Y.C.,
Don't worry about it k.
We're all in the process of learning.. me included.
Like I said earlier.. we learn new things everyday!

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Added on October 4, 2008, 12:37 amgabanyayaya,
this is basic.
the presence of a capacitor on a resistive or inductive circuit will always act like a filtering network.
the arrangement between the capacitor/inductive will decides if it's a lo pass or hi pass filtering network.
normally, low pass in parallel to the input, while hi pass in series.. Thats how I remember them.


This post has been edited by jazzy939: Oct 4 2008, 12:37 AM

Y.C.,
Not at all lah... the process of learning never stops as long as we're willing to learn..

Honestly after testing the stock 5th. board, I was amazed (again) by the quality of the sound..
trying to tweak an already good sound amp is not an easy path.. one wrong turn and we'll messed up a well balanced sonic..
I think we've been careful to a certain extend.. venturing well within known boundaries.. although some of us did ventured out but all is not lost.

For all what it is worth, on top of getting the right tune to suit our tastes, we certainly learn a few things right? I learn a whole new game with respect to input caps and the difference the type of the dielectric made to the sound... Not to mention winding my own toroid inductors...

Blair,
That is a good attempt to explain about 'filtering'
But I like this part: "best thing to do is just accept that it does!"
That is what I did!
But you were right about the charging and the discharging characteristics of the caps that affect the sound somehow..
Ideally no caps would be the best.. then again nothing is perfect including the world that we live in.. I think that makes it interesting...

no one.
I was mentioning earlier about a new Class D amp made by MAXIM that does not require any input caps and output filtering

probably..

here's an extract:

"Maxim Integrated Products has introduced the MAX9768 highly efficient, 10W, mono, single-supply, Class D speaker amplifier with versatile, analogue/digital volume control. Class D architecture enables this device to operate over a wide, 4.5V to 14V supply-voltage range. This wide voltage range allows direct battery operation in portable applications, thus eliminating the need for a DC-DC converter between the battery and speaker amplifier. Additionally, the amplifier's high 87% efficiency eliminates the need for heatsinking. To further reduce BOM cost, the MAX9768 utilises Maxim's filterless, spread-spectrum modulation technique, which minimises EMI-radiated emissions and eliminates the need for the bulky, costly inductor-capacitor filters typically required to achieve acceptable EMI performance. The MAX9768 significantly reduces overall solution size and cost, thus making it suitable for battery-operated equipment, TVs, PCs, GPS, and personal/security radios.
The MAX9768 integrates flexible, dual-mode volume control, which enables either analogue or digital control of a 64-step volume-control circuit. Analogue control can be achieved using a DC voltage, potentiometer, filtered microcontroller PWM signal, or other analogue signal. Digital control is possible using the on-board I2C-compatible interface.

The MAX9768 delivers up to 10W of output power into an 8 ohm speaker with a 14V supply, and features high 77dB PSRR, low 0.08% THD+N, and SNR up to 97dB. Additionally, it provides robust short-circuit and thermal-overload protection, comprehensive click-and-pop suppression, and a low-power shutdown mode. Fully specified over the -40 degrees Celsius to +85 degrees Celsius extended temperature range, the MAX9768 is available in a small, 4mm x 4mm, 28-pin TQFN package."

Blair..
this would be interesting...

morning folks!
ongbs, you're constantly in at around 3am ya.. I can no longer do that.. am beat with all the celebrating and makan...

So much talk about the MAXIM Class D, I don't think it is meant for DIY..

At any rate, I am terribly happy with the TA2024.. few 'minor' tweaks left to do and thats about it! And I am afraid.. the thread may come to an end..(?)

OK Now a very important thing to discuss. OUR FIRST T-Amp TT Session!
Where and when?

Note: We're at PAGE 100 today!

This post has been edited by jazzy939: Oct 4 2008, 10:12 AM

hi folks! Selamat Hari Raya! We're still celebrating,yes?

Wow, we're stuck on page 3 for quite a while!

I have been in few times but nothing to post as there's nothing new on my side.. modification wise that is.

My DIY activities has been put on HOLD during the festive period.. no clearance from the Home Minister

Heyy those wood coned speakers by JVC looks good eh? I have seen those a while back that came with a midi HiFi setup.
Never heard how it sounds... but I think its expensive!

hey ekool, you currently hold the record for highest input caps of 22.2uF! But hey, if it sounds good in your system, leave it!

errr guys, we have yet to decide on our TT session ya?

Food for thoughts..

These are extracts from an interview with Hyodo San, the designer of Leben amplifiers.

Full article here.

"For example, when designing an amplifier, audiophile grade components don't always bring better sound. If I were to make an amplifier with nothing but premium audiophile components, there is no guarantee that the amp will sound good. It is more important to select components by listening so that as a whole, the amplifier plays music better. The most important thing is to achieve a total musical balance....."

Good thing is, this is what most of us is doing.. tune by the ears..

Have a nice day folks...

Vincent Pang, your point is?

