dynabok said:
I will not be testing different amps, but I am building a setup where I will be testing 4 different PSU configurations with the same amp. The rectifier board is modular and will be changed out. I have 2 rectifier boards, one with a single 2,200 uF cap per rail and the other has a single 15,000 uF per rail snubberized with a 0.1 uF and a 0.1 uF in series with a 1 ohm resistor.
One amp board has 0.1 uF + 10 uF + 1000 uF and the other amp board only has 0.1 uF + 10 uF. So I can compare channels to see about the extra 1000 uF on the amp board. The amps are bridged LM4780s.
TDA is my favourite! i ve built 2 x TDA 2005 (20+20) TDA7386 (4 x 45w) 2 x TDA 2002.. amps so far.. they are excellent. the only lm ic i tried was LM386.. my very first amp.it is awesm too
Both TDA7293 and LM1875 accurately reflects the quality, care, and design that goes into support circuit creation. As a simple op-amp, LM1875 faithfully obeys, so if you ask it for garbage, then it will give you garbage as precisely as possible. But just think of how nice it could sound if you built it correctly. For example, consider that a correctly built TDA7293 sounds almost exactly like a correctly built LM1875 because, and in this case they sound almost exactly like the music source, which is the point of doing a good job.
OK, i guess i'm not exactly finding the answers i'm looking for here YET as there doesn't seem to be a total consensus, several are bi-amping, and there isn't a lot of comparison talk about the sound of each unit.
i recently bought a NICE pair of energy RC-10s on closeout for about $220 and am finding they're a little clinical sounding with my already clinical sounding panasonic class D that really woke my NHT superzeros up like onkyo and especially NAD just couldn't, so i'm looking to get a warmer more organic sound. right now, i'm just researching, but the plan is to build a dual mono system and drive it using an eastern electric tubed minidac ("the hot $750 DAC" from what i've been reading) as a pre-amp in the future after getting a behringer DEQ2496 to flatten my EQ as i'd expect that to have mediocre DACs at best.
i do all of my listening at low levels, so low level resolution is a top priority along with speed and imaging. i love the sound of properly broken in maggies when they lose their aluminum foil ping sound, but the superior imaging of minimonitors too if that gives you an idea of the sound i like. rolled off bass, as long as it's tight, works for me. after already having a boxy sounding pair of mission M71s with foam port plugs to play with, i'm sticking to my acoustic suspension speed & clarity guns and not even trying my energys without their plugs. actually, that's a big reason why i wanted those. i loved the speed and imaging of NHT classics, but they have some aluminum in their sound. so far, my energy tweeters have been ping free and FAST as reviewed if not quite as revealing as bowers' $20k. besides, it's easy to boost weak bass with a digital EQ. i think i could be happy with as little as 15wpc as my sonic impact amp had more than enough power for the levels i listen to at home.
as the amps will be driven directly from the DAC, pre-amp concerns should be moot.
taking all that in, what would you suggest as the clearest sounding chip amp, not class D... too sterile on my aluminum domes, that can be used as a monoblock.
i see that the audiosector (patek... very respected) LM3875 is very popular, haven't seen much about their 4780 to even make a comparison and am now just hearing about the LM1875 which it sounds like it might be where my "first watt" preferences are leaning. i'm NOT a techie, so slew rate this and damping factor that etc. don't mean as much to me as "liquid treble with an expansive soundstage" does.
i'd like the absolute most bang for the buck amp i can build and would like to use premium components like really good caps, and like the idea of the PCB free direct soldered approach and would prefer to buy the components separate then in a kit for that shortest circuit path approach. i don't care if it looks fugly as long as it sounds beauteous.
anyone have anything to recommend to this noob for the "ultimate hot-rodded" low power chip amp? i was planning on modding my own case & inputs too. dual torroids? 1 cap vs a bank of smaller ones?
just reading this thread alone, my eyes kind of glazed over at all of the technospeak and little of the plain english. is LM1875 what i'm looking for and even MORE resolving than the more popular 3785? are there differences in sources for chips? what about heat sinks? i don't see them in most designs. i'm a little out of my element here, but i DO like elegant simplicity in all of it's minimalist forms. i love acoustic suspension minimonitors afterall, and don't even sub them usually.
i could read every page of every thread here and only get more confused than i am at the moment with the 1875 thrown in the mix, so i'll just take the direct route asking everyone what they think suits my priorities.
