Bugle 2 LME49720HA

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Flyin_V

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Bugle 2 LME49720HA
« on: 6 Jun 2015, 07:58 pm »
Just installed one of the 49720 cans in my B2 but it doesn't work. The can got hot in a few seconds and the area where the plug is also got warm. I checked all the solder joints and they're good. Could the 49720 be installed wrong?

Does the pin below the tab go in the same location as where the original op amp's dimple was located, that is the top left?

Anything else I should check?

Thanks.

Folsom

Re: Bugle 2 LME49720HA
« Reply #1 on: 6 Jun 2015, 08:32 pm »
Nope. The tab is pin 8. There's a diagram pg.33

The pins are the same though, pin 8 to socket 8.

http://www.partsconnexion.com/prod_pdf/76010.pdf

Flyin_V

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Re: Bugle 2 LME49720HA
« Reply #2 on: 7 Jun 2015, 12:40 am »
So the tab goes on the top right side. Got it.   :duh:

Is the best way to remove it just cut the leads at the board?

Thanks!

Folsom

Re: Bugle 2 LME49720HA
« Reply #3 on: 7 Jun 2015, 01:53 am »
Depends, are you going to try and use it? Sockets are nice...

Desoldering tools are helpful.

You could cut it out, then unsolder the legs (and probably never use it again). I think using a socket with these is best.

Mouser has a good price if you need new ones.


Flyin_V

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Re: Bugle 2 LME49720HA
« Reply #4 on: 7 Jun 2015, 06:05 am »
Those adapters look great, think I'll wait to install the other two with those. Trying to stuff the 49720s into a socket takes at least 3 hands I think!

I did cut the leads and then installed it into a socket and soldered it in.  Workin' now.  :D

Going to spring for that de soldering iron. Looks like it will save time and make for a neater job.

Thanks for the  information.


Folsom

Re: Bugle 2 LME49720HA
« Reply #5 on: 9 Jun 2015, 01:53 am »
Awesome! It's a much nicer sounding OPAMP huh? Modifying heatsinks to go on them is tough. One might be able to easily make a version on their own, anything really, that's metal and connected.

Replacing signal capacitors will give you a good improvement. But by far the best thing I've done is an LDR for the input resistor. I know people are like "OMG the distortion!" well how about the "OMG IT SOUNDS ALIVE!" factor that's much more noticeable?

Flyin_V

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Re: Bugle 2 LME49720HA
« Reply #6 on: 9 Jun 2015, 03:59 am »
With one can installed (and the heat sink you recommended), the preamp sounds better; can't wait for all three! I did install the Nichicons, PRP resistors and a couple of .22mfd K 75 PIO caps.

Could you recommend a LDR for this use? I'm not sure which ones will work.

Thanks!

Folsom

Re: Bugle 2 LME49720HA
« Reply #7 on: 9 Jun 2015, 04:03 am »
I was using ones from Uriah Dailey at diyldr@gmail.com

Flyin_V

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Re: Bugle 2 LME49720HA
« Reply #8 on: 11 Jun 2015, 06:18 am »
Sounds like you used the 'resistor replacer' (as Uriah calls it) that is adjustable and about $7?

Looks like a tight fit with the larger Nichicons in the neighborhood.

Thanks again.

BobM

Re: Bugle 2 LME49720HA
« Reply #9 on: 11 Jun 2015, 02:07 pm »
I used a nude Vishay in that position on my Piccolo - yes it was a nice improvement.

Anyone have any comparison of the nude Vishay's vs the LDR's? Differences, improvements, etc?

« Last Edit: 11 Jun 2015, 05:18 pm by BobM »

Folsom

Re: Bugle 2 LME49720HA
« Reply #10 on: 11 Jun 2015, 02:11 pm »
Sounds like you used the 'resistor replacer' (as Uriah calls it) that is adjustable and about $7?

Looks like a tight fit with the larger Nichicons in the neighborhood.

Thanks again.

Yes.

It looks like R1L and R1R, from the PDF.