[CameronA]

I've been looking into buying a TEAC AL700P, but college has me at a budget and i've been having a hard time finding an affordable preamp. The TEAC has volume pots on the back, but from what i've heard they're not the best to use, so i've been looking for an affordable and reasonable way to control the volume.

I have a component switcher lying around the house, so to my knowledge all I really need my preamp to do is adjust the volume.

This popped up after browsing around these forums: (scroll down to see the SonoSilence Two)
http://www.sonocable.com/products_silence1.shtml

It has seperate L/R volume controls, which should fix balance issues, and I have the budget to afford upgrades on it, but I have ONE big question.

Is this what i'm looking for? I'm afraid i'm not entirely clear on the function of using a seperate amp/preamp, will the SonoSilence Two and the TEAC AL700P give me all of the functionality i'm looking for?

Thanks!

[ghersh]

I've been looking into buying a TEAC AL700P, but college has me at a budget and i've been having a hard time finding an affordable preamp. The TEAC has volume pots on the back, but from what i've heard they're not the best to use, so i've been looking for an affordable and reasonable way to control the volume.

I have a component switcher lying around the house, so to my knowledge all I really need my preamp to do is adjust the volume.

This popped up after browsing around these forums: (scroll down to  ...

My first reaction when I took a look at  that mode  - what's inside? Certainly not Alps. For less than a $100, I doubt you'll get something decent.

If separate channel control is important to you, take a look at

http://tweakaudio.com/EVS-2/Ultimate_Attenuators.html

They don't look that fancy, they are more expensive ($350), but they have excellent track records. No, I don't own one, but I'm in the same position - looking for some kind of passive preamp, and this is one of the options I consider.

[CameronA]

My first reaction when I took a look at  that mode  - what's inside? Certainly not Alps. For less than a $100, I doubt you'll get something decent.

If separate channel control is important to you, take a look at

http://tweakaudio.com/EVS-2/Ultimate_Attenuators.html

They don't look that fancy, they are more expensive ($350), but they have excellent track records. No, I don't own one, but I'm in the same position - looking for some kind of passive preamp, and this is one of the options I consider.

That just feels odd spending 100$ on an amplifier and 350$ on a pair of volume controllers.

Is there no low cost alternative to volume control?

[skrivis]

That just feels odd spending 100$ on an amplifier and 350$ on a pair of volume controllers.

Is there no low cost alternative to volume control?

You could build your own, it doesn't involve rocket science.

Or you can get a kit preamp from AVA for $499 and that will sound much better than any passive "preamp." It's what I have for my system. It wasn't very hard to build the kit either. http://www.avahifi.com/root/ordering_info/price.htm#preamp

[skrivis]

My first reaction when I took a look at  that mode  - what's inside? Certainly not Alps. For less than a $100, I doubt you'll get something decent.

If separate channel control is important to you, take a look at

http://tweakaudio.com/EVS-2/Ultimate_Attenuators.html

They don't look that fancy, they are more expensive ($350), but they have excellent track records. No, I don't own one, but I'm in the same position - looking for some kind of passive preamp, and this is one of the options I consider.

Cripes! I just looked at their site. That's one of the most moronic things I've ever seen. You're putting a bunch of weight on the input jacks, so you can tear them out. And there's absolutely no shielding.

Furthermore, there's a really good chance that one of these things will fall right out of the input jack since it's so heavy and clunky. That could send a transient heading right for your expensive speakers.

[ryno]

Don't forget Channel island audio, They have a forum here. I have their passive pre and their DAC on my teac, both sound very nice.  Two inputs and volume.
Ryan

[JeffB]

CameronA,

You have about 4 different ways to control volume.
1) Passive.  Since there are no active circuits and the signal path is short there is the possibility for excellent sonics if your source and amplifier are well matched in terms of impedance, and your interconnects are very short and of extremely low capacitance.  The main expense here is the type of volume control.  You can spend anywhere from $3 to $400 for a volume control.  The downside to passives is that there is no buffer to deal with impedance mismatches.  This can result in a harmonically thin sound and harsh treble.  Passive can be found for between about $200 and $1000.

