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Audioengine A5+ Speaker Upgrades - Page 5

post #61 of 123
Quote:
Originally Posted by qusp View Post


I speak mainly of the ceramics, there is more to specs than voltage and capacity. replacing them how you described will make the circuit performance worse. even replacing with the same type and increasing the capacitance may be worse by setting up resonances. as HF decoupling/bypass caps, the silmics (especially with long inductive leads like that) are completely useless, this isnt a subjective matter.

SMD ceramics have low impedance at high frequency and the fact they have no leads means they are very low inductance. the 'bipolar silmic' is practically the opposite of this and at high frequency they look almost like no caps at all, mostly inductive. genuinely high frequencies will simply pass them by, taking a short while to radiate RFI from the leads as they go. it looks a bit like a dipole antenna.

of course this isnt terrorism, but I do think people who illustrate technical mods on their blog have at least a small amount of due diligence to follow. realize that people less informed than you will look at your blog and perhaps incorporate another round of misinformation into it. its very easy to appear an expert online (even if you dont intend to present that way), even myself (I have no blog) I get messages all the time that assign me more depth of understanding than I have and as a publisher you should keep this in mind. otherwise real knowledge will become more and more diluted.

now of course we cant protect people from themselves....

Mr Jung most likely did not have point to point wiring in mind when suggesting this technique. Analogue circuitry was also not so full of VHF as it is today.

These are some of the more representative pictures I took of the stock amp plate.  Based on what the OP's mods look like, it appears (to me) that the OP installed the Wima caps in place of some existing polyester caps (in yellow in the pictures) and through-hole ceramics.  There were also some through-hole ceramics that you can't see in my pictures, but do see in OP's pictures from a different angle.  I am not convinced that these PARTICULAR ceramics that are through-hole should have been replaced by films (mainly because I can't remember their function in their circuits, my current guess is that they are NOT rail bypass/decoupling caps, as all existing rail bypass/decoupling caps are polyester films).  The other green ones (seen clearly in OP's pictures) are fine with either the stock polyesters or polypropylenes.  The other through-hole electrolytics around this area (the chip-amps section) are for boot-strapping the amp chip and AC coupled-feedback.  The boot-strapping capacitors are absolutely irrelevant to the sound quality (one set of 22uf caps, if I remember their values), and the other set of AC-coupled feedback can be changed in theory for something more audio-suitable.  Based on what the OP said, it was wise to replace them anyway, as the stock caps suffer from "bad caps" symptom and will eventually vent and become unusable (as per experience with AudioEngine A5's).  Replacing the polyesters that were stock with the polypropylenes MIGHT yield a small improvement in theory, but who knows if this is big enough to be noticed. 

 

 

 

The ceramics you see in OP's and my pictures that are at the lower bottom of the PCB and are surface mount are responsible for 3 duties, there was a ton of power rail bypassing/decoupling for each op-amp, and I think some for compensation of the op-amps (can't remember this one), and the larger ones that are 10uf each are for signal coupling.  I would advise to shunt the signal coupling caps here (SMD ceramics) as part of my mod.  Equivalently, at the right most side near the jumper connector, there are those polymers for signal coupling, that I advised to replace with some Silmics.  Since there wasn't a bias voltage on these caps, I would recommend as I did, a set of these Silmics in back to back forming a bipolar capacitor.

 

There were NO SMD ceramics that were either replaced with Wimas, or replaced with Silmics.  The relevant SMD ceramics that are signal coupling are shunted to allow DC-coupling between stages of the pre-amp.  All rail bypass capacitors (such as the 4 polymers you see around the NJW volume control chip) are left alone in my mod, and are suitable in their applications.

 

 

OP's amp plate showing where the red Wimas were installed:



 

Pictures of the Stock Amplifier plate from my images collection:

 

 

 

 

I hope this clears up everything that's been discussed thus far...


Edited by Handy Ray - 2/2/13 at 7:36am
post #62 of 123
Thread Starter 

Thank you for clarifying for the readers Steve.

 

In your last picture, with the two yellow film caps.

They gave me a gray one and a yellow one instead.. bo hoo.. bigsmile_face.gif


I'm surprised you still have some of your old pictures. popcorn.gif

 

Tim

post #63 of 123
Thread Starter 

Section 3 Completed.

post #64 of 123
Thread Starter 

Section 4 Completed.


Edited by cssarrow - 2/21/13 at 3:57am
post #65 of 123

Any updates??? I'm really curious as to how the speakers sounds after these mods. Thanks.

post #66 of 123
Thread Starter 
Quote:
Originally Posted by Scallywag View Post

Any updates??? I'm really curious as to how the speakers sounds after these mods. Thanks.

Hello,

Upgrades costed around $100-150 and valuable time.
I painted the the rings/tweeter cup, so during the process of removing the cup, i opened the tweeter magnets and let too much ferro fluid leak out.
Its important to have them as it needed for their intended purpose, the higher frequencies.

