Changed preamps. Seems like less power now?


I recently changed my preamp from a Rotel 1070 to an Anthem TLP-1, and have noticed that my system seems to have less power. I have to really push up the volumn to get any decent high levels, where is with the other preamp, it got very loud easily. Does a preamp effect the output of the power amp. I don't know if I should change it back out, or maybe go with a higher powered amp. I run Thiel CS.5, and they seem to be hard to drive compared to some other speakers I have owned. Thanks for any help
jeffo19
Different preamps provide different amounts of gain. Some may provide only say 6 db. of gain, some as much as 26 db. or more. Depends on the design of the preamp. This variance definitely means there is some degree of component matching required. However, just because one preamp requires more rotation of the volume knob than another may mean nothing other than the taper of the volume control is diffferent. I believe your Anthem works in .5 db increments, so that may mean you've really got to rotate it if your your amp is of a lower gain design and/or your speakers are inefficent. When you crank it up, is it sufficiently loud for you? If it is, don't worry. It's generally worse to have a preamp with too much gain as your volume adjustment is imprecise and it may affect the signal to noise ratio adversely.
It sounds as if your new preamp has lower voltage gain than your previous one. Yes, the preamp can affect the output of your power amp as it amplifies the signals from your front end so that it can be used to drive your power amp. There is nothing inherently wrong in using a higher volume control setting unless you start amplifying noise. If your preamp doesn't have enough gain, however, it could not drive your power amp to full power. Going to a higher-powered amp may not necessarily cure the problem. Going to a power amp with higher voltage gain, even though the ultimate power output may not be higher, is probably the solution you are looking for. If your disc player or phono preamp has variable gain you could increase the gain on these to account for the lower voltage gain of your preamp.
If I'm understanding your question....Don't know the specs of the PA's you mention but...it's likely an issue of higher gain (i.e. resulting in greater signal strength to the PA outputs) with your old PA. You SHOULD be able to attain the same volume, albeit, with the volume control closer to 100% with the new one as the old one... Some PA's (e.g. the Calypso) have a jumper that you can change gain (check your manual)...and affect volume control range. Generally speaking, if the (unclipped)volume that you attained before cannot be (mostly) attained with the new pre. there's probably something wrong with the PA(or one of your pres has a really exotic design/gain). Yes, absolutely, a speaker change will modify the volume but...that's a whole 'nother discussion.
The previous preamp was very sensitive, but also would only be at say 10:00 O'clock position at a given loudness, while the other one has to go to 2:00. I am thinking that maybe I should match my components, and use an Anthem power amp. Wheather or not that will make a difference or not, I don't know.
I have an Anthem AVM-30 in my HT system and as Photon notes it does have .5 db increments, which means several clicks on the remote to get a significant volume change. This is nice if you're looking for subtlety but it does seem like you're really turning it up to get loud, and the volume control is a continuous type which also exaggerates this effect. It does look like that model doesn't have a lot of gain but as everyone says, if you can get it loud enough and it's still quiet and sounds good then you're fine.

Oh, and mine has an adjustable "power on" gain level (mines set around -30db) this might help get you started closer to your normal listening level.
Yeah. I like that feature. I did not know it was adjustable. Still going through the manual. The Volume range on this shows -80dB to +8.0 Odd. -30 is quite low, and I have to bring it up to -15 for decent volumn, and that's with a 130W power amp. The -80 to -50 range almost seems inaudible to me. I use to have an Arcam that allowed you to change the increments, but I don't think this has that option.
Adjustable increments seems like a nice feature, haven't seen it in the Anthems. You may have adjustable input levels which will also affect your output, but it's more important to level match between inputs (if your signal's good you might use the tuner as a reference).

I would be worried if "0" wasn't loud - near as loud as you ever listen (that doesn't mean your system can handle "0", you be the judge of that.) I think you can expect the preamp to be within its capabilities at 0 (unless your input is very high which it doesn't sound like it is.) I regularly listen between -20 & -10, occasionally louder, rarely I've hit 0 and above (and when I do I'm not worried about my preamp).
Alright. So for Anthems, -20 & -10 is normal. I figured that if +8 was the Max, and the Min is -80, then -20 would be extremely loud, but I guess this is just how they are.
As others have noted, it could be the anthem has lower gain. It could also be an issue of the type of profile for the volume control (linear vs. logarithmic).

With regular potentiometers, it is actually preferrable to be working toward the higher range (less attenuation) because the two channels of the pot tend to track better. With stepped attenuators, this is less of an issue, and often the steps are wider near the top and bottom of the range, which makes it harder to find an ideal position.

As long as you can get your system as loud as you want with the Anthem, I don't see any real problem with having to operate the volume control at the higher end; this may actually be an advantage.