The tale of two subs - solid state Consumer puffery (rant and solution).
Oh , how the unclean public is now raked over the coals with utter solid state garbage.
My beloved POLK 10" sub failed after 2 years. (below 1) is the AMP. I laughed (and cursed)
when I saw IT (below 1). What a POS !!!~ 100W amp my ar$e !! No wonder it failed.
Design seems to be an op-amp driving a high beta to-220 EF2 , how nice of POLK to outsource
to cost cutting cheap manufacturers.
Rant # 2 - I bought a dayton sub 100 (10") for 20$ , which I knew was at least slightly defective.
It worked for 2 hours. (below 2) is it's amp. It is 2010 , at least they used TIP35/36 and REAL class
AB (simple complimentary IPS). This subs flaws were the "good cheers" 50VA trafo and leaky unknown
electolytics , "jacek"?? Why have a decent amp with a sub par power supply ??
Both subs have things in common.
- Bare minimum power supply with dubious capacitors.
- Using the amp plate as the heat sink and designing a integrated electronic
thermal shutdown into the control circuitry. I suppose it is easier to
use a few chips instead of a pound of aluminum for a proper heatsink.
- Ratings and use factoring are in the realm of "puffery". The units
can not handle normal use - let alone abuse !! They are definitly designed
to hit the local landfill in 2-3 years. AS IS most of what you buy these
days. I understand this , buy a sub every 3 years ... as you do your PC.
This is why I DIY. I found AMPS for 14$ on EBAY - Harbinger AP12's and 15's
have nice a "blameless" layout , simple/compact onboard amps.
(below 3) is what I got (link) Harbinger APS15 200W Power Amplifier PCB Board, NEW | eBay
Not a bad deal. I reverse engineered the Harbinger circuit.
The last two attachments are the amp and it's 20- 150hz response.
There are so many blown 10 -12" OEM subs out there , why not design
a simple blameless type circuit to be a drop-in replacement. The Harbinger
circuit , by the reviews of the other buyers of this (replacement) amp .... seems to last
20-25 years with road musicians .
I would prefer this to the "puffery" of the 3 year OEM SCAM!!!
An IRATE OS....
Features of the built-in amplifier - work in a confined space. He is also subject to vibration.
In the "good old days " of American manufacturing everything was built big-solid- heavy --lasted for decades .
Bumped into it you knocked yourself out ---now if you bump into anything manufactured "elsewhere " you would probably damage what you bumped into.
Now its outsourced and well your "rant " says it all .
My Sub is over 30 years old. A relay got sticky but other than that it's still good. Last hurrah of infinity when they were still ok.
Had a Paradigm PS1000 years ago. We used it for a New Year’s Eve party one year. After a few hours it developed a rattle instead of producing bass. Turned out the voice coil had become detached from the cone. The amplifier unit did survive though.
My homemade creations (x2) using xls10 drivers and BK Electronics plate amps have survived since 2009. These are tough and don’t mind being run hard for extended periods.
I consider a significant proportion of consumer hifi to be toys rather than serious equipment.
Household subwoofers are designed to work as part of a home theater (single explosions in a movie)))
I still maintain my “toy” comment though. Ever opened up an Arcam Alpha 7 amplifier?
I had a "brainfart" and hooked the trafo (below) wrong on one of
the Harbinger amps. I was going to recap these 2 amps anyway.
What I did is hook the trafo center tap to one of the AC inputs on the
bridge rectifier. I was testing for the +/- 55V - nothing !! All of a sudden
Both rail caps let out room filling smoke.
Electolytic "goo" spewed out all over the board and the 200VA Antek
trafo became warm.
I swapped the caps out from the other amp and this unit still worked !!!
So , here I did a full screwup and the amp still worked.
I am running this "smoked amp" on my sub now.
With the 4 new 4700uF/80V Nichicon 105C caps , both amps should be golden.
I was worried this amp would not be "anal" enough for me , but here is
the 100hz full power simulation. Under .01% should be good enough for LF.
I might save my (spare) second amp
for a real 12" DIYA sub build. The POLK is going to get a real amp -
I just ordered everything to build it's plate amp.
That looks like a real good EI trafo ... No "good cheers" alibaba POS.
But , look at the PS 1000 schema ( 2) - It is just tip35/36 driven by a CHIP.
Not what I would like for 500 - 1000$ subs.
Dayton audio makes what they call a SPA 250 (below 3). Ha ha , another chip driven Chinese wonder. all for 170USD ... damn.
I'm glad I DIYA ... I have a Fully discrete 2sc5200/sa1943 sub amp with
an Antek toroid.
Wow !! the BK BSBP 275 is a REAL - REAL amp !!! Toriod and a bloody EF3 class AB.
Like my Slewmasters !!! British still make real amps !! I'm impressed -
for about the same price as the Dayton.
Klipsch is garbage as well.
Same "grifter" TO-220 darlington BS as the POLK's. (below)
Why not at least bridged LM3886's like logitech ?? I would even prefer that.
I suppose one would need to go to the level of the SVS -pro to
get any thing that is not a toy. But , for 800$$ ???
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