Burning Amp Tweets

[nicoch58]

speaker info ? no one ?

 

[Decker]

Does anyone know what crossover frequency Mr. Pass was using for his Lowther/Eminence open baffle speakers at BAF? I didn't think to ask while I was there.

 

[Decker]

bump

 

[Nelson Pass]

Woofer 2pole @ 80 Hz
Lowther 2 pole @ 160 Hz

 

[Decker]

Thanks!

 

[Telstar]

Hi Generg,

F3 without feedback (and with some passive correction circuit as described in Nelson Pass article about transconductance amps) makes Visaton B200 on open baffle sounds much better than it does with feedback, not to mention any other SS amp. It sounds good enough that I stopped bothering about any other amps...

Can you shed some details? I have an f3 driving hemp fr and I wouldn't mind improving it.

 

[Telstar]

Woofer 2pole @ 80 Hz
Lowther 2 pole @ 160 Hz

Interesting! ESP the low xo point for the lowters. With their low xmax I expected no less than 250hz.
Food for thoughts. Hopefully soon some plan and xo details for the woofer

 

[Jon Ver Halen]

Lowther crossover point

If you run the numbers, the x-max limit of 1 mm is more than enough for a 160 hz. note, even if you are playing real loud. More than 100dB is easily obtainable.

 

[nicoch58]

front size from pic something like 140x70cm (55x27.5 inch)
slot load with a little back air load , a sort of u baffle ?
the eminence qts 0.5 , fs 42hz, 96db

 

[Wavebourn]

I have Bruno's speech about Class D recorded. Projector's fan is heard as well, but Bruno spoke still louder.

 

[ra7]

It's probably too late, but here's a few pics from my visit.

1. LX521: Linkwitz's new speaker was superb. The sound was utterly seamless, neutral and realistic. Superb!

2. BBQ boys: Shout out to the boys who cooked food. That was a great dog!

3. The First Watt: Nelson was showing how much power the SIT-2 was putting out. Even on crescendos it never moved outside 1 watt.

4. Nelson's OB: Slot loaded OB using a different arrangement. Field coil Lowther mated to Eminence Definimax.

5. F6: Got to hear the F6! Yayyy!

 

[gl]

That 'first watt' oscilloscope display was a real eye opener. The scope wouldn't even trigger until the output went above about 300 milliwatts. It was amazing to me sitting in a row 2 center seat (to my own amplifier actually) how loud the music was playing before the scope even triggered.

I really do understand now the importance of that 'first watt'.

Many thanks to Nelson. The oscilloscope was an inspired idea.

Graeme

 

[ra7]

The key is efficient speakers. Those Lowthers were nearly 100 db/W. Try an 88 db/W bookshelf and it will need more than 1 watt, but probably not a lot more.

 

[nicoch58]

The key is efficient speakers. Those Lowthers were nearly 100 db/W. Try an 88 db/W bookshelf and it will need more than 1 watt, but probably not a lot more.

yes this is the key ,we need a 100db speakers and a low power amp, but class A ,ss or tube ...

 

[Zen Mod]

.....

Many thanks to Nelson. The oscilloscope was an inspired idea.

......

damn he

spiritus movens

 

[buzzforb]

Do not show that to the HIFI world. It wold deflate so many strongly held beliefs.

 

[gl]

The key is efficient speakers. Those Lowthers were nearly 100 db/W. Try an 88 db/W bookshelf and it will need more than 1 watt, but probably not a lot more.

I generally agree.

But let's take your 100 dB/W number and consider that a satisfyingly loud listening experience was being produced by what I assume was approximately 250 mW of power. If we hike the power level by 12dB to 1000 mW and run that into an 88 dB/W (12 dB/W less) system we should still be producing a roughly equivalent experience and staying within that first watt.

And to be honest I don't know if the scope was displaying peak or average watts. I've always assumed that Nelson's 'first watt' is expressed as average power. So if the scope was displaying peak watts, then there's another 6dB of margin in there.

Graeme

 

[Zen Mod]

1 or 10

who cares

I care and refuse zero more

 

[nicoch58]

that amp is xo at 160hz ... W is much lower.....

 

[Antoinel]

The key is efficient speakers. Those Lowthers were nearly 100 db/W. Try an 88 db/W bookshelf and it will need more than 1 watt, but probably not a lot more.

A mere 250 mW is trivial. I continue to wonder if it may be possible to simultaneously energize the field and voice coils of this Lowther with a SIT amp. Please see the Thread "Pass at BAF 2012"; posts #15-20 for the attendant dialog. Fortunately, Mr. Pass has these Lowthers,the SIT amps, and the critical hearing assets to do this experiment.