Sorry, its going to take a bit of time. Work has set in for now, so it will be some days before there's a "head to head" comparison of the two amps.
For TDA1554Q, the power circuit used is 100nF//47uF at the amp chip, cabled out to 3300uF at the size M jack, and these caps are signal grade high quality models. You can, of course, substitute nearby values. The power supply is an SMPS.
STK test, head to head against STK459 running on capacitive multiplier power supply, is an old amplifier which is the prior "gold standard" of decent quality mid-fi (for comparison), shows TDA1554 giving at approximately this quality of performance.
Any handbuilt amp should be able to pass this test before its considered a worthwhile project to repeat. The TDA1554 does pass this test and thus shows that it can provide some entertaining music replay, and its Not likely to be discarded. The TDA1554 isn't hifi, but it is a worthwhile project, due to price versus performance ratio. In comparison, most amplifiers in retail stores cannot pass this test, regardless of their terribly higher prices.
In addition, you can pre-set the bass-n-treble by your choice of input cap size for bass and your choice of bypass cap (smaller cap parallel with input cap) for treble. This allows you to match it somewhat to your speakers without having to use an eq or tone control.
Not bad for less than $20 and a bit of of soldering!
Soon (when work lets up) we'll check out 8561Q and see if that one can do better resolution, such as hi-fi. I'm hoping. . .
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Still misleading the general public, eh?
Changing input capacitance values will only affect the bass response. You would need a low-pass filter to affect the treble, and a capacitor in series running to a resistive load is a high-pass filter.
If your thinking is that low frequencies go through the big cap, and high frequencies through (just) the small cap, this is incorrect.
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The smaller cap affects signal in its passband, which is treble.
This method is not helpful all of the time; however, it can be noticeable in conditions where gain is applied.
If you haven't explored this yet, then now might be a good time.
Input filter cap + tiny bypass cap in parallel with it is a fantastic method to combine two cheap caps to approximate the performance of a single spendy cap. Therefore, I do believe that the common technique is appropriate for this low budget amplifier.
Clearly put:
No, a bypass cap will not make a large difference in treble.
No, a bypass cap cannot compete with the effectiveness of a baxandall (bass-n-treble) circuit.
Yes, a bypass cap will potentially make a slight boost in treble response.
Yes, if all you needed was a slight treble boost then a bypass cap can help you avoid the overall signal quality reduction of using a baxandall/eq.
And, unfortunately, a System with TDA1554Q cannot withstand a further reduction in quality, so we really do need to omit the equalizer.
Hopefully there will be better luck with the newer model, which is TDA8561Q (not yet interviewed). . .
P.S.
I don't wish to explore input cap tomfoolery any farther than the simple, common and classic methods; because, almost all other areas of the amplifier are much more important. Please do let this be the end of it, because when "getting close is still off the mark" then we need to explore a different car chip amp.
P.P.S.
Information: LA4628 is already recommendable on both fidelity and ease of use (put speaker zobels onto nearby speaker jacks), but it comes with the caveats (trouble) of needing a larger heatsink, stronger power (laptop cord will do fine) and a few more components than its competitors from Philips.
My reason to play with the Philips parts is fascination over the fairly dramatic decrease in price due to its high efficiency costing less for power and heatsinks.
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Sure.
The chip you already have will maximize a 12vdc power supply, it really must have a potentiometer, and it probably should have a metal box. That deal is a bit noisy, but it can be used with compact speakers, which are inefficient and thus more difficult to hear noise (and everything). Its an odd chip, because whatever isn't noise is hifi. lol! weird, but fun! Check DC offset before connecting speakers--larger size input caps cause greater DC offset, so use at or close to spec (from the datasheet).
For the 15vdc econo laptop supply: TDA8561Q/TDA1554Q also run cool and will heatsink easily onto available metal scrap or direct-mount to a metal enclosure. Oddly enough, it will take the Philips TDA1554Q about two weeks of use or more before its transistors run smooth (you'll hear a bit of "grit" when the amp is new, but mine smoothed out).
