Amp Gain / Amp power

[av_phile]

12 volts, still high. Saw an Aragon line stage preamp whose spec says Unity Gain. So I can expect the 1V input to remain 1V at full volume if i mated this to the Acurus, right? With the tono or anything like it with a gain of more than unity, i'd expect the volume control to be just in the 8 or 9 o'clock position and I'll be close to clipping, right?

[arnoldc]

a unity gain will be perfect for power amps with 1V sensitivity, right. additional gain will be useless.

[RU9]

With the tono or anything like it with a gain of more than unity, i'd expect the volume control to be just in the 8 or 9 o'clock position and I'll be close to clipping, right?

Yes, that is my experience with the Rotel amp, Input impedance/Sensitivity = 33K Ohms/1 volt.

[av_phile]

Yes, that is my experience with the Rotel amp, Input impedance/Sensitivity = 33K Ohms/1 volt.

I think this is precisely what happens for most integrateds and receivers out there where you can reach full volume at the 10 o'clock or 11'o'clock volume positions. Either the gain of their internal preamps overdrives their internal amps, or their volume potentiometer is not linear enough.

I noticed this when my Onkyo receiver's preamp died on me. Using a Rotel preamp with the standard 1V output connected to the 1V input-sensitive main-in of the Onkyo, I wasn't getting anywhere near the loudness of my former set-up at the same volume setting. My listening volume setting shoot up to 3 o'clock for the same loudness. Seems to me that the internal preamp of the Onkyo had a higher gain than the external Rotel preamp.

I think this is another marketing ploy for some receivers and integrateds to impress the market. A customer will just exclaim, "if it sounds loud at 10 o'clock, how much more when full!!!" Knowing fully well no salesman will ever allow his wares to be tested at full volume.

[RU9]

I noticed this when my Onkyo receiver's preamp died on me. Using a Rotel preamp with the standard 1V output connected to the 1V input-sensitive main-in of the Onkyo, I wasn't getting anywhere near the loudness of my former set-up at the same volume setting. My listening volume setting shoot up to 3 o'clock for the same loudness. Seems to me that the internal preamp of the Onkyo had a higher gain than the external Rotel preamp.

Hi avphile,

If I get another tube preamp, what are the specs that I need to know,
to match my Rotel? Need to avoid costly mistakes.

Thanks.

[arnoldc]

RU9, you have several options:

1. passive linestage (no tubes, and no gain)
2. unity gain linestate (tubes, typically 0 gain, sometimes a little bit negative 0.9dB for example)
3. tube buffer (such as the musical fidelity X10D)

[av_phile]

RU9

Arnoldc gave you the options you can take. Any of the them will do well. Just be guided by the 1V sensitivity of your ROTEL to reach full power and see if the preamp's output at FULL volume is in that range. I think even a 2-3V pre-out is just fine. You just can't bring the volume to its max without serious clipping. Personally, in the interest of audio purity, a passive preamp that simply gives you input choice selection ability, a volume control and a record out control is sufficient.

I know some audiophiles with good commercial CD players that have variable output connected directly to a power amp. (Almost all CD players output in the 1V-2V peak to peak max, which is about the input level a typical SS power amp expects.) They just use the output level control on the CD player as their volume control. They ofcourse lose the flexibility of having selectable input choices. Not elegant, but it does eliminate anymore active or passive circuits in the signal path, especially if you're listening exclusively to CD. OTH some audiophles criticize these buffer or op-amps in many commercial CD players as inadequately designed and introduce some unwanted sonic artifacts. Your call.

[RU9]

Thank you, Arnold and Av_phile

RU9

[vintage_dog]

ru9,

send me a pm. you can bring over your rotel at home and try them out with different preamps and speaker combinations.

i have a tube buffer/unity gain preamp, a passive, a few actives with different gain. you can then decide which is best.

also, i use my tono for some of my amps..some with very sensitive inputs. on some amps, i can only bring the control to 9oclock max. that does not bother me at all because what i'm after is the sound, and not the setting on my volume control.

[RU9]

ru9,

send me a pm. you can bring over your rotel at home and try them out with different preamps and speaker combinations.

also, i use my tono for some of my amps..some with very sensitive inputs. on some amps, i can only bring the control to 9oclock max. that does not bother me at all because what i'm after is the sound, and not the setting on my volume control.

Thank you VD, but I am here in Zambo City.

I was hoping to learn preamp amp matching and the the TONO's design.

I can live with the Tono preamp, just must be extra careful not
to overdrive my speakers.

[dogears]

Binasa ko nga't di ko din naintindihan I was hoping I can understand what I could find here [this thread] but I can't.

Tingin din ako sa ibang site and here's something that I think is a good read for you guys:
http://mitglied.lycos.de/Promitheus/equ ... preamp.htm

[JackD201]

Mods please move to Tech Archive. Tnx guys!

[tony]

What's the general relationship between amp gain and amp power? If gain is the ratio between input signal and output signal, how does power come into play?

amp gain as explained by others before me is the ratio of output voltage to input voltage.

amp power is like this, supposing you have an amp rated 100 watts at 8ohms. output voltage then is given by this relationship:

Vout = sqrt[100*8] = 28.3 volts

so if 1volt is needed to drive the said power amp to full output:

gain then becomes 28.3/1 or simply 28.3.