Preamps for the 120.....

So I ordered my 120 with the optional stepped attenuator since I will be feeding in the output directly from my phono stage, When I spoke with Bob he confirmed many are running just like that without issue but this got me to thinking....

I would eventually like to run more then just the turntable into this thing, also adding the attentuator does add an item into the signal path which I would prefer to avoid if possible....

I am going to build with the attenuator for now, but was looking at the SP14 as a possible pre-amp and have some questions.

1) As the 14 is a Tube pre-amp, how hot does it get? I know tubes by their very nature get hot (No filament glow, no electron flow ) but as this is not doing the kind of amplification that the 120 is doing will it get as hot? Reason I ask, is the Mrs prefers clean looks in our living room (I know I keep posting how she wants this and that, but in actuality she's extremely easygoing and supportive of my Hobbies, she just likes a look in the home and as she supports me with this, I support her with what she wants ) so any pre that I get would need to go in a cabinet we have (it's a closed cabinet) and I worry it would get too hot.

2) Would I get any benefits other then input switching from running my phono stage into the 14? (Phono Stage is a Tube Box DS) I know that I would benefit when running the iPod for FLAC files or the radio, but what about the phono?

3) Is this worth the $, or am I better off going SS for the Pre?


Thanks in advance as always!!!

https://www.amazon.com/TC-716-Stereo-Selector-BLACK-VERSION/dp/B0001F347K

As you have an attenuator in place, all you need is a switch. And, really, a tiny one at that. Only one of a great many is linked above.

The *primary* reason for a pre-amp to my way of thinking is for adding additional controls such as balance bass & treble, filtering if useful and so forth. And in some cases, a greater-than-standard line-level output (my Dynaco PAT-5biFet will give up to 7V out). But otherwise, not so much.

So in essence you don't need one? Just confused why people spend tons on them if a simple switch would do

I think the applicable term would be the Hebrew/Yiddish term "Yiches".

Which may be defined as the difference between the same suit from Krass Brothers or Brooks Brothers (just look it up).

Back in the day, a pre-amp gave one a phono-stage (necessary device at the time), and the means to tame all sorts of problems common to the recording industry.  And Dynaco was generally well ahead of that game as well, giving filtering, loudness contour and blend functions. Other manufacturers did other things to justify a separate box as well.

As vinyl went away, even as tape went away, the need for multiple inputs and phono amps also went away. And, the moment attenuators went onto power-amps, the need for electronics in that separate box went away.  

So, today, as long as your sources are capable of driving the amp adequately, and you do not need any sort of equalization/filtration/tone/balance controls, there you are.

Flip that around a little bit - if your sources are *not* capable of driving your amp, there are not that many pre-amps that will raise output voltage beyond what the source voltage gives - except as they include phono (RIAA), head (NAB) or microphone amps (FLAT).

While some think a preamp isn't necessary I go the other way and consider it essential. I have an SP13 in a fairly large box. Perhaps bigger than necessary but I like to give my electronics space to breathe and room for improvements. You could certainly fit it into a smaller box. That being said tube electronics shouldn't be hidden inside of a cabinet. They should be free of constraints and appreciated not only for their glorious sound but also their aesthetic beauty!

Thanks,
So why do you consider them essential? Better sound?

How much heat does that puppy throw?

I've got a VTA ST-70, an SP-14 and PH-14. The SP 14 doesn't put out anywhere near the heat from the EL-34's in the VT70. The heat from the SP 14 is hardly worth mentioning (I wouldn't leave an LP sitting on top of it though).

Cool, do you feel the 14 was worth the $?

mcgyver74 wrote:Thanks,
So why do you consider them essential?   Better sound?  

How much heat does that puppy throw?

Actually the heat from the SP13 isn't too bad but you still wouldn't want to set anything on top of it. The tubes measure over 200 degrees each!

