[Scallywag]

OK, I can do that. Question... in the case that my ohm reading was wrong, would having the wrong value resistor there (22K vs. 2.2K) result in serious damage or inability for the amp to function properly?? Perhaps I'm being paranoid here, second guessing my ohm reading because all the other resistors in and around that area are of a much higher value than 2.2K. If I purchase both and end up first installing the wrong value would I know it right away?? This is what I'm considering calling Audioengine about... to see if they can confirm the value of my missing resistor. 

 

[cssarrow]

Quote:

OK, I can do that. Question... in the case that my ohm reading was wrong, would having the wrong value resistor there (22K vs. 2.2K) result in serious damage or inability for the amp to function properly?? Perhaps I'm being paranoid here, second guessing my ohm reading because all the other resistors in and around that area are of a much higher value than 2.2K. If I purchase both and end up first installing the wrong value would I know it right away?? This is what I'm considering calling Audioengine about... to see if they can confirm the value of my missing resistor. 

Dude, i'll just take my A5+ out today and measure that resistor and tell you what to buy.
 
Quit being a:
 

If you didn't know, 22K and 2.2K is off by 20,000 which is pretty significant.
You could end up hurting another part (due to heat/short) if you use the wrong resistor (or have shunted/jumpered it)
Audioengine won't tell you crap.
I asked them about their film caps, and they said they had to call their Chinese department, which the main place is in China anyway, and still, never gotten back to me.
 
Just let me finish a few cable orders, and i'll have the resistance measured for you.
Simply just buy a replacement with my given value and solder it there.
It was probably to lower the voltage that was going to your amp chip (maybe), so that's probably why you weren't getting sound.
 
As for your picture, the input wire with the blue label, why is it not soldered?
Whats with the whole yellow/yellow, red/red, blue thing?
 
Tim

 

[Scallywag]

The large difference in values is what I'm concerned about. Sorry, just trying to be careful. Too careful I guess. Wow, that's awfully generous of you to check that resistor for me. Man you must be getting sick of dealing with me at this point

 I really really appreciate you doing that. Very kind. 
 
The blue input wire came off while handling the amp board. The wires are (well, were) already soldered to the input board and the stress to that joint from me trying to figure our what was wrong cause it to come loose. It's ok though, I'll reattach it once I get this resistor problem solved. It was soldered and working fine when I powered up the amp to test it.
 
The colors were just to help me keep the wires in order. I only have white wire so I color coded them on each end with electrical tape to make sure they were installed correctly (they do line up horizontally, as you mentioned.) I did check continuity, they all checked out fine. Colors are doubled up because I attached them in two groups of three. I actually did braid the wires there (see photo) but space was tight on the amp side to I un-did some of the braiding to make it easier to set the wires into place. Looks a bit funny, I know. I may re-do that side before putting everything back together. We'll see. 
 
Thanks again, man. You are awesome.
 
 

 

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I'll have the value for you by today, still a little busy with some cables.
 
Just by looking at your wiring, red > yellow > blue + repeat seems pretty darn correct to me.
 
Only problem seems to be that the one specific resistor came off, which is preventing sound.
Let me know once you've cleaned that trouble area, it looks like a mess.
 
What i did with the braid, was do a 3 conductor round braid first, then heat shrinked the ends with some 1/8".
After that, i soldered it onto the boards while doing some continuity checks.
 
Check the wire that connects to the LED light and volume knob.
Make sure no wires are ripped off.
If it did, fix it and hot glue it.
If it didn't, hot glue it.
 
The reason for this, is when you're testing it, pulling that cable in and out for testing will put strain on the wires and cause them to rip.
The hot glue will be the strain support.
 
Tim

 

[Scallywag]

The volume/LED cable is intact and I put some hot glue on there. 
 
I cleaned up the resistor area with some isopropal and it's now nice and clean. Well, not nice but very clean. It does look a whole lot better than it did in the photo I posted. Should be workable. 
 
Thank you for checking that resistor. It's a pain to take out your amp board, certainly, so there is no big hurry. I'll have to buy one of your cables to repay you!! I dig your website. Is the business up and running?? I'm serious about checking out your cables.
 
OK, one quick question... in one of photos of your right crossover, what's the purpose of the wires you soldered on the bottom of the board?? See red lines in the photo below. 
 

 

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The volume/LED cable is intact and I put some hot glue on there. 
 
I cleaned up the resistor area with some isopropal and it's now nice and clean. Well, not nice but very clean. It does look a whole lot better than it did in the photo I posted. Should be workable. 
 
Thank you for checking that resistor. It's a pain to take out your amp board, certainly, so there is no big hurry. I'll have to buy one of your cables to repay you!! I dig your website. Is the business up and running?? I'm serious about checking out your cables.
 
OK, one quick question... in one of photos of your right crossover, what's the purpose of the wires you soldered on the bottom of the board?? See red lines in the photo below. 
 

Haha, good job gluing the volume knob wires down!
Hope that wasn't too hard for ya.
 
