Hello,
First time posting here, I know it's a well discussed territory over the years but after hours of reading older threads and trying out different solutions nothing seems to work for me so I thought I would ask for your opinions before throwing more money at it.
My problem is, like mentioned in the title, disappointing bass performance from my LM3886 based amp. Mids and highs I like a lot actually. But it's not just a they-are-louder-than-cheaper-amps issue. I played some pure sine waves through it and around A1-C2 (55hz to 65 hz) it gets real quite suddenly. When I turn the volume all the way up it sounds like there is a light distortion too. This test I did with my computer, both with its onboard soundcard and a USB- soundcard, which is my main sound source. But the lack of bass is also noticeable with my record player + OPA2134 based RIAA preamp.
Now, the amp itself. It's the most simple design, I tried to build it after BrianGT's recipe, since reading about that one made me interested in building it. It's on a different PCB but I used the same values. Here are a some points to mention which might be asked:
1. There is space for an input cap so I have a 2.2 uF Wima there (replacing this with a wire did not have an influence on the lack of bass).
2. After reading about more capacitence on the board, I soldered 470 uF paralel to 100 uF caps and this did not have any influence either.
3. I have 8 ohm speakers. First I used a 120VA 18VAC transformer. Replacing it with a 225VA 24VAC transformer made it not better, bass sounds weaker actually.
4. Zobel network is there but no thiele network.
5. On the power supply board, I omitted the snubber. It has the first 2.2k resistor and the .1 uF cap between the pins of 10.000 uF cap.
6. The heatsink (one per channel) is rated 1,8 K/W. The termal compund used is Arctic MX-4.
I would be really happy if anyone has any idea what might be the problem and shares it with me because the joy of it working after wiring it all up for the first time is slowly replaced by the frustration of it not sounding good.
First time posting here, I know it's a well discussed territory over the years but after hours of reading older threads and trying out different solutions nothing seems to work for me so I thought I would ask for your opinions before throwing more money at it.
My problem is, like mentioned in the title, disappointing bass performance from my LM3886 based amp. Mids and highs I like a lot actually. But it's not just a they-are-louder-than-cheaper-amps issue. I played some pure sine waves through it and around A1-C2 (55hz to 65 hz) it gets real quite suddenly. When I turn the volume all the way up it sounds like there is a light distortion too. This test I did with my computer, both with its onboard soundcard and a USB- soundcard, which is my main sound source. But the lack of bass is also noticeable with my record player + OPA2134 based RIAA preamp.
Now, the amp itself. It's the most simple design, I tried to build it after BrianGT's recipe, since reading about that one made me interested in building it. It's on a different PCB but I used the same values. Here are a some points to mention which might be asked:
1. There is space for an input cap so I have a 2.2 uF Wima there (replacing this with a wire did not have an influence on the lack of bass).
2. After reading about more capacitence on the board, I soldered 470 uF paralel to 100 uF caps and this did not have any influence either.
3. I have 8 ohm speakers. First I used a 120VA 18VAC transformer. Replacing it with a 225VA 24VAC transformer made it not better, bass sounds weaker actually.
4. Zobel network is there but no thiele network.
5. On the power supply board, I omitted the snubber. It has the first 2.2k resistor and the .1 uF cap between the pins of 10.000 uF cap.
6. The heatsink (one per channel) is rated 1,8 K/W. The termal compund used is Arctic MX-4.
I would be really happy if anyone has any idea what might be the problem and shares it with me because the joy of it working after wiring it all up for the first time is slowly replaced by the frustration of it not sounding good.
That chipamp (like all others) is ruler flat from infrasonics to ultrasonics and anything in between, so if you are lacking Bass I wouldn´t blame it.
Check your speakers instead.
Check your speakers instead.
Well, the same speakers (Bose Syncom tested) have no problem with filling the room with bass with my 50 years old amplifier (Dual CV40) so I don't think the problem is with them.
Do you have a schematic of your amplifier that you can post here? I've not experienced a lack of bass in the LM3886 I built, but I haven't tested it to any degree other than listening to it.
I suggest to put 8 ohm dummy load at output, drive it with say 1 watt, measure fr response, distortion, phase...and post the results.
I use RightMark audio software, it's free.
I use RightMark audio software, it's free.
Are You driving the amp with a low impedance source ?
Don't use phones or mp3 players since most of them lack bass.
Don't use phones or mp3 players since most of them lack bass.
Subjective lack of bass isn't going to be shown in the FR, it'll be due to inadequate PSRR. Noisy bass is perceived as lack.
The old dual amps have a reputation for "generous" bass. You might be used to a boost in that region, something the lm3886 would not provide. Maybe a simple EQ is in order ?
......yes, these old amps often have a loudness network built in (e.g. on the volume pot) that gives you more bass (and treble)..........
Loudspeakers?
LM3886 works better with 8 Ohms nominal or higher.
With 4 ohms nominal speakers, better idea two chipamps by channel.
LM3886 works better with 8 Ohms nominal or higher.
With 4 ohms nominal speakers, better idea two chipamps by channel.
Odd.... my UpdatemyDynaco Lm3886 based amp has an abundance of solid deep bass. Lotsa uf 's in the PS tho.
What it arguably lacks is good high end sounds... ergo a moderately constrained 3d soundstage results
What it arguably lacks is good high end sounds... ergo a moderately constrained 3d soundstage results
If its based on the Akitika design then its actively regulated and operates the LM3886 from a single rail PSU, neatly side-stepping the p*ss-poor PSRR on the negative rail. So decent bass looks to have been designed in.
You know...I've noticed a pattern here with your posts that I've seen over and over again.
Seems like no matter what problem(s) someone is having with their project/design, you always seem to blame their problem(s) on their PS...LOL.
Do you really think that everybody's PS's are the sole cause of their problems??
Seriously, a newcomer builds an amp, won't really describe exactly what he built, and all these elaborate diagnoses come out?
What's your sample size here?
Odd, in your case it was more likely your layout. Forgot that? 😀 You blamed the manufacturer for having a poor-sounding part, I blame the implementation.
Power supplies are the low-hanging fruit, not the sole cause though.
Last edited:
What exactly does "sample size" have to with anything I posted??
I haven't forgot anything and you know absolutely nothing about my layout or implementation skills, though you think you do...LOL.
I can gladly state whether I think a particular op-amp sounds okay or not so okay if I wish while kindly ignoring your common replies that the poor sound quality must either be the PS or the layout.🙄
I'll not be wasting anymore of my time replying to your criticisms of everyone's power supplies or layout skills since all of this is already OT and I'm not looking for any heat from the moderators.
Quite simple really, you referred to something you'd noticed in my posts. I was curious how many of my posts you'd based your generalization on.
Okay, thanks for your reply. Now I understand.
Hope you have a wonderful evening.
I apologize for any misunderstandings on my part.🙂
- Status
- Not open for further replies.