which components to replace for better audio quality?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi guys! Well, to call myself a newbie in this field would be an understatement, so I am hoping you guys will cut me a bit of slack for a probably pretty basic question. I have a pair of Event ASP-* studio monitors. One of the amps is going bad. I am going to attempt to replace some of the probable failing culprits (LM3886 chips.) I figure, while I a at it, I might as well replace any parts that might make a noticeable difference in audio quality with the best components I can. I am attaching the schematic, and wondered if you guys would chime in and tell me specifically what parts really affect audio quality and what you would order if you wanted the best results. I hope this makes sense. I am basically just planning on desoldering parts and resoldering replacements. Thank you so much!!!
 

Attachments

  • ASP_8_6_schematic.pdf
    910.4 KB · Views: 115
  • DSCN4679.jpg
    DSCN4679.jpg
    197.8 KB · Views: 326
From a quick glance at the schematic, the power supply's the weakest part and the SQ will be improved by attending to it. Specifically, lowering its output impedance. There's no sign of decoupling applied to individual opamps, just a single pair of 100nFs (C38/43) which is woefully inadequate if decent dynamics are called for.

Secondly the design looks ill-conceived from the point of view of the paralleled LM3886s on the LF - there's no sign that their gains and offsets are adequately matched to work successfully as a 'team'. If you're going to address the SQ deficienices it would also make sense to sort out the matching issue.
 
From a quick glance at the schematic, the power supply's the weakest part
and the SQ will be improved by attending to it. Specifically, lowering its output
impedance. There's no sign of decoupling applied to individual opamps, just a
single pair of 100nFs (C38/43) which is woefully inadequate if decent dynamics are called for.

Hi,

I noticed that but it depends where the 100nF is placed as
to whether it is adequate or not to prevent oscillation.
It also depends on the circuit layout / compactness.
Multiple 100nF's won't effect the audio dynamics.

rgds, sreten.
 
I wasn't thinking about oscillation but you raise a good point. Multiple 100nFs won't affect the SQ unless by 'multiple' is meant thousands of them. Better to fit low ESR electrolytics to get the supply impedance down - a pair of zeners doesn't give low enough Zout for high quality subjective dynamics from an array of opamps.
 
seems a specific sonic complaint should be lodged before any Rx can be prescribed.
I tend to think the box, drivers and the filters would be the low hanging fruit for the most improvements. If it's working now and you still don't like it , best just to sell it and move on, before apraxalito changes make it unsellable with cling ons.;)
 
I've not so far understood the seeming preoccupation with resale value in audio electronics....:confused: If you don't mod, how can you learn what contributes to great sound?

I haven't understood the OPs problem so I cant tell him what the problem might be. my primary experience is ...great speakers lead to great sound. its easier to trade up or down than futz with adding multitudes of bypasses.
it is what it is <chip amp > probably the main issues, if there aren't others ( a big IF) cant be fixed economically, with a fixed PCB layout.
 
Last edited:
well a couple of bypasses across the Op-amp zeners would be easy ,
do you think filter breakpoints and driver matching might need sorting.
yeah they have issues in parallel egads they should of used at least <1% gain setting, not 5%
I cant believe that, they must of had a BOM cost reduction meeting w/o the engineer!
being this is a clone of another clone best to move on. IMO
 
Last edited:
Hi guys! I can't thank you enough for your input on this. Here's a bit more detail. This is the amplifier inside the Event ASP-8. I actually have liked their sound (subjectively) for a while. I have not been entirely happy with their accuracy in mix translation, however. I read a post where a guy literally just rebuilt this amp based on the schematic after his died. He claimed that the sonic improvement was palpable. All he did was use his own parts and he felt the sonic clarity of the monitor went way up. You can't buy replacement amps as they ran out. My left monitor is doing a thing where, when you turn it on, you get the sound of random scratchy static. It keeps doing this for several minutes and then, suddenly, it seems to kind of snap into silence and it sounds fine. As long as I leave it powered on, I have no problems after that. If I turn it off and back on, it goes through the same junk. I spoke with Event and the engineer told me that most often the 4 audio amplifier chips are what seem to go bad. He suggested I replace all 4. So I thought, since I am going to have to replace them, should I replace any caps / resistors / other stuff while I am at it in order to hopefully replicate the guy's success who built the copy of the amp. I would be happy to use an external amp and drill a hole in the back of the monitor to run speaker wire, but I don't know anything about crossovers and I think that would be key. I really don't know what I am doing, sadly. (though I would love to learn.) I just happen to have decent soldering skills and I know how to identify and replace parts on a board.

