Another Amp / Impedance / Bi-amp question

[Mark F]

Just purchased a pair of SL3 speakers locally that sound perfect but have holes in the panels where cats used them for a jungle gym. The price reflected panel damage so everyone is happy.

Three amp are under consideration to drive them:
1. Used Sunfire Symphonic Reference Load Invariant amp 300W x 2 at 8 ohm but only two channel (no bi-amping). This amp is 600W x 2 at 4 ohm and 1200W x 2 at 2 ohm. It is also stable into 1 ohm for short periods.
2. Used Sunfire Cinema Grand 200W x 5 at 8 ohm (400W x 5 at 4 ohm, not rated below 4 ohm). Because this amp is 5 channel, it would be wired using 4 channels to bi-amp L & R panels and woofers independently.
3. Enlightened Audio Designs PM500 100W x 5 at 8 ohm, (150W x 5 at 4 ohm, not rated below 4 ohm). Again, 4 channels would be use to bi-amp L & R panels and woofers. While this amp is lowest power, EAD amps are very musical and I own a PM1000 used in another system.

All these amps are available used for $600 - $800 which is my mental price point.

Suppose the real question is whether bi-amping improves fidelity more or if its better to use a single amp capable of driving very low impedance loads? Thoughts?

 

[Robert D]

I use a single two channel amp to drive my Prodigy speakers and it sounds great. I'd buy the 1st choice, the 2 channel Sunfire.
I use an Aragon 2 channel amp that I bought new.

 

[Mark F]

I use a single two channel amp to drive my Prodigy speakers and it sounds great. I'd buy the 1st choice, the 2 channel Sunfire.
I use an Aragon 2 channel amp that I bought new.

Hi Robert,

Thx for the quick reply. Which aragon amp do you have? Used 2004s are in the right price range but only 100wpc. Used 4004s are above my price point.

 

[Robert D]

Hi Robert,

Thx for the quick reply. Which aragon amp do you have? Used 2004s are in the right price range but only 100wpc. Used 4004s are above my price point.

It's a 8008. 200 wpc at 8 ohm and 400 woc at 4 ohm. If that 2 channel Sunfire is in your price range I'd just get that since it's in your price range. There are quite a few members on here using their amps and they love them. I owned a Carver subwoofer that was really good. I'm pretty sure Sunfire is what Carver became.

 

[Robert D]

Hi Robert,

Thx for the quick reply. Which aragon amp do you have? Used 2004s are in the right price range but only 100wpc. Used 4004s are above my price point.

Also, that Sunfire doubles it's power going fron 8 to 4 ohm. That's what you need with electrostats.

 

[ttocs]

Get the amp that has the least amount of difficulty with low impedance. Above all else, this is a more audible difference than biamping, which I've done in the past btw so I know when it can make a difference and when it won't. But the small difference biamping can make pales in comparison to what a very capable amp can do without biamping.

So, #1 is my #1 choice.

 

[Jazzman53]

$600-$800 is a good price for the Sunfire 300x2. Those amps have headroom to burn and no problem driving the ESLs.

I've run my 6-channel homebuilt ESLs with a Sunfire 400 x 7 and barely had to crack the throttle.

 

[R.I.P]

My understanding biamping works best when both amplifiers are identical or at least have similar gain. If one amp does not provide enough amperes to optimal drive loudspeakers, then another identical map is required. Therefore, used together they adequately drive or if they match the loudspeaker optimally drive speakers.

Sunfire symphonic reference has more than adequate power. Hope also optimal sonic match. I would recommend this choice over bi-amping.

Hope your unit is defect free.

Mentioned in martin logan manual, punctures in mylar does not cause deterioration in sonics. I guess if a patch or area of mylar is missing it may affect the sonics in proportion to the missing area.

 

[Mark F]

Wow, thanks for all the thoughtful replies! Given the many threads suggesting bi-wiring and bi-amping, the feedback to go with a single amp suitable for low impedance use is a little surprising.

Its an easy decision to support given Carver Symphonic Reference Amps are readily available and closer to the $600 price point. I have zero experience with Sunfire amps but own a legacy Carver M-500t purchased new in 1986 which served me faithfully for 35 years before failure.