For the 15vdc econo laptop supply:
LA4628 is the premium option, but needs a higher amperage 15vdc~16.5vdc laptop cord, such as the one that I've got listed here in your thread (earlier), and LA4628 needs a Real heatsink. The "extra parts" of LA4628 are simply speaker output zobel, and those may be mounted onto the speaker jack itself.
All of these chips are designed for unit ground, and thus Ground, Signal Ground, and NC are all ground. You can easily re-bend the chip (pins bend about 3x before losing integrity) so that the power pins are all closest to the chip's face, the ground bus pins are in the middle and the audio pins are at the bottom. This is like "3 rows across" and the spacing in-between rows is about the same as the pin spacing of a capacitor. Holding at maximum 100uF size parts, these amps have no need of a circuit board.
On-amp power circuit has 100uF//100nF with additional capacitance a short distance away (dc input jack of enclosure) via cable.*
A bit of 4 conductor zip wire from the auto parts store has the exact spacing of the Philips chip's speaker output pins, and this cable can keep the pins from touching.
Input filter capacitors go between potentiometer and amplifier; however, these are tiny caps and may be mounted upon the potentiometer itself. For amps that take output zobel, those parts can be mounted upon the speaker jack.
*If the power supply is weak, it may not be able to deal with a bass beat, and for this reason, I put a larger capacity cap (1500uF~3300uF) in parallel with my DC input jack. I found this cap(s) on an old computer motherboard and simply recycled it.
Voltage and clipping:
The 15vdc econo laptop cord will make less clipping than a 12vdc wall plug. Higher voltage makes for less clipping because it makes for a more powerful amplifier. Most automotive chips top out at 15.5vdc soa.
Caveat: Using higher than 12vdc requires a regulated power supply in order to insure expected voltages and resistance to surges.
Output versus clipping (Speakers are the output):
Generally, you could use the 12vdc supply if your speakers are 4 ohm; or you could use the 15vdc supply if your speakers are 8 ohm. A possible combination of 15vdc with 4 ohm speakers needs good quality heatsinking because that combination is absolute maximum power (and heat!). Consider that some 90db 8 ohm speakers will play as loud as some 87db 4 ohm speakers; however, any 8 ohm speakers will make Much less heat in the amplifier.
Interesting research: See Parts Express website and have a look at woofers that have a generally flat response (less crossover losses that way) and high efficiency too, because this sort is ideal for speakers that work well with small amplifiers. Edit: The exception is that if your particular model of car chip amp is stuck at excessively high gain then that one is best used with commonplace inefficient speakers in order to decrease noise floor output; but that just further reinforces the idea that speakers are the output.
Other thoughts: These low voltage technologies work best in small rooms, probably because that is decently close to expected usage. The low voltage car chip amp brings with it the high availability of inexpensive regulated power supplies, and even though the datasheet figures of the amplifier itself may be inferior to hi-fi amps, use of small regulated power supplies (with their considerably cleaner power) may help the little car chips compete with a hi-fi amplifier. The expected performance of this combination (handbuilt car chip amp on regulated power) exceeds the quality of products available at Best Buy and other mass production black-box retail audio vendors. So, its probably worth your time to play with the car chip amps.
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Efficiency exploration
Given a larger enclosure with an AC mains power switch to cut off the APFC switchmode power supply and. . .
A circuit that would exchange the speaker load for a 120 ohm load and simultaneously operate the mute/standby function upon detection that no music has played for a few minutes; and, also given an additional circuit that would power down the amp if it was forgotten left on, then the Philips products could qualify for and exceed the Class IV energy efficiency rating, which is the current highest standard.
So if you want an amp to "leave on" but don't want the nonstop treble output, extraneous complexities and durability issues of Class-D, then try out the Philips class A-B instead. One thing is for sure, the heatsink ratio is much cheaper than average for a Class A-B linear amplifier.
