how about this amp

[AndrewT]

Hi,
build a preamp with buffered input and output.

 

[lineup]

Tip2955 Tip3055 Bd249 Bd250

if i use 3055 and 2955 instead of bd249 and bd250 do i have to change any other parts, or do i just solder these transistors instead?
how would it be the best to make volume control for this amp. i'm building two channels, and it would be nice to contro volume on both channels with just one knob (pot or whatever)
any advice?
cheers

An externally hosted image should be here but it was not working when we last tested it.

I think you can just solder them in.
Without any changes.
I think same pin configuration, BD249, BD250 and TIP3055, TIP2955.

Use this link to get PDF datasheet with description, data of any transistor / IC:
http://www.datasheetarchive.com/
you just search for those transistors


-------------------------------------------------
If you want to read more about such amplifier, note the
References
Ref. 1 "Audio Power Amplifier Design Handbook" by Douglas Self (ISBN 0-7506-2788-3)
Try to find it in a big, good library and study!

The Author Douglas Self homepage, with a very wellknown investigation paper:

Distortion In Power Amplifiers.
by Douglas Self
ABSTRACT.
The distortion produced by a typical solid-state Class-B power amplifier is shown to consist of eight mechanisms, all of which may co- exist and whose distortion products overlap to give a complex result. Methods for isolating each mechanism for study, and minimising its contribution, are given. If the avoidable distortions are designed out, Class-B amplifiers of unusually low distortion (Below 0.0005% at 1kHz, 0.003% at 10 kHz) may be designed as a matter of routine, and without significant extra cost. Such amplifiers define a distortion benchmark, and I have named them "Blameless" amplifiers.

http://www.dself.dsl.pipex.com/ampins/dipa/dipa.htm#R


lineup

 

[pudge667]

build a preamp with buffered input and output.

i was told it could be done using a "double pot", something like two pots, but the adjustment pin is on one axis for both pots... it seems simpler and cheaper? so i'd rather go for that solution
what preamp would you suggest just in case? any links plz?
cheers

 

[lineup]

what preamp would you suggest just in case?
any links plz?

ESP Project88 is a popular preAmp. Many here have built it.
It uses OP-Amplifiers in form of IC Chips.
It should be fairly easy to build even for unexperienced builders,
as it is well documented.
You can order ready made PCB for a low fair price.
This preamplifier also holds very good quality.

Designed by the website owner, Rod Elliott from Australia.

http://sound.westhost.com/site-map.htm

 

[pudge667]

ok, so im guessing this would be the complete schematic
http://img206.imageshack.us/my.php?image=preampyx5.gif
(on the site it's broken in tree parts, 1st gain, bal and vol control, 2nd gain)

this pot would be ok to use?
http://img529.imageshack.us/my.php?image=potlogny1.jpg (stereo version?)

i would order the pcb from the author, but it would cost me too much then, so i would rather build the pcb myself, does the layout affect the sound much?any advice on that?

those input selectors, what are those?
i guess i dont need them since this preamp will be operating from one sound source (my pc sound card),
will it be ok if i put my preamp and amp in the same casing, and to use transformer which powers the amp to power the preamp also? using the 7815 and 7915 regulators...
cheers

 

[lineup]

i would order the pcb from the author, but it would cost me too much then,
so i would rather build the pcb myself, does the layout affect the sound much?
any advice on that?

those input selectors, what are those?
i guess i dont need them since this preamp will be operating from one sound source (my pc sound card),
will it be ok if i put my preamp and amp in the same casing, and to use transformer which powers the amp to power the preamp also? using the 7815 and 7915 regulators...
cheers

There are guys that have made own layouts for PCB
for ESP Project 88
I am sure they would let have a copy of the layout
so you can make your own PCB.

Search forum for:
project88

Hope somebody reads this, too.
That can help us find those topics with Project88 PCB

Regards, lineup

 

[pudge667]

yea, i searched before posting, but i haven't found it... i'll try searching some more later...

could you answer this plz
is the schematic i posted link here complete and correct?
those input selectors, what are those?
i guess i dont need them since this preamp will be operating from one sound source (my pc sound card),
will it be ok if i put my preamp and amp in the same casing, and to use transformer which powers the amp to power the preamp also? using the 7815 and 7915 regulators...
cheers