Nice and clean will surely make the job more workable.
 
I'll have the resistance value for you by today along with a link to purchase it online.
Shouldn't be over $2 for 100 pieces.
 
I have my speakers mounted to the wall, so i'll have to take down the left one and open the back, shouldn't be a problem.
 
You might want to get one of these Pinpoint AM-40 wall mounts.
Having it angled and pointed at your ears improve you so much as an audience.
It's way better than just having it sitting on a desk and "blowing" music by you, right past the torso.
 

 
Business is ok, all HTML coding (for the website) was left on a hard drive that then.. err.. kind of died.. so i now have to start from scratch.
If you're ever need a cable (any kind), do let me know.
 
To address your question.
I'm a cable guy, I believe a lot about conductance and impurities (from metals that don't conduct so well).
The left side speaker crossover is connected by wires, being wires, you can choose the quality.
It isn't the same for the right as it's connected to the tin plating, that's why i kind of ditched that and went with a straight wire.
The higher conductance of that wire, should make that pathway more accessible (for signal) than the tin plate with the mounting screw.
 
I simply soldered a silver plated copper wire to that copper ring, then soldered it onto the brass outpost.
You might not want to try it, since the solder won't stick to the brass, unless you use like insanely high temperatures.
It ended up melting the plastic that held it a bit, but didn't really bother me.
As long as the wire touches or wraps around outpost, then you should be good.
I say just solder the wire to the copper rings, (but leave a good length) then wrap it around each post (on appropriate size).
 
I noticed you copied my idea to dampen the crossover pcb, how cute haha.
Did you source your parts from Parts Connexion? I see the M-Resist.
When i tried to buy it there, they only had one in stock, so i had to go to Madisound for mine.
 
Tim

 

[Scallywag]

I've considered using wall mounts, I'm still considering it. But that would require running all the relevant cables behind the wall in my den. I'm a bit OCD when it comes to equipment and wiring looking clean. Cords and cables hanging all over drives me nuts and my girlfriend doesn't like it, so I'd have to hide everything. It's just drywall so it's not difficult but I'll have to make sure my cables and power cords are long enough to accommodate. Little things like that make my relatively small Manhattan apartment feel much bigger and that's important to me.
 
Right now my A5's sit atop some grungebuster pads I bought from Herbies Audio Lab to aid in vibration control and decoupling (nice products.) They really made an improvement to the sound, took some of that bass out from the dresser that the speakers sit on. The speakers are about 6' apart, 6'- 7' from the listening position and are at the same height as my head. Unfortunately it's not a solid wood dresser and there is a fair amount of resonance going on in there, easily heard when I put my ear up against it. It does bug me a bit. I understand wall mounting tightens things up so perhaps I'll do it. My A5s are about 6" from the back wall. I found that any less of a distance results in muddier bass with those rear-firing ports, in my room anyways. Again it's a small room so certain bass frequencies can quickly get out of control (hence my previous mid-bass comment.) I wonder if you don't have that problem even with your speakers being so close to the wall they're mounted on? 
 
My big conundrum is what to do about the subwoofer. It sits in a corner about 2 ft off the ground and 6" from each wall. The bass just goes straight to the wall and floor- an issue sometimes for my downstairs neighbors. I understand the cause of this phenomenon, such is the nature of bass frequencies, but aside from proper acoustic treatments to the room I'm not sure how to remedy the issue. But...that's a problem for another day. 
 
Yes, I sourced my parts from Mouser and Parts Connexion. I figured dampening as much as possible couldn't hurt and I have lots of foam. So why not? 

 

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All my wires are extremely the "exact" length, so it's not going all over the place.
That's pretty insane that you need to put it through the wall, never heard that one before.
 
Pads?
Haha.
You know the acoustic foam that you're using to dampen the speakers?
Well, when i had the speakers on my desk, i would put lay a 2mm silicone piece (cut for desired size) then a 1/2" acoustic foam over.
The speakers of course, goes on top of the foam.
Helps stop that wood desk coloration bass you were talking about.
 
I put a 2mm silicone piece before mounting the metal plate to the wall.
Screws are all fastened to the 2x4's behind the wall, not to drywall.
I also put a 2mm silicone piece and foam underneath the speakers before equipping it onto the mount.
Gets rid of the vibrations that would ultimately end up going into the drywall, wood support, etc.
 
You're using the S8 right?
It should have those pointy speaker feets.
Try putting something soft underneath the feets to dampen it, so it doesn't move the floor.
That's what i did to mine, but of course, i remove it when i watch Action movies, as i like to have the room shake.
 
Tim

 

[Scallywag]

I don't need to, I choose to. i'm not that crazy!! Plus it makes my woman happy (we live together.) It's easy to do with the hollow wall that my TV hangs on. 
I used to use foam but, with it being so soft, the weight of the cables attached left speaker, along with the heat sink, would cause it to lean back so that driver was pointing above my head while the other one was level. The grungebuster feet work well and they keep that left speaker seated. Honestly I was surprised at how well they absorb vibrations. Even with that the bass is getting into the dresser so I may do the wall mount.
 
