$30 amp upgraded

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#242
#245
mourip said:


Thanks Motherone. I have been looking for a couple more for several weeks. Ordered two from eFunctional today. They show as in-stock. We shall see.

This little amp is amazing. It could change the whole industry if they take notice... or even if they don't 🙂

Best,

Paul
Click to expand...

I am replying to myself. Is this like talking to myself 🙂

Even though eFunctional shows the units as instock they are backordered. If you are in a hurry and do not mind spending $39 instead of $21 for an amp that betters $1000 amps(with the right speakers) you can get one today from Sonic Impact. They ship same-day... I just had one shipped for a friend.

Best,

Paul
 
#246
41mz.com

Hi,

I emailed the 41mz.com folks after seeing some links here and and on Audio Circles. The boards look good so I asked a few questions. The only real reservation I have is that the user has to solder the surface mount components.

Here is the exchange posted with their permission. My questions are near the end...


> >>> <projects@41hz.com> 02/18/05 9:47 AM >>>
> Hi,
>
> When I ask Tripath they say that "basically the only difference is
> the packaging". The 2021B has the heat slug on top while the
> 2024 has it on the "belly" side. But I have not made a direct
> comparison.
>
> The PCB and through hole components:
>
> Most Tripath chips are surface mounted. These amps work in a
> frequency range varying from 200 kHz to 1200 kHz. It is essential
> to have bypassing caps and some other components very close to
> the chip and therefore it is strongly recommended to use surface
> mounted components. Also with the high frequency involved and the
> potential problem with the audio path picking up signals, it is good
> to keep all siganl paths as short as possible. Now with this in mind,
> I have used surface mounts also for most of the rest of the components.
> I think the Sonic Impact is the same. There are some through hole
> coponents; like the bulk ecaps for the power supply and the toroids.
> On my larger boards, especially the AMP2 there is a number of through
> hole components, but still the number of SMT:s is higher.
>
> There is a difference between my boards and commercial
> boards that are assembled in automated mounting. On my boards
> I use size 0805 or larger while large series commercial products
> often use smaller components. While the 0805 components are
> small, they are still managable IMO.
>
> I think when you read the disaster reports, most people will have
> had the problems removing the components cleanly. Even removing
> a SMT resistor is a bit tricky, as you preferably need two soldering
> irons or one with a double tip. Not to mention the problem with multilead
> chips. If you have a clean board to start with you have much greater
> chance of success. With ther price of this board I think these boards can
> be a good starter for those who would like to try surface mouneted
> components. After all, these can be expected to become more and
> more dominant in the future.
>
> For the big AMP2, I provided space for alternate components
> but so far almost everyone who bought these boards, bought the
> component kit.
>
> Anyway, I will take your comments into consideration. Maybe
> I can make an alternate version of the AMP3 or another
> amplifier, with space for through hole components in the future.
>
>
>
> On 18 Feb 2005 at 7:59, Paul Mouritsen wrote:
>
> >
> > Thanks for the reply. I appreciate it.
> >
> > I have aseveral questions. First, how similar is the 2021B chip to the 2024 chip found in the
> Sonic
> > Impact amp? Second,the photo on your web site shows regular components that pass through
> > holes in the pcb but in your forums you describe how to solder surface mount components. Are
> > most of the components surface mount? Are any components "through pcb" type? Is the tripath
> > chip presoldered or does the end user solder it? Are you considering a board with presoldered
> > components? Would you consider a board with pre-soldered surface mount components but the
> > signal path devices of the trough pcb type so that folks could easily substitute "audiophile"
> > resistors and capacitors?
> >
> > I think that you will run into a lot of resistance to a kitwith user installedsurface mount
> > components. Take a look at the forums on DIYAudio, AudioCircle, and Head-Fi and
> AudioAsylum.
> > You will get a lot of clues and suggestions from there. Most folks dread working with surface
> > mount devices. There are lots of threads regarding mods to the SI amp and lots of stories of
> > destroyed boards from soldering disasters.
> >
> > If you would consider a board with some presoldered surface mount components but the signal
> > path devicesbeing the "through pcb" type so that folks could easily substitute "audiophile"
> > resistors and capacitors then I think that you would have a hands-down winner. Just my two
> cents
> > 🙂
> >
> > Best,
> >
> > Paul
> >
> >

> >
> >
> > >>> <projects@41hz.com> 02/17/05 5:57 PM >>>
> > Hi,
> >
> > I will email you when it is time. Should be about four
> > weeks from now.
> >
> >
> >
> >
> > On 17 Feb 2005 at 12:17, Paul Mouritsen wrote:
> >
> > >
> > > Hi,
> > >
> > > I would be interested in being notified when Amp3 is available.
> > >
> > > Thanks,
> > >
> > > Paul
> > >
 
#247
Surface Mount Station Needed.

