Sonic Impact Gen 2 mods (for a newb) - diyAudio
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Old 12th January 2009, 05:52 PM   #1
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Default Sonic Impact Gen 2 mods (for a newb)

Hi folks, I have read the original thread on the Gen 2 but being a newbie to amplifier modding I'm going to need a little more hand holding. I plan to document my progress with photos so that other newbies may learn from my mistakes...and that hopefully you won't have to answer the same questions twice. I'd like to make some improvements while keeping it in the original case, if possible. I don't know where to order parts from so if you make suggestions please point me in the right direction.

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First on the list, input caps? What farad, type, brand, and most importantly, how and where do I put them!

Second on the list, what other mods can I easily make while retaining the original case?

Third on the list, power supply? The original thread mentions a Skynet SNP-9037 switching power supply. Where do I get one and/or how do I build one?
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Old 15th January 2009, 03:27 PM   #2
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No love?

I've been trying to research but there is just too much info out there since the original SI amp came out and I'm not sure where the finish line is as far as what mods to attempt. That in combination with the fact that the gen 2 is slightly different is overwhelming.
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Old 16th January 2009, 12:33 PM   #3
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I recently posted this information about my upgraded components in my SI Gen 2 T-amp here.

Basically, most people have moved on from modding the Sonic Impact T-amps, because there are many better T-amps out there that are more worthwhile to mod and upgrade (Trends TA-10.1, Sure Electronics TA2024 board, 41Hz T-amp kits, etc.). I have a modded Sure Electronics board that performs better than my modded SI Gen 2 T-amp and a stock Trends TA10.1. This amp has even outperformed my Onix SP3 integrated tube amp.

From my own experience, I liked the Skynet SNP-9037, but dweekie, another diyAudio forum member, introduced me to higher wattage power supplies like the Power-One MAP110-S148. This is a 110 watt switch mode power supply that has been discontinued in production. Power-One currently makes similar power supplies that you can occasionally find at electronics surplus stores for a lot less than their $200+ regular price. I bought my Power-One power supply from All Electronics. Then I upgraded the nine (9) secondary stage smoothing caps on the power supply from the stock Nichicon caps to Panasonic FMs. Rubycon ZL caps also work well in this power supply cap upgrade.

As for other mods, Panomaniac (Mike Mardis) had listed his definitive mods for the SI Gen 1 T-amp here. This would also correspond to the SI Gen 2 T-amp as well.

Hope this helps.
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Old 16th January 2009, 12:49 PM   #4
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Thanks Rich. I"ll look into those links. Maybe I'll use my gen 2 as a learning experience before I purchase one of the more expensive amps.
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Old 17th January 2009, 02:11 AM   #5
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Rich, do you have any photos of the mods you've done to the gen 2? I'd like to see where you placed everything inside the stock case.
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Old 17th January 2009, 01:59 PM   #6
rhing is offline rhing  United States
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I am out of town right now, but when I get back next week, I can pop open the lid and snap a photo. Basically, I removed C3 and C4 and soldered some 0.5mm Mundorf Silver-Gold wire to the pads. The pads are extremely small and delicate, so you have to be very careful when removing the SMD caps without damaging the pads. You'll have to use small diameter wire (22AWG or higher) to cleanly solder it to the pads. Anything larger can make things rather awkward. Next, I planted a drop of solder on top of the pads and positioned the wire on top of the solder bead before heating it. Some hot melt melt adhesive on top of the pad and wire joint will help as a strain relief. Then I soldered the shortened Axon cap leads to the wires and used some Blue Tack adhesive to dampen and hold the caps down to the chassis. I wouldn't spend too much money on the input caps, so something like the Radio Shack Model No. 272-1055 metallized Polyester film caps (1.0uF/250V; you'll need 2 pcs/channel) or the Axon 2.2uF/250V metallized Polypropylene film caps are fine.

To keep everything within the confined chassis space, I had to cut out the molded-in battery compartment to make room for the speaker binding posts and the input caps. A good hobby knife and a lot of patience will work here. I also had to bend the leads of the Panasonic FM electrolytic cap (C10) to orient the cap horizontally since the cap is too tall to fit under the lid standing up.