as a suggestion, it would be nice if everyone that's tried different chips and mods too would directly compare their SOUND as to which stuff does what better. bass rolloff and low power? that's not a big issue with me as long as the sound is organic. class D does that a lot, but with resolving speakers on lower end amps, yeah, it starts to get dry and clinical. chip amps sound like the middle ground to warmth without as much wet blanket sound as i've been unimpressed by the one time i auditioned a tube amp.
i guess the simple question is
"how can i get even better sound than a patek with the best bang for the buck, but taking no shortcuts?"
my RC-10s are still breaking in, but i'm finding a weird dichotomy... they have speed and intimacy that superzeros can't match with vocals and percussion, but they sound like they'd rather be turned up more to reveal the low level details. they don't seem to like playing at low volumes as much, but man are they ever ruthless on crappy TV station boom mics! LOL
i recently bought a NICE pair of energy RC-10s on closeout for about $220 and am finding they're a little clinical sounding with my already clinical sounding panasonic class D that really woke my NHT superzeros up like onkyo and especially NAD just couldn't, so i'm looking to get a warmer more organic sound. right now, i'm just researching, but the plan is to build a dual mono system and drive it using an eastern electric tubed minidac ("the hot $750 DAC" from what i've been reading) as a pre-amp in the future after getting a behringer DEQ2496 to flatten my EQ as i'd expect that to have mediocre DACs at best.
i do all of my listening at low levels, so low level resolution is a top priority along with speed and imaging. i love the sound of properly broken in maggies when they lose their aluminum foil ping sound, but the superior imaging of minimonitors too if that gives you an idea of the sound i like. rolled off bass, as long as it's tight, works for me. after already having a boxy sounding pair of mission M71s with foam port plugs to play with, i'm sticking to my acoustic suspension speed & clarity guns and not even trying my energys without their plugs. actually, that's a big reason why i wanted those. i loved the speed and imaging of NHT classics, but they have some aluminum in their sound. so far, my energy tweeters have been ping free and FAST as reviewed if not quite as revealing as bowers' $20k. besides, it's easy to boost weak bass with a digital EQ. i think i could be happy with as little as 15wpc as my sonic impact amp had more than enough power for the levels i listen to at home.
as the amps will be driven directly from the DAC, pre-amp concerns should be moot.
taking all that in, what would you suggest as the clearest sounding chip amp, not class D... too sterile on my aluminum domes, that can be used as a monoblock.
i see that the audiosector (patek... very respected) LM3875 is very popular, haven't seen much about their 4780 to even make a comparison and am now just hearing about the LM1875 which it sounds like it might be where my "first watt" preferences are leaning. i'm NOT a techie, so slew rate this and damping factor that etc. don't mean as much to me as "liquid treble with an expansive soundstage" does.
i'd like the absolute most bang for the buck amp i can build and would like to use premium components like really good caps, and like the idea of the PCB free direct soldered approach and would prefer to buy the components separate then in a kit for that shortest circuit path approach. i don't care if it looks fugly as long as it sounds beauteous.
anyone have anything to recommend to this noob for the "ultimate hot-rodded" low power chip amp? i was planning on modding my own case & inputs too. dual torroids? 1 cap vs a bank of smaller ones?
just reading this thread alone, my eyes kind of glazed over at all of the technospeak and little of the plain english. is LM1875 what i'm looking for and even MORE resolving than the more popular 3785? are there differences in sources for chips? what about heat sinks? i don't see them in most designs. i'm a little out of my element here, but i DO like elegant simplicity in all of it's minimalist forms. i love acoustic suspension minimonitors afterall, and don't even sub them usually.
i could read every page of every thread here and only get more confused than i am at the moment with the 1875 thrown in the mix, so i'll just take the direct route asking everyone what they think suits my priorities.
as a suggestion, it would be nice if everyone that's tried different chips and mods too would directly compare their SOUND as to which stuff does what better. bass rolloff and low power? that's not a big issue with me as long as the sound is organic. class D does that a lot, but with resolving speakers on lower end amps, yeah, it starts to get dry and clinical. chip amps sound like the middle ground to warmth without as much wet blanket sound as i've been unimpressed by the one time i auditioned a tube amp.
i guess the simple question is
"how can i get even better sound than a patek with the best bang for the buck, but taking no shortcuts?"
my RC-10s are still breaking in, but i'm finding a weird dichotomy... they have speed and intimacy that superzeros can't match with vocals and percussion, but they sound like they'd rather be turned up more to reveal the low level details. they don't seem to like playing at low volumes as much, but man are they ever ruthless on crappy TV station boom mics! LOL
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Believe it or not, expansive soundstage is hard to do with a chip amp. Setting low gain and using a CRC power supply with a good (watts*3=VA size) transformer can help. But, setting low gain on your power amp can can get you into a preamp project with today's modern sources, such as a computer, that isn't quite as loud as a CD player.
