Phono pre-amplification options - advice needed

[hifi_dave]

Phono stage in the Sony is good, so you need to hear any other phono stages in a direct comparison before committing your cash.

[Svend N]

Hi Dave -- yes the phono stage in the Sony is quite good. Very clear and transparent....I like it. However, it's the main preamplification section that backs it up that may or may not be so great. About 20 years ago I had it modded to act as a passive device in order to improve the transparency and open up the sound. It worked, but only on a high output source like CD. Now that I'm putting a good analogue front end into the system, I need that oomph back to make the phono stage really work properly.

So yesterday I got busy with my soldering iron and reversed the mod to the Sony, so now it's back to being an active device. I didn't have a chance to listen as yet, but I will have an extended session tonight, starting with the Sugden in the system, then swapping in the Sony. I will post back here with my impressions.

When I opened up the Sony yesterday I was rather surprised to see it had already been recapped! (see pic below) I had totally forgotten about that. My good friend Peter Sutcliffe, who is an audio engineer and loudspeaker designer, must have done it at some point before it was converted to a passive device.

IMG_20171029_142016.jpg

I've no idea if those caps are of good quality or not. I don't recognize the big S logo.

In any case, back to your point re. spending money on a separate phono stage, it's not the phono stage in the Sony that was the problem, it was the main preamp section. So if that's not up to snuff, then even a separate phono stage won't sound right, and in fact may be held back by the Sony's line stage.

I will know by tonight.... I've made quite a few other changes to the system since the Sony was converted from active to passive (all new cabling and CD player mods being the main ones), so who knows - maybe it will surprise me.

Thanks, and regards,
Svend

[RothwellAudio]

...It can get to a reasonable volume, but the attenuator has to go to 11 to get there...not good.

Why "not good"? If it goes loud enough, what's the problem?

Some years ago the preamp was modified to become a passive device for the line stage section, which really lifted a veil from the music, as the saying goes.

So going from active to passive was an improvement?

As a quick trial to see how an active preamp would behave in my system, I swapped out the Sony for my Sugden C28. Immense improvement! The sound was far more dynamic and fluid, fuller and richer, much better soundstage, more immediate presence...
The Sugden has a CD Direct button which bypasses the active line stage (basically exactly what the Sony was modded to do), so I used this to switch back and forth to compare active to passive -- no comparison. The direct path sounded lightweight, thin and distant, basically exactly like the Sony did.
So lesson learned -- the Belles power amp and those speakers really need an active preamp to come alive. I suppose a passive amp would sound great in many systems, but not in this one.

So you want an active preamp because active sounds much better? Why didn't you notice the sound get much worse when you modded the Sony from active to passive?

...it's the main preamplification section that backs it up that may or may not be so great. About 20 years ago I had it modded to act as a passive device in order to improve the transparency and open up the sound. It worked, but only on a high output source like CD. Now that I'm putting a good analogue front end into the system, I need that oomph back to make the phono stage really work properly.

When a signal comes in to the preamp, how does it "know" whether the signal came from CD or from a phonostage?

Basically, none of this makes sense to me. My best guess is that you much prefer the music loud rather than quiet. After listening to loud music it's not surprising that the same music played again quietly sounds "lightweight" and "thin". For a given position of the volume control the music is louder with an active preamp, therefore active sounds better - unless you set the volume control for the same SPL each time. I suspect you haven't been setting for the same SPL and therefore have been misled by the active/passive tests.

That's just a guess.

[Light Dependant Resistor]

Hi Svend
The primary purpose of an audio system is to deliver audio with as little added or made artificial. Keep that in mind and your quest
will be much easier. If active parts add or make audio artificial then you are better without them, but those that preserve audio and
assist its proper reproduction, you are better with them.


Cheers / Chris

[Svend N]

Chris -- I completely agree with you. The nice thing about the Sugden preamp is that it has that neat little CD Direct button so I can switch back and forth between active and passive. For this preamp at least, I can hear some rather subtle differences, and some not so subtle but significantly better. Which really says something about the Sugden design. In active mode there is no loss of transparency at all, no added warmth or leanness. On the plus side there is slightly more well defined and deeper bass; better imaging; more dynamic pace (more jump, if you will); and a MUCH more rounded, fluid delivery. The passive mode sounds a bit more cohesive tonally, not quite as disjointed; but leaner and less dynamic. Overall I greatly prefer the active mode -- sounds more musical and lively, a fuller and richer sound but still neutral tonally. Wonderful amp! So in response to your last sentence, it's a wholehearted Yes: the active parts of this amp improve the sound rather than take away or mask it.

[RothwellAudio]

Svend, sorry if you've mentioned this already in the thread and I have overlooked it, but here's something you could try: you could take the output from the Sony's phonostage via the Tape Out sockets and feed that into the Sugden. That way you get to compare the Sony phonostage and Sony linestage with the Sony phonostage and Sugden linestage. Maybe an interesting experiment.

[Svend N]

Hi Andrew -- good idea! I hadn't thought of that, and to be honest had totally forgotten about how the tape circuits work in a preamp. I haven't used those since the late '80s I think. I'm looking forward to hearing the phono stages of both amps once I get the Heybrook running and have a good TT to run into them. Should be interesting!

BTW, I listened to the Sony again last night, for a bit longer this time, and was impressed at how good it really is. I think it's a keeper. Having heard the Sugden in the main system now, it will be hard to take it out again as it does sound very sweet. But the Sony will work very well for the second system. I'm happy I reverted it back to an active amp.

Regards,
Svend

[Svend N]

An update here... I decided to have the Sony modded to see if I could eke out more performance from it. Here is the result of that: http://theartofsound.net/forum/showt...106#post940106

Dave, this may be of particular interest to you, since you also own one of these.

Cheers,
Svend