From what I've learned it seems preamp output voltage and output impedance and amp input sensitivity and amp input impedance are key to determining if a preamp and amp are a good match. However it seems very few manufacturers list all those values. Am I missing something or do they need to be calculated for preamps and amps when those values are not listed?
thanks
thanks
Preamp outputs at "line level" are a standardized value of 0.894 Vpp, so as to be inter-changeable from amp to amp. The only reason amps have an adjustment is for fine tuning.
------------------------------------------------------------------------------------------------------------------------------------------------------------Rick...
------------------------------------------------------------------------------------------------------------------------------------------------------------Rick...
They should be given, but if you can't calculate them from what is given, maybe they don't know.
In some combinations, the preamp may not be able to drive the power amp to full output.
So always check.
In some combinations, the preamp may not be able to drive the power amp to full output.
So always check.
I've read that preamp outup voltage should be => than amp sensitivity and preamp impedance should be 11 times lower that amp impedance. I can't find those values in specs. for my Audible Illusions M3A preamp and my Neurochrome Paralell86 amplifier. How can I determine if the they are a good match?
Line out to amps use Impedance Bridging, a line out that can support a very low value, appx. 300 ohms...conversely, the target of the amplifier is way up there at greater than 10K...no problem whatsoever.
My Yamaha pre-amp failed completely & since the earphone mini-jack off my laptop drives 8-30 ohms max, I merely bypassed this failed preamp . My Carver amp has one of those "fine-tuning" adjustments, so I dialed in the level to match...I just don't have the multiples of input choices.
-------------------------------------------------------------------------------------------------------------------Rick...
My Yamaha pre-amp failed completely & since the earphone mini-jack off my laptop drives 8-30 ohms max, I merely bypassed this failed preamp . My Carver amp has one of those "fine-tuning" adjustments, so I dialed in the level to match...I just don't have the multiples of input choices.
-------------------------------------------------------------------------------------------------------------------Rick...
Here are the specs. The preamp line stage has ridiculously high gain, so you won't have any problems,
even with the lower than usual phono stage gain. The impedance matching is fine also.
Output impedance: 1.2k ohms (main), 150 ohms (tape). Input impedance: 47k ohms.
even with the lower than usual phono stage gain. The impedance matching is fine also.
Audible Illusions Modulus 3A preamplifier
Phono section gain: 28dB at 1kHz (MM), 27dB (MC). Line section gain: 30dB.Output impedance: 1.2k ohms (main), 150 ohms (tape). Input impedance: 47k ohms.
The paralell86 input sensitivity is 2.25 Vrms so it considerably higher than the Audible Illusions M3A output voltage of 1.5V pre out. This doesn't fall within guidlines that preamp output should be => than amp input sensitivity.
"In principle" and lately with VERY rare exceptions, preamp output impedances are low and can drive almost any amplifier unless it uses some niche interface such as 600 ohm balanced.
And amplifiers in general strive to show 10k input impedance or higher.
Combine both and you´ll see that matching is a given, and requires detailed specs only if deviating from that.
But most user manuals state them anyway.
EDIT:
Care to share the schematic?
Googling parallel86 yields countless ECL86 schematics and a lonely PCB picture.
You should have said so earlier, not wait for a generic answer (which is perfectly valid) and then argue it.
And amplifiers in general strive to show 10k input impedance or higher.
Combine both and you´ll see that matching is a given, and requires detailed specs only if deviating from that.
But most user manuals state them anyway.
EDIT:
So YOUR amplifier is hard to drive.
Care to share the schematic?
Googling parallel86 yields countless ECL86 schematics and a lonely PCB picture.
You should have said so earlier, not wait for a generic answer (which is perfectly valid) and then argue it.
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Standard was set at 1.6 Vrms in 1961 by macintosh & dynaco. Most PA amps will take 2.0 Vrms, with variable gain for preamps/mixers that produce less voltage.
12AX7 vacuum tube output preamps will not drive 100 kohm or less input impedance amps. Most transistor & op amp output preamps will drive that low.
I'm not saying it is hard to drive. I was hoping someone could tell me if a preamp with .75V pre out less than an amplifier input sensitivity could pose a problem.
The Audible illusions M3A pre out is 1.5V and the Paralell86 intput sensitivity 2.25Vrms. The .75V is the difference between them that I'm concerned about.
Short literal answer to what you asked: your preamp will not drive your power amp to full power.
Short practical answer: your preamp most probably can put out way more than 1.5V RMS which is the nominal output.
So most probably it can drive your power amp well.
For a better answer we´s need useful preamp specs as in: acceptable load impedance , maximum/clipping voltage level, etc.
Sadly preamp page only shows useless junk such as:
As you see, not only the "voltage difference" is important, impedance is a big factor too.
Glad to help further but we lack important data.
If you can find it, it´s welcome.
EDIT:
asking again: we need Parallel 86 schematic which I guess is known, or at least a clear statement about its input impedance.
If you are asked for data and not provide it, how do you expect us to answer?
Short practical answer: your preamp most probably can put out way more than 1.5V RMS which is the nominal output.
So most probably it can drive your power amp well.
For a better answer we´s need useful preamp specs as in: acceptable load impedance , maximum/clipping voltage level, etc.
Sadly preamp page only shows useless junk such as:
I am somewhat worried by:
which might mean it can NOT drive a, say, 10k input power amp but hey, no better data is offered.
As you see, not only the "voltage difference" is important, impedance is a big factor too.
Glad to help further but we lack important data.
If you can find it, it´s welcome.
EDIT:
asking again: we need Parallel 86 schematic which I guess is known, or at least a clear statement about its input impedance.
If you are asked for data and not provide it, how do you expect us to answer?
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My preamp has gain setting switches and can be set to 30dB or 23dB. My amp has 20dB. Would either of the preamp gain settings be preferable?
Test and decide. Connect everything while they are powered off. Set your pre to 23db. Turn things on. Play your source(s) through the pre and see if there is enough volume available for how you listen with the combination. If you run out of volume, increase the gain. Test again. Go up to 30 if needed. Typically it is better for signal to noise ratio to operate with the least amount of gain for your use case.
That’s the simplest empirical way of seeing if you have a good match.
Good luck!
That’s the simplest empirical way of seeing if you have a good match.
Good luck!
I built a Parallel86 and know input sensitivity is 2.25 Vrms, input impedance is 48k and gain is 20dB.
If you increase the gain to 26dB, your sensitivity will be cut in half. See the preamp's Stereophile measurements and decide what distortion level is acceptable but there's no 1.5V clipping on display.
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Thanks.
In principle your preamp "should" be able to drive it to full power.
Seeing Preamp schematic would be great; lacking that you can actually test it. which of course will provide the definitive answer.
I would load preamp out with a 47k 1W resistor, scope it, drive it to clipping, lower drive somewhat so it does not clip any more, and measure RMS voltage.
Hopefully way higher than 2.25V ; the difference in dB will give you available headroom.
As an extra test, I would load it with 10k and repeat test, to know how "universal" that preamp is, given that many SS power amps have 10k input impedance or nearby.