Does a SUT help or harm more ???

[joessportster]

Odd question I know but here's the rub, if you can get enough gain by turning up the preamp more than normal say the 2 o'clock posistion would this be better for the sound or cause a degrade ?????? I guess this really boils down to is a step up simply an amplifier that SHOULD add no sonic sig. ?????? Or are they designed to impprove in more ways than just amplify the signal ????? I know the ultimate goal is to have neutral equipment that just gets outta the way but typically that is just a pipe dream........... Everything adds it's oun sig, question is are those sig good or bad. Joe

[Cal Blacksmith]

I think I understand the question but I am not sure of what a SUT is but here goes anyway.

I think the gain / knob position issue comes down to how well the preamp and amp match with each others inputs and outputs. My preamp is a little hot for my amp and thus my "normal" listening position of the gain control on the preamp is about the 9:00 position. If it gets to 12:00, it is hard to stay in the room with the gear. I think it is more of an issue of being able to get more or more precise adjustment out of the gain knob, more ease of adjustment if you will. I have been toying with the idea of adding attinuators to the output of my preamp or input of my amp to get more rotation on the knob, just so that it is a little easier to get the listening level I want.

In a perfect world, no component will alter the sound of the signal, regardless of the gain. I have not noticed an improvement in the quality of the sound at any output level on my preamp, that said however, things ramp up from 80 db to over 120 db real quick, so it is a little tough to notice subtle changes LOL

I hope I hit the mark with your question, if not sorry for taking your time but that is my statement on the issue and I am standing by it![]

[joessportster]

Cal I've been where you are now and your response touches on the thread SUT means step up transformer and they are used between a low output cartridge and phono pre-amp to increase the gain. I use only. LOMC cartridges and have been on a quest for a SUT. Last night I got a bug up my &$$ and decided to run the phono pre without a SUT. And was suprised that my denon with .3 mv output could actually put out about 85 db with volume knob around 2 o'clock I have a friend that beleived SUT were a necessity for dynamics. However every SUT I have ever heard introduces hum. I of course will do comparisons but a little insight doesn't hurt a thing. Joe

[thebes]

Far from an expert Joe, but it sounds like you need a SUP, or a preamp with a setting for moving coils.

2 o'clock position to get just 85 db seems wrong to me. Should be around 10 o'clock for such a moderate volume. I think most peoples rule of thumb is that past 12 o'clock you are getting into clipping territory with most audio gear.

That said, I've got a Ortofon MCA-76 which is a head amp instead of a true SUP. I'd be happy to lend it to you for experimentation purposes. I had it briefly in my system and it was very quiet using a Zu/Denon 103 . Here's a link to the info on it:

http://www.vinylengine.com/library/ortofon/mca-76.shtml

[muel]

2 o'clock position to get just 85 db seems wrong to me. Should be around 10 o'clock for such a moderate volume. I think most peoples rule of thumb is that past 12 o'clock you are getting into clipping territory with most audio gear.

I agree but it depends on your goal. In the living room I set the gain low enough so that when the kids spin the volume control all the way up it won't do any big damage. My youngest thinks that horrible clipping sound is "funny" [:'(] Luckily, she hasn't done that to any klipsch.

[LarryC]

I agree with Thebes! Preamp volume controls tend to sound better in certain parts of their rotation. It might be worthwhile to track that down in yours by trial and error. I'd be surprised if it were 2 o'clock in any VC.

I'd especially expect background noise to be VERY high at 2 o'clock, and the cart output too low to surmount it. At 0.3 mv out, the phonostage needs to have at least 60 db of gain to bring the cart, phonostage, preamp, and amp into balance. Most MM phono stages have only 33 to 45 db, which is not nearly enough for such a low-level cart output from what I've seen. I suggest that you take Marty up on his offer, to see if the music won't stand out a lot better from the background hum and noise.

