Safe volume on pre to avoid clipping?

[philv]

Hi,

I'm using -

echo dot or airport express
tisbury passive pre
el84 se 5.5 wpc
jbl L96 89db sensitivity

Am i correct in thinking the tisbury cannot cause clipping as it is a passive?

I need step 15 (20 steps in total) on the tisbury to get to the maximum listening level i need.

Thanks

[struth]

Yup it's passive so at max the volume is 100%. Hopefully nothing added or taken away.

[walpurgis]

Your power amp may clip regardless of pre-amp choice. That depends on sensible use more than pre-amp choice (as a rule).

I can't see you running into much bother with an EL84 amp driving JBL's, it should be loud enough for normal, sane levels.

[Macca]

Even with only 5 watts you'll get a maximum spl of 98dB at 1 meter from the speakers - which is very high volume.

But it depends on how far away from the speakers you are and what average level you play at. Assume you want 80db average level you have 18db range to play with for dynamic peaks, but with every doubling of distance from the speakers you lose 6db - so if you sit 3 metres from the speakers you only have 6db of range before the power amp clips. But being a valve amp it will probably clip softly so won't sound bad.

Ideally you want a more powerful amplifier or more sensitive speakers but if it ain't broke, don't fix it.

[philv]

The tisbury has 20 steps.

I can easily live with using only 15 steps.

Should be safe from clipping, softly or otherwise?

[Macca]

No, not really, it depends on a lot of factors.

First thing to do - if you really want to know - is play some music with a high dynamic range - a well-recorded and mastered symphony orchestra would be best - at you usual volume level and use an SPL meter to find the dB level at your listening position when the orchestra hits the peaks. That will give you an idea of how much of the 5.5 watts you are using in a worst-case scenario.

It might be that you are never clipping the amp, it might be that you are clipping it a lot.

[philv]

No, not really, it depends on a lot of factors.

First thing to do - if you really want to know - is play some music with a high dynamic range - a well-recorded and mastered symphony orchestra would be best - at you usual volume level and use an SPL meter to find the dB level at your listening position when the orchestra hits the peaks. That will give you an idea of how much of the 5.5 watts you are using in a worst-case scenario.

It might be that you are never clipping the amp, it might be that you are clipping it a lot.


Well i used an app to measure the db at approx 1m from one speaker.

Speakers are rated 89db sensitive at 1m 1w.

I measure comfortably less than 89db on app for my music.

Does that mean i am using only 1w when on step 15 out of 20 on the tisbury?

Doesn't seem right?

[Macca]

The Tisbury is attenuating the signal from the source, not the power amp.

I'd guess that either the source has a low output voltage or your power amp has low input sensitivity. Not unusual to have to run a pre-amp almost wide open in that situation.

You probably using less than 1 watt most of the time, that's pretty normal. It's the dynamic peaks that you need the extra power for.

[Lawrence001]

You're lucky you can get that high on the knob at normal volume, it means you have a lot of steps to choose the right level. The issue is when you get to the level you want with just a few steps, then you often can't pick the exact volume you want at any given time .

Have you checked the dip switches on the bottom, they vary the gain (if it's a MK2)?

Sent from my BKL-L09 using Tapatalk

[zanash]

I suspect your hearing some thing from closer to the source of the audio chain ...you don't describe it so this is speculation at best !
Have a play with the output levels of the source components ....reduce these to say 30% of normal output and then play with the volume on the passive. If you have eliminated your issue ..job done ! you can over drive the outputs of the echo dot or airport express . Conversely it maybe a router issue or in my case was due to very old broadband external connections creating dropout and other issues.