K4 sound problem

[rockrailsnsnow]

Greetings,
I was helping a friend the other night with a new spectrum k4 with sound.  All he had available to test it was DC (analog).  Now, I was under the impression that the decoder was the OEM Tsunami such as is used in the On30 locos.  Is this correct?  When trying to run it, as I advanced the throttle (I was aware it would need a fairly high minimum voltage to begin to respond) All I got was a "whoop, whoop, whoop (not the whistle, or possible a short whistle) or "chirp, chirp chirp.."  Well, may be  "whoop, chirp, whoop, chirp..." but you get the idea.  Almost as if it would start up the sound sequence and then short out, and start again.  With careful checking and cleaning I have ruled out dirty track...in fact when I got brave and advanced the throttle to about 3/4 ( old MRC twin pack, NO pulse power) it finally ran OK, but without much speed control range or power.
I have not yet had the opportunity to bring the loco home and test on my DCC and tweak the programming, but wondered if anyone has experienced similar operation?
Bad power pack?  Bad decoder?  Or is this the best one can expect on DC (analog)?
Thanks,
Michael
State College, PA

[r0bert]

the mrc twin doesn't have enough power output for sound locos to operate propeerly.

[rockrailsnsnow]

That's what I suspected...was looking for confirmation of symptoms.
I'll have a chance to test and program the loco this weekend on my Digitrax DCC system and I also have a separate 4 amp DC (analog) to test with it.  I built the pack many years ago...variac, full wave bridge and filtered or conditioned 16VDC output(large capacitor).  We'll see if that doesn't boil the proverbial magic smoke :-)
Michael State College,
State College, PA