Phoenix Gold Phorum

My MiniDSP processor (only) has a signal voltage of 2Vrms.

This "enough" for the PG M-Series or should I look into a line driver?


Please only post if you really can stand behind your words. Increasing the voltage doesn't exactly mean it's "better." Most mobile audio amplifiers are designed for signals from 2Vrms-7Vrms (perhaps 8Vrms).

Just curious on the O/S PG M series

WOW ...pretty strong words for someone lookin' for input to a question

The higher the voltage input to the amp the more efficient and clean it will run, so yes, you will benifit from a line driver and "I CAN BACK UP MY WORDS" as I use an Audiocontrol DXS inline before my amps and I can tell a huge difference in sound quality as well as amp performance (heat, sound level and clarity). Just my .02c, so take it or leave it.

i would not go higher then about 4V rms for the m series.....

zx and zpa's are another story.........

i'm guessing when you would use a pld1, you will not be able to put the gain higher then about 50 %.......

personnally i prefer to give an amp it's max input voltage but also not more then that.......

if you here strange noises coming out of you're amp when turning you're HU off, perhaps the input voltage

is already too much !!!

2V is plenty for a M series amp.

4V will clip the preamp section of an M series amp. I have personally modified M series preamp sections for people who wanted to use them with 4V or more of input.

When using M series amps, any advantage from a line driver will be best with the use of a rear signal processor. With say an EQ215x, you could run 8V from the head unit to the EQ215x, then cut this down to 2V or so for the M series amps. The signal to noise will be greater on the long run to the rear where picking up noise is of concern, and the signal will still be great for the short few feet distance from the EQ215x to the amplifier's inputs. This is just one example though.

I am guessing your mini DSP goes up front? If so, you can't really gain from my example.

4v back in the M days was big deal.

So your saying a PLD1 before an M100 will actually be harmful to the amp? I have never heard this before.

LL

LowandLoud wrote:So your saying a PLD1 before an M100 will actually be harmful to the amp? I have never heard this before.

LL

you can take this as a yes.....

i always played my m series directly off a 4v preout of an alpine HU and this worked pretty fine without issues.....

But i would not take Eric's words in doubt.....he knows what he is talking about....

I would rather believe those alpine preouts are 4V max, not 4V rms......so about 2V rms......

Correct me if im wrong but even 2V RMS will clip the preamp (and power stage) of an M series amp if you turn up the gain enough.

A "4V signal" wont clip anything before its a 4V signal = before you turn the volume up all the way.

The difference here is that with a 2V signal you cant make the amp clip if the gains are at min.
With a 4V signal you can.

Mr. Wild wrote:Correct me if im wrong but even 2V RMS will clip the preamp (and power stage) of an M series amp if you turn up the gain enough.

A "4V signal" wont clip anything before its a 4V signal = before you turn the volume up all the way.

The difference here is that with a 2V signal you cant make the amp clip if the gains are at min.
With a 4V signal you can.

Yes, I think what you are stating here is correct.

On the M series amps, you only need about 0.2V to drive the amp with the gain all the way up, and around 3V to drive it with the gain all the way down.

My numbers are not exact, it has been over a year since I worked with this issue on these amps.

Most people like some gain overlap in their system (clipping), as it lets them get more bang for the buck. In this case a 4V RMS head unit would be perfect, as 4V will over drive the amp enough with its gain all the way down to not have much noticeable (audible) clipping.

Too much input voltage (to a point) won't harm the amplifier, it will just clip its signal. However, if you do feed too much input voltage into an amplifier, it will damage the preamp circuit. On a lot of these older amps, 8V from a line driver will probably exceed the thermal capacity of the resistors in the initial voltage divider circuit of the amplifier. I have come across many an M or ZX series amp with toasted and damaged input resistors, but have never really confirmed the issue was from too much input, or some sort of failure on the part of the head unit.

Eric D wrote:

Mr. Wild wrote:Correct me if im wrong but even 2V RMS will clip the preamp (and power stage) of an M series amp if you turn up the gain enough.

A "4V signal" wont clip anything before its a 4V signal = before you turn the volume up all the way.

The difference here is that with a 2V signal you cant make the amp clip if the gains are at min.
With a 4V signal you can.

Yes, I think what you are stating here is correct.

On the M series amps, you only need about 0.2V to drive the amp with the gain all the way up, and around 3V to drive it with the gain all the way down.

My numbers are not exact, it has been over a year since I worked with this issue on these amps.

Most people like some gain overlap in their system (clipping), as it lets them get more bang for the buck. In this case a 4V RMS head unit would be perfect, as 4V will over drive the amp enough with its gain all the way down to not have much noticeable (audible) clipping.

Too much input voltage (to a point) won't harm the amplifier, it will just clip its signal. However, if you do feed too much input voltage into an amplifier, it will damage the preamp circuit. On a lot of these older amps, 8V from a line driver will probably exceed the thermal capacity of the resistors in the initial voltage divider circuit of the amplifier. I have come across many an M or ZX series amp with toasted and damaged input resistors, but have never really confirmed the issue was from too much input, or some sort of failure on the part of the head unit.

I'm with Eric, unless you are going for uber crazy sound quality, I would at least give myself the option of 5-10db of overlap so 4V-5V would be plenty. If the overdrive ends up not to your liking you turn it down, but typically the minimal amount of clipping you'll see will be barely/inaudible and worth the gain in overall performance, and you'd need to be pretty careless to do any damage.

Well that was a waste of $60. (PLD1)

Oh well, it sits for another install then. Like maybe a Ti based system? I just came across a guy selling a ZX600Ti and a ZX475Ti for $100 apiece. Sounds like a killer deal but the last thing i need right now is more amps.

LL