Your wiring is indeed clean. I wasn't implying that it's a mess. Apologies if it sounded that way. 

 

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Oh no man, i wasn't trying to sound mean or anything, didnt even know i made my words like that actually.
Pinpoint AM-40 wall mounts has clamps, so regardless of cable weight, it will stay there.
 
To give you an update,
The resistor code value is 751.
Which is of 751Ω resistance (R49 on PCB).
 
I went ahead and measured it anyways using multi-meter set as 2K, which measured .748 = 748Ω.
So basically you need a replacement 750Ω resistor in either size 0603 or 0805.
From the looks of it, i would say go with 0805.
Even if 0603 ends up being too small, as long as you solder it to each end, you're good to go.
http://www.ebay.com/itm/100x-SMD-Chip-Surface-Mount-0805-Resistor-750-ohm-751-/120823591947?pt=LH_DefaultDomain_0&hash=item1c21a5b40b
http://www.ebay.com/itm/100x-SMD-Chip-Surface-Mount-0603-Resistor-750-ohm-751-/120823582356?pt=LH_DefaultDomain_0&hash=item1c21a58e94
 
While taking out my board, i was able to restock my thermal paste behind the amplifier chips with some Prolimatech PK-3 Nano Aluminum.
It's one of the top performing thermal paste as of 2013.
I'm a computer nerd, so i know a lot of stuff when it comes to thermal conductivity.
 
If you don't like waiting for the item to ship all the way from Macau, what you can do is just go buy a 750Ω Axial Resistor instead of the SMD.
Just solder each end to where it's suppose to go and you're good.
Try and keep it +-1% or +-5% Tolerance rating.
I don't know too much about the wattage rating, but it shouldn't matter much.
 
Tim

 

[Scallywag]

Ah, thanks so much. I don't know how I got such an errant reading but I'm glad that you confirmed the value for me. I'm going to order some from mouser and just be done with it. 
 
Also decided to try the wall mounts. I can also reclaim some surface area on my dresser by mounting the speakers so that's a plus. 
 
You really helped me with all this and I appreciate it. I'll let you know how everything works out when I'm finished with this project.
 
Until then take care!

 

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My Audioengine A5+ modded edition is going for sale.
 
If anyone is interested, PM me.
 
Tim

 

[Scallywag]

Been a while... so finally, after a lengthy shipping ordeal, I received the resistors in the mail. I installed it carefully, tested it and reassembled the amp to see if my problem was solved... but still no good sound. However, this time I could hear music coming through but only with the volume cranked to max and even then it's extremely quiet. I can only hear it when my ear is pressed against the tweeter. I mean whisper quiet. I went back and started checking over everything. In the process I lost a solder pad on the C4 Bipolar. Managed to repair it by pulling up the trace and installing a small jumper wire. I'm not thrilled about the longer unshielded lead but I have no choice.
 
Anyways, I'm not sure what to do now. All the caps are installed properly. No solder bridges anywhere, no metal parts touching, etc. The volume wire is OK. I'm apprehensive to keep tinkering blindly because each time I do I end up losing another solder pad or something and the board becomes even more shredded.  
 
The signal is getting through... I can hear music, barely, but it's not being amplified or something. Any ideas?? I've exhausted my limited knowledge in this area and the hope that I'll be able to get my speakers working again is fleeting.  
 
Help me Obi-Wan...

 

[Scallywag]

Not sure who's listening, but... progress!! I'm getting clean amplified music. I had to re-do all of my clumsy work on the board but it worked. However the right channel is louder than the left... significantly so. I swapped the drivers and crossovers and I reversed all the external cabling. Got the same result so the problem is with the amp itself and not those external parts. Man... after all this work I was really excited to be done. Alas, work remains. 
 
So, can anyone out there point in the right direction to troubleshoot this thing?? I have a sneaking suspicion that it's the left amp IC causing the issue. This is based on nothing concrete, as I have no experience here. The last few pages of this thread may shine some light on the issue to those who know better. 
 
What can cause one channel of this amp to be louder than the other??? There is no internal or external balance pot. I've triple-checked all my wiring, mods, etc. Both sides of the amp are identical, far as I can tell, in terms of components and design. Should I test both amp IC's (TDA7294V) and compare readings?? If so, how would I do this with a multimeter??
 
Any help is appreciated. I WILL get this thing working properly once again!!!

 

[Scallywag]

Problem solved!!! The amp is working as it should and I'm now almost done reassembling the enclosures. This has been quite the learning experience...
 
Once I'm completely finished and the speakers are up on my wall I'll perform due diligence and post my impressions. From what I've already heard during testing with an iPhone I can say that the various mods have culminated in a not-so-subtle improvement in SQ.
 
Tim, if you're out there, thank you again for your guidance and patience.  
 
More to come.