Maximum SPL amp A vs. amp B

[James Romeyn]

The speaker load is rated 96 dB @ 4-ohm nominal. The room is 3300cf and the subject occasionally enjoys live or almost-live SPLs.

Stereo power amplifier A is class AB, rated 100/200W @ 8/4 ohms, weighs about 59#, has a 400VA transformer. Power amp A shuts off @ elevated SPL. It occurs to me that maybe amp A shuts off because the speaker's EPDR falls considerably below 4-ohms.

Now using two Schiit Audio Vidar 2 in mono, rated only to 8-ohm @ 400W https://www.schiit.com/products/vidar2

Two Vidar 2 mono play virtually any tolerable SPL with no audible distortion in this application. It occurs to me that Vidar 2 mono rated only to 8-ohms might shut off driving a load that drops below 4-ohms.

I shall audition another stereo power amp B, 53#, 2000VA transformer, class AB, rated 100/200/400@ 8/4/2 ohms. Driving the same speaker load described above, what difference if any might you expect in maximum output between amp B and Vidar 2 mono?

Many thanks!

 

[Blumlein 88]

Your post is confusing to me. Are you using mono Vidars, one Vidar? What is the other amp? What is amp B?

Just put a label on the speakers and what amp A and amp B is. Makes it easier to give good advice.

You seem to be talking about 3 amps, and two speakers.

The Vidar has a microprocessor that monitors the amp, and might shut down for reasons that are not directly due to the power amp capabilities.

 

[DVDdoug]

The speaker load is rated 96 dB @ 4-ohm nominal...

...It occurs to me that Vidar 2 mono rated only to 8-ohms might shut off driving a load that drops below 4-ohms.

Of course, with 4-Ohm (nominal) speakers your amplifier "should" be rated for 4-Ohms.

 

[Blumlein 88]

BTW, with a 96 db rated speaker and 4 ohms, it occurs to me a class D amp will have plenty of power, some of them unbothered by the load and be very quiet.

 

[Looneybomber]

I shall audition another stereo power amp B, 53#, 2000VA transformer, class AB, rated 100/200/400@ 8/4/2 ohms. Driving the same speaker load described above, what difference if any might you expect in maximum output between amp B and Vidar 2 mono?

Many thanks!

I would expect an insignificant difference with a [email protected] speaker being fed a 20+dbW capable signal. It’s well into the range where I would have ear plugs in. In other words, they’re both too loud and there would be no difference in maximum output because I would never reach it.

If you have a client that is pushing nearly 120db in their room and putting amps into protect, have them get a class AB pro amp that’s fan cooled.

 

[solderdude]

The speaker load is rated 96 dB @ 4-ohm nominal. The room is 3300cf and the subject occasionally enjoys live or almost-live SPLs.

Stereo power amplifier A is class AB, rated 100/200W @ 8/4 ohms, weighs about 59#, has a 400VA transformer. Power amp A shuts off @ elevated SPL. It occurs to me that maybe amp A shuts off because the speaker's EPDR falls considerably below 4-ohms.

Now using two Schiit Audio Vidar 2 in mono, rated only to 8-ohm @ 400W https://www.schiit.com/products/vidar2

Two Vidar 2 mono play virtually any tolerable SPL with no audible distortion in this application. It occurs to me that Vidar 2 mono rated only to 8-ohms might shut off driving a load that drops below 4-ohms.

I shall audition another stereo power amp B, 53#, 2000VA transformer, class AB, rated 100/200/400@ 8/4/2 ohms. Driving the same speaker load described above, what difference if any might you expect in maximum output between amp B and Vidar 2 mono?

Many thanks!

The fact that amp A went into protection and Vidar did not may mean the customer did not reach clipping point of the Vidar (amp B) yet.

When you are afraid the customer, eventually will break the Vidar or make it go in protection because it has a load it is not designed for and you want an alternative (amp C) then perhaps use an amp that can provide at least 800W in 4Ω (= same output voltage of Vidar in mono mode into 8Ω)
I don't think the amp necessarily would need to reach 1600W in 2 ohm either.
some of the better class-D can reach those levels or does the customer not want class-D ?

 

[MaxwellsEq]

The speaker load is rated 96 dB @ 4-ohm nominal. The room is 3300cf and the subject occasionally enjoys live or almost-live SPLs.

Stereo power amplifier A is class AB, rated 100/200W @ 8/4 ohms, weighs about 59#, has a 400VA transformer. Power amp A shuts off @ elevated SPL. It occurs to me that maybe amp A shuts off because the speaker's EPDR falls considerably below 4-ohms.

Now using two Schiit Audio Vidar 2 in mono, rated only to 8-ohm @ 400W https://www.schiit.com/products/vidar2

Two Vidar 2 mono play virtually any tolerable SPL with no audible distortion in this application. It occurs to me that Vidar 2 mono rated only to 8-ohms might shut off driving a load that drops below 4-ohms.

I shall audition another stereo power amp B, 53#, 2000VA transformer, class AB, rated 100/200/400@ 8/4/2 ohms. Driving the same speaker load described above, what difference if any might you expect in maximum output between amp B and Vidar 2 mono?

Many thanks!

1. What is the maximum undistorted output of the source (and has it been checked for DC offset)?

2. What are the gains of the two different power amplifiers?