Questions about preamplifiers

[arbalest]

I am a vintage integrated-amp, vintage receiver kind of a person and sometimes a user of AVR type stuff to drive 2 channels. So, I don't have direct experience with preamplifiers and I have accumulated some general questions that I am not finding good answers for via searching.

0) I am not talking about some passive device that is mostly for input selection.

1) On occasion I think about using a T-amp (I mean something real small as I am not clear on the class distinctions) to drive some speakers and invariably someone will suggest putting a preamp in front of it. I thought the beauty of these amps is be minimalist and that seems to be defeated by adding a separate box. Would I get a significant improvement in sound with the addition of another tiny box in the form of a preamp? I was thinking that this arrangement would be driven by a phone's wired earphone plug, a BT adapter or a CCA.

2) I have some thrift finds like my Pyle PAMP 1000 which I had future plans for but running a phone to the Pyle to speakers has not been that impressive. Would a preamp really be called for in this case?

3) I also picked up a Ramsa WP-9055 amp which has XLR inputs. I've read that since this is considered "
pro" equipment it is expecting input voltage levels a lot higher than my consumer stuff puts out. Are their preamps that bridge this consumer/pro divide? Would a regular preamp be sufficient?

4) Searching Amazon just now (for info, not to buy) I see a few tiny tube-based preamps. They sure are cute but would this actually contribute to the "tube experience" for us solid state folks? I mean, is this a gimmick or not?

 

[sqlsavior]

A mediocre preamp is where the sound from a good source goes to die.

The weakest part of a chip amp is often its volume control pot.

If your sources are robust, and your amplifier's input impedance is high enough, you could do a lot worse than 0).

I believe @Poultrygeist has found a good example of 4) in something called a Sain-Smart, IIRC. I wouldn't count on just any of them (4) to sound good. Somebody else likes Nobsound.

 

[Rex81]

1) No, a preamp wouldn't really improve anything. A lot of these little amps have two inputs: 1 set of RCAs, and one 3.5mm. If you don't need more inputs, and you don't need more power, just run one of these. Many (especially those based of the TPA3116 chips) sound excellent when operated within their limits. If you have reasonably efficient speakers (more than 90db for instance), just hook up a Chromecast Audio and enjoy.

2) The Pyle is technically an integrated amp because it has input switching and volume control, so again, a preamp wouldn't really help you here either. I don't have any experience with this model, but Pyle is not known to be particularly high end sound. You would likely do better with a chip amp like above. However, no chip amp would deliver the power the Pyle has. If your speakers are a difficult load, this may be your best choice.

3) This may or may not be a problem, depending on the amp and your speaker sensitivity. Try plugging your stuff in directly, and if you need more output, you can get one of these: https://smile.amazon.com/dp/B0002IL...e-scomp-wm-4-wl-prc1&ref=bit_scomp_smile_sav1

4) You're most likely referencing a "tube buffer". Some people say they add just that little bit of tube "sweetness". In my experience, it's more a gimmick. If you want to play around and experiment, that could be fun, but don't go in expecting a big difference.

 

[whoaru99]

3) I also picked up a Ramsa WP-9055 amp which has XLR inputs. I've read that since this is considered "
pro" equipment it is expecting input voltage levels a lot higher than my consumer stuff puts out. Are their preamps that bridge this consumer/pro divide? Would a regular preamp be sufficient?

You have read a widely spread old wives' tale/urban legend, based on misunderstanding of the relevance of "consumer level" vs. "pro level". These levels refer to fixed level outputs such as Rec Out, it does not apply to the variable level pre out / power amp input type of connection.

The input sensitivity of the Ramsa is +4dBu which is 1.23V. 1.23V is right in the meat of the normal range of input sensitivity for power amplifiers. Practically any active preamp on the planet should be able to put out more than that. In fact, most of the time, despite being a "pre amplifier", a pre amp is attenuating the signal of the source device. The routine exception would be in the case of a turntable where the miniscule output of a phono cartridge pretty much always requires a boost/gain to make any useful sound happen.

That said, where one could run into more of a concern is with the input impedance. Pro amps typically have lower input impedance than many "consumer" power amps. In the case of the Ramsa it is 40k balanced so it probably would be 20k if you used an unbalanced connection scheme. 20k is on the lower side relative to typical consumer amps, but it is not impracticably low. Most pre amps will have no problem with that. Where you might run into a problem would be using a source direct, passive volume control, or a pre amp if either had (relatively) high output impedance.

 

[arbalest]

Here is a refinement to the question item #2 above. If I run my cellphone earphone jack to the Pyle amp plus a pair of speakers, then I turn up the volume to the max on both the phone and the Pyle it is a little louder than normal listening levels. When I replace the earphone to input cord with a Bluetooth adapter the comparison is similar.

But if I run the phone to some old AVR around here and run the "pre-out" of the AVR to the Pyle then to speaker volume is very much louder and it also sounds really good to my ear.

So okay, all this tells me is that the pre-out is amplified a bit and that this arrangement is quite satisfying except for the overkill. I think I would do as well skipping the Pyle and just using the regular outputs of the AVR. It also means the Pyle by itself with the addition of a set of speakers is not so satisfying and maybe less useful than a T-amp as a spare room or outdoor system. And if I try to solve this problem with yet another component like a tube-buffer I'll be barking even louder up the same wrong tree.

It looks like I am trying to combine thrift finds with good (but not great) excess speakers from around the house PLUS the addition of a new purchase (preamp/bluetooth adapter/CCA) to just to get the equivalent if a good powered Bluetooth or Wifi speaker. I guess the question is just - is it true that because I can use the Pyle (or similar) direct this way, it doesn't mean that I should?