|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
64.47.232.1
In Reply to: RE: 6550/KT88 suggestions for McIntosh MC60's posted by Jim McShane on August 21, 2014 at 09:52:43
yeah, i've been told i wouldn't hear the 10 watts.
question for you though... i thought MC60's put out close to 65-70wpc... is 45wpc or 55wpc cause for concern?
my tech (arden allen) replaced the usual audio couplers and installed new cans. he DID NOT "over-cap" the power supply. still the stock uF. would adding more capacitance beef up output or not really?
i also believe he gave maximum output based on McIntosh's stated distortion limits. so, perhaps when people say MC60s put out close to 70wpc, they are pushing them past the company's stated distortion figures?
i'm running the amps with Yamaha NS-1000M monitors and a powered REL Q100 sub. been the same core system for about 7 years. so i have a pretty good feeling about what the system can do. and it USUALLY rocks like there's no tomorrow. it seems like it's hitting a "rev limiter" now ;-)
Regards,
Robby
Follow Ups:
Robby,
His measurement may have been made under more stringent conditions than the factory spec. Or the tubes themselves were at fault. The factory rating is 60 watts, it's possible others weren't so careful about how they measured the power out. There are a lot of ways to look at the output and find it is higher - drive the amp to higher distortion levels, restrict the power measurement to a mid band frequency like 1KHz, or measure just one channel at a time, etc. From the sound of it, I think your tech is closer than the other measurements you're aware of.
Using larger amounts of capacitance has relatively small effects on RMS (continuous) power, but it does improve the amp's peak power performance which I maintain is every bit as or even more important than the RMS power. For instance, a stock Citation II has a peak power rating of 130 watts/channel. After Don or I get done completely redoing one we see in excess of 150 watts per channel peak power, probably about 180 or so is the actual. So there's where it comes into play.
The KT88 Genalex produce full output in the Deuce as long as they are healthy and the driver tubes are also in good shape.
So get a quad of Genalex KT88s, be sure the driver tubes are healthy - and enjoy that FINE amp!!
awesome info Jim!
the driver tubes were NOS american tubes from a few years ago. they sounded better to my ears than my decent testing smooth plate telefunkens.
just as my then new CED 6550's sounded better than my good testing tungsol 6550's.
the rectifiers were good testers from a friend. they are different than the ones which were in the amps when they were gone through.
i'm assuming as rectifiers age, power drops too?
would you buy new russian 5U4GB's or stick with good testing american ones?
Robby
What Eli Duttman said is good advice - the EH are quite good, the GEs are a very good tube and a bargain compared to RCA.
Some rectifiers drop more voltage than others. More voltage drop = lower B+ (supply) voltage = less power.
The current production EH 5U4GB is a good tube. All other 5U4 variants made in China and Russia are junk.
JMO, look for NOS GE 5U4GB stock priced competetively with current production EH tubes. NOS RCA and TungSol 5U4GB stock may be somewhat better, but the price premium is (IMO) too high.
Eli D.
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: