Need a power a 40Watt RMS Sub...

[Maples]

Alright I got this additional subwoofer today - a Roadmaster RSW80 - the online manual said it's 40WattRMS (200peak) so I need an amp for it. I've never built an amp before so I need one with PCBs available that can hit around 40Watts into a 8Ohm load.

Full kits would be cool too, since I am new to this game and haven't engineered my own electronic components. I was going to do an ESP sound project but those require one to locate the correct components on their own which I have gotten frustrated doing in the past so I want to see if I can avoid that this time. Then I was thinking about going with a full ia352 kit from AMPS Lab but they're across seas, shipping is expensive and slow.

What do you suggest I do?

[sreten]

bridge this ?

http://www.apexjr.com/D25Sub.html


sreten.

[destroyer X]

Since 9 years old i am beeing happy assembling and listening amplifiers trying to find perfection (do not exist).

The ones i send to laboratories and showed me perfection was all of them the worst sound.

Good Sound is class A, low powered as Jlh.

This one i show you is a very old amplifier, made in the seventies, today the topology is already been used, Elliot P3A made it first i think, Sony, Kenwood and others go into this thopology and stayed with this kind of schematic for 10 years, you can see professional units for Guittar and Bass using it, as Cube models and more 20 or 30 brands.

The sound, in bass, is impressive.... all house shackes.... but is not precise as P3A or P3B from Mr. Elliot, and some others using darlington that seems to be better (people say darlington no good!).

My personal opinnion, despite of being a little bit worst in scope, and distortion analisys, and simulators, in our ears it is wonderfull.... can use transistors you like, respecting voltage of around 100 volts.... output units around 10 amperes to be guaranteed, a 60 watts driver, and some BC model, as 557, or other respecting voltage.... 556 or 557 (in pnp or npn, i do not remember).... good to increase input condenser... also put 220 uF together the emitter driver resistor, parallell with this emitter resistor.

How it sounds.... imprecise..... wonderfull!..... when the bass is heard in an other amplifier as boom.... this one makes booooooom...longest bass, uncontroled, awfull to measurements!.... P3A is better related to measurements!...but i prefer this unit...personal taste.

If you want, try it... easy to construct, 1 hour maximum and it will be working.... every transistor will be fine... good sound transistor exists....but i am already trying to find them (hahaha)... bad sound units, i found 2SC2922 and his complementary awfull.... good warm sound 2N3055..... all personal...not guaranteed results.... money back not guaranteed! (smile)... i am not hi level knowledge, also not God, but i cry when good sound touch my ears... this way.... touching my heart may be good. Jlh is not more listened...because i cry too much.... wife said.... do not use it anymore... too much good, can kill you with emotions.

No troubles man cry here.... real man cry.. others real man do not do that... it depends where you born and your culture.

We wash dishes too, and we took care of babies too and woman gave the order too... related house, they are the one that do not have the last word.... we have it.... always YES!

Power, mine can not give more 35 clean watts into 8 ohm speakers.... real world sittuation is really very different from my scope and whole measurements..... something alike "standing wave ratio" a problems you face when using Radio transmitter appear in audio in a different way.....counter electro motion forces, voltage, and current return, phase problems... and eletrons unhappy!... do not know....but you can feel those problems sometimes, some speakers....amplifier can go to 70 Watts...but bad sound..... related to P3A a little different.

In a resistor, also P3A, This one and many others show better figures..... but real world is sometimes different.

Maybe someone, has knowledge enougth to improve them to reach a clean (to ears) sound gaving whole power.

You wanted 30 watts or 40 watts.... exactly you gonna have it clean!.... chips are wonderfull....but when they say can go to 100 watts.... expect 20 percent real watts undistorted!

Carlos

[destroyer X]

This Stk is a very good chip... i use it in many equipments here... they came as original amplifier for many brands.

STK 4141
STK4142
STK4142 II

And many others. Sreten unit real produces clear sound, also some uncontrolled bass that i like, and 25 real watts i never measured in the reallity, over the speakers is something alike 18 Watts undistorted....but this different makes no change... you have to double power to perceive this is stronger!

Very good idea too...but glue all pins.... small shorts when measurements and bye bye Chip.... whole circuit died.

And them we oppen the case and cry a lot.... wonderfull inside... they must put a glass and a lamp.... will sale millions of units for us!


Carlos

[destroyer X]

This internal circuit is really almost equal, the same, related the circuit i am sending to you.... Mr Elliot can became a very rich man if he open a law process.... you can see P3A and many others... as this one i show you inside.... thopology is the same.... if voltage also the same.... calculating, result will be almost the same values.... can not scape!

They reduce chip size in 65 percent... and put a thopology that a lot of people likes.... cheap, easy, guaranteed and a lot of models all them the same inside... some with bigger output units.... others with other resistance values..... models with power from 20 to 100 rms each channell.

I suppose is made to compete with LM3885... also the exploder one (once explode here) LM3886 and some others.

But no protection against SOA, over this an that, not invertion protection and no short protection...unprotected, just because protection sometimes makes a big mass with the sound.

Carlos

[destroyer X]

Look and compare.

Regards,

Carlos

[destroyer X]

Here's the image... sorry..... 52 years is some trouble...mistakes are easy to happens....but long time experience.... and a long time analysis, made us , old ones, more precise in long time studies results.

Carlos

[destroyer X]

Old guy.... repeating this always.... really... double click, message goes and attachment stays.

Carlos

[Maples]

I read the page a few times but I don't understand how to bridge this amp you reccomended sreten :-/

[sreten]

Originally posted by Maples
I read the page a few times but I don't understand how to bridge this amp you reccomended sreten :-/

Well I presume you need to buy the amp and
get full details for it to make perfect sense.

TBH although A & B are the complementary outputs
the "cuts" on the board don't make any sense to me,
why not simply use connections 2 & 5.

Ahh.... now I see it the cuts are sends to 2 & 5
of the additional circuit and A & B are returns.

sreten.