To install a large number of SM parts a proper Surface Mount installer is needed. This is a hot air tool to melt the solder without damaging the components. If you try to populate a complete board with an iron, the number of boo boos with be high.
A poster here mentions resistors drifting in value. The ceramic caps also can crack due to heat cycling. Both problems will lead to early failure.

George
 
#248
Re: Surface Mount Station Needed.

Panelhead said:
To install a large number of SM parts a proper Surface Mount installer is needed. This is a hot air tool to melt the solder without damaging the components. If you try to populate a complete board with an iron, the number of boo boos with be high.
A poster here mentions resistors drifting in value. The ceramic caps also can crack due to heat cycling. Both problems will lead to early failure.

George
Click to expand...

Thats about what I had figured. Seems like a ticket to frustration.

I would like to see either a presoldered kit with premium parts or a kit with all the surface mount parts presoldered but the signal path parts as "normal" through-the-hole type so that we could experiment to our hearts content...
 
#249
I would like to see either a presoldered kit with premium parts or a kit with all the surface mount parts presoldered but the signal path parts as "normal" through-the-hole type so that we could experiment to our hearts content
Click to expand...

I suppose the Sonic Impact board answers some of these wishes - presoldered SMT parts.

Looking at the 5066 board pictures (Top & Bottom) it does seem to be close in design to the Tripath TA2024 eval board. Obvious differences appear to be

- eval board uses two supply bypass caps(470uF/25V Panasonic FC) -close to TA2024, one from VDD1 to PGND and another from VDD2 to PGND

- SI board uses only one and it is further away from the chip pins (although 01.uF SMT caps seem to soldered directly under chip accross these supply pins to ground?

Has anybody tried soldering supply wire directly to VDD1 & VDD2 (one end of each of these SMT chip caps) and quality elcos (Pana FC) directly onto this supply wire and bypassing to ground (which I presume is the solder pad right next to these SMT caps?

What improvement did it make?

- Ta2024 design notes also also recommends a charge pump cap (01.uF) soldered directly between pins 2 & 3.
- I can't see evidence of this in SI board pictures

Anybody try this?
 
#250
jkeny said:


I suppose the Sonic Impact board answers some of these wishes - presoldered SMT parts.

Looking at the 5066 board pictures (Top & Bottom) it does seem to be close in design to the Tripath TA2024 eval board. Obvious differences appear to be

- eval board uses two supply bypass caps(470uF/25V Panasonic FC) -close to TA2024, one from VDD1 to PGND and another from VDD2 to PGND

- SI board uses only one and it is further away from the chip pins (although 01.uF SMT caps seem to soldered directly under chip accross these supply pins to ground?
Click to expand...


The SI 5066 also has a few other differences:

1) The input also includes an inductor and 100pf cap for a HF filter.
2) The DC-blocking cap on the inputs are .33uF rather than 2.2uF

jkeny said:

Has anybody tried soldering supply wire directly to VDD1 & VDD2 (one end of each of these SMT chip caps) and quality elcos (Pana FC) directly onto this supply wire and bypassing to ground (which I presume is the solder pad right next to these SMT caps?
Click to expand...


Vinnie R sells a modified SI 5066 in a new case with SLA battery. I believe he puts 2x 1200uF or 1500uF Panasonic FC caps directly on the pins of the chip, with SMT chip caps bypasses directly soldered to the FC's. I also believe he runs separate power leads to these pins.


jkeny said:

What improvement did it make?
Click to expand...


No idea.. I don't have the $500+ to try his modded $30 amp 😀


jkeny said:

- Ta2024 design notes also also recommends a charge pump cap (01.uF) soldered directly between pins 2 & 3.
- I can't see evidence of this in SI board pictures

Anybody try this?
Click to expand...

C7 on the board is the 0.1 uF charge-pump capacitor.
 
#251
Successful mods?

Motherone,

My point was that it might be easier to solder on top of SMT parts on the SI board than to populate a blank board with SMT parts .

For instance the electro bypass caps could be soldered directly on top of the existing SMT bypass caps under the board and thereby move the electro caps much closer to chip which is a good thing.

It might also be possible to solder the supply wire directly to here also?

Anybody try this?

I am waiting on delivery of two SIs and beforehand am checking out with active members on the most successful mods (this sort of thing happened with the Gainclone in its early activity and proved useful for all)
 
#252
Re: Successful mods?

jkeny said:
Motherone,

My point was that it might be easier to solder on top of SMT parts on the SI board than to populate a blank board with SMT parts .
Click to expand...


I guess this would depend on your soldering skills. I removed parts from the SI board and soldered in replacements. I've had a few problems with the values measuring correctly after doing this. It looks like I'm going to need an Air Pencil to continue further (and even then, I don't know if that will really help).

jkeny said:

For instance the electro bypass caps could be soldered directly on top of the existing SMT bypass caps under the board and thereby move the electro caps much closer to chip which is a good thing.

It might also be possible to solder the supply wire directly to here also?

Anybody try this?
Click to expand...


