Hello, I'm going to get an Aleph 3 DIY power amplifier, and I'm wondering if I could in the future use the Pearl 2 phono preamp to put directly to the Aleph 3 the signal of my MM cartridge (obviously through a volume control pot). I would be grateful if you give me an idea of the signal levels involved in this chain and related others (MM/MC, line, power amp input and so on) and necessary gains.
Thank you very much!
Thank you very much!
^ What information are you having trouble finding using Google or similar?
Show what you've found. All the information you're requesting is likely just a simple search away.
Look up -
"Gain Aleph 3"
"Input sensitivity Aleph 3"
"Gain Pearl 2"
For your cartridge, the output voltage should be spec'ed or...
Look up -
"Average output for MM cartridge"
"Average output for MC cartridge"
Then...
What is the sensitivity of your speakers?
Do you need more gain?
Does either the output impedance of the Pearl 2 or the input impedance of the Aleph 3 factor if you put a volume pot in the middle of those two components? Any particular value? Would you be better off with a buffered unity gain pre-amp?
That might get you started to answering your own questions.
Show what you've found. All the information you're requesting is likely just a simple search away.
Look up -
"Gain Aleph 3"
"Input sensitivity Aleph 3"
"Gain Pearl 2"
For your cartridge, the output voltage should be spec'ed or...
Look up -
"Average output for MM cartridge"
"Average output for MC cartridge"
Then...
What is the sensitivity of your speakers?
Do you need more gain?
Does either the output impedance of the Pearl 2 or the input impedance of the Aleph 3 factor if you put a volume pot in the middle of those two components? Any particular value? Would you be better off with a buffered unity gain pre-amp?
That might get you started to answering your own questions.
Thank you for having helped me to rearrange ideas, I'm not really confident with amplifier gains and sensitivity concepts (RMS, peak) and with MM/MC differences beyond voltage output (load impedance and capacitance).
So far, Pearl 2 should work well for my purpose having 55 dB of gain, but I don't know/understand if its input stage match an MM cartridge in terms of impedance and capacitance, or I have to modify something.
More, I know that Aleph 3 has 22 Kohm of input impedance, but I haven't found what's the Pearl 2 output impedance, so will it be good a simple pot of 2.2 kohm between Pearl 2 and Aleph 3, without a buffer stage?
Any desire for help and clarification on what has been explained will be precious for me, thank you very much.
Found only gain, 20 dB (= 10x), from which I surmised that, for a 30w output on 8 ohm, and so for about 16 volt (16*16/8 = 30) RMS (?) of output, I could have an input sensitivity of 1,6 volt (RMS?), am I right?
Found that MM has 3-6 mV, MC 0.3-1 mV, let's say MM 4.5 and MC 0.6, so using an MM cartridge, to reach Aleph sensitivi of 1.5 volt I need about 330x of gain, which is 50 dB, am I right?
So far, Pearl 2 should work well for my purpose having 55 dB of gain, but I don't know/understand if its input stage match an MM cartridge in terms of impedance and capacitance, or I have to modify something.
More, I know that Aleph 3 has 22 Kohm of input impedance, but I haven't found what's the Pearl 2 output impedance, so will it be good a simple pot of 2.2 kohm between Pearl 2 and Aleph 3, without a buffer stage?
Any desire for help and clarification on what has been explained will be precious for me, thank you very much.
Perfect! This is an excellent beginning.
I did not double check your figures, but it all seems very reasonable.
I asked you to look up the input sensitivity to see if with the output of the Pearl 2, you will ever run the Aleph 3 to maximum power. That may be totally fine. However, in this community, there are some people that are very concerned if their source or pre-amp cannot deliver the voltage swing necessary to drive an amplifier to full-rated power into an 8 ohm load. I am not one of those people, and it seems you are not either. That is a good common ground to begin.
My approach is simply... will it be loud enough for my taste? Will there be any obvious issues? I have no concerns at running a lot of amps at 1/30th to 1/100th their rated power most of the time. Some people cry out. Again, not a concern for me, but it is worth at least mentioning.
Let's assume your numbers are perfect (we can triple check later)...
Let's go from start to finish... We'll look at it a bit differently. Let's also assume that the Pearl 2 can deal with and is appropriate for whatever cartridge you choose (for now) and that it will perform very well.
We'll assume the lowest and highest output from the cartridges - 0.6mV and 6mV. That also makes math / comparisons easier.
55dB gain => ~560X (leave out the bass gain ... that's probably part of RIAA, but I admit I haven't a clue).
What I was attempting to determine is... do you need any additional voltage gain, and if so, how much?
Output of Pearl 2 (on average) might be between 3V36 and 0V336 based on gain alone. I don't own a Pearl 2, but I'm also not sure of the highest output voltage. That would be the next thing I'd check.
"What is the output voltage limit on a Pearl 2" may be a good search.
Let's assume that since the Pearl 2 would normally be paired with a pre-amp of a relatively similar input impedance to the Aleph 3, that we can ignore that for now.