Waiting 100uL of ferro fluid i bought from parts express to reapply, so i'll give you impressions real soon.

From what i can tell with one of them hooked up, was the detail was soooooo much better. I heard sound from one side multiple times in the past, and it would always sound like what it was, one speaker. Now it sounded more lively, like one and a half.

I'll review the sound quality within the week.
Thanks for checking up on the thread smily_headphones1.gif
Edited by cssarrow - 3/12/13 at 2:02pm
post #67 of 123

Looking forward to it.

post #68 of 123
Thread Starter 
Quote:
Originally Posted by Scallywag View Post

Looking forward to it.

I'm done.

 

Added the picture for finished model, and will do a Sound Quality Review soon enough.

As of now, what i can tell you is that it sounds much closer to neutral studio monitors.

+ Detail

+ Sound Stage (a tad)

+ Separation

+ Vocal Definition/Veil

+ Bass Impact

 

Was going to replace these speakers, but looks like now i'll keep them for another few years as they're now able to give me what i was searching for.

The other side of the picture i never got to see, now, i'm getting the entire image from these set of speakers.

 

Tim

post #69 of 123

Question... I'm sourcing caps right now and I'm having trouble finding the Nichicon KG 4700uf 35V caps that will fit OK on the amp board. I'm wondering... can I use 50V caps instead of 35V as long as they fit?? I think using a higher voltage is OK in general but I wanted to make sure. Here's a link to the cap I'm asking about. Thanks!!

 

http://www.mouser.com/ProductDetail/Nichicon/LKG1H472MESBBK/?qs=sGAEpiMZZMtZ1n0r9vR22d%252blFeYd%252bH4E4y%252blePlNK%2fk%3d

post #70 of 123
Thread Starter 

50V will work fine, it should have even better ripple current actually.

 

Just make sure you don't go over 30mm diameter, otherwise it will hit nearby film capacitors.

 

If you plan on upgrading the inside wire, 18AWG is the largest size that will fit in the hole. (16AWG it too large).

Personally, i ended up using 20AWG, as i didn't have enough 18AWG wires.

 

Ask any question you require, i'm here to help.

 

Tim

post #71 of 123
Thread Starter 

Review completed.

 

End of Mod.

post #72 of 123

How many feet of hookup wire do you recommend I purchase for this project? Thanks for your help.

post #73 of 123
Thread Starter 

I would say that you'd be safe with using under 15FT, but if i were you, i'd grab a 25FT bundle just in case (ease of mind).

 

http://www.ebay.com/itm/25-feet-18-AWG-Silver-Teflon-Wire-White-19-strand-/230950852679?pt=US_Audio_Cables_Adapters&hash=item35c5be5847

 

The silver plating on the wire decreases the resistance for AC signals, and the PTFE insulation doesn't melt under a soldering iron which also has excellent dielectric strength.

Lower resistance for AC signal = more micro-detail.

If you want an even better upgrade (wire wise) than what i had done, you can use some silver plated OCC wire.

The OCC should help it sound a little better than the regular, but for speakers, it's harder to tell when compared to headphones.

 

Tim

post #74 of 123

OK, I have all the parts and I'm about to start this mod. 

 

Question... I'm wondering about the poly caps to be replaced at C21 & C22 (pre-out coupling.) Is there any benefit to using polar caps (Elna's) there are opposed to bypassing with a wire, as you did?? I use the pre-outs only for subwoofer usage. Will subwoofer performance be affected either way?? I suspect not but I figured I'd ask. Everything else in that section, including making the bi-polar caps, is clear. It's only C21 &C22 that I'm wondering about. 

 

I'll post some pictures of my progress...should be fun. Thanks again!

post #75 of 123
Thread Starter 
Quote:
Originally Posted by Scallywag View Post

OK, I have all the parts and I'm about to start this mod. 

 

Question... I'm wondering about the poly caps to be replaced at C21 & C22 (pre-out coupling.) Is there any benefit to using polar caps (Elna's) there are opposed to bypassing with a wire, as you did?? I use the pre-outs only for subwoofer usage. Will subwoofer performance be affected either way?? I suspect not but I figured I'd ask. Everything else in that section, including making the bi-polar caps, is clear. It's only C21 &C22 that I'm wondering about. 

 

I'll post some pictures of my progress...should be fun. Thanks again!

Signal will be better without polymer/polar caps.

 

Steve told me that its only there to make sure no dc line is going through.

I've already measured it, and it's in the  millivolts, which is close to none, so having it bypassed (jumper), better sonic's is achieved.

I'm using the pre-out to a powered subwoofer (Polkaudio/Audioengine S8) and everything checks out fine.

 

The C3 & C4 will need the bipolar though, however, it would still work with it bypassed.

 

Tim

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