Feeding 4V into a 2.5v line in amp

[Yanuk]

I'm looking at an amplifier right now. The stated input of the amp is 2V, however, my HU outputs 4V. Will this cause any problems (eg, clipping)?

[User12343]

should not really clip, unless u have the habit of blasting full volume all the time. just keep the amp gain at the minimum position, listen with care and shd be ok. else, get another amp with a 4V input.

[Hyun]

actually hor, when the amps or HU publish voltage for the lines, are they usually talking about RMS or max, or can be anything? normally not specified leh.

[Kwongwing]

Hyun,

Thought you always read specs so shld know better.

 

Amplifiers usually state their output power/wattage in RMS, though some do also state theirs in PMPO (Peak Music Power Output) also.

 

E.g.

Power: 60W x 4 (Max), 26W x 4 (RMS)

 

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For HUs, not all state their RCA/Line output voltages. Some examples of how such line output values are stated when such specs are available as follows:

 

E.g. 01 (Alpine CDA-9835R)

Maximum Pre-Output Voltage 4 V/10k ohms

 

E.g. 02 (Clarion HX-D2)

Line Level Output (CD 1 kHz)

Vol 0db = 4V

Vol +6db = 8V (Max)

[Hyun]

E.g. 01 (Alpine CDA-9835R)

Maximum Pre-Output Voltage 4 V/10k ohms

 

E.g. 02 (Clarion HX-D2)

Line Level Output (CD 1 kHz)

Vol 0db = 4V

Vol +6db = 8V (Max)

 

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so in these 2 examples, max = 4V for first one, and 8V for second.

seems that many amps don't accept a high voltage input. so be prepared for clipping? strange that people don't mention much about amp input sensitivity when recommending amps. everyone just looks at output.

[Kwongwing]

Not that many people play at such high levels as we do for normal listening circumstances. And hardly anyone maxes out their HU's output anyway - so usually not a concern.

For those people who do max out their HU's output, they should know how to match the gain settings.

 

E.g. what is your personal setting for your HU's output as a percentage of its max? <75%?

 

For my HU I usually play at 80 - 90% of the HU's max output. I get clipping only for the louder rock tracks, otherwise OK AND the output voltage for the D1 is in fact hugher than that for D2 i.e. > 8V.

 

So long and short of the matter, input sensitivity of amp usually not a concern for usual "normal" setups

[Hyun]

for low level tracks like the IASCA CD, i end up using easily 75%-90% of HU output. it can go 100% and sound real loud but i've seen reports of HU's having clipping WITHIN itself - nothing to do with amps. some HU's, even nice models like Alpine etc, were found to clip its output at close to 100% level. but none of them clip at 90%.

 

but on normal volume tracks, pleasant realistic listening tends to be about 65-70% max level.

[Kwongwing]

Like you have stated, your usual listening level is 65 - 70%. S like I said before - HU output level usually not a concern for most people.

Anyway, I believe that HUs are not designed to play at maximum levels - like just about everything else. Usually good HUs can be played till about 90 - 95% before their outputs start to distort; lower end models may start to distort from about 85% of their max outputs onwards.

[Hyun]

the thing is, if it wasn't meant to play at 100%, why design the 100%. stop at 95%. stop when it can't handle.

 

there are quite a number of low-level tracks lying around, and on those, i'll end up cranking all the way to the max.

[Kwongwing]

Just an example - let's say your car's maximum speed is 300 km/h

Does it mean that it is meant to be driven at the maximum speed all the time? It is just a spec - that the car can go that fast that's all. Similar logic for the HU's output

 

As for your tuning, you would have to strike a compromise. Quite of number of good recordings (e.g. Sheffield Lab) have lower recording levels when compared to pop and other recordings in general - perhaps to cater for more headroom when recording due to a greater dynamic range for the particular recording I suppose.

Golden Ear I's recording level is quite low too - so if you are going to listen to such CDs on a regular basis then you have to tune your HU/amp to play such low level CDs at your HU/amp's optimal setting then.

[Kwongwing]

Further "food" for thought for you to ponder over:

Did some checking for my setup,

 

Clarion HX-D1 Max Line Output - 9V

|

V

Alpine PXA-H701 Input Sensitivity - 2V; Rated Output - 4V (w/ 10 K ohm load)

|

V

Butler TDB 2150 Input Sensitivity - 450 mV to 12V

 

[Hyun]

aiyoh u know my little car cannot go 300kmh, how i know whether go 300kmh is shiokz or not?? :P

 

analogy not same leh. 300 kmh reach destination faster. for low-level music, effect is the same even when going 300 kmh, just that the level is so low, have to 300kmh to get same effect.

 

9V into 2V how come it works ah?

[Yanuk]

Thanks guys.. I think I sort of get the gist of it now.

[Bosebani]

>>Just an example - let's say your car's maximum speed is 300 km/h

Does it mean that it is meant to be driven at the maximum speed all the time? It is just a spec - that the car can go that fast that's all. Similar logic for the HU's output >>

 

Thats a good example

 

 

 

 

 

>>As for your tuning, you would have to strike a compromise. Quite of number of good recordings (e.g. Sheffield Lab) have lower recording levels when compared to pop and other recordings in general - perhaps to cater for more headroom when recording due to a greater dynamic range for the particular recording I suppose.

Golden Ear I's recording level is quite low too - so if you are going to listen to such CDs on a regular basis then you have to tune your HU/amp to play such low level CDs at your HU/amp's optimal setting then. >>

 

Just to add on, 1 of the lower cd recording level i have, lower than The Golden Ear is Focal JM Lab 3, especially Track 11

[Kwongwing]

Track 11 is

I would call it a "torture" track

[Bosebani]

Ya, volume need to on to super low level, is a good "torture" track to speakers, amps and sub

[Sarong1]

Its important to get the input and output level of the gains right and if possible, optimal. It has effects on the manner sound is presented through the speakers. My experience with the HU volume control is generally about 2/3 the max volume while the amp gain should not be set beyond 3 o'clock' (using scale of 7 being the lowest to 5 o'clock being the highest), in fact, a good gauge would be somewhere 11 to 12 o'clock, not more...

 

Now, my normal listening level is generally at about -30dB (out of +6dB to -95dB) and my amp gain setting is at 11 o'clock.

 

To share, I am running a Clarion D2 with an output of 8V while my amp delivers 28.28V output (into 4 ohms per channel) . Using 1KHz tone as reference, I set the input with my HU volume control at 0dB and Max (i.e. +6dB) and output level through my EQT and into the amp at 5V. Therefore, at 0dB, 2 volts are delivered to the amp and at +6dB, I know that 5 volts are delivered.

 

Nevermind if my amp can handle more, the more important thing here is that the input and output that of the HU and amp is matched. The end result is, the volume control from the HU is more balanced, gradual and does not stress the amp too much ( my amp's heat sink is not that hot as before now). Thereafter, I continue with the rest of my tuning and EQing using 1KHz sine wave as reference and match that with warbled tone at 20Hz to 20KHz and so on so forth to ensure that all freq response is balanced.

 

Therefore, the HU and amp input/output is one of the first most important to set and get right before the rest of the procedures fall in place.

Edited September 25, 2006 by Sarong1

[Bobcatsysop]

Hi Bro Sarong1,

 

Did some checking for my setup too.

 

HU: Pioneer DEX-P80RS

Max Line Output - 5V Hi-Volt

|

V

Critical Mass Tube Pre-Amp P3-GTX

Input impedance