I consider preamps essential for dynamic drive. Passive preamps get the job of passing and attenuating the signal done but you're relying on your source to drive the signal to the amp. I have found dynamic drive of the music can suffer without the extra gain of a preamp. Others feel different but it all boils down to the components you choose to put together and how well they match up.

corndog71 wrote:

mcgyver74 wrote:Thanks,
So why do you consider them essential?   Better sound?  

How much heat does that puppy throw?

Actually the heat from the SP13 isn't too bad but you still wouldn't want to set anything on top of it.  The tubes measure over 200 degrees each!  

I consider preamps essential for dynamic drive.  Passive preamps get the job of passing and attenuating the signal done but you're relying on your source to drive the signal to the amp.  I have found dynamic drive of the music can suffer without the extra gain of a preamp.  Others feel different but it all boils down to the components you choose to put together and how well they match up.

In a thread above, Peter W. said this about the subject:

So, today, as long as your sources are capable of driving the amp adequately, and you do not need any sort of equalization/filtration/tone/balance controls, there you are.

Flip that around a little bit - if your sources are *not* capable of driving your amp, there are not that many pre-amps that will raise output voltage beyond what the source voltage gives - except as they include phono (RIAA), head (NAB) or microphone amps (FLAT).

If many preamps don't raise the output voltage above the source voltage, then how could dynamics be improved?  And a preamp is just inserting another device into the chain, albeit if you prefer the influence of more tubes then that could be a good thing.  But from an amplification standpoint, if you have a DAC or other source that can output enough voltage to drive an amp adequately, then why wouldn't a source direct to amp connection using an attenuator be sufficient?  Ideally whatever passes along the source signal should just be a straight wire (i.e., doesn't modify anything), shouldn't it?

That said, I have an attenuator on my ST120 but am using a Schiit Saga preamp. I really don't notice any difference but I like the way the Saga looks.

Thanks guys

So from what I am hearing some think it helps and some don't. But I think the general consensus is that the 14 would get too hot to be in the cabinet that has been designated... Guess I will try my hand with just the attenuator for now and see how it sounds

Thanks again

I tried an SP-10 and SP-12 but both had ground loops and wouldn't stop humming so I decided to go with a factory built Cary SP-100 preamp. I thought the amp would sound better with some gain but the amount with the Cary was negligible. I then built an Akido AE-2 tube buffer and I think it enhances the sound.

However...after trying all these preamps out I then tested just plugging my CD player directly into the amp. I have the stepped attenuator and to be honest I think it sounds better without any preamp.

I love my SP 14 and PH 14. I don't have an attenuator on my VTA ST 70. Whether it's worth the money depends on what the money is worth to the buyer.

Previously I had an SP/PH 10 and there was quite a sonic improvement when I went to my current set up.

I sold my 4K tube preamp after I tried a passive preamp. I currently own 5 different passive preamps and switch between them just for fun.

I've both the SP-13 and SP-14 pre-amps, each with some Don Sachs mods (better caps, film resistors, 48-step volume controls, etc.) Either "out of the box" or tweaked a bit I wouldn't part with either. Ever!
Both pre-amps, if capped to the right values, will drive low-impedance inputs for sand amps as well and take much of the rough edges off the transistor sound of your amp.

Mild Snarkiness and Personal Bias Warning:

Dynamics: Once upon a time when everything from Sears to Neiman-Marcus had audio sections, and when the likes of Sam Goody's and Silo were on every street corner, and when there was a boutique audio shop around each corner, unscrupulous sales people would steer customers towards high-profit, low quality speakers by making them slightly louder during auditions - which were also made standing in front of quantities of speakers all lined up in ways to favor the profits as well. Louder 'felt' more dynamic, and, roughly, 80% of those customers ready-to-buy, bought.

Tube Influence: This treads terribly close to the line between the mantra of "straight-wire-with-gain" to "pleasant euphonics", second vs. third order harmonics, and so forth. Or, whether the goal is to reproduce the signal *without* adding any artifacts, or whether the electronics are another instrument in the process.