Now to chase down a Carver 300x2 with some music left in it. Thanks again for all the quick and consistent feedback!

 

[Mark F]

Oh yea, regarding the cat claw punctures in the mylar. Is it possible they improved the sonic signature? We dialed up the new-to-me SL3s complete with perforations and they absolutely rock. Played a wide variety of music at concert levels (using my EAD PM1000 amp) and I'm pretty sure the punctures didn't degrade the sound.

 

[Robert D]

When were the speakers produced, and are those the original panels? Usually panels are worn out withing 20 years. I replaced my Prodigy panels when they were about 20 years old and the improvement is incredible. The old panels dont put out near the volume and lose a lof of high frequency. Perhaps your's have newer panels. ML still makes them, and you could get new panels to make them really sound great.
You can use the speaker serial number decoder on here to help you figure out their age. The speakers should have a serial number, and the panels then have their own #. There is a thread on here that has the decoder. I think its a sticky.

 

[Mark F]

Thanks for the suggestion to use decoder ring to get speaker age. These SL3s are from March 2000.

I withheld some information. We also own a pair of Sequel II's purchased new which are operating right next to the SL3s. Both speaker pairs have original panels and both sound good to my ear. The SL3s are a little nicer on the low end but that's likely the difference in crossover design. Both have warm and neutral mids and highs. Both image like magic. Of course, this is all based on my hearing which is subjective.

To your point, it would be better to compare the SL3s to something with new panels, not 25 year old Sequels IIs.

Wish there was another way to confirm panels do not have diminished output or range without spending $1,440 on fresh panels. I've gotten daily use from our sequels so wouldn't feel bad investing as we have gotten our money's worth from them for sure. It's just hard to justify the cost when current panels are pleasing to my (possibly compromised) ears.

 

[Robert D]

Thanks for the suggestion to use decoder ring to get speaker age. These SL3s are from March 2000.

I withheld some information. We also own a pair of Sequel II's purchased new which are operating right next to the SL3s. Both speaker pairs have original panels and both sound good to my ear. The SL3s are a little nicer on the low end but that's likely the difference in crossover design. Both have warm and neutral mids and highs. Both image like magic. Of course, this is all based on my hearing which is subjective.

To your point, it would be better to compare the SL3s to something with new panels, not 25 year old Sequels IIs.

Wish there was another way to confirm panels do not have diminished output or range without spending $1,440 on fresh panels. I've gotten daily use from our sequels so wouldn't feel bad investing as we have gotten our money's worth from them for sure. It's just hard to justify the cost when current panels are pleasing to my (possibly compromised) ears.

So you found the serial numbers for both the panels and the speaker cabinet, because they have their own. I had to look real close to see the serial number on my panels. Its kinda small.

If the panels are original and 24 years old, they have most likely lost quite a bit of performance. When I had my old Prodigy speaker panels hooked up to my Marantz receiver and ran Audyssey, it had to crank up the level on the front channels to max. Thats like +12 db if I remember right. If you have your's hooked up to something like that, youll know. Mine still sounded good as long as the Audyssey filter was running. If I turned it off, the speakers sounded muffled and lacked treble a lot. They sounded terrible.

 

[thomasmasi]

Just purchased a pair of SL3 speakers locally that sound perfect but have holes in the panels where cats used them for a jungle gym. The price reflected panel damage so everyone is happy.

Three amp are under consideration to drive them:
1. Used Sunfire Symphonic Reference Load Invariant amp 300W x 2 at 8 ohm but only two channel (no bi-amping). This amp is 600W x 2 at 4 ohm and 1200W x 2 at 2 ohm. It is also stable into 1 ohm for short periods.
2. Used Sunfire Cinema Grand 200W x 5 at 8 ohm (400W x 5 at 4 ohm, not rated below 4 ohm). Because this amp is 5 channel, it would be wired using 4 channels to bi-amp L & R panels and woofers independently.
3. Enlightened Audio Designs PM500 100W x 5 at 8 ohm, (150W x 5 at 4 ohm, not rated below 4 ohm). Again, 4 channels would be use to bi-amp L & R panels and woofers. While this amp is lowest power, EAD amps are very musical and I own a PM1000 used in another system.