[mikebse2a3]

2 o'clock position to get just 85 db seems wrong to me. Should be around 10 o'clock for such a moderate volume. I think most peoples rule of thumb is that past 12 o'clock you are getting into clipping territory with most audio gear.

Depending on design some equipment's volume controls actually perform their best (most accurate with finer gain adjustments available) from the 12 o'clock position on..! They are also often assuming systems with average gain structures working into loudspeakers with 85db to low 90db ranges.

Keep in mind the volume control is only a voltage divider and it's physical position has nothing to do directly with clipping a gain stage.

The only way your going to clip the pre-amps gain section is by driving it with a large enough signal that it can no longer supply the voltage/current into it's load. Another way to look at this is by example, If we for example take a CD source and mute it's output then turn the Volume Control all the way up on the pre-amp there is no clipping going to happen and the same thing is true if you send a signal that is simply to low to to cause the pre-amps gain stage to clip even if the volume control is turned to maximum.

In Joe's case, If he is able to acheive the maximum listening volume level with his system without the added step-up then it is a valid option that also could have the possible benifit of less noise heard from the system. There is without a doubt some impedence interactions within and between different equipment that can influence the sound heard from a system and this will often come down to the listeners preference in each individual situation. I will also add that Joe's mention of a dynamics is something to listen for because if impedence matching isn't good or the source lacks the drive voltage/current then dynamics is one area that will suffer.

mike tn

[joessportster]

thanks for the input guys,

thebes i truely appreciate the offer, i have a couple pairs of sut's here at the house and my piccolo head amp is out for repair right now. i was able to pounce on a couple good pairs of step ups after a long drought so i am playing around with them,

my pre amp has stepped attenuator for volume so theoretically it has the same contact at every detent, no evidence of clipping in the system however i am leaning twords adding gain either by sut or head amp

Joe

[fini]

I'd especially expect background noise to be VERY high at 2 o'clock, and the cart output too low to surmount it.

It's even worse at 4 o'clock when people are starting to get off work and whooping it up.

[LarryC]

It's even worse at 4 o'clock when people are starting to get off work and whooping it up.

[][][{]

[thebes]

Boy I was on a roll there for awhile. Gingerly answering a technical question,which is decidedly not my forte, yet people were chiming in and agreeing with me.

Then, my audio mentor, my electronics guru, my sensi for all things high voltage, slaps me down like a mother with her errant cub.

Actually, it's hardly that and Mike's comments make perfect sense, I guess where I went awry is bringing the concept of clipping into it. What I should have said is that a standard Moving Magnet, on a standard RIAA phono stage, being run through something like a Scott, Fisher or the vast majority of preamps/receivers/intergarted's what have have you, would probably clip your speakers at 2 o'clock.

Now a LOMC with only .3 using a standard RIAA 47k loading most probably would not cause clipping at 85bd at 2 o'clock, but it sure sounds like a mismatch to me. In other words, using LOMC's with standard RIAA equalization is not an optimal solution. To muddy the waters further, there's also questions of capacitance and resistance loading available on many higher cost end preamps, and those also play a role in perceived dynamics. Beyond that the technical nuances of arm mass, compliance, etc. make it so confusing my eyes start rolling up int my head and I pass out on the floor.

So Mike? Is that better? (wagging his tail). Whatever you do just don't sic that dog on me again. []

[mikebse2a3]

So Mike? Is that better? (wagging his tail). Whatever you do just don't sic that dog on me again.

Thebes said what [:|]...sic..em..Boy....[&]+[G]+[ap]...means you have very little...[O]..!!!!

Alright you've changed my mind Thebes..! You might have a fighting chance if you follow my directions exactly and make friends with the DOG..!!!! The Dog will not attack as long as there is great Blues Playing such as Muddy Waters, Sonny Boy Williamson, Otis Spann, John Lee Hooker, BB King, Buddy Guy...etc...!!! Play the blues like you never have my friend ..!!!!!!!

mike tn[Y][H]