Cutting to the chase: Look up the specifications of your amplifier and determine what input voltage is needed to drive it to clipping. THAT VOLTAGE is all you need from whatever source you are using. No more. All more does is drive it to clipping faster. And everything derives from there.

Writing for myself, I have never really been able to make up my mind what it is I want - put better - what it is I want to the exclusion of everything else. That failing, adding a tolerant and supportive wife, a nicely sized house and a summer house allows me to run, at this moment, six (6) separate audio systems. Two utilize either an integrated amp or a receiver (AR-based systems), the rest use separates. None of my power-amps have attenuators, so they all use pre-amps. Dynaco x 2, Revox A720, Citation 17. They are capable of as much as 14 V output (PAS3X) to as little as 4V output (A720), all are far more than enough to drive every amp in the inventory. I have run several amps straight from tuners or straight from CD players and found none of them wanting or objectionable. But not every tuner has an attenuator, nor does every CD player. Nor is every recording perfect. So, I find pre-amps convenient. I appreciate the Revox as it has about every option, switch, input from MC Phono x 2 to everything else, various outputs, and more controls than a 787 - and a tuner with Nixie tubes!! Then, I like the AR receiver with fewer controls than a 1963 VW beetle.

Do what makes you happy. There are a LOT of very good pre-amps out there. Make sure you get one with a decent phono-stage on board, separate phono stages are a needless PITA. That would be about my only suggestion. And you cannot do better than what is on-offer or suggested here. But unless you need vinyl, and unless your components have no internal attenuation - the *need* is not absolute.

Peter W. wrote:Mild Snarkiness and Personal Bias Warning:

Dynamics:  Once upon a time when everything from Sears to Neiman-Marcus had audio sections, and when the likes of Sam Goody's and Silo were on every street corner, and when there was a boutique audio shop around each corner, unscrupulous sales people would steer customers towards high-profit, low quality speakers by making them slightly louder during auditions - which were also made standing in front of quantities of speakers all lined up in ways to favor the profits as well. Louder 'felt' more dynamic, and, roughly, 80% of those customers ready-to-buy, bought.  

Peter, W., they do kinda the same stunt with flat-screen TVs now. The brighter the display is set, the "better" the picture looks in a show-room.
And don't forget Crazy Eddie's. His prices were "insane."

Attenuators on  *some" s/s inputs actually cut bits, so you're reducing information to the DAC (or from the DAC) as you reduce their volume. At least that's how my Marantz CD player works.

-d-

Attenuators on  *some" s/s inputs actually cut bits, so you're reducing information to the DAC (or from the DAC) as you reduce their volume. At least that's how my Marantz CD player works.

I would think that would deliver a rather poor outcome?

I would expect that an attenuator would be on the analog output of the DAC? Cutting bits seems strange. Would not "cliff effect" be a concern?

Peter W. wrote:

Attenuators on  *some" s/s inputs actually cut bits, so you're reducing information to the DAC (or from the DAC) as you reduce their volume. At least that's how my Marantz CD player works.

I would think that would deliver a rather poor outcome?

I would expect that an attenuator would be on the analog output of the DAC? Cutting bits seems strange. Would not "cliff effect" be a concern?

Peter, this is all kind of "inside baseball" stuff to me. IIRC the Marantz manual warning that using the digital output attenuator on the CD player reduced the amount of information in the output signal. Whether this turns into actual sound degradation, I dunno. Here are a couple of threads on the subject:
http://www.whathifi.com/forum/hi-fi/digital-vs-analog-volume-control
http://www.learndigitalaudio.com/normalize-audio
Again, whether this is germane to the normal (vs. oscilloscope) listening experience is way above my pay grade. But your erudition would be appreciated.

Thank you! The explanation on sampling and reducing from 24 to 16 bits does make sense.