All these amps are available used for $600 - $800 which is my mental price point.

Suppose the real question is whether bi-amping improves fidelity more or if its better to use a single amp capable of driving very low impedance loads? Thoughts?

Hello Mark, I have owned monolith iii's, Sequel 2's which were my first martin logan speakers 30 or so years ago plus others models. I presently have a pair of Prodigy's which I just replaced the panels that are driven by 2 sunfire signature 600 biamped. As for your questions definitely try biamping using the current output for your panels and the voltage output for the woofers if you go with the sunfire amplifier. I tried the Sunfire Cinema 5 x 200 amp and it worked great. So much that when I found 2 signature 600s for sale I jumped on the sale. I have owned krell ksa 80, krell ksa 250, Cary, primaluna, Antique sound labs, crown, qsc, and others. My advice is take everyone's opinions but what matters is what you believe is the best sound to your ears. Hopes this helps. Tom

 

[JonFo]

I'd go for the Stereo Sunfire; it's a beast. I have three Sunfires, a Stereo, CG 5ch, CG Signature 5ch, and a Sanders ESL amp. The Sunfires are really good match for ELS.

If you want to bi-amp, I suggest going active bass crossover, as the XO in the Sequel II and SL3 is not that great and miles behind what a modern active XO can deliver. A Crown XLS1002 has built-in crossovers that can be set to match the passive XO and has gain controls so you can level-match to the panel. Many here have done that, and all rave about the significant improvement in the quality of the bass and mid-bass. See this thread: https://www.martinloganowners.com/threads/how-to-active-bass-section.19237/

 

[Mark F]

So you found the serial numbers for both the panels and the speaker cabinet, because they have their own. I had to look real close to see the serial number on my panels. Its kinda small.

If the panels are original and 24 years old, they have most likely lost quite a bit of performance. When I had my old Prodigy speaker panels hooked up to my Marantz receiver and ran Audyssey, it had to crank up the level on the front channels to max. Thats like +12 db if I remember right. If you have your's hooked up to something like that, youll know. Mine still sounded good as long as the Audyssey filter was running. If I turned it off, the speakers sounded muffled and lacked treble a lot. They sounded terrible.

Hi Robert,
Thanks for the feedback. I continue to learn new information on this forum... Had to google Audyssey. Seems like a great system. No, we are not using it but it seems like a pretty slick package. My only preamp / amp combination capable of driving electrostats is a 20 year old EAD Ovation preamp + matching EAD PM1000 amp. It does not have any equalization capability so sound is reflective of the gear with no adjustments. Think I'll find a Martin Logan dealer and listen to new speakers in the showroom. That should tell me how tired my panels are and if new models have improvements worthy of consideration. Our panels have likely degraded some given their age but its hard to justify replacement when they are pleasing to my (old tired) ears.

 

[Mark F]

Hello Mark, I have owned monolith iii's, Sequel 2's which were my first martin logan speakers 30 or so years ago plus others models. I presently have a pair of Prodigy's which I just replaced the panels that are driven by 2 sunfire signature 600 biamped. As for your questions definitely try biamping using the current output for your panels and the voltage output for the woofers if you go with the sunfire amplifier. I tried the Sunfire Cinema 5 x 200 amp and it worked great. So much that when I found 2 signature 600s for sale I jumped on the sale. I have owned krell ksa 80, krell ksa 250, Cary, primaluna, Antique sound labs, crown, qsc, and others. My advice is take everyone's opinions but what matters is what you believe is the best sound to your ears. Hopes this helps. Tom

Hi Thomas, Thanks for the feedback and kind words. It looks like Prodigy's and SL3s / Sequel IIs have similar impedance so would pose the same loading to amplifiers. Was ready to pull the trigger on a used Sunfire Invariant 250x2 but think I'll hold out for the Sunfire 200x5 or Signature 300x2. The Sunfire Invariant 250x2 lacks current outputs and the bigger models are nominally higher cost when purchased used. Did the Sunfire Cinema 200x5 have long enough legs to drive the Prodigy's? Was it configured to use the extra channels to bi-amp? This seems like a pretty flexible little amp assuming it can drive the sub 4 ohm loading without stressing output stages of the amp.

