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Old 18th January 2013, 12:43 AM   #631
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Quote:
Originally Posted by doctordata View Post
The ram heatsink might alter your inductor's ferromagnetic properties .

Cheers ,

Rens
I don't have an inductance meter right now so I can't check if it will change if I put a heatsink on top of it.

Quote:
Originally Posted by nigelwright7557 View Post
Your inductor shouldn't get hot, I have a 750 watt amp that runs slightly warm all the time.
Which core did you use ?
I use a t106-2.
It uses an inductor that looks like a Sagami 7G17A, but it has no label, that's why I am doubting if it is an original one.

I will also check if the inductor will run cooler if I raise the osc freq.
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Old 18th January 2013, 12:50 AM   #632
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Quote:
Originally Posted by jlester87 View Post


It uses an inductor that looks like a Sagami 7G17A, but it has no label, that's why I am doubting if it is an original one.
.
Its probably the wrong core material.

My first class d inductor was a power toroid and it got to 120 degrees c !
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Old 18th January 2013, 10:59 AM   #633
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Default Inductor

Anyone know where to get the inductor in Germany? Googleing for it results in pdf files for the IRS2092!!

I was thinking of replacing the indcutors on my L25D boards along with replacing the current protection resistors R12 and R18 to be in line with the AMP7S-150 values for my 4Ohm speakers, also the filter caps CP7, CP8 with Panasonic FC 100V 470uF value as in line with the iraudamp7s.pdf. R114, R117 and R118 will be changed to 3 Watts.

Big thanks to alkasar for his great work in the Mounting Guide L25D.doc

Also anyone know why the R24 and R25 are listed in the iraudamp7s.pdf as 20 Ohm and in the Application Note irs2092.pdf they are listed as 10 Ohm.

BTW: I have amazing sound and serious *** kicking bass with a Cambridge Audio Azur DacMagic (using RCA output - will change to XLR) and a 10K Pot from my L25D boards. I removed the input cap CP1 and bridged it with some resistor leg wire. This improved the sound a lot. I had originally planned to replace the input caps with WIMA MKP 22uF and purchased some, but my DAC has practically zero DC in its output and I also have DC protection boards as recommended in this thread.

Cheers
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Old 19th January 2013, 03:55 AM   #634
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Just finished amp with L25D 's, stereo.... I use toroid 52vac per side to rectifier PCB with 68
of those 150 mfd 80v electrolytic caps... The transformer is 550va size.... Also I use a 30 amp speaker protection PCB... Using little NE5532a preamp module with Bass, Mid, Treble, Volume controls... Anyway my layout was nice and when I turned power on I was and am
Very Pleasantly surprised! It works so nice! I am very pleased. I did have to purchase some speakers that can handle the power, and they turned out to be very nice too! Anyway bottom line is the LJM L25D power amp module sounds like a million bucks! Start building your new power amp today! I'm going to start working on a preamp that get rid of the NE5532's in favor of discrete, however I want Gain, Bass, Treble, also a vacuum tube buffer along with hi filter and loudness switch! So much for purest! It is going to sound nice! This I know! -Joe
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Old 19th January 2013, 06:51 AM   #635
4real is offline 4real  Netherlands
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Yesterday I put a unity buffer between miniDSP and L-15D-PRO, and now bass is just as is should be. Looks like the miniDSP just can't drive the amp directly. Well I'm happy now. Just need to make a few more buffers for all of the eight amps, or also try replacing the opamps if the miniDSP.
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Old 19th January 2013, 04:43 PM   #636
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Interesting, a german bloke saarmichel has 4 L15Ds with a Mini DSP connected to a 4Ohm system with 2.8 Ohm in the Bass and reckons sounds very very good.

You can see the mini dsp on the back on the right.

Bild: minidsp-4k-ampfu7q.jpg - abload.de
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Old 19th January 2013, 04:58 PM   #637
4real is offline 4real  Netherlands
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Well, if he used REW to EQ for his room response he probably won't notice it

I also see some resistor network on the inputs f the amps. That might also have something to do with it?

Last edited by 4real; 19th January 2013 at 05:00 PM.
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Old 14th March 2013, 08:13 PM   #638
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I'm wondering if anyone has seen this b4 or has any suggestions they can lend.

I connected the 2nd l15D-Pro board to share the same power supply as the 1st. Music plays from both channels at very low volume but as soon as I even slightly turn up the volume the 2nd board loses power until I turn the volume back down (Power LED goes out, music cuts out, almost as if the board's going into protection but the speaker protection doesn't engage). The 1st channel is operating as it should.

Has anybody seen this before?

Thanks
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Old 15th March 2013, 10:55 PM   #639
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Resolved. There was a short in the speaker protection circuit. I addressed that and it's singing beautifully
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Old 21st March 2013, 10:32 AM   #640
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Hello.
I've built 6 of the L25D amplifiers now, and 2 L15D to power my surround system. I use them to bi-amp front an center, while the L15D's are connected to the surround speakers.

The "processor" is a Yamaha RX-A810, receiver with pre-out. Last time I ran YAPO, room correction, I got the message that all my speakers where miswired.

Therefor I tried to measure input/output with an oscilloscope, an learned that the L25D reverse the phase from input to output. Anyone else who has discovered this?

The "prove" is in the picture below, keep in mind that for test purposes I used a small transformer 2x30V/120VA. I normally use 2x45V/500VA for two amplifier connected to a Klipsch RF-82.

Click the image to open in full size.

No problem to fix the bug, but I find it strange that I have not read about this before I discovered it myself.
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