Thank you for the ideias 
I will do it (first) with the DRV134 because it's fast to do it.
I will use it to test my 2xbridged STK401-330 amp.
After optimize the amp maybe I will do a new pre
Ps: Does any one knows if Analog Devices have any chip like the DRV134 ?
I like analog devices products, normally they sound great
I will do it (first) with the DRV134 because it's fast to do it.
I will use it to test my 2xbridged STK401-330 amp.
After optimize the amp maybe I will do a new pre
Ps: Does any one knows if Analog Devices have any chip like the DRV134 ?
I like analog devices products, normally they sound great
My "pre" (DRV134) will give 6dB gain.
Should I lower the power amp gain for 20 ?
(changing 2K for 1K)
Does the LM3886 work well in 20dB gain?
I didn't put any resistors or capacitors in the input and output because I want to optimize that values with my speakers.
(I want to "see" how it changes the sound)
Ps: I got some free adjustable inductors, do you think I should use in the output ?
(I don't like to much inductance, It gives a slow bass....)
Should I lower the power amp gain for 20 ?
(changing 2K for 1K)
Does the LM3886 work well in 20dB gain?
I didn't put any resistors or capacitors in the input and output because I want to optimize that values with my speakers.
(I want to "see" how it changes the sound)
Ps: I got some free adjustable inductors, do you think I should use in the output ?
(I don't like to much inductance, It gives a slow bass....)
carlos answered this already, im not sure if it was here or in another thread.
anyway, lower value resistors generate less noise. i think (but may be wrong) that since the resistors are of lower value more current is flowing and thus the signal is less influenced by interference or noise. much in the same way low impedence input provides better noise regection in interconnects.
anyway, lower value resistors generate less noise. i think (but may be wrong) that since the resistors are of lower value more current is flowing and thus the signal is less influenced by interference or noise. much in the same way low impedence input provides better noise regection in interconnects.
Dear Carlos,
I am confused, which is not new.
Looking at your Snubberized Regulated PSU and NI LM3886 Amp version 3.0, the note at the bottom of each schematic says:
Quote:
-Use 1000~2200uF + 100nF on the chip's V+ and V- pins.
-0.47R/1W + 47nF snubber just before these caps. End Quote.
Do you want the snubber to be immediately adjacent to the large capacitors:
1. on the Power Supply Side of the capacitors (LM3886|snubber|electrolytic), OR
2. on the LM3886 side of the capacitors (LM3886|electrolytic|snubber), OR
3. does it not matter as long as they are physically as close as possible?
This is complicated by the sheer size of the large electrolytics, which pushes them physically away from the LM3886 chip. Given that the snubber is to counteract as much badness in these as possible, and that the little bypass capacitor also provides "life" or "high frequency agility" to the response of electrolytics, which of the following arrangements should be acceptable:
4. LM3886|100nF|largish gap|Electrolytic|snubber
5. LM3886|100nF|largish gap|snubber|Electrolytic
6. LM3886|largish gap|100nF|Electrolytic|snubber
7. LM3886|largish gap|100nF|snubber|Electrolytic
8. I need to get out more? (You are not allowed to select this as an option. It is only so that you know that I have some insight into my problems.)
Does keeping R3, the feedback resistor, as close to the LM3886 still take absolute priority?
And finally, what type of capacitor do you recommend for Cs, a little MKT or a ceramic, which I have seen in lots of amplifier kits?
With thanks,
George.
I am confused, which is not new.
Looking at your Snubberized Regulated PSU and NI LM3886 Amp version 3.0, the note at the bottom of each schematic says:
Quote:
-Use 1000~2200uF + 100nF on the chip's V+ and V- pins.
-0.47R/1W + 47nF snubber just before these caps. End Quote.
Do you want the snubber to be immediately adjacent to the large capacitors:
1. on the Power Supply Side of the capacitors (LM3886|snubber|electrolytic), OR
2. on the LM3886 side of the capacitors (LM3886|electrolytic|snubber), OR
3. does it not matter as long as they are physically as close as possible?