I haven't checked into the forum for awhile so looks like I'm kinda behind on posting this, but to McGyver (and everyone else) I would say this.
Given the choice between having either a tube preamp or a tube power amp, I would take the tube preamp everyday of the year.
A preamp has MUCH more influence on the overall sound of your system than a power amp does.
In these modern days, if you're just using a DVD/CD player or DAC or streaming audio, then a preamp isn't as essential as it was 10-20 years ago.
That out of the way, a tube preamp has a relatively small amount of heat output compared to a tube amplifier.
And smaller tubes (such as an SP12 or SP13) put out less heat than bigger tubes (SP14).
Tube preamps will never feel HOT. They will radiate warm air, and they do need space above for ventilation. But they aren't a 500w space heater like a power amp.
More like a 50-100w space heater.
CORNDOG - beautiful SP13 !! Just the basics, done well ! DeePee99 has both SP13 and SP14 so he can tell anyone the difference, to my ears about equal,
but in general I find I do like the large 6SN7 tubes of the SP14, but I do prefer the smaller size of the SP13, and a well built SP12 is 90% there, the biggest difference
besides the tubes is the much simpler power supply. Corndog has also boiled it down to the essentials - I consider preamps essential for dynamic drive
ANYONE (except Pedrocols, it seems) that has ever had a passive or no preamp and then gone to a tube preamp will tell you it makes an unbelievable difference in sound quality. And to me, an ESSENTIAL difference.
WELL WORTH the $$$. I'd take a $2000 tube preamp with a $500 SS amp anyday over a $2000 tube amp and a $500 SS preamp. I wouldn't even take a $500 SS preamp, ever!!!

Boy, do I concur with Roy on this matter. There is an ineffable improvement in "dynamics" with a great tube preamp and the ST-120. I propose that a reason may be that overall levels sound somehow louder at a softer level with the SP-XX. Therefore there is more headroom at a given basic and acceptable level. I find myself listening at quiet basic levels, which allows the "loud" parts to jump out.
There is a further yet controversial rationale for using both the ST-120 with attenuator AND an SP-XX pre. I swear one can sculpt the tone by adjusting the relative levels of the components. AND one can maximize the S/N levels as well. Try it - you'll love it.

Since my last post I also took the time to try out my McIntosh C37 and Parasound Halo P3 preamps. Both are also SS the same as the Cary SP-100 preamp. The difference being they do have phono stages where the Cary does not. Out of all of the SS preamps I have id say the McIntosh sounds the best with the VTA ST-120 (or the McIntosh amp it was purchased for)

The one nice thing about the AE-2 Tube Buffer is that I can roll tubes with it. It was built with the intention of using 12AU7's. I have 12AT7's and which do add gain in addition to glow much brighter than the 12AU7's. I imagine there life would be a lot shorter if I used them continuously.

I also have a Cambrige Audio phono section that I use primarily with the VTA ST-120/Cary SP-100 since even though the AE-2 Tube Buffer is the better preamp in my opinion it doesn't look that good. It looks much like a science project.

Maybe some day I will put the Tube Buffer in a nicer enclosure and then maybe add a tube phono section but for now I'm happy with the setup I now use.

Kentley wrote:Boy, do I concur with Roy on this matter. There is an ineffable improvement in "dynamics" with a great tube preamp and the ST-120. I propose that a reason may be that overall levels sound somehow louder at a softer level with the SP-XX. Therefore there is more headroom at a given basic and acceptable level. I find myself listening at quiet basic levels, which allows the "loud" parts to jump out.
There is a further yet controversial rationale for using both the ST-120 with attenuator AND an SP-XX pre. I swear one can sculpt the tone by adjusting the relative levels of the components. AND one can maximize the S/N levels as well. Try it - you'll love it.

I did enjoy my tube preamp a lot when I had solid state amps. Now that I have tube amps I like the combination better with the passive preamp at least for now as I haven't tried multiples tube preamps. Good tube preamps can get very pricey very quickly...