Some of the warm organic sound you mention can be done with a Class A preamplifier, that could be quite handy in several ways. Run on regulated power, the portion of gain provided by the preamp is very clean, and if Class A, it is not polluted by switching/crossing noise.
Amplifier options should sound very similar. In fact, all "good" amplifiers sound very similar because they're supposed to be linear. If you want a different effect, try that with a fun preamp project.
Moosefet at Classic Valve Design is one such preamp.
Parts:
Board, ferrites, resistors, and matched IRF710's from Classic Valve Design.
Nichicon ES 50v 0.47u (input) and Nichicon ES 50v 1u paralleled with Elna Cerafine 16v 47u (output) from Handmade Electronics
Panasonic FC, a voltage regulator chip, heatsinks, and some 10 turn trimmers from Digikey
And a little metal shielded transformer from the Radio Shack.
IRF710's will give you 6922 sound (warm sound that younger men like). IRF510's will give you 6n3p sound (has treble that older men like to freshen up mp3's). Either can have RF filtering added to the preamp just in case your DAC is brash.
After choosing either mosfet selection, you can vary the sound a LOT by turning the trimmer dials.
That tube simulation preamp project lets you dial in clean sound or add some triode sound. This is quite a bit cleaner and clearer than typical tube distortion though, so its not useful for guitar amp at all.
The audio caps mentioned are for the purpose of minimizing insertion loss, as it is always necessary to exercise some care in the selection of audio caps for singleton preamplifiers. No need to stock up excessively, since ideal caps are different per each project.
Decibel Dungeon also has some Class A preamplifiers that can be fine tuned however you like.
I'm suggesting to fine tune the preamp because it has regulated power and lower gain, so the chances of causing noise are a bit less than an overly tweaked power amp can do. AND, you might not have to replace your power amp at all.
P.S.
Some of your description sounds like you need to subtract the inbuilt ear curve from your speaker crossover so the treble doesn't annoy you. All good amplifiers sound REALLY similar if they also test out for low distortion, and that's because they're all supposed to be linear. In your description, it seems like endlessly replacing amplifiers because speaker crossover has a glitch.
So, places to start, include sorting the speaker crossover and some fun class A preamp projects. Some of the preamp projects are designed to facilitate tone variations, in which case it is done far cleaner and clearer than an EQ could do. Any super clear preamp can make the less obvious become more obvious simply because of a gain stage run from clean power. A good practice would be to rig a cancel/bypass switch (to any tone modification devices) for whenever a particular source or track does not require that sort of help.
Some of the warm organic sound you mention can be done with a Class A preamplifier, that could be quite handy in several ways. Run on regulated power, the portion of gain provided by the preamp is very clean, and if Class A, it is not polluted by switching/crossing noise.
Amplifier options should sound very similar. In fact, all "good" amplifiers sound very similar because they're supposed to be linear. If you want a different effect, try that with a fun preamp project.
Moosefet at Classic Valve Design is one such preamp.
Parts:
Board, ferrites, resistors, and matched IRF710's from Classic Valve Design.
Nichicon ES 50v 0.47u (input) and Nichicon ES 50v 1u paralleled with Elna Cerafine 16v 47u (output) from Handmade Electronics
Panasonic FC, a voltage regulator chip, heatsinks, and some 10 turn trimmers from Digikey
And a little metal shielded transformer from the Radio Shack.
IRF710's will give you 6922 sound (warm sound that younger men like). IRF510's will give you 6n3p sound (has treble that older men like to freshen up mp3's). Either can have RF filtering added to the preamp just in case your DAC is brash.
After choosing either mosfet selection, you can vary the sound a LOT by turning the trimmer dials.
That tube simulation preamp project lets you dial in clean sound or add some triode sound. This is quite a bit cleaner and clearer than typical tube distortion though, so its not useful for guitar amp at all.
The audio caps mentioned are for the purpose of minimizing insertion loss, as it is always necessary to exercise some care in the selection of audio caps for singleton preamplifiers. No need to stock up excessively, since ideal caps are different per each project.
Decibel Dungeon also has some Class A preamplifiers that can be fine tuned however you like.
I'm suggesting to fine tune the preamp because it has regulated power and lower gain, so the chances of causing noise are a bit less than an overly tweaked power amp can do. AND, you might not have to replace your power amp at all.
P.S.