2) Active.  Actives provide a buffer to deal with impedance mismatches.  Actives need power to drive the current through the volume control.  A quality active preamp can get very expensive.  You can spend as much money as you want on power supplies and power conditioning trying to eliminate noise in the circuit.  Actives generally provide more harmonic richness along with a little more noise and distortion.  Actives can be found for about $200 to $infinity.

3) I know of one passive, the FT-Audio little wonder that uses an X-coupler to help deal with impedance mismatches while still being a passive.  The reviews on the unit are good, but I have not heard it.  I think there are good Actives that are better than this unit, but at more cost.  This unit is about $550.

4) Transformer based preamplifers.  These are also passives, but use a transformer to deal with impedance mismatches.  These seem to be fairly new and look to possibly provide the best of both passives and actives.  But transformers are non-linear devices so it is still difficult to say for sure.  These range from $1000 to $2000.

In case you haven't figured it out, all a preamplifer does is provide switching and volume control.  Some preamplifiers can provide gain.  This is needed for phono to boost the input signal to a level the amplifier can handle.  Also some Tube amplifiers may require some gain applied to the source to drive them.  Most CDs put out 2 volts and most amplifiers require 2 volts to reach full volume, but this varies from device to device.  Some tube amplifiers need 3 volts.  Phono stages put out milli-volts.

For passive units to work, your source should output 2 volts and your amplifier should reach full volume at 2 volts.  You also need the source output impedance to be low(<1000 ohms) and you amplifier input impedance to be high(>100,000 ohms).  If you're passive has a 10k resistance, then you have a 10x difference between a 1000 ohm output and the passive input.  10x is considered the minimum delta for this configuration to work.  The resistance will increase as the volume is turned down.  The increased resistance raises the output impedance of the preamp, which is bad.  So you also need the 10x factor between the preamp's output impedance at low volume and the amplifier's input impedance.

[Jon L]

Cripes! I just looked at their site. That's one of the most moronic things I've ever seen. You're putting a bunch of weight on the input jacks, so you can tear them out. And there's absolutely no shielding.

Furthermore, there's a really good chance that one of these things will fall right out of the input jack since it's so heavy and clunky. That could send a transient heading right for your expensive speakers.

Umm, Rick Schultz does not do too many things that would qualify as "moronic" in general.  I don't think he'll appreciate that comment, at all, because you have obviously never used EVS ultimate nude attenuators.  

I have used a pair for a very long time, connecting/unconnecting literally hundreds of times to dozens of equipment and cables.  Not once did it come loose, "send transients," or add RFI noise, or break any jacks.  I am actually quite amazed how Rick was able to make it so grippy and sturdy.  

Of course, I couldn't give rat's a$^$ about all that if the darn thing didn't sound so transparent.  It's VERY far and few between preamplifers at any cost that has the transparency of EVS Ultimates.  You'd better be careful b/c if Rick sees your post, he's likely to throw one of his Virtual Dynamics Master interconnects at you  

[Steve]

Dear CameronA,

To be up front, I am a manufacturer.
In your case, on a  budget, my advice is get something cheap, just to get by. College is more important.

For educational purposes, a certain amount of gain is needed before the output devices in any amplifier. No way around it.
A passive device is simply a volume control, while all the necessary gain is incorporated in the amp. In otherwards, the preamp gain stage is put in the amp, often called an integrated amp.

The question then becomes whether incorporating this gain stage in the amp is better than an outboarded gain stage with an Interconnect. Depends on the quality of 1st gainstage in the amp vs the gainstage of an outboarded stage (Preamp) and interconnect.

For average to much above average quality, an integrated is great for the buck, no doubt about it. But there are at least minor, if not major problems in this configuration too.

