Sunfire 300x2 VS B&K EX-442

VSAT88

About once a year I get a wild hair up my @55 to buy another amplifier, like I need another amplifier. Any Sunfire users here listened to the B&K 442 (Toshiba mosfet) or had both to compare. Always wanted to try a Sunfire for some reason. 800.00 or so is a bit of money just to find out what one sounds like though. Still running the SDA2'bs btw.

honestaquarian

The Sunfire puts out a hundred watts per channel more than the B & K.
That is only about 1 decibel of extra total output at 8 ohms I believe. Both amps are excellent. The Sunfire however is a true voltage source-meaning it will double its output with each halving of the impedance. I own a Sunfire Cinema Grand Signature which I had lusted after for more than a decade before I got my greasy grabbers 🖐🏾🖐🏾 on one. I have heard B & K amps and have always been impressed with them. Haven’t heard one in years though.
The Sunfire has one of the first successful commercial implementations of a continuous signal tracking power supply. Even before class D digital amps came out.
Meaning it is extremely efficient in that it takes more than 80% of the power from the wall and turns it into actual output at the speaker terminals no matter the signal large or small. Hence the signal tracking power supply.

erniejade

Both sound different from each other. Cones down to personal preference I feel the B&K would last longer before a recap. If you have a speaker that is difficult to drive AND the sunfure has been recapped, the sunfure is the way to go. If your speaker is a normal load, I would say B&K.


Now if it was the sunfire sig II, that's a different story.

honestaquarian

I bought mine used on eBay about a decade ago. It hasn’t been recapped and when I did the upgrades in my SRS 3.1’s and the impedance dropped, the amp never flinched. I WOULD like to recap it someday though. Same goes for all of my old amps.

VSAT88

I have pulled the amp boards in the 442 and put new electro's in as well as thermal insulators. It sounds great, always has. Still thinking on that Sunfire though. Thanks for your comments.

daddyjt

Having had quite a bit of experience with all things Carver (SS, not tube), I will tell you that Sunfire is not a good choice for difficult, low impedance loads. Low impedance needs a current source, not a voltage source. I occasionally run Kappa 9 speakers, and the only Carver/Sunfire SS amp that can handle them at full volume is the Silver 7t/9t mono blocks. That said, I have not had the opportunity to try them with Lightstar. The Sunfire is a wonderful amp, and does a lot of things really well - but running extremely low impedance loads isn’t one of them.

A good friend of mine and highly qualified tech summed it up well: the Sunfire will sting like a bee, but it won’t drill for oil.

As always, YMMV

honestaquarian

@daddyjt what happened when you ran a Sunfire into the Kappa's?
Which model did you use?
The lighstar and sunfire are largely the same amp power supply -wise

VSAT88

My mains are modded Polk SDA 2B's @ 6 ohms and Snell E III's at 8 ohms.

VSAT88

Of course not at the same time...^

daddyjt

I have run the Kappas with a 300x2 and a 400x5. The 300x2 has difficulty controlling the low end, which is not surprising considering the <1Ω dips in the bass range of the Kappa 9. I ran the 400x5 with 2ch in stereo (400w per speaker), and bi-amp, using 4 channels of the amp. In the 2ch mode, it was passable, but there was still some slop in the bass. Using 4ch of the amp was terrible - midrange became “gritty” and lost imaging, and bass was still not right, and the amp went into thermal shutdown. I don’t know quite why, as I went in thinking that the bi-amp would work well. I suppose it goes back to the fact that the power supply can only do so much. Incidentally, that’s why I think the Silver 9t mono blocks do so well - separate power supplies.

I do not want to give the wrong impression here - you will have difficulty finding a bigger fan of Bob’s designs than me - I tend to keep that fact relatively quiet here, as I am aware there is little love for Carver gear on this forum (which is fine - we all have our preferences). The Sunfire will drive any Polk speaker all day, any day. In fact, there are probably less than a dozen speakers in the world that it would have a hard time with.

My only other gripe with Sunfire is that they are a beast to service - the chassis are densely packed, and the double-sided PCBS are a challenge to de-solder old components. But that should not be a consideration for the function/sound of the amps.

Would I buy another Sunfire for the right price? Absolutely.

honestaquarian

@daddyjt Thanks for sharing. You are absolutely right about the whole Carver thing on this forum. I would challenge you when you say "you will have difficulty finding a bigger fan of Bob's designs than me"
I AM😉😜
I have the Sunfire Cinema Grand Signature 400x5 btw.
I also have a Carver TFM-45 and a Carver M-400a. All in use right now in my home theater system driving all Polks. I also have a TFM-25 in use in the bedroom system right now.

VSAT88

All the Carver I have amounts to a Cube and A PL 700.I have used the cube amp in my shop for years without any problem and it will drive the crap outta any speakers I ever put in there. In fact I feel like I need be careful with the volume control. Had a PL 400 l completely rebuilt to original with help from the guys a Phoenix ( plus new protect circuit ) but sold it to a friend. May still get this Sunfire. I like it. I don't worry too much about talking about Carver here or anywhere else. I am asking people who have had experience with Carver about Carver. If the person has negative high bias that's OK too. We all have had our experience.

honestaquarian

Which cube do you have?
The original M-400?
The second generation M-400a?
Or the third and last gen M-400t?
I've had all three starting with the last one and working my way backwards.

VSAT88

Actually have three. The M-400 x 2 and a 400 a . Two are in rebuild status. The M-400 sounds great in the shop.

honestaquarian

I bought two M-400t's (the gray/pewter colored ones) back in 1988 to drive my SDA-1B's in bridge mode. Only to find out that was a no no. I had been getting all kinds of confusing and conflicting information about the M-400t's having trouble with Polk SDA's, but I couldn't get anything concrete or that made sense to me. So I wrote a letter to Bob Carver and much to my surprise he responded! I still have that letter to this day.
He told me that only one channel was common grounded and showed me a way to be able to use both amps without having to bridge them by bootstrapping them together using only one channel of each amp. The design of the amps allowed them to essentially "borrow" unused power from the other channel that wasn't being used. Thereby increasing output power to something like 325-350 watts per channel.

It worked!

Howevah when I cranked the volume the amps would go into that unique Carver clipping-where they don't clip the top of the waveform. Instead they take a chunk out of the side of it. I've seen it on an oscilloscope, there is a kind of V shape dent in the side of a sinewave. When that happens you hear loud snapping/popping noises. Being young and impulsive I wound up selling them and realized years later what a stupid mistake that was. Then in 1994 I got a used M-400a that I am still using to this day. I bought a used M-400 around 1997 or 98 and that only lasted about a year and was torched accidentally by the DC fire department.

erniejade

I tried running a set of original carver amazing on a Carver cube. Shut it down and smoked it. Then i picked up a 300x2. Then the 625x2 sig II. The 300 vs the sig Ii wasn't even in the same ballpark. The sound quality of the sig II was a huge step up in my opinion.

honestaquarian

Bob Carver created the TFM series of amps BECAUSE of the Amazings. He realized he created a monster with them and didn't even have amps which had the thermal capacity to drive them. I drove a pair of bridged M-1.0t amps into clipping on a pair of original Amazings. Those things put out 1,000 watts in bridged mode!

pitdogg2

I've always been a Carver fan. They suited my need for a couple of decades. I also called Carver one day to complain about service on my C16 preamp, Bob picked up the phone and we talked and he sent a next day air package to my house to next day air my pre back to him to personally work on it two days later my pre was back and work wonderful for another decade and a half before needing work again.

honestaquarian

Ah yes the C-16!
I had a C-19 tube preamp once which is kinda what started me down the home theater rabbit hole. I was using it to drive a pair of bridged TFM-55 amps and had a Dynaco QD-2 Hafler/Dynaquad matrix surround extractor. At first it was a great system until I started having issues with the preamp and then the amps. The system was down for a year and then I finally gave in and got a used Parasound surround preamp. Wound up selling the C-19, buying another TFM-45 and fixing the others.

VSAT88

The M 400 in my shop is an a version. I just went and looked and noticed that. It is the same color and all as yours @honestaquarian . My bottom two LED's light up when it is powered on. The top five have never lit. Don't bother me at all in fact I am not even sure what the indicators mean. It sounds just fine and has been re capped so I am happy with it.

honestaquarian

Those are power output meters. However in order to get them dancing ya gotta really crank the volume and then watch them go!!
They are not like regular LED meters like you would find on a cassette deck for example where the bottom ones stay lit and the dance is only at the top.
You have to see it to understand how unique it is and it’s fun to watch.
Again ya gotta SERIOUSLY CRANK THE VOLUME in order to see it happen!

VSAT88

That ought to prove one thing. I never really crank it up. It gets plenty loud to me as is but I will have to try that one day.

honestaquarian

Put some plugs in your ear holes and have some fun!

daddyjt

VSAT88 wrote: »

Actually have three. The M-400 x 2 and a 400 a . Two are in rebuild status. The M-400 sounds great in the shop.

You possess the patience of Job if you are willing to work on the cube amps, lol!

VSAT88

Got a Kenwood KR-9600 on the bench right now... Talk about fun. I am not a tech. Just love working on them. I did not do the re cap on the M 400 I have though. I have one taken down now though. I need to order parts for it but been had other stuff on my mind. The 9600, a Kenwood C2 and a Kenwood C1 are taking priority as of now. Who knows what is next !

honestaquarian

https://youtu.be/-N31CRS7mpI

In the last few minutes of this video you will see a demonstration of the power meters. This is the second of two videos that he made on this amp. It was blown up and he rebuilt it.

VSAT88

I saw the 1st half of that one day not too long ago. Never watched the second half. Thanks, that looks cool as all get out. Mine must be broken. No matter how hard I jam it only the two bottom ones light up.

VSAT88

BTW, the 9600 turned out really good. Almost no offset, sounds super nice. All new caps on the amp boards, transistors too. New filter caps as well as built the power supply board. I can see why folks say they sound so good after a good going over...They do.

VSAT88

Ha, Ha..Forgot one more thing. I decided not to buy the Sunfire amp. Not right away anyhow. I decided that being I have already went thru the amp boards in my B&K I am going to rebuild the power supply on that one and see how it sounds after. Then, who knows. I still have a PS Audio 200C to finish up..

cuda12

That sunfire 300 should have came close to driving the Kappas but would have really needed the apogee scintilla mod, I have the 600 signatures and they drive my 2 ohm new style ribbons to crazy levels. I used to have the 300 but I never had it with the new 2 ohm ribbons.

honestaquarian

@cuda12
Welcome to the forum.
What is the Apogee Scintilla mod for the Sunfire?