Matching SET Amps to Speakers

[Atmasphere]

I have a pair of Avantgarde Duo Grossos that I purchased over 10yrs ago as the cornerstone of a long overdue system upgrade. Next came a pair of Lamm ML2.1 mono blocks which at the time made sense to me because of the low output tube amps and powered subs in the AG's. It has been a long process but learned over the years that the Grossos are not the easiest speakers to set up and still find myself with the urge to tweak placement, toe in etc. Basically I have found that they require both precise equipment matching and positioning, otherwise they just sound off...which is to say that even though I have found pleasing combinations, I am still not completely satisfied.

Reading this and other threads concerning SET amps and horn speakers I am finally starting to understand the love/hate opinions that many express when talking about AG speakers. So perhaps it is time to come full circle and look at replacing the Grossos. My inclination is to go old school and look at a pair of Classic Loudspeakers w/field coils. I have spoken with John Wolfe, who is a really informative guy and he recommended the T-3.4 models due to the fact that the ML2.1 output is only 18 watts and that the sensitivity of the T-3.4 is in the range of 97dB/w/m compared to 107 in the AG. Additionally, as I dig into the technical aspects of amp/speaker matching I find that the Lamm elevates output frequency performance by using a monstrous output transformer.

According to the rules of thumb you mention above, I should expect to be able to use a bit less than 4 watts to avoid getting into distortion issues. And therein lies my concern, for John himself stated that he would rather see his speakers driven with amps more in the range of 30watts to fully experience his designs. Regardless, he felt that I would be fine unless I wanted to push rock or classical music at full tilt boogie levels. Reading between the lines I think he is saying that the ML2.1 are not quite up to the task even with the performance of the large output transformers.

The question becomes, do I take a chance with the T-3.4's and if the ML2.1s are not up to snuff am I going to be chasing my tail again?

Brock

It will sound OK. But John is right (I have T-3s). Its nice to have some power on them- not for authority, just so that the amp isn't working hard for a living. In that way it makes less distortion and so is more transparent.

 

[Tirebiter]

It will sound OK. But John is right (I have T-3s). Its nice to have some power on them- not for authority, just so that the amp isn't working hard for a living. In that way it makes less distortion and so is more transparent.

Thanks for confirming, having so little power available from my amps, especially if they are tasked with 15" drivers, seems too much to ask of them.

It is a shame I love the speaker concepts that John has put together.

 

[Atmasphere]

Thanks for confirming, having so little power available from my amps, especially if they are tasked with 15" drivers, seems too much to ask of them.

It is a shame I love the speaker concepts that John has put together.

The 15" drivers have nothing to do with it- that's a common myth that you need a big amp or something to control 15" woofers! I know this because my preamp, if directly connected to my CALs plays bass just fine, and I've no doubt it makes less power than your 'flea powered amp'

 

[Tirebiter]

The 15" drivers have nothing to do with it- that's a common myth that you need a big amp or something to control 15" woofers! I know this because my preamp, if directly connected to my CALs plays bass just fine, and I've no doubt it makes less power than your 'flea powered amp'

See? Even at my age I am capable of learning something new!

 

[Atmasphere]

See? Even at my age I am capable of learning something new!

FWIW John also makes a Hartsfield reproduction which is much improved over the original (of the 1950s...), having improved drivers and crossover. Its also considerably more efficient; IIRC nearly 10dB, meaning that 1/10th the amplifier power will do the same job.

 

[Alrainbow]

Ralph in the amps you make how do they control bass so well. i always thought it was damping factor doing this. I’m curious ?

 

[Tirebiter]

FWIW John also makes a Hartsfield reproduction which is much improved over the original (of the 1950s...), having improved drivers and crossover. Its also considerably more efficient; IIRC nearly 10dB, meaning that 1/10th the amplifier power will do the same job.

Have you heard them? If so, how do they sound?

 

[Atmasphere]

Have you heard them? If so, how do they sound?

Many times and they sound quite good. They don't make quite as much bass, but the design is meant to be placed in a corner (IOW its a corner horn) and I've yet to hear them that way.

 

[cat6man]

The Bache look interesting but am exploring options that don't involve built in powered subs...the list is limited for sure.

if you are still looking, consider the Bache 002 Limited Edition.
i was in Brooklyn yesterday and with the Alexus 300B 15W amplifier, it was extraordinary even with a meh DAC feeding it.
at the NYC audio show this year, they had the best sound that i heard (hence the visit yesterday with an audio buddy who likes them more than his wilsons). i can't tell you how much was due to the speakers and how much due to the 300B amp, but the combo is wonderful.

 

[Cellcbern]

if you are still looking, consider the Bache 002 Limited Edition.
i was in Brooklyn yesterday and with the Alexus 300B 15W amplifier, it was extraordinary even with a meh DAC feeding it.
at the NYC audio show this year, they had the best sound that i heard (hence the visit yesterday with an audio buddy who likes them more than his wilsons). i can't tell you how much was due to the speakers and how much due to the 300B amp, but the combo is wonderful.

In my opinion Bache represents one of the handful of best values in high end speakers available today. The augmented wide band design is magic in the midrange, and designer Greg Belman will customize his speakers for you and contact you when he discovers something that improves the sound.

 

[cat6man]

I have nola metrogrande speakers that I very much enjoy.
The amps are Ayon monoblocks run in triode mode rated 60W per channel which is plenty of power for my room.

I see that Alexus Audio has 50W/ channel monoblocks, the 845SE.
Do you think they would drive my Nola metrogrande speakers?

 

[fitmartin]

Magnepan Tympani IV powered by 4 Gryphon s100 amps, the attack and the transparency are incredible. I wanted to listen to the TW Acustic tonearm with different pickups, I was at Thomas Woschnik's home. I've heard his Cessaro Beta, the dynamics and bass are as close to life as I haven't heard them anywhere else. I didn't listen to music at home for a week after that so as not to ruin this memory View attachment 83655

Wow!

 

[Phantom-Audio]

The large one is the LM Field Coils Speakers 16ohms and 105db

The smaller one is Classic Audio Loudspeakers Also Field Coils 16ohms 100db

Both will work extremely well on SET Amps anything above 3-5 watts is sufficient for the LM.

Anything over 5-8 Watts is sufficient for the Classic Audio

Very easy to drive OTL sounds magical on these. SET do too.

When i say sufficient i mean its loud enough for most humans.