For the ultimate in audio, separates can be quite superior. But it costs more, maybe much more.

Hope this helps.

[CameronA]

Thanks for all the advice guys.

I've been sufficiently confused to now believe that if I buy a budget preamp I will blow up in a catastrophic explosion, so i'll be buying the next sonic impact t-amp that comes by.

Spending 400$+ to power a pair of paradigm titans is a little far out for me, especially when I want to upgrade my source. I think i'll wait until summer when i've got a full time job and maybe then i'll be back here.  

[ghersh]

Thanks for all the advice guys.

I've been sufficiently confused to now believe that if I buy a budget preamp I will blow up in a catastrophic explosion, so i'll be buying the next sonic impact t-amp that comes by.

Spending 400$+ to power a pair of paradigm titans is a little far out for me, especially when I want to upgrade my source. I think i'll wait until summer when i've got a full time job and maybe then i'll be back here.  

The bottom line is that the cheap passive preamp may sufficiently degrade the sound. I would rather hunt for inexpensive integrated.  Just do some searches. For instance, here is a review of inexpensive integrated for under $300.

http://www.soundstage.com/fringe/fringe031999.htm

[ryno]

Excuse my thread jacking, but how do most integrateds work? An amp with a passive volome control, so a passive pre and an amp would be the same, only in two boxes. Or do they have an active pre section with an amp section.
Ryan

[JoshK]

Excuse my thread jacking, but how do most integrateds work? An amp with a passive volome control, so a passive pre and an amp would be the same, only in two boxes. Or do they have an active pre section with an amp section.
Ryan

Many do the prior but there are quite a few that have active preamp sections as well.  Case in point, my Perreaux integrated has dual mono active preamp section in addition to a dual mono amp.

[Steve]

Excuse my thread jacking, but how do most integrateds work? quote]

There are alot of different designs, but T will try to keep it as simple as possible.

Integrated amps are very sensitive, sometimes down to .5 volts for max output. But even at 2 volts sensitivity, it May be that sensitive because an extra stage is included for more sensitivity. The theory being that one can rid of the preamp power supply, extra chassis, ICs etc, thus less expensive and at the same time better sounding. So, in essence, the preamp active stage is incorporated into the amp. What is left is basically a volume control of some sort, usually external.

Unfortunately, theory and practicality are two different things, if we are talking about ultimate designs and ultimate sound quality. And let's face it, the budget is the controlling factor for almost all of us. Integrates make alot of sense, a terrific bang for the buck.

Now, the important question is how well the 1st stage of the amp is designed. Is it as good, or better than an outboard stage with an extra IC.

That is why comparing actives to passives is like comparing apples to oranges. The passive isn't checked with the following gain stage. When both are compared to an active, the active may win out.

Another question is how good is the CD players analog stage, usually an OP amp. I'd rather bypass that stage more than any other stage, basically use an active preamplifier to replace the op amp. But that is a chore, and no manufacturer will run separate outputs, bypassing the op amp for the average consumer. So the sound quality suffers.

Anyway, my .02 worth.

[bundee1]

Luminous Audio Axiom passive preamp. $162 shipped with the upgraded Caddock resistors. 1 input but it is the cleanest sound I have ever heard. Money back gaurantee as well.

[skrivis]

Umm, Rick Schultz does not do too many things that would qualify as "moronic" in general.  I don't think he'll appreciate that comment, at all, because you have obviously never used EVS ultimate nude attenuators.  

I have used a pair for a very long time, connecting/unconnecting literally hundreds of times to dozens of equipment and cables.  Not once did it come loose, "send transients," or add RFI noise, or break any jacks.  I am actually quite amazed how Rick was able to make it so grippy and sturdy.   ...

I'm glad you've been lucky so far.

I don't need to use something to know that it's engineered poorly.

I'm not thrilled with passive "preamps" in general. They will normally change the sound by loading down the source beyond its limits, but I don't feel that this is an improvement.