Some of your description sounds like you need to subtract the inbuilt ear curve from your speaker crossover so the treble doesn't annoy you. All good amplifiers sound REALLY similar if they also test out for low distortion, and that's because they're all supposed to be linear. In your description, it seems like endlessly replacing amplifiers because speaker crossover has a glitch.
So, places to start, include sorting the speaker crossover and some fun class A preamp projects. Some of the preamp projects are designed to facilitate tone variations, in which case it is done far cleaner and clearer than an EQ could do. Any super clear preamp can make the less obvious become more obvious simply because of a gain stage run from clean power.
A good practice would be to rig a cancel/bypass switch (to any tone modification devices) for whenever a particular source or track does not require that sort of help.
if you're talking to me, though i think you aren't as you get technical, i won't be needing any pre-amp as the plan for me is to use a western electric minidac which has it's own preamp built in, so i'm looking to go direct into monoblocks.
as to soundstaging, i think the biggest factor there is the speakers. my former superzeros had NICE soundstaging with any consumer grade receiver i used and competed very nicely with B&W top of the line speakers on macintosh gear. they were no match for the bowers' tweeters or have anywhere near as deep a bass, but they slugged it out admirably in the soundstage department with tighter bass to low midrange. less is more.
personally, i'm not a fan of class A simply because it's the worst power hog with something like 20% efficiency when A/B is around 50% and D 80% or more. that's part of the appeal for me for a low power chip amp if it truly does offer better sonics than typical entry level gear.
i actually have a couple 15wpc class D modules i intended to use for a portable system and a 25wpc sure i should probably build to see how they fare against my panasonic, possibly even using battery power, but i'd like to try a chip amp just to hear what they sound like. besides, it should be possible to build one for under $100n easily if they're only 9 parts each.
still looking for descriptions and comparisons of different modules and/or mods.
TDA2003 has singleton input. It likes to run from clean regulated power. That combination produces a gigantic soundfield easily as do many singleton input amplifiers.
It has low power, but for 8 ohm speakers it can be bridged:
Mono Audio Power Amplifier 20W 2X TDA 2003 Assembling Kit Circuit HK1002 | eBay
It takes two kits for stereo. And, it needs a heatsink.
They have forgotten the input cap and input load (or volume pot).
It would probably appreciate some RF filtering added.
It would like an additional 2200u cap added to the main power cap.
The price is very low, but, it doesn't come with a power supply.
15vdc is about max and in this case, regulated power is good.
Even bridged and run to max, it not powerful. But, it can be pretty.
Without an LTP in its design (without much power noise rejection), the TDA2003 relies on active devices at the power board for really clean DC that it needs. You can use a spare laptop power pack, or you can use a linear regulator for better quality. I'm just saying that the quality control for power is not inside the TDA2003 chip and cannot pollute the negative feedback circuit with power noise rejection traffic. The only good thing about that is, there's no chance of it throwing the baby out with the bath water. The kit represents an inexpensive way to experience the different performance of a non-LTP amplifier.
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♦ Pretty Class A preamp consumes about as much power as a night-light bulb.
♦ Chip amp set to lower gain gives bigger sound stage. Apparent with most chip amplifiers.
♦ Works best together, so you can hear (otherwise either too quiet at low gain or smaller soundstage if high gain)
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oh, you were talking about pre-amps. i just think amp & SET when i hear the word class A, but i don't like the idea of adding extra electronics in the circuit path either. that violates the KISS principle, and, if the minidac already has it's own preamp built in, then gain shouldn't be an issue. that's why i'm looking to go the monoblock route instead of getting the high rated class D integrated which, just like a class A preamp, will add distortion to the signal chain. i'm trying to do that straight wire thing.
why would you say using the minidac's own pre-amp is inferior to adding another pre-amp to the circuit? i don't buy that musical fidelity tube buffer hype myself. i don't know if the minidac is class A or not, but it has both tube and solid state outputs.
while i'm thinking of it, if i'm going direct into the amps from a pre-amp, i have to invert the amps, don't i? pre-amps invert the signal? that's an impression i got reading what i could understand here in another thread.
if you know of any good info on chip amp mods and parts upgrades, i'd like to read that. i saw someone mentioning carbon resistors to soften sound as one tweak and i know capacitors make a difference in sound, at least in speakers, but i bet in circuits too.
when you mention "setting the gain", are you talking about modifying the input with resistors or something? i really know little about circuits. i can make out a circuit diagram if it isn't too complicated, but still don't know how to read resistor directions for example.
i don't want to get too complicated and keep everything minimalist as well as easier to understand. i'd just like to make something even better than a patek if possible.
