Forums - Speakers must be connected to torii mkIV?

RF

Verified Member

Posts: 42

Speakers must be connected to torii mkIV?
03/21/19 at 19:51:25

Hi Friends,

It it required to have the speakers connected to torii mkiV when it’s turned on? What happens if they are not?

The reason why I ask is I have one set of speakers doing double duty of home theater TV/ music. I am using ZU soul supremes as fronts along with ZU sub.

While watching tv I use emotiva amp to drive 7.1

While listening music I use torii + schiit DAC/preamp + Apple TV for streaming music.

Currently I am using a speaker switch to change between the Amps... in my opinion the torii sounds amazing after about 1 hour of warm up time... which means I have to turn it on and let it sit and not watch any tv while it warms up...

Hence the question... can I turn on the torii and source (DAC/pre) without the speakers until I am ready for music?

Thanks,
RF

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maddog07

Seasoned Member

seeker of truth

Posts: 585

Re: Speakers must be connected to torii mkIV?
Reply #1 - 03/21/19 at 22:43:19

I have a Torii 3... I have on numerous occasions had my amp on with no speakers connected (warming up). And I have unhooked and hooked up speakers while it was on - no issues.

I've also seen this practice in use at numerous Zenfests.

I have also had a face-to-face conversation with Steve about this at a Zenfest, and he stated it was "OK" to do this - with the caveat, that you turn the volume control all the way down to avoid accidents....

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ScottNC

Seasoned Member

Posts: 335

Re: Speakers must be connected to torii mkIV?
Reply #2 - 03/21/19 at 23:04:04

Hi RF,
If you haven't downloaded the owners manual for your Torii MKIV I'd encourage you to. Here is a mention on I think page 3, it is different than other Decware Amps I believe.

"This switch can be operated “on the fly” to turn on or off the reconstructive (positive) feedback. A rare feature to have on any amplifier because it is so difficult to define a window of stability that works on everyone’s speakers. Therefor, we do not claim this feature will work with everyone’s speakers. You’ll know if this feature is compatible with your speakers if you don’t hear the amp start to whistle when the switch is ON.
The reconstructive feedback switch has an ON and OFF. When facing the front of the amplifier, reaching over it and flipping the switch towards the back of the amplifier is ON, while the switch pointing towards the front of the amplifier is OFF. It is important to keep this switch off any time speakers are disconnected as damage could occur.
If you hear the amplifier start to whistle, turn the reconstructive feedback switch OFF until the cause has been corrected. While we don’t anticipate many if any speaker incompatibilities, if you have a pair of speakers that are not compatible with this feature just contact us and we can discuss one of several possible solutions."

Hope this helps.
Best,
Scott Smiley

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RF Verified Member Posts: 42	Re: Speakers must be connected to torii mkIV? Reply #3 - 03/22/19 at 00:13:01 Thanks Maddog07 and ScottNC for your response. I tried that on page 3 and was not able to tell any difference with On or off with my speakers so I leave it off. I am assuming if I want to leave the torii on without speakers I should leave it off. Thanks, RF
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pursuitofnow Seasoned Member Posts: 449	Re: Speakers must be connected to torii mkIV? Reply #4 - 03/22/19 at 01:51:35 Not 100% sure with the torii mkIV, but it has been my practice with tube amps to always have a speaker load when the amp is on or transformers fail.
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Steve Deckert

Administrator

If the 1st watt
sucks why continue?

Posts: 6246

Re: Speakers must be connected to torii mkIV?
Reply #5 - 03/24/19 at 03:55:52

As a general rule with higher-power tube gear it is always a good idea to keep the output transformers loaded or at least shorted. The reason for this is because most amplifiers do not come with input gain controls that can be turned all the way down. Instead these amplifiers are wide open, so if the amplifier is setting there turned all the way up and you have no speakers connected despite the fact you have no signal going to the amp, farther Murphy (fallen angel) will appear and make sure you trip over the interconnect feeding the amplifier in such a way that it un-plugs from the preamp instead of the amplifier. You now have a giant 60 cycle antenna on one channel that causes the amplifier to put out a blood-curdling cry at full power and since there was no speaker to absorb the energy, the output transformer becomes the speaker and shorts itself out which in turn causes the tube(s) to blow.

Decware does not make amplifiers without an input gain control, #1. Secondly, the output transformers are generally oversized. Because of these two things, little or no signal and being over built, we have yet to see a single fried output transformer since the beginning of this journey in 1996.

So what happens if you turn a Decware amp all the way up and play it without speakers.... so far nothing has happened, but you can be certain that the output tubes and probably the coupling caps do not like it. Best thing to do if you think you might forget and turn up the volume without speakers connected for any length of time would be to make yourself a pair of shorting plugs for the outputs of the amplifier. Rather than making them from wire (0 ohms) make them from a 5 watt ceramic 8 ohm resistor. This way the amp thinks everything is normal and it has a speaker connected to it. Should you have the amp all the way up and signal on it for a long period of time the resistor will get hot enough to stink alerting you that there is about to be a problem.

With non-Decware tube gear including a lot of vintage gear, much of it is push-pull and laden with negative feedback so when a strong signal is applied to the front end that has no gain control and a speaker happens to come disconnected at that time, the amplifier will often oscillate causing the output tubes which are fixed bias to have a thermal meltdown similar to a nuclear power plant. This event is almost certain to cook an output transformer.

Despite the warning in the TORII owner's manual about oscillation there have never been any reports of it ever actually happening. And virtually all of the other amplifiers we make or have made simply do not oscillate, they are stable as a stone. This is another secret to why we can offer a lifetime warranty on our amps and no-one else does.

Steve

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RF Verified Member Posts: 42	Re: Speakers must be connected to torii mkIV? Reply #6 - 03/26/19 at 02:57:07 Thanks Steve for feedback. Now I can leave the Amp on while watching tv. Is it ok to leave the amp on for a long period of time? Let’s say 2-3 days or longer? Thanks, RF
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Steve Deckert Administrator If the 1st watt sucks why continue? Posts: 6246	Re: Speakers must be connected to torii mkIV? Reply #7 - 03/26/19 at 04:38:36 The record so far is 7.5 years before the output tubes shorted.
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