At this time, my Philips has been left on, and without the additional circuits to force energy efficiency. The 3"x3"x1" heatsink ($1.80) is approximately room temperature despite the 4 ohm load which is connected to a linear amplifier (how the heck?). Given a switch to disconnect the power supply from the AC side, this amplifier could probably still qualify for an energy efficiency rating.
Given a larger enclosure with an AC mains power switch to cut off the APFC switchmode power supply and. . .
A circuit that would exchange the speaker load for a 120 ohm load and simultaneously operate the mute/standby function upon detection that no music has played for a few minutes; and, also given an additional circuit that would power down the amp if it was forgotten left on, then the Philips products could qualify for and exceed the Class IV energy efficiency rating, which is the current highest standard.
So if you want an amp to "leave on" but don't want the nonstop treble output, extraneous complexities and durability issues of Class-D, then try out the Philips class A-B instead. One thing is for sure, the heatsink ratio is much cheaper than average for a Class A-B linear amplifier.
At this time, my Philips has been left on, and without the additional circuits to force energy efficiency. The 3"x3"x1" heatsink ($1.80) is approximately room temperature despite the 4 ohm load which is connected to a linear amplifier (how the heck?). Given a switch to disconnect the power supply from the AC side, this amplifier could probably still qualify for an energy efficiency rating.
I have not yet had time to optimize support circuit for this one. My apologies.
Its best performance has not yet been observed--no evaluation on it at this time.
Great work, daniel..
But seems that there s some pessimism by there.
I ll order a 8561Q soon for verification purposes.
Anyway, those chips are in need of an input potentiometer,
as they were designed to be used this way.
A direct connection to a laptop would be catastrophic,
whatever the amp used.
But seems that there s some pessimism by there.
I ll order a 8561Q soon for verification purposes.
Anyway, those chips are in need of an input potentiometer,
as they were designed to be used this way.
A direct connection to a laptop would be catastrophic,
whatever the amp used.
TDA1554Q Lengthy testing complete.
I wondered what it would be like living with TDA1554Q and have run it as my only system for some time now.
Like most of the car amps, its tonality beats most gainclones, quite easily (but that is mostly due to the regulated power supply).
Oddly enough, it sounded like "transistor grit" for some days but has since smoothed that out completely and then the amp got more powerful. Break-in takes an so long that the timeframe isn't plausible. But, I can definitely confirm that it got more powerful after being left on for a week.
To power my big 8 ohm speakers, I used a 15vdc regulated high-efficiency Toshiba laptop supply (vendor listed earlier in this thread). At 12v, the amp was disappointing. At 15 it works fine. For reference, my car would have powered it to 14.4~14.8vdc with the car running.
The expectation for this amplifier was, at long last, met when it exceeded the performance of the reference headphones because of assisting in extrapolating a compressed audio file. The effect is not strong; however playback of WMA@48kbits (flat soundfield--very boring) demonstrated a large soundfield and thus this amp can amplify more than just voltage. It can amplify music. For that, it has earned itself an enclosure.
I do think that more is possible; however, TDA1554 is a good amp, once past its lengthy break-in(!), and then fine tuned a bit.
Summary:
A pleasant tone for lengthy listening
Easy assembly--high probability of success
Runs well with 15vdc cheap ebay laptop cord
Very inexpensive
Extreme high efficiency!!!
P.S.
This amp wasn't sufficient with the 12vdc wall plug (I'm running 8 ohm speakers). Sorry about that. Will try again later. Perhaps there's another model that will run well under-volted?
I wondered what it would be like living with TDA1554Q and have run it as my only system for some time now.
Like most of the car amps, its tonality beats most gainclones, quite easily (but that is mostly due to the regulated power supply).
Oddly enough, it sounded like "transistor grit" for some days but has since smoothed that out completely and then the amp got more powerful. Break-in takes an so long that the timeframe isn't plausible. But, I can definitely confirm that it got more powerful after being left on for a week.