So... you know that with the highest (maybe) output level of the Pearl 2 that you can drive the Aleph 3 to voltage clipping. With the lowest output, you won't drive the amp to max power, but ... it may be plenty.
0V366 x 10 (gain of Aleph 3) => 3V66.
Will 3V66 output from the Aleph 3 be enough to drive your speakers to a volume level you'll love? Again, that's the lowest barrier...
So... everything so far seems reasonable from a voltage gain point of view.
Impedance matching and adding a pot. I'd assume that since the Pearl 2 would typically feed a pre-amp AND I'd add that most pre-amps have roughly the same range of input impedances as power amps (high enough) => therefore... I'd assume a "low enough" output impedance from the Pearl 2. So, you could possibly add a 10k pot (easy to find) and use it without a buffer between the two.
If it were me ... I might even stop with the analysis and just give it a try. I don't see anything that makes me think that it won't work OK, without danger of damaging anything or having a high frequency roll-off that would impact real-world listening.
However, I am NOT an expert. That's why I type it all out. Actual experts may see what I type... and say NO.
tl;dr - if it were me... I'd try it.
If it sounded odd to me, I'd try a unity gain pre-amp.
If it didn't play loud enough with a low output MC cartridge, I'd add some gain.
I'd make sure that if I had a high output MM cartridge that I wasn't exceeding the output of the Pearl 2. I did not look up that spec to see if it would support 3V36.
I hope even if I don't have exact figures / specs that the methodology and thought process helps.
Edited for clarity around input sensitivity => driving the amp to max power.
Edited one more time. With a 22k input impedance on the Aleph 3, a pot with a value lower than 10k may be a better choice. 5k if easy to find.
I did not double check your figures, but it all seems very reasonable.
I asked you to look up the input sensitivity to see if with the output of the Pearl 2, you will ever run the Aleph 3 to maximum power. That may be totally fine. However, in this community, there are some people that are very concerned if their source or pre-amp cannot deliver the voltage swing necessary to drive an amplifier to full-rated power into an 8 ohm load. I am not one of those people, and it seems you are not either. That is a good common ground to begin.
My approach is simply... will it be loud enough for my taste? Will there be any obvious issues? I have no concerns at running a lot of amps at 1/30th to 1/100th their rated power most of the time. Some people cry out. Again, not a concern for me, but it is worth at least mentioning.
Let's assume your numbers are perfect (we can triple check later)...
Let's go from start to finish... We'll look at it a bit differently. Let's also assume that the Pearl 2 can deal with and is appropriate for whatever cartridge you choose (for now) and that it will perform very well.
We'll assume the lowest and highest output from the cartridges - 0.6mV and 6mV. That also makes math / comparisons easier.
55dB gain => ~560X (leave out the bass gain ... that's probably part of RIAA, but I admit I haven't a clue).
What I was attempting to determine is... do you need any additional voltage gain, and if so, how much?
Output of Pearl 2 (on average) might be between 3V36 and 0V336 based on gain alone. I don't own a Pearl 2, but I'm also not sure of the highest output voltage. That would be the next thing I'd check.
"What is the output voltage limit on a Pearl 2" may be a good search.
Let's assume that since the Pearl 2 would normally be paired with a pre-amp of a relatively similar input impedance to the Aleph 3, that we can ignore that for now.
So... you know that with the highest (maybe) output level of the Pearl 2 that you can drive the Aleph 3 to voltage clipping. With the lowest output, you won't drive the amp to max power, but ... it may be plenty.
0V366 x 10 (gain of Aleph 3) => 3V66.
Will 3V66 output from the Aleph 3 be enough to drive your speakers to a volume level you'll love? Again, that's the lowest barrier...
So... everything so far seems reasonable from a voltage gain point of view.
Impedance matching and adding a pot. I'd assume that since the Pearl 2 would typically feed a pre-amp AND I'd add that most pre-amps have roughly the same range of input impedances as power amps (high enough) => therefore... I'd assume a "low enough" output impedance from the Pearl 2. So, you could possibly add a 10k pot (easy to find) and use it without a buffer between the two.
If it were me ... I might even stop with the analysis and just give it a try. I don't see anything that makes me think that it won't work OK, without danger of damaging anything or having a high frequency roll-off that would impact real-world listening.
However, I am NOT an expert. That's why I type it all out. Actual experts may see what I type... and say NO.
tl;dr - if it were me... I'd try it.
If it sounded odd to me, I'd try a unity gain pre-amp.
If it didn't play loud enough with a low output MC cartridge, I'd add some gain.
I'd make sure that if I had a high output MM cartridge that I wasn't exceeding the output of the Pearl 2. I did not look up that spec to see if it would support 3V36.
I hope even if I don't have exact figures / specs that the methodology and thought process helps.
Edited for clarity around input sensitivity => driving the amp to max power.
Edited one more time. With a 22k input impedance on the Aleph 3, a pot with a value lower than 10k may be a better choice. 5k if easy to find.
Last edited:
^ Definitely! I should have said...
using the incredible Iron Pre. It is the obvious choice.