Y.C.,
So it seems

Modifications wise, be it an amplifier or even a car for that matter, there are limits to modifications even if 'money is no limit' scenario..
If you got the money might as well buy the ready made absolutely better stuffs!

bro march,
interesting maths there!

anyway, I do agree with your last statement.
With the T-Amp which starts at RM55, my MAX budget for 'upgrade' would be RM55, RM60 tops. Any higher I will no longer consider it to be the 'best bang per buck' amp. Might as well go for higher T-Amp model, right?

The other factor during the 'upgrade' exercise is the 'learning experience'... these are the intangible gain that you'll get that no money can buy..
NOT to mention the TOTAL satisfaction achieved...
It doesn't matter how good the specifications is on paper, how excellent is the review and what other users said/praised about it. It is our own experience that matters! If you have a golden ear that can differentiate all the sonic differences, then all is well and good! If not, why bother?
To me these are just a guideline to decide in which direction I need to take... In the end of the day, say what you want, if my ears say otherwise, I'll stick to what I hear! eg. the F-ELNA caps that I and some of us used or ekool's 22.2uF input caps

I also agree to what metalmania said. The cost has got nothing to do with what we like although some people simply like 'expensive' things
Expensive does equate with quality products, no doubt but not necessarily the sound that we wanted/liked.

A story.
I had a friend who got started in HiFi kinda late but within a short time starts to buy and sell things(ugrading) in the quest for the 'right and balanced' sound that suits his taste. Finally he did achieved what he wanted but still looking for a 'perfect' sound.At this juncture I cautioned him,there is no such thing as 'perfect sound' and IF he were to change any part of his system, it might 'upset' or lose the system balance and MAY required total system 'change'. Sure enough, one (expensive)link was 'upgraded' and the whole system sounded 'wrong'. In the end, he gave up and sold off almost all his hardware...

Lesson learned? Individually, each system components may be good, heck may even be excellent, but when working together, they may not be sonically compatible or synergized to each other strenghts.. hence the importance of getting things 'balanced'...as I earlier quoted..

Again HiFi/audio isn't an exact science.. you draw the line/limit in what you're doing..

my 2 sens

wui223,
actually in stock form the T-Amp is one great performer! Yes. the bass as we all know is kinda lacking.
Start with the input caps change. that would be the minimum I'd recommend if you do not want to mod anything at all.
What speakers are you using? Of course speakers are the final limitation..

bro March,
I recently bought the Hakko Presto too! About the same price
The pistol grip does helps in the soldering works.. So now you're up to some major jobs eh?

I am wondering what was bsl's comments on your T-Amp..
Hey, when will your CA640P comin'? I wanna listen to it too! A separate TT Session on that?

Oh yeah.. the T-Amp TT Session! when?when?

We're moving fast into page 102. good work guys!
Looks like we're back in action!

xtorm,
good proposal! only I am NOT free this weekend ler.. next weekend better chance. Anyhow, Y.C. is yet to complete the mods/upgrade. So we'll let our first host be ready
How big is the crowd ler?
What about ongbs? When are you coming down?
mysghooi, I know you're in Perak but do you keen in joining us?

The anticipated attendees would be:
1. xtorm
2. Y.C.
3. ME
4. march05
5.(ongbs)
6.metalmania(?)
7.gabanyayaya

Did I missed anyone or is there anybody else that like to join us?

bro march,
I think that is a workable solution! Go for it!

bro march,
bsl has said it all!

I think to mark the default position, use a fine tip marker and.. well you know the drill!
Now I wonder, if you don't connect to your 'live' speakers then how would you know exactly how much to adjust/turn? You turn very sloowwwwly...

bro march,
you're right about using a fine jewellers screwdriver! OR if you're a 'macgiver' kind of guy, a small swiss army/victorinox knife, which any good DIYer should also have, should do the trick nicely
Yes I know they are rather tiny.. normally I would mark the position of the screwdriver slots on the board adjacent to the trimpots, with one half of the top of the trim head 'painted' with the marker and to make sure you don't really messed up, take a macro pix of the default settings.. too much huh?

bsl proposal of using a dummy load is good. you can actually take the default reading of the output. It is definitely AC out.. what signal you should fed.. well if you have a signal generator.... To keep thing simple (KISS) a contant tone should be sufficient.. how? I think you know how..

Good luck bro!

Certainly this would a daunting task not to be taken lightly, but I guess with a service manual, good DMM and the necessary data/figures available, these would help in getting the right 'tune' so to speak.. otherwise it would be a 'hit & miss' affair?

bro march,
I couldn't help but smile on the term "hidden-warehouse-disguised-as-a-normal-house" Me and Madziz, we suspected there's a few underground levels... That would certainly explains where 'those' things came from! hahahaha..

You read my mind lah! Now who among us would have a tone/signal generator?

1 kHz would be sufficient I think as my 'signal injector' (DIY KIT) that I sometime use, also transmit around the same frequency region, unless 'sifu' bsl says otherwise...