Apogee Scintilla Power
Several excellent options not previously mentioned: Roger Sanders Magnatech, or his earlier Innersound Electrostatic amplifier or one of the Coda amplifiers. Any of these can dump very very large quantities of very high quality current into your apogees without breaking a sweat, at very (IMHO) reasonable prices. |
westerlmThe Apogee Scintilla are only 79db so you’ll need "at least" 150watt/8ohm to get them going. But they go down to 0.9ohm right through the lower bass and also 1.2ohm around 1-2khz in the upper midrange. http://www.lippaudio.org/old/MySystems/Scintilla/impedance.html So this says, that the amp should come "close" to doubling it’s wattage for each halving of impedance from 8ohms right down to 2ohms. Look at big amps with bi-polar (bjt) output stages. eg Krell KSA250 or similar ect ect ect Anything else "may sound OK" but will be a compromise, especially tubes, and won’t get the best from them. EG: 150w/8ohm 300w/4ohm 600w/2ohm Cheers George |
Great feedback. Confirmation as well as some new thoughts. For my Apogee Duetta Signatures the Mc MC7270 (with autoformer) works pretty well but my CJ MF2500a (bipolar) is fantastic. Using it in a bi-wire configuration is most coherent. Using it with my CJ Premier 11a on high end in gain matched (26db), passive bi-amp set up is also VERY good with tube magic on the MRTW ribbons just a bit lagging with some attack transients (ie.guitar strings, piano, etc.). For my Apogee Scintilla's the Mcintosh MC7270 runs out of gas. It can definitely handle the load fine with autoformers. The CJ MF2500a works well on the high end MRTW ribbons but does heat up. The CJ Premier 11a cannot play anywhere with the, Scintillas. The Sunfire 300's with Scintilla mod speak for themselves. I have recently picked up a Plinius SA250 MkIV that is being refreshed and turned into a Reference. Has proven to operate steady at 1ohm load handling scintilla dips down to .85ohms with high power and current. Operates in class A and class AB for some flexibility and energy savings. We shall see how it goes. Plinius, will be done in a month but Scintilla rework is a few months out for the ultimate test. When that happens I will get some feedback out for anyone that may be interested. Thanks again for all the feedback. |
westerlm OPThis "could" be the one for you, Plinius usually use mosfet in their output which sag not increase into 2ohms But it "seems" for this SA250 they may have used bi-polar (bjt) in this model, but! not complimentary npn/pnp but just npn for top and bottom rails. Maybe they meant N channel only top and bottom (not npn) and it is Mosfet, then that would explain this comment when tested into 2ohms " the amplifier is clearly less comfortable with the 2 ohm load" which means not so good with your Apogee’s 0.9ohm loading Still it can give a good wattage increase for every halving of impedance 320W into 8 ohms 480W into 4 ohms 740W into 2 ohms (single channel driven) Cheers George |