Once you throw a couple of pots in the signal path, it's too much to expect to then have the source drive the amp inputs too.

Those EVS nude attentuators would be quite useful if built into the amp chassis, they do look like they're well done as attenuators. Where I disagree is with them being unshielded and hanging off the input jacks.

I also feel that not using an active preamp is a concept with very limited use. There are a number of preamps that are done quite competently and won't harm the signal.

There are also far better places to put your money. All these fancy switches and wires, assuming they actually provide a benefit at all, are working on the micro level. Many power amps and all speakers have problems at the macro level. Why spend your money on things that make minute differences when there are far larger problems in your system that need to be fixed first?

[tschanrm]

If you want to see how a passive pre-amp sounds, build this:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=2608&perpage=10&highlight=%22passive+preamp%22&pagenumber=1

Cheap to do (about $20 in parts), and sounds good as long as you're amp has a higher input impedance (50k or 100k) and you run short cables.  I built the passive above, liked the sound, and then built another one around an alps blue velvet which I still use today.  Granted I do tolerate the shortcomings of a passive pre, such as short interconects.  Currently I'm using 6 inch interconnects for my passive pre-amp, so my power amp is backwards in the cabinet.  

Written below is some other info that I've found about passive pre-amps.  This is my personal take on my homemade passive-pre from mesurements-subjectively and through the computer, so please don't be overly critical.

The most important cable I think is the one that goes from the passive-pre to the amp.  I've done testing in Rightmark Audio analyser to see how cables interact with my pre.  Using a 6 inch cable from pre to power amp is fine, using a 6 foot is not.  In fact, I couldn't even reliably test in RMAA with the 6 foot cable from my passive to my power amp.

I always hear people complaining how they lose treble from using a passive pre.  Well, with my passive pre and 6 inch cable I tested a frequency response of -.3db at 20khz and -.2db at 20hz in RMAA- basically the tolerences of my power amp.

Now using a 6 inch from source to the passive pre-amp is of course fine.  Oddly enough, when I used the 6 foot cable going from my source to my passive pre, there was no major measurable difference between using the 6 inch and 6 foot cable.  I did feel a loss of detail, though thats due to the fact that I have 5 1/2 more feet of cable going from my source.


Some things to know about passive pre-amps.  First, the 100k pot will lose about 1db at minimum attenuation (meaning the volume control is turned all the way up).  Switching to a 20k pot will give you a 6db drop at minimum attenuation.  Read page 12 in the link I gave above for more info about attenuation  The advantage to using a smaller resistance pot is that you have more lower volume control to work with.  A 100k will get louder more quickly than a 20k pot.  Anyway, just some info to get you started.  

Try building the passive preamp, its really easy even if you;ve only used a soldering iron once.  If you don't like the sound of a passive pre-amp, you've found out in a cheap way, not expensive way.

[roymail]

OK, everyone has an opinion and some experience, I assume, to base it on.  As a passive user for more than a year and a true believer, and as a guy on a audio budget, here's mine.

I use a DACT CT2 10K stepped attenuator.  It's made the most noticeable difference in my small system... it puts my integrated to shame.

I would suggest you try one but no need to spend alot a this point.  First, I recommend an impedance rating of approx 50 to get sufficient volume using a 10K passive.  Your CD player will probably output 2 volts which is plenty.  Keep cables no longer than 3 ft (the shorter the better).  I've heard good things about the Luminous which is probably as cheap as I would go.  For a quality stepped attenuator, consider Goldpoint, DACT or the new Red Wine Audio model... all under $300 I believe.  Also, you may want to check out the Sonosilence standard model or the Channel Island passive.  Watch Audiogon.com for some used deals.

As far as passives rolling off the treble or upper frequencies is concerned, that's nonsense.  If anything, mine got better, and my system is modest.  Just some things to consider.

[skrivis]

I have no need for a passive switchbox. My preamp does a wonderful job.

I'd rather spend my money on solid engineering than snake oil.