Oblivion | UltraSonic Studios
Dec 26, 2019 at 2:29 AM Post #227 of 1,415

SonicTrance

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Hey there Mordy. The model that was send to me has speakers out. For some reasons, Sonic says you can either have preamp or speakers out and not both. Pre-amp out to the Redgum might be interesting. I think it will be a good balance.
It's a matter of space. I can't fit both speaker outputs and pre-amp outputs in the same amp.

Does Redgum have balanced inputs? If it does you can use the speaker outputs or even the headphone jack to feed Redgum.

All outputs on Oblivion are balanced so there needs to be a balanced input for this to work.

Edit: I realized that if I have both the speaker outputs and pre-amp outs on the same switch at the front, and there's only one set of input jacks, I could fit both speaker-, pre-amp outs and impedance switch on the same amp.
Just thought I'd mention that.
 
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Dec 26, 2019 at 7:07 AM Post #228 of 1,415

baronbeehive

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Lounge size is 6 x 4 metres. Carpeted floor and curtains makes for a good acoustics room. Even John Reilly commented on that when he came over to listen to my system. LS88 is a classic years ago. It's more of a British sound. It's not bright but the top end is revealing. Bass can go really low and when the bass drops (driven by the Redgum), you will feel the music, not just hear it.

So yeah, I was just interested to know if Oblivion could actually drive the floorstanders. At lower volume levels the details are lost. Bring it up to 12 noon and beyond and that's when you start to think that the Oblivion is quite remarkable. :)

Yes, fairly large room. Interesting that the floorstanders could be driven with all that sub bass draining power out. Obviously matching equipment is most important so I would imagine that something like the Zu, Tekton, or Triton speakers, or something around 95db would be an excellent pairing. Unfortunately I don't have these so can only speculate. It would be interesting to see what the Citadel is like as someone has said.

The low volume test is perhaps not a fair test as inevitably much of the music will be lost the lower down you go but for someone who likes listening at moderate levels it is good to knnow if it still sounds good at moderate levels.

Edit: My Miniwatt, rated at only 3.5W has more than enough power to drive my 87db speakers in a medium sized room, which I find quite surprising. I never go past 12 oclock volume so clearly low power systems work well, especially when matched up properly.
 
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Dec 26, 2019 at 11:49 AM Post #229 of 1,415

baronbeehive

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Christmas present for me from the family is this doubles Beatles LP.


I noticed your music on display btw…excellent gift... I have all the Beatles albums remastered. Tangerine Dream, Pink Floyd and Dire Straits are all favourites of mine. Have you heard Tangerine Dream Exit, Pink Floyd Pulse and Dire Straits On Every Street out of interest, I have these myself. Sorry if I've gone off topic a bit but I can't help discussing music, especially from the prog rock era lol!
:).
 
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Dec 26, 2019 at 2:45 PM Post #230 of 1,415

MrCurwen

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One of my clients eventually gave up my balanced amp because he enjoyed seriously loud volumes with no-so-effective-speakers. The design makes 1 watt go a surprisingly long distance, much longer than most would think, but there are physical limits.

Mainly, the Ia thru the output tubes. The sensation of audible power would be enhanced if there were more current swing capability. But, that opens up a bunch of other problems, which is why I personally just resigned to using the amp as it is, with it's limitations. I use my amp with big full sized speakers every day, but with moderate volume. At moderate volumes the sound is 'perfect' to my personal tastes, comparable to headphones (with obvious limitations).

Also if the output impedance driving the OT primary were lower, then bass transients would be "more powerful", i.e. the waveform wouldn't bend. The output impedance is determined by two components, the top FET (which as a follower can output some 10 to 50 ohms, depending on the exact type used) and the bottom tube (again, depending on type some hundreds to a couple k ohms output impedance, I think the common TV tubes are around 800 to 1200 ohms).

Now that 1k output impedance is going to bend the big bass waveform much sooner than say a 100 ohm output impedance, or a 20 ohm output impedance.

I did some things to try and go around this, they worked, but created a world of new problems. In the end I personally (I think Sonic agrees as well) think it's better to just accept the limitations and use the amp at moderate listening levels.


Sonic has done really well, the amps look simply amazing and well built. I'm a mad scientist type, my builds look... mad.

Buy amps from Sonic, I want my design to spread to all corners of the Earth.
 
Dec 26, 2019 at 2:58 PM Post #231 of 1,415

MrCurwen

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Comment regarding tube rolling:

The amp is 'immune' to tube rolling, as far as the tubes that are substituted have exactly the same curves.

So in effect the amp is not at all immune to tube rolling, since no two tubes in existance actually have physically identical curves!

I'm just being silly here. If you get two high quality tubes of the same type, say Tesla or military Soviet, that come from the same factory, same decade, they will have 97 to 99.5 % same curves.

Now take a Tesla high quality tube from the early 1960's, and a crappy RCA tube from the late 1970's... Yes they will sound different, because they have very different build quality and the curves WILL BE different.

But, within reasonable limits, i.e. using similar quality tubes, the differences will be almost nonexistent.

If some tube sounds "more top heavy" or "clearer" that is because it has a different inner capacitance between the control grid and the anode.

Generally more pronounced in triodes, since the 'anode' in a triode connected tetrode or pentode is actually a grid, which has nonexistent capacitance compared to a solid anode of a triode. So, EL81 and EL36, while clearly having differing inner geometry (just look at the elements with your eyes), sound much more similar, because the g1 to g2 capacitance is in both cases similar, nonexistent.