 

[thomasmasi]

Hi Thomas, Thanks for the feedback and kind words. It looks like Prodigy's and SL3s / Sequel IIs have similar impedance so would pose the same loading to amplifiers. Was ready to pull the trigger on a used Sunfire Invariant 250x2 but think I'll hold out for the Sunfire 200x5 or Signature 300x2. The Sunfire Invariant 250x2 lacks current outputs and the bigger models are nominally higher cost when purchased used. Did the Sunfire Cinema 200x5 have long enough legs to drive the Prodigy's? Was it configured to use the extra channels to bi-amp? This seems like a pretty flexible little amp assuming it can drive the sub 4 ohm loading without stressing output stages of the amp.

Hello Mark, the sunfire cinema did a great job. I used 4 of the channels to drive the panels and the woofers. Remember the Sunfire is rated at 200 watts @ 8 ohms so if the sl3 are 4 ohm then the Sunfire will be outputting 400 watts respectively to each panel and woofer which is way more than enough. I also replaced the bulbs myself, these usually burn out with blue leds. Remember the Sunfire is going to be atleast 20 plus years old so take it to a reputable repair shop for a check up. Feel free to reach out with any questions. The guys on here are great and knowledgeable. Have a great weekend. Tom

 

[Mark F]

I'd go for the Stereo Sunfire; it's a beast. I have three Sunfires, a Stereo, CG 5ch, CG Signature 5ch, and a Sanders ESL amp. The Sunfires are really good match for ELS.

If you want to bi-amp, I suggest going active bass crossover, as the XO in the Sequel II and SL3 is not that great and miles behind what a modern active XO can deliver. A Crown XLS1002 has built-in crossovers that can be set to match the passive XO and has gain controls so you can level-match to the panel. Many here have done that, and all rave about the significant improvement in the quality of the bass and mid-bass. See this thread: https://www.martinloganowners.com/threads/how-to-active-bass-section.19237/

Hi Jon, If I'm interpreting the thread correctly, the Crown XLS1002 provides includes an adjustable crossover and built in amplifier for a few hundred dollars? That would be a steal. You are correct that x-overs in Sequel are not ideal... muddiness on the lower end has always bothered me. Biamping and more power seem to help. It seems like the panel and woofer could be slightly out of phase with each other? The SL3s sound considerably better to my ear. Thanks for the link and tip on the Crown amp. Will read up on it a bit more and perhaps give it a try.

 

[Robert D]

Hi Robert,
Thanks for the feedback. I continue to learn new information on this forum... Had to google Audyssey. Seems like a great system. No, we are not using it but it seems like a pretty slick package. My only preamp / amp combination capable of driving electrostats is a 20 year old EAD Ovation preamp + matching EAD PM1000 amp. It does not have any equalization capability so sound is reflective of the gear with no adjustments. Think I'll find a Martin Logan dealer and listen to new speakers in the showroom. That should tell me how tired my panels are and if new models have improvements worthy of consideration. Our panels have likely degraded some given their age but its hard to justify replacement when they are pleasing to my (old tired) ears.

The only problem is that if they are worn out, your amp is going to be forced to work extra hard to drive them. I had bought a brand new Aragon amp and was unknowingly pushing it very hard all of the time. Having it set to +14 db all of the time. Whatever amp youre using, its having to work extra hard to obtain the same volume level that a new panel can achieve. Youre adding wear and tear on that amp. My Aragon did hold up, although I once blew a fuse on one channel, and it was then that I realized how hard I had been pushing it. Shortly after that I replaced those panels.
If you found both sets of serial numbers on the speakers, then youll know if those are the original panels. Its possible that the previous owner might have replaced them, and if they did then the serial number on the actual panel would reflect a different date than the speaker cabinet.