Hi Wushuliu,
Do you have any faint white noise emitting from the speakers issue when there is no music playing ? I can hear a faint white noise with my ears within 6 in from the speaker coil.
How do you ground your evaluation board ?
The application note says to tie the J8 speaker ground to the power supply ground and this is taken to ground. Do you implement this ?
My entire upper stream equipments are not tied to power ground at all.
thanks for the clarification
kp93300
Do you have any faint white noise emitting from the speakers issue when there is no music playing ? I can hear a faint white noise with my ears within 6 in from the speaker coil.
How do you ground your evaluation board ?
The application note says to tie the J8 speaker ground to the power supply ground and this is taken to ground. Do you implement this ?
My entire upper stream equipments are not tied to power ground at all.
thanks for the clarification
kp93300
Yes, it is only audible on the 36db gain setting when the dcb1 buffer is off. When the buffer is on, it is gone. The board is grounded to dcb1. If I bypass the buffer and connect direct to the amp there is no noise at all.
HI
This is a follow up.
I installed a 470uf cap on the undersurface of the board in parallel with the 220 Uf caps for the evaluation board..
I bypass the 470 uf with a 101 ceramic caps salvaged from another amp.
The improvement is obvious .Improvement is across the spectrum with better high, mid and bass.
Sound stage gain depth and width and dynamic is very impressive. Silence between notes is better and reverberation of drums sound from the recording is more distinct.
The perception of space around the performers is impressive.
I listen through the entire album IL Divo The promise. The crescendo when the music build up is the best i have . Sound stage and instrument placement is maintained with loud dynamic passage and is life like.
Bass is well resolved and bettered Trend audio amp now.
This board is clearly more dynamic than Trend audio. The sound stage depth and width is also better.
My modded trend audio works wonders with SLA battery and i prefer the forward vocal that i think may not be accurate .
I am very impressed with the evaluation board and would like to thank Wushuliu for highlighting it here.
I have not changed the 1uf input caps on the board. I am looking for a low dc leakage small cap as specified in the manual for the chip.
I think i will take a break from building class A amp for a while.
I hope someone here will design a board that is more diy friendly.
cheers
kp93300
This is a follow up.
I installed a 470uf cap on the undersurface of the board in parallel with the 220 Uf caps for the evaluation board..
I bypass the 470 uf with a 101 ceramic caps salvaged from another amp.
The improvement is obvious .Improvement is across the spectrum with better high, mid and bass.
Sound stage gain depth and width and dynamic is very impressive. Silence between notes is better and reverberation of drums sound from the recording is more distinct.
The perception of space around the performers is impressive.
I listen through the entire album IL Divo The promise. The crescendo when the music build up is the best i have . Sound stage and instrument placement is maintained with loud dynamic passage and is life like.
Bass is well resolved and bettered Trend audio amp now.
This board is clearly more dynamic than Trend audio. The sound stage depth and width is also better.
My modded trend audio works wonders with SLA battery and i prefer the forward vocal that i think may not be accurate .
I am very impressed with the evaluation board and would like to thank Wushuliu for highlighting it here.
I have not changed the 1uf input caps on the board. I am looking for a low dc leakage small cap as specified in the manual for the chip.
I think i will take a break from building class A amp for a while.
I hope someone here will design a board that is more diy friendly.
cheers
kp93300
As someone who is interested in eventually being less reliant on "the grid", I'm actually thrilled to hear that these 90% efficient circuits are getting to the point of sounding excellent. My experience with 100mHZ digital video processing circuit and board design tells me that with a circuit like this where you have these very fast edges on many of the waveforms, the board itself is very much a reactive component, and any changes relative to the evaluation board will have to be looked at very closely. Excessive ringing anywhere would be bad. It may be as simple as that. Grounding will need to be about perfect. But I'm excited. I think we are finally to the point where switch mode power amps are as good as anything else out there. My "yammy mammy" (Yamaha) receiver is all switch mode and sounds pretty good to my ear. Thanks for the info. I can't believe those chips are as cheap as they are. I wonder if there's a way to buy small quantities (?)
Oh, a fellow francophone in Europe. Do you expect the Euro to last? :O
Allo, comment ca va? (Haha, je plaisante.)
I could lay out a circuit board, but boards are likely to cost about $80 each here in Oregon for small quantities, and by the time you get the whole thing built in a box with a power supply you're probably at a price point comparable to just buying a Crown or QSC poweramp already built, fully tested and with a proven track record. Most things made in China are cheaper than the cost of the parts here anymore. Our Republican Mafia (as I call it) has made it impossible to compete with the offshore labor rates and environmental laws. They have gotten rich enough to effectively own the governments, by taking away tens of millions of college educated peoples careers. Those who haven't been hit by this won't likely get it.
No offense Bob but anyone considering a QSC or Crown is likely not considering a 30w 'audiophile' amp. Also you can power these amps with a $30 Meanwell power supply, so aside from the PCB cost why would it cost as much as the amps you mentioned? Thanks for the PCB offer. No comment on the politics, except to say happy to be in SoCal!
(Be honest you just wanted a reason to rant!)
(Be honest you just wanted a reason to rant!)
Plain boards will be a lot cheaper but the parts will be hard to get for me. I can do a design but will need the parts to be ordered in the US. If I do it it will have to be a cooperation with somebody in the US. Also I would like to make it a quality design and no cheap job so good parts, good connectors etc. That was why I was asking if somebody could take the challenge. I can but with the aforementioned construction.
BTW I think high hourly rates in the western world are the main cause for the success of the far eastern countries. No political party can change that. It is way too easy to blame somebody else.
BTW I think high hourly rates in the western world are the main cause for the success of the far eastern countries. No political party can change that. It is way too easy to blame somebody else.
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Please no politics, guys
Jean-Paul do you mean just a single order of parts for testing? That i can do.
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