This is complicated by the sheer size of the large electrolytics, which pushes them physically away from the LM3886 chip. Given that the snubber is to counteract as much badness in these as possible, and that the little bypass capacitor also provides "life" or "high frequency agility" to the response of electrolytics, which of the following arrangements should be acceptable:
4. LM3886|100nF|largish gap|Electrolytic|snubber
5. LM3886|100nF|largish gap|snubber|Electrolytic
6. LM3886|largish gap|100nF|Electrolytic|snubber
7. LM3886|largish gap|100nF|snubber|Electrolytic
8. I need to get out more? (You are not allowed to select this as an option. It is only so that you know that I have some insight into my problems.)
Does keeping R3, the feedback resistor, as close to the LM3886 still take absolute priority?
And finally, what type of capacitor do you recommend for Cs, a little MKT or a ceramic, which I have seen in lots of amplifier kits?
With thanks,
George.
It's down to translating a circuit diagram into a practical circuit. I used to be puzzled until I saw component leadouts as tracks rather than the component itself. (Hope you can understand that 
)
George, if you mount the 'extras' on the leadouts of the caps, and the caps to the pins of the chips, that sort of negates the question of do those 'extras go before or after the cap. I hope this helps.
)George, if you mount the 'extras' on the leadouts of the caps, and the caps to the pins of the chips, that sort of negates the question of do those 'extras go before or after the cap. I hope this helps.
carlosfm said:Will someone s'plain me how to make it more clear than what's on the schematic?
I'm at a loss...
Technically, a schematic only shows the logical connections between components not the physical layout. When you read your schematics, your brain automatically sees it as a physical layout, others that have not build one or two hundred GC and PSU may not make this translation.
Your written instructions on the schematics are clear but if you are suffering information overload like many of us here it could become confusing.
My only suggestion is, if you feel like that is, if the schematics were even closer to the physical layout by making a connector bullet equivalent to a solder joint then it may be clearer to others. This requires you to angle connections wires to the common points.
BTW: I find your schematics very precise and clear, but I was a electrical draftsman for many years.
Apologies
Dear Carlos,
I appreciate your frustration. You probably should have used THIS emoticon:
when referring to my letter. My letter was also too verbose, and I apologize.
I think that your schematics are very clear and I could build a nice amp from them alone. The advice you give on many threads here at diyaudio is also very clear.
I was mainly trying to establish the meaning of the word "before" at the bottom of the two schematics I mentioned (Snubberized Regulated PSU and NI LM3886 Amp version 3.0), in order to squeeze as much out of my effort with these amps as possible. As my Grandma said: "If the job is worth doing ..." etc.
With best regards and many thanks,
George.
Dear Carlos,
I appreciate your frustration. You probably should have used THIS emoticon:
when referring to my letter. My letter was also too verbose, and I apologize.I think that your schematics are very clear and I could build a nice amp from them alone. The advice you give on many threads here at diyaudio is also very clear.
I was mainly trying to establish the meaning of the word "before" at the bottom of the two schematics I mentioned (Snubberized Regulated PSU and NI LM3886 Amp version 3.0), in order to squeeze as much out of my effort with these amps as possible. As my Grandma said: "If the job is worth doing ..." etc.
With best regards and many thanks,
George.
Re: Re: Re: Improving the Non-Inverting chipamp
Carlos,
Very interesting concept and look interested to try. To my understanding, keep the low value is to highA). er to feedback and make the chip more stable and control. Right?
I have 4.75K and 150 on hand now, and wonder if they can be used as replacement of yur origincal design's 2K + 100R ( I need ~ 30x gain as an integrated amp) ? If so, I will try it during the coming weekend (25W version).
Thanks,
carlosfm said:
Carlos,
Very interesting concept and look interested to try. To my understanding, keep the low value is to highA). er to feedback and make the chip more stable and control. Right?
I have 4.75K and 150 on hand now, and wonder if they can be used as replacement of yur origincal design's 2K + 100R ( I need ~ 30x gain as an integrated amp) ? If so, I will try it during the coming weekend (25W version).
Thanks,
nina said:I prefer the direct drive from CD via the passive pre.
Because these chips sound better at lower gains.
And they do benefit from a good pre, with (of course) constant output impedance.
You can do what you have in mind for now, anyway.
One day you'll try this.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.