If you are interested, here is the thread with the description and picture of the guy's rebuild. Scroll down to post post 17.
https://www.gearslutz.com/board/good-news-channel/355966-event-asp8-wow.html
 
Last edited:
Hi guys! I can't thank you enough for your input on this. Here's a bit more detail. This is the amplifier inside the Event ASP-8. I actually have liked their sound (subjectively) for a while. I have not been entirely happy with their accuracy in mix translation, however. I read a post where a guy literally just rebuilt this amp based on the schematic after his died. He claimed that the sonic improvement was palpable. All he did was use his own parts and he felt the sonic clarity of the monitor went way up. You can't buy replacement amps as they ran out. My left monitor is doing a thing where, when you turn it on, you get the sound of random scratchy static. It keeps doing this for several minutes and then, suddenly, it seems to kind of snap into silence and it sounds fine. As long as I leave it powered on, I have no problems after that. If I turn it off and back on, it goes through the same junk. I spoke with Event and the engineer told me that most often the 4 audio amplifier chips are what seem to go bad. He suggested I replace all 4. So I thought, since I am going to have to replace them, should I replace any caps / resistors / other stuff while I am at it in order to hopefully replicate the guy's success who built the copy of the amp. I would be happy to use an external amp and drill a hole in the back of the monitor to run speaker wire, but I don't know anything about crossovers and I think that would be key. I really don't know what I am doing, sadly. (though I would love to learn.) I just happen to have decent soldering skills and I know how to identify and replace parts on a board.

If you are interested, here is the thread with the description and picture of the guy's rebuild. Scroll down to post post 17.
https://www.gearslutz.com/board/good-news-channel/355966-event-asp8-wow.html

Hi,

If ain't bust don't fix it.

When the one channel is duff, if both bass and treble is duff,
its basically not the power amplifier chips. Your first option
should be to resolder the boards carefully and systematically.
(Noting the problem that caused the rebuild.)

Looking at it again the op-amp supply is pretty woeful.
Add 2 x 220uF, in parallel with the 15V Zeners.
Add 47nF across the supply pins of each op-amp.

The rebuild to an external amplifier also changes the layout and
is more likely to be the improvement than new components.

Try the above first.

rgds, sreten.
 
Last edited:
This is the amplifier inside the Event ASP-8. I actually have liked their sound (subjectively) for a while. I have not been entirely happy with their accuracy in mix translation, however. I read a post where a guy literally just rebuilt this amp based on the schematic after his died. He claimed that the sonic improvement was palpable. All he did was use his own parts and he felt the sonic clarity of the monitor went way up.

Chimes in with my experience of various active monitors I've bought. The electronics is the weak point, universally. More specifically, the power supply is the achilles heel.

I spoke with Event and the engineer told me that most often the 4 audio amplifier chips are what seem to go bad. He suggested I replace all 4.

Amp chips only go 'bad' when abused. If the design was a good one it would be the caps that fail, eventually through drying out.

So I thought, since I am going to have to replace them, should I replace any caps / resistors / other stuff while I am at it in order to hopefully replicate the guy's success who built the copy of the amp. I would be happy to use an external amp and drill a hole in the back of the monitor to run speaker wire, but I don't know anything about crossovers and I think that would be key.

Internal amps are severely constrained by the dimensions of the speaker box itself. I'd take it out and use it externally, this allows a decent power supply to be constructed alongside the existing board.

I really don't know what I am doing, sadly. (though I would love to learn.) I just happen to have decent soldering skills and I know how to identify and replace parts on a board.
Here's a great place to learn - just ask. And keep on asking.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.