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odd ball pramp question (mini amp not loud enough -whoda thunk!)

Started by petey twofinger, March 28, 2012, 03:05:55 AM

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petey twofinger

i built a battery powered minamp using some car speakers , a sure tda 2024 15 watt tripath stereo amp . the "front end" is a korg pandora x5 . anyway i am a little surprised that it isn't as loud as i had imagined it would be . looking around i saw about impedance mismatching when you plug an ipod into a stereo . this lead me to ponder that perhaps if i had some sort of boost circuit between the pandora and the tda tripath amp it would perform much better (loud) .

i have monkeyed around and read a little about boosters so i ended up building an oorman mosfet bost . i also saw on beavis hifi he had a jfet circuit for ipod to stereo . anyone famaliar with this conundrum ?  any recommendations ? ideally it would be quiet , provide the right range of gain (i know) not use too much power , and sound great (hah) , i am impressed with the pandora sound quality , it is pretty loud but i really think something in between will set this thing off like a rocket . i have some mini speakers i could chop that circuit in , also a circuit from some pc speakers that has a headphone jack , but thats in my cbg ....

as far as powering goes the amp has a 12 volt sla , and internal ac power supplies/dc regulators for 4.5 volts , 9 , and 12 . so i can run it ac or dc . it also powers the sustainer in my fernandes thru a custom hacked mic cable that carries 9 volts to the guitar .

i can not access the bevis hifi site , curious if someone had that page (jfet ipod pre) or schmo saved , a vero would be a dream come true  ! another option may be a mini headphone amp (ipod booster) , i have seen those too , but not sure . realize this is an oddball , but figured it wouldn't hurt to ask . (sorry i am not an EE , i am a goof) i just figured maybe someone had been thru something similar and could maybe point me in the right direction so i can save time , being disabled with this chronic back pain sucks . it kinda makes me want to cut the tinker time down if i can .

i can post more info about the pandora and the actual amp if needed , i am uploading a huge video to  YT right now so bandwidth is tight ....

should i try and measure the output of the pandora and then see if i can get specs for the tripath amp to see how much headroom i have ?

thanks in advance for any feedback , ideas , or insults directed towards my lethargy and (lack of) intelligence !!

J M Fahey


You mention using it for an ipod, are you only using this for an ipod or also guitar use?  If guitar use, get some real guitar speakers like Juan suggested.  If ipod, get some cheap hifi speakers from jameco.com or partsexpress.com, get the highest SPL rating you can afford.
Life is what you make it.
Still rockin' the Dean Markley K-20X

petey twofinger


the front end on this amp is a korg pandora x5 .

from what i have read this unit does sound much better when run thru full range speakers . guitar amps , especially tube amps or stacks it doesnt sound so hot . i did try several speakers including an ancient guitar speaker before settling on the full range 6.5 w/ tweeters .

i was hoping someone had saved the schemo from beavis hifi site for the jfet ipod preamp . that particular site is doww , beavis audio research is up ...

so i am looking for something that will handle the out put of the korg pandora x5 but boost it up to say 10x gain ? not sure ...

thanks !

J M Fahey

Quotefull range 6.5 w/ tweeters
may sound good but not loud.
Hi Fi speakers trade efficiency for flat sound, instrument ones do the opposite.
Anyway 15W RMS (forget PMPO rating) won't bring the house down anyway.
Just for testing: connect your multimeter to speaker leads , set on 20VAC and play a couple full chords; what do you measure?