It sounds like a lot of work, but if you plan things ahead of time, it really doesn't take much time. The hardest part was removing the molded-in battery compartments without damaging the enclosure. Aside from the Vampire binding posts on the outside, it still looks like a stock unit. Your reward will be deeper and better defined bass, smoother and more detailed midrange, lower noise floor and a larger soundstage. As others have said, there are better T-amps out there. However, like you I just liked the challenge of working with the confined space of the stock enclosure while significantly improving the sound.
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Old 17th January 2009, 03:04 PM   #7
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How do you remove the original caps? Do you heat up the pad and just pull them out? Or do you clip them off?

Will I need a real soldering station to prevent damaging the board or will my current 15w iron work?
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Old 17th January 2009, 03:16 PM   #8
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I was just poking around All Electronics and found this Power One supply that might be of interest. http://www.allelectronics.com/make-a...-SUPPLY/1.html

From this series: http://www.power-one.com/resources/p...eet/mpb125.pdf
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Old 19th January 2009, 06:21 PM   #9
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Quote:
Originally posted by chuyler1
How do you remove the original caps? Do you heat up the pad and just pull them out? Or do you clip them off?

Will I need a real soldering station to prevent damaging the board or will my current 15w iron work?
I wouldn't try to clip them off. Just heat up one pad and then the other quickly and the little thing should just come off. Alternately, slip an X-acto knife tip under one end as you heat it and lift one end GENTLY as you heat it. The do the other end to free the part.

I expect your existing iron will do the job. As rhing mentioned, those little pads are real delicate, and repeated heating melts the glue that holds them onto the board. I like to get the new caps in place and fastened securely, either with some kind of clue or a plastic strap, before connecting them to the board. If you're planning on wanting to swap out different caps, it might be worth hooking up small screw terminals that can be epoxied to the board somewhere, that the caps can attach to.

The other improvement worth making might be the power reservoir caps. These will be the highest-value (and likely the largest) electrolytic caps on the board. I can't remember what's on there now, but you might see benefit of up to 2,500 uf or so, and you can use one cap or two paralleled to reach that value. This theoretically can give you a little more oomph, especially in the bass. People like Panasonic FM series (Digi-Key), and I've had good results fom the equivalent Nichicon low impedance that Mouser sells. The original Si was especially deficient in this regard, but I don't know how needy this one is.

And while, yes, there might be better boards out there, the sound from the SI is amazing and well worth using. For the next step, look at boards or kits) like the Amp6 from 41hz.com) that use either the 2021B or the 2020 chips as they have a bit more power than the 2024, but still run on 12v.

Good luck.

--Buckapound
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Old 20th January 2009, 06:41 PM   #10
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Ok, so for mods, in order of priority I should do the following:

Upgrade Power Supply
The Skynet SNP-9037 is recommended as well as the Power-One MAP110-S148.
Where could I get the Skynet or Power-One or something equivalent? My google searches only turn up wholesalers for the Sky-net and i didn't see anything on All Electronics. Any more info on the Power-one # MPB125-S322 that BradJudy suggested?

Upgrade Input Caps
Replace C3 and C4, the input caps, with Axon True Cap 2.2uF/250V metallized Polypropylene film caps or Radio Shack Model No. 272-1055 metallized Polyester film caps (1.0uF/250V; you'll need 2 pcs/channel).
Is there anything at Parts Express that I could use? I have other stuff I will order from them and if one of the caps they carry will work then I'll go with that to save on shipping.

Upgrade Power Rail Cap
Replaced C10, the power rail cap, with a Panasanic FM 2,200/16V electrolytic cap.
Again, is there something from parts Express i could use?

Upgrade speaker output caps
Your original post mentioned replacing stock caps on the speaker posts with some Radio Shack (Xicon) 0.1uF/250V metallized Polyester film caps. Could you explain this a little? Is this mod necessary. I do plan on swapping out the spring posts with some banana style binding posts so i might as well do this mod at the same time. What from the Parts Express bin could I use?
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