To power my big 8 ohm speakers, I used a 15vdc regulated high-efficiency Toshiba laptop supply (vendor listed earlier in this thread). At 12v, the amp was disappointing. At 15 it works fine. For reference, my car would have powered it to 14.4~14.8vdc with the car running.
The expectation for this amplifier was, at long last, met when it exceeded the performance of the reference headphones because of assisting in extrapolating a compressed audio file. The effect is not strong; however playback of WMA@48kbits (flat soundfield--very boring) demonstrated a large soundfield and thus this amp can amplify more than just voltage. It can amplify music. For that, it has earned itself an enclosure.
I do think that more is possible; however, TDA1554 is a good amp, once past its lengthy break-in(!), and then fine tuned a bit.
Summary:
A pleasant tone for lengthy listening
Easy assembly--high probability of success
Runs well with 15vdc cheap ebay laptop cord
Very inexpensive
Extreme high efficiency!!!
P.S.
This amp wasn't sufficient with the 12vdc wall plug (I'm running 8 ohm speakers). Sorry about that. Will try again later. Perhaps there's another model that will run well under-volted?
Better sound than , say, the LM38xx series .?...
Quite amazing...I thought the NS where superior in all ways..
As you mention it, 12V is not enough to extract the good
juice from these amps.
15V is way better, and i use a 16.4V smps..
National Semiconductor's LM1875 is superb; and it doesn't contain the noisy spike system. Unfortunately, the larger scale chips, LM3875, LM3886, LM4680 have the spike system whereby if there is clipping there is noise added by the spike system; and, this is not good at low voltage because low voltage amplifiers don't have enough headroom to avoid setting off the Spike system.
We could use LM1875 for this project. Given eight of LM1875, then bridged topology and 4 ohm speaker support is possible. That can also run a 19vdc econo laptop power cord per each channel. Amperage on those power sources is insufficient for stereo amp. Dual mono (individually powered left and right) is workable. At 30 watts per channel, the heatsinks would be rather large.
I doubt that you'd notice a difference in output power between 22~24 watts car amplifier versus 30 watts, because the additional decibels output at the speaker is 1 or less decibel.
12 v chip amps
hmmm how about TDA7385 ( i thin thats the no, )
or probably TDA8561 /62 elecktor has a single side pcb layout for the chip,
plus get 2003's elektor it has a complet single sided board for active filter input and a amp on single board very very neatly done, if interested i will mail the pdf to you,,, let me know
interested in having a peek in it daniel... whats up
hmmm how about TDA7385 ( i thin thats the no, )
or probably TDA8561 /62 elecktor has a single side pcb layout for the chip,
plus get 2003's elektor it has a complet single sided board for active filter input and a amp on single board very very neatly done, if interested i will mail the pdf to you,,, let me know
interested in having a peek in it daniel... whats up
There is certainly enough gain for use with an MP3 player.
I'd give it a go. Like the rest of its family, its super efficient (on my 8 ohm speakers, the amp runs cool), assembles fast and has a nice range to it. On a spare 15v laptop cord, it will easily keep pace with a bigger amp. It can handle 4 ohm speakers and that (4 ohm speakers) would make it play very, very loud but also require a bit larger heatsink.
With some ordinary 8" speakers, it will play loud enough to crash the heads on your hard drive. My hard drive met an early demise this way. This is sufficient bass. The basic tonality can beat most tripath amps quite easily, and that is mostly because the Philips is so much easier to work with.
Like the rest of the car chip category, the Philips is a bridged amplifier, and this does several things well. You get less blare. Louder bass will come from sealed box speakers (louder lower notes than compared with a non-bridged amplifier). In trade, the bridge amp likes smaller rooms, and its not for outdoor use.
I liked a polyester Wima 330nF input cap on the Philips chips, if when the amp is going to power 6" and smaller speakers. I simply paralleled it with a really small value electrolytic (maybe 0.5uF?) to boost the range for use with the great big speakers.