why would you say using the minidac's own pre-amp is inferior to adding another pre-amp to the circuit? i don't buy that musical fidelity tube buffer hype myself. i don't know if the minidac is class A or not, but it has both tube and solid state outputs.
while i'm thinking of it, if i'm going direct into the amps from a pre-amp, i have to invert the amps, don't i? pre-amps invert the signal? that's an impression i got reading what i could understand here in another thread.
if you know of any good info on chip amp mods and parts upgrades, i'd like to read that. i saw someone mentioning carbon resistors to soften sound as one tweak and i know capacitors make a difference in sound, at least in speakers, but i bet in circuits too.
when you mention "setting the gain", are you talking about modifying the input with resistors or something? i really know little about circuits. i can make out a circuit diagram if it isn't too complicated, but still don't know how to read resistor directions for example.
i don't want to get too complicated and keep everything minimalist as well as easier to understand. i'd just like to make something even better than a patek if possible.
The answer to the first question could be "yes," but it is actually more involved than that, as I wrote in my first post. I doubt it's important except in an overall system viewpoint.
For the other question, I assume you mean va rather than just v. The transformer va rating is referred to the rms output. A capacitor-input power supply charges at the peak voltage, so the va must be derated to account for that. Then you have amplifier efficiencies of <25% for Class A and <78.5% for Class B, so the transformer must be derated some more. Now add some overhead for good-practices engineering and you should begin to see that 300va isn't overkill for a 100W amp.
For the other question, I assume you mean va rather than just v. The transformer va rating is referred to the rms output. A capacitor-input power supply charges at the peak voltage, so the va must be derated to account for that. Then you have amplifier efficiencies of <25% for Class A and <78.5% for Class B, so the transformer must be derated some more. Now add some overhead for good-practices engineering and you should begin to see that 300va isn't overkill for a 100W amp.
There's no problem doing Class A with Solid State, which is nice for high resolution.
Both inverting and non-inverting are available.
Have you heard the term "fixed l-pad" or "voltage divider"? Those are just volume controls that use resistors and there's no dial. Adjustment is done by replacing resistor(s).
To see your gain, divide the feedback resistor and its partner, the feedback shunt resistor and then add 1. Or see National Semiconductor Overture Design Guide and if you need spreadsheet software, Oxygen Office is free.
Right on! That will be low ripple. VA=watts*3 looks pretty good.
He's doing monoblocs, perhaps 50 watts each. Perhaps a pair of 150va transformers for it?
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no, i haven't heard THOSE terms, but it sounds like the same idea as a step attenuator. when you talk technical, you'll lose me. i only speak plain english.
i still don't see the point of adding an extra gain stage ahead of a DAC if that already has it's own pre-amp. you might add euphonics, but that's just another word for distortion.
part of my problem seems to be that my speakers have been really stubborn about breaking in with low level signals, but today i noticed that they really opened up and relaxed and the bass is surprisingly deep for 5 1/4" acoustic suspension. i might keep my panasonic after all and just get the DAC even if it would bother me that it has a pre-amp i don't need. i have and issues with two pre-amps.
regardless of class of amp, you can get plenty of power out of just 12 volts although class D likes 24 or even 36 i see. i'm starting to feel better about my original choice in gear now with my minimonitors starting to loosen up. i guess that etched sound was just a stiff woofer & tweeter. i've been using grey noise on them for over a week when i sleep, but last night i boosted the output a few dB and noticed much deeper bass as well as a relaxed crystal clear midrange. maybe they'll keep improving and i'll be happy with what i have. then, a chip amp in the future might just be something fun to check out. i really do like the fast clear sound of class D since my first sonic impact amp, but gainclones seem to have more warmth from what i've read.
the FIRST thing though is just getting a digital EQ and see what that does for my system. if it has lousy DACs, my receiver's sound is very similar to my sony DVD player. i guess i was just being impatient for my speakers to break in, but i'll keep following this forum to learn more. i've seen another panasonic get KOed early in an amp shootout, so i should be able to improve my sound.
i'm interested in this just for the sound and not so much the technical number crunching stuff everyone else is into. getting a parts list and a diagram of the "9 parts per channel" is as deep as i want to get into this though. i'll leave all the tech details to the hobbyists.
if i were to use the digital outputs out of the EQ and actually did need a pre-amp, i'm still inclined to go the passive less is more route. i like clinical sound actually, but my speakers WERE sounding thin a couple days ago to the point of even being bright. they're more liquid now. hope they still improve more.
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