the joints as they will bear. Place a pair of pliers or something that can lift the part on it. Then alternate the iron tip between the two joints until they pick up enough heat to be molten at the same time. The part falls off. With small parts you don't even need the pliers, the part will stick to the iron and you can wipe it off on the soldering station's sponge.

I haven't destroyed a part yet, using this method.

It doesn't really work for big chips, but that's not the case here anyway.

The trick is to add LOTS of solder. The increased mass retains more heat.

See these videos for more info:
Surface Mount Soldering Techniques
How to Desolder Electronic Parts
From here: Tangent Tutorials
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Old 2nd September 2011, 07:25 AM   #905
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Quote:
Originally Posted by nige838
I have a question. The new amps appear to have 2 preamps. why?
I reasonably certain one pair of op amps act as a buffer for the tone circuit input. I'm not sure about the other two. I regret not finding out when I had mine opened up, but IMO tracing a SMD multilayer board is about as much fun as a toothache.
Quote:
Originally Posted by kristleifur
alternate the iron tip between the two joints until they pick up enough heat to be molten at the same time. The part falls off.
+1 That is the trick. When it stays molten, the part will lift without taking pad with it.
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Old 3rd September 2011, 07:22 PM   #906
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I finished upgrading my Lepai today - at least until I find someone post a proven replacement for the stock inductors (and maybe the volume pot too).

My stock volume pot has a slight bit of imbalance - enough to notice.

I replaced the two 1.7uF bipolars in the tone cirucit with Nichicon Muse ES bipolars.

I also placed a .56uF film bypass cap across the 5600uF cap.

Listening to it now - I think it sounds pretty darn good.

I will open it back up if/when the time comes that I hear about people sucessfully upgrading the inductors or volume pot.

And maybe one day down the road I will get comfortable enough to replace the smd opamps.

By the way - to replace these smd input caps - how did you do it? Any pics? Are the replacement MKT caps smd also?

Thanks all
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Old 6th September 2011, 02:17 PM   #907
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I brought the amp in to the office today and hooked it up to larger, more detailed speakers than I was using at home (JBL 4311 vs. Radio Shack Minimus 7) and I immediately notice the right channel is much louder than the left channel.

I can get them to sound balanced if I use the computer balance level to cut the right channel down to 75% power.

I assume this is due to the tracking being off on the stock volume pot.

Has anyone changed the volume pot to a better unit? I would love to know which model pot I should purchase.

Thanks much,
Rob
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Old 8th September 2011, 07:24 PM   #908
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I've had one for a few weeks. It has decent sound, esp for the cost.

Sometimes I prefer the tone bypass, sometimes I need to boost the high freq. It really depends on the source. This is only a temp amp so I can live with that.

My biggest complaint is the thud it makes when being turned on/off. Any mods to address that? I have only scanned a few of the pages in this posting so forgive me if it was covered previously.

Thanks
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Old 10th September 2011, 06:18 AM   #909
nige838 is offline nige838  United States
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Originally Posted by Rockyhill View Post
I've had one for a few weeks. It has decent sound, esp for the cost.

Sometimes I prefer the tone bypass, sometimes I need to boost the high freq. It really depends on the source. This is only a temp amp so I can live with that.

My biggest complaint is the thud it makes when being turned on/off. Any mods to address that? I have only scanned a few of the pages in this posting so forgive me if it was covered previously.

Thanks
The newer ones have relay protection, so that doesn't happen. The Leapi TA2020(A+)
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Old 11th September 2011, 01:40 AM   #910
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Originally Posted by nige838 View Post
The newer ones have relay protection, so that doesn't happen. The Leapi TA2020(A+)
I have a new one from PE (TA2020A+) purchased recently and indeed it does do that. It sounds like there is a relay kicking in a couple seconds after power is turned on. That's my beef.
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