Of course capacitance affects 'tone', linearity is another matter. But those TV tubes are all superbly linear. Also superb in durability, they were made to withstand huge repeating current pulses without melting.
 
Dec 26, 2019 at 3:12 PM Post #233 of 1,415

SonicTrance

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Hey MrCurwen, great to hear from you it's been a long time!

One of my clients eventually gave up my balanced amp because he enjoyed seriously loud volumes with no-so-effective-speakers. The design makes 1 watt go a surprisingly long distance, much longer than most would think, but there are physical limits.

Mainly, the Ia thru the output tubes. The sensation of audible power would be enhanced if there were more current swing capability. But, that opens up a bunch of other problems, which is why I personally just resigned to using the amp as it is, with it's limitations. I use my amp with big full sized speakers every day, but with moderate volume. At moderate volumes the sound is 'perfect' to my personal tastes, comparable to headphones (with obvious limitations).

It does! I have these amps biased to put out about 2W peak into 8 ohms.

I also use my amps with speakers, more than with headphones actually. But that's mainly because I listen to music while tinkering, lol.

I did some things to try and go around this, they worked, but created a world of new problems. In the end I personally (I think Sonic agrees as well) think it's better to just accept the limitations and use the amp at moderate listening levels.
Indeed. I did adopt those workarounds in the beginning but could not for the life of me get the amp stable. I still think I can listen pretty damn loud without distortions with my 89db floor standers. Loud enough anyways.

Sonic has done really well, the amps look simply amazing and well built. I'm a mad scientist type, my builds look... mad.

Buy amps from Sonic, I want my design to spread to all corners of the Earth.
Thanks man! I really appreciate that!
 
Dec 26, 2019 at 3:16 PM Post #234 of 1,415

UntilThen

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Yes, fairly large room. Interesting that the floorstanders could be driven with all that sub bass draining power out. Obviously matching equipment is most important so I would imagine that something like the Zu, Tekton, or Triton speakers, or something around 95db would be an excellent pairing. Unfortunately I don't have these so can only speculate. It would be interesting to see what the Citadel is like as someone has said.

The low volume test is perhaps not a fair test as inevitably much of the music will be lost the lower down you go but for someone who likes listening at moderate levels it is good to knnow if it still sounds good at moderate levels.

Edit: My Miniwatt, rated at only 3.5W has more than enough power to drive my 87db speakers in a medium sized room, which I find quite surprising. I never go past 12 oclock volume so clearly low power systems work well, especially when matched up properly.

I did not think that high efficiency speakers such as Zu or Omega are needed with Oblivion because the amp is driving both LS28 and LS88 to moderately loud levels which most people would listen at. At that volume level, the details and imaging are very good. Bass is taut and tight. I'm not much of a bass head so I actually find such tonality quite pleasing to my ears. Sure it's different to the full on effect of my main amp but it's a good variation.
 
Dec 26, 2019 at 3:21 PM Post #235 of 1,415

UntilThen

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I did some things to try and go around this, they worked, but created a world of new problems. In the end I personally (I think Sonic agrees as well) think it's better to just accept the limitations and use the amp at moderate listening levels.

I agree on this too. Use the amp at moderate listening levels (which most of us do anyway) and it's enjoyable. Love the clarity and details. Soundstage is wide and open. I love all these traits.
 
Dec 26, 2019 at 3:23 PM Post #236 of 1,415

leftside

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You'll read a lot on other forums (especially the McIntosh forums) about how much power you'll need from amps to drive speakers well. I simply don't believe it. My speakers are low efficiency at 85db, and some people thought my tube amps at 75 watts (measure at 90 watts) might not be enough... Maybe if my listening room was very large it might be an issue, but with my current listening room and the preamp volume at half way, It's already starting to get uncomfortable to listen to.
 
Dec 26, 2019 at 3:27 PM Post #237 of 1,415

UntilThen

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Comment regarding tube rolling:

The amp is 'immune' to tube rolling, as far as the tubes that are substituted have exactly the same curves.

So in effect the amp is not at all immune to tube rolling, since no two tubes in existance actually have physically identical curves!

I'm just being silly here. If you get two high quality tubes of the same type, say Tesla or military Soviet, that come from the same factory, same decade, they will have 97 to 99.5 % same curves.

Now take a Tesla high quality tube from the early 1960's, and a crappy RCA tube from the late 1970's... Yes they will sound different, because they have very different build quality and the curves WILL BE different.

But, within reasonable limits, i.e. using similar quality tubes, the differences will be almost nonexistent.

If some tube sounds "more top heavy" or "clearer" that is because it has a different inner capacitance between the control grid and the anode.

Generally more pronounced in triodes, since the 'anode' in a triode connected tetrode or pentode is actually a grid, which has nonexistent capacitance compared to a solid anode of a triode. So, EL81 and EL36, while clearly having differing inner geometry (just look at the elements with your eyes), sound much more similar, because the g1 to g2 capacitance is in both cases similar, nonexistent.

Of course capacitance affects 'tone', linearity is another matter. But those TV tubes are all superbly linear. Also superb in durability, they were made to withstand huge repeating current pulses without melting.

Thanks for this most informative discourse on tubes. I think my days of tube rolling are over. The RCA 6AV6