I think you're better off soldering the elctro bypass caps directly to the pins rather than the bottom of the board. The reason being that the bottom of the board is rather messy, and when resoldering, you'll most likely have the SMT bypass caps just fall off the board.

jkeny said:

I am waiting on delivery of two SIs and beforehand am checking out with active members on the most successful mods (this sort of thing happened with the Gainclone in its early activity and proved useful for all)
Click to expand...

I think that for detailed information on what various mods do, you may want to check out the audiocircle forums. Vinnie R's mods have been evaluated by a few folks over there.

I don't pretend to be able to describe the differences between my mods and a stock SI. I don't know if my speakers are even of a high enough resolution to notice a difference 😀

In the meantime, though, I'll keep playing with these little guys to see what I can come up with.
 
#253
I've assembled all the parts to build this thing (except the amp itself... lol) Anyways, I'm here looking at my Rat Shack 100k pot, and none of the terminals are labled. Which terminal is which? Also, I've got 8 terminals, and can only think of a use for 6.
 
#254
Usually they print the schematic for the pots on the back of the boxes they come in. If it's the standard 100k alps pot from Radioshack, I think the pinout is (looking from the front of it with the shaft pointed at you, left to right):

1 - In
2 - Out
3 - Ground

The 4th pin is probably a loudness tap, or it may have an integrated on/off switch. I've never seen an 8-pin potentiometer from Radioshack before, though.

The best way to verify this stuff is with a multimeter. If you have one handy, you can figure it out pretty quickly.

Good luck
 
#256
Hey guys, I ordered some parts I needed from parts express to finish modding one of my amps and ran into a bit of a problem. The 4uf Dayton poly caps I ordered for the inputs were way too BIG to fit in the case I bought. I guess I need to learn a little more about the metric system 🙁 .

Anyways, if anyone in the US has two suitable 2-4uf caps I can use for the inputs I would be more than happy to trade these for them.

If your intested you can reach me @ MEXXX37@yahoo.com.

Thanks in advance,

MEXXX
 
#257
MEXXX said:
Hey guys, I ordered some parts I needed from parts express to finish modding one of my amps and ran into a bit of a problem. The 4uf Dayton poly caps I ordered for the inputs were way too BIG to fit in the case I bought. I guess I need to learn a little more about the metric system 🙁 .

Anyways, if anyone in the US has two suitable 2-4uf caps I can use for the inputs I would be more than happy to trade these for them.

If your intested you can reach me @ MEXXX37@yahoo.com.

Thanks in advance,

MEXXX
Click to expand...


What's the maximum size of the caps that can fit in your case? I'm using some 2uF 100v poly's on mine.. They're about as tall as the stock electrolytic, and about as long as the board. They fit almost perfectly over the input pins (they're radial caps) and drop the other lead off right on the other edge of the board.

You could probably find these pretty easily. Maybe something like part# BD-1829-ND from digikey: http://dkc3.digikey.com/PDF/T051/0951.pdf
 
#258
MEXXX said:
Hey guys, I ordered some parts I needed from parts express to finish modding one of my amps and ran into a bit of a problem. The 4uf Dayton poly caps I ordered for the inputs were way too BIG to fit in the case I bought. I guess I need to learn a little more about the metric system 🙁 .

Anyways, if anyone in the US has two suitable 2-4uf caps I can use for the inputs I would be more than happy to trade these for them.

If your intested you can reach me @ MEXXX37@yahoo.com.

Thanks in advance,

MEXXX
Click to expand...

A 1 ufd cap may work if the resistors are let stock. Looking at a "stripped down'" 2024 evaluation board it uses 40K resistors where the SI uses 36K. The stripped down board has a 1 ufd cap compared to the 2.2 ufd in the normal evaluation board. The normal evaluation board has a 20K resistor in this position.
For caps, I have to stick with SM multilayer ceramics. The pads are miniscule, they would not support any size leaded cap. Doing like others, and shorting out the cap and removing the 10K shunt will work fine. But sonically it may not be an better.
The multilayer ceramics are nice caps. Remember how good the stock SI is from 200 hz up. The el cheapo 0.33 ufd ceramics are not hurting the mids or highs one bit.
If you can solder them in, I have plenty of 2.2 ufd Murata ceramics that are the exact same size as the stock. But working with parts this small is harder than it looks. In fact, it is a PITA. I can mail you four to try, four so a few can disapear. They are really small.

George
 
#259
George, Thank you for your generous offer for the smd's. I have already removed the stock caps and bridged the pads and to be honest I think I would fry those replacements trying to ge them on.

Motherone, the case im using is extremely small and theres not much room for anything bigger than the size of the supply cap, so I'm sure you can imagin how big my eyes got when I saw those huge dayton caps 😱 .

I would like to use at least 2uf caps, doesnt anyone make poly caps that have a lower voltage rating to cut down on size? I mean they only need to handle +-2v. If not, would it really be that bad to use a top shelf electrolytic like a black gate or panasonic?

Thank you guys for the responses and help,but I'm still scratchin my head on this one.

MEXXX
 
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