Differences between model of chip are extremely small in comparison to component variety, power supply and music source. And, every one of the car chip amps gives availability of the really inexpensive super clean power from 15v laptop power packs.
For some reason, one of the Philips chips took quite a while to break in and run decently speedy, but after a few weeks of run time, the slow transistor sound was gone and it sounds awesome now.
Like any "laid back" amp, it exposes its own little flaws (and its power supply too), but this is true regardless of price range. The deal is that shouty amps aren't any fun loud, and laid back amps like the Philips are fun loud (when loud isn't piercing). So, I do like the Philips quite well. All of the power that is has is also useful for music. It doesn't whimp out or screech and there's no mandatory minimum level either. Instead, the behavior is quite good.
Caveat: You must pick a compliant source device, and here's a comparison. Driven from an X-Fi Music/Gamer source the results are horrible indeed; however, a nice cheap Via Tremor (with some approximately 500nF~330nF caps paralleled to the Tremor card's huge output caps to augment the treble clarity) will inspire the Philips to rock down the house with a nice big concert sound.
Likewise if your MP3 player sounds great with some Koss Porta Pro (or the really similar Grado SR80's) then it will sound great with the Philips amp too. That concept is true of most chip amplifiers that don't have preamps.
Well, I just thought I should mention that the source device is super-important if you're going to be amplifying its output a heck of a lot.
A buffer circuit, or an input transformer, or a chb, or an optoisolator based volume control, or a mild preamp could possibly increase the entertainment value, and that is true of any chip amplifier. I think its time for some soldering.
preamp for TDA1554Q
I was rebuild my oldy TDA1554Q, and I more like the TDA1554 sound compared to LM1875 whan playing oldies song... smooth performance, not too much detail
I use W200i walkman phone for the input source, what is the best preamp voltage gain for TDA1554Q with W200i?
suggested OpAmp to be used, any idea?
regards,
I was rebuild my oldy TDA1554Q, and I more like the TDA1554 sound compared to LM1875 whan playing oldies song...
smooth performance, not too much detailI use W200i walkman phone for the input source, what is the best preamp voltage gain for TDA1554Q with W200i?
suggested OpAmp to be used, any idea?
regards,
I was rebuild my oldy TDA1554Q, and I more like the TDA1554 sound compared to LM1875 whan playing oldies song...
I use W200i walkman phone for the input source, what is the best preamp voltage gain for TDA1554Q with W200i?
suggested OpAmp to be used, any idea?
regards,
Its a bit unusual to need any voltage gain with an already high gain amplifier. Most MP3 players can push the bridged 1554q most of the way or all of the way into clipping.
A Walkman is designed to drive headphones and the very light load of the TDA1554Q amplifier may be giving the walkman "nothing to do" and thus you might employ a buffer chip at the amplifier input. There is room to use a very slight amount of gain. Nevertheless, the chip is the same--a "Unity Stable" op-amp is what you're looking for.
Some Unity Stable op-amps have voltage tolerances in the 12vdc-15vdc range, which could be convenient. Perhaps you can find a unity stable op-amp with a J-fet input? That could be fun, but a buffer or preamp really isn't necessary with TDA1554Q.
hi Dan,
I'm not sure about W200i V_out. from 8 bar of volume control, best sound I get from 4.5 to 6 bar, I've got more noise(@ lesser volume) and lesser dinamic(@ more volume). Thats why I intended to use a PreAmp
.and somehow at maximum volume, the sound isn't quite loud.
it can only drive earphone, driving a headphone wasn't load at all, with the same impedance (32R).
I've built the preamp, the circuit is attached.
C6 and RL(bridged TDA1554Q Z_in) are in TDA1554 kit.
Now I use Ti NE5532, can be operated with VS as low as 10Vdc, low noise, unity-gain stable, good PSRR too.
next week I will use Philips ones, 6Vdc minimum (ALL PHILIPS CHIP
).regards.
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