Sunfire owners + ML ?

[akm3]

I know the Sunfire amps are popular here with the Martin Logan crowd.

The Sunfire amps have a feature where you can use a current output on the main speakers to give them a more 'tube like' sound. I've never actually heard from anyone what they though of these. How many folks use this feature? Can anyone describe how they think they sound?

I'm sure everyone who has ML's + Sunfire has at least TRIED it - what did you think? Did you leave it that way?

 

[gordonmenninger]

I have the sunfire Cinema Grand and have tried both outputs. I however really could not tell any big difference between the 2...

Sunfire amps are great though with the ML speakers for sure!

 

[eknuds01]

We have mixed results with those settings. I have a symphonic reference and this amp only has one set of outputs.

Some people say that can tell a slight difference, others not so much.

Overall Sunfire amps represent killer bang for the buck.
Erik

 

[Feltran]

I tried both, and I wasn't sure if I could tell a difference or not. Unfortunately, the way my system is set up it's difficult to get to the back of the amplifier and so it takes a few minutes to switch the cables around, which makes it tough to compare. Ultimately, I left it with the current output mostly because that's what Sunfire recommends for electrostatic speakers.

 

[wink]

I've had Sunfire amps with my ReQuests since '98 and have switched them back and forth periodically. I've always found the Current setting on the panel to be the best for the ReQuest. Current will give the panel a more laid back sound where the voltage output will give a brighter sound. On the woofer, voltage gives a tighter bass where the current will give a mushier bass. I've found the larger, more revealing panels will give you a more noticable difference.

Hope this helps.

Dan

 

[akm3]

ANOTHER QUESTION:

Is the Amplification in the for example Sunfire Ultimate Receiver II (7x200watts) identical to the amplification in the for example Sunfire Cinema Grand (5 or 7x200 watts?)

For the purposes of driving Logans, could the Receiver be a bargain buy compared to some of the amps only (the used market is strange...)

I don't care about having the latest DTS Master everything, my favorite audio mode is on my Lexicon MC-1 Logic7 from analog RCA inputs or digital two channel (or plain jane Dolby Digital 5.1) into Logic7.

-Allen

 

[JMAUSGP]

I have two Sunfire Amps, TGA 5400 and TGA 7400. I use the current outputs with both of my ML speaker systems. I found with the Summits that the preferred set-up at least for me was biwire with current output to the panels and voltage output to the woofers. This was outstanding and never ceased to amaze me. Then came the CLXs and I run current on them and voltage on the sources which are surround in a 5.1 system. In the big 7.2 HT system upstairs I run current to the Stylos and Stage and voltage to Frescos. Don't know if that really helps you, but when I tested the voltage and current outputs one set-up did seem to sound better connected to a panel and the voltage seemed to sound better with the woofer and surround sound modes. But hey, your mileage may very.

 

[JonFo]

I know the Sunfire amps are popular here with the Martin Logan crowd.

The Sunfire amps have a feature where you can use a current output on the main speakers to give them a more 'tube like' sound. I've never actually heard from anyone what they though of these. How many folks use this feature? Can anyone describe how they think they sound?

I'm sure everyone who has ML's + Sunfire has at least TRIED it - what did you think? Did you leave it that way?

/edit: This should have been in the Amplifier sub forum, I fear. I assume a moderator will move it for me, sorry to use up some of your time Tom!

Actually, this is generally relevant to all. Here's why:

The big difference between the two output styles on a Sunfire is resistance. The Current source features 1 Ohm resistance, voltage has essentially zero resistance.

Electrostats change their frequency response characteristics depending on the resistance of the input network.

Without getting into the vagaries of Rep and other EE stuff, it basically affects how the combination of ESL audio step-up transformer interacts with the panel.

The fundamental effect is that added resistance in the input causes a dip in the high-frequency response of the speaker.

So whether it’s a ‘special’ output type on an amp, or ‘special’ speaker wires (some esoteric wires have boxes that contain elements that add resistance and/or capacitance), these WILL affect the frequency response of the ESL.

I specifically tested this during my SL3XC build, and in this picture, I show the significant change in response between no resistance between amp and ESL, and adding 1 Ohm of resistance.

As you can see, pretty major drop off in high-frequency response from 5K on, and down by more than 5dB at 10KHz.
(note: the rise at 11KHz in this shot is due to absolutely no crossover components in the path before the ESL audio step-up transformer, usually there is some resistance (Rep) in the path that tames that peak).

 

[JonFo]

I recall being surprised when I first opened a Sunfire and found that the Current source output binding posts had one large 1 Ohm resistor linked to the Voltage source output. That’s it. No other ‘Magic’ required.

So actually, anyone can add a 40watt (or preferably 60Watt) resistor in the hot signal path between their amp and the Panel binding posts and get the same results as the Sunfire crowd gets from their Current source.

See, cheap mods are indeed available

 

[JonFo]

Now, as for how it sounds and what I prefer, I’ve tried both ways over the years.

But now, I use voltage source (no resistance) and let Audyssey correct the response.

Between that, and the room treatments, I find the results satisfactory.

But if your room is too ‘live’ and you have high-frequency ringing, then using the resistance to reduce HF response can be a more pleasing sound.

So by all means, experiment and see what works for you.

But in no case should Current source be used on dynamic drivers (woofers), it totally screws up their response. So bi-wire (or bi-amp) if you are going to do this.

 

[JohnA]

...As you can see, pretty major drop off in high-frequency response from 5K on, and down by more than 5dB at 10KHz.
...

Interesting experiment, quite useful.
Thanks JonFo, once again:bowdown:

 

[tsmooth]

But in no case should Current source be used on dynamic drivers (woofers), it totally screws up their response. So bi-wire (or bi-amp) if you are going to do this.

I currently have the Sunfire Cinema Grand with the current source going to the panel and the voltage source going to the woofer. For me the change is night and day, maybe due to the non-powered woofer section of the Vista. I spent almost a whole day going back and forth on the same music and really trying to hear the difference. With the current source, the panel sound was outstanding but the woofer had little attack. The voltage source brought back the low end but the panel lost a bit of the ML magic. That led me to connect the current source to the panel and the voltage source to the woofer. Being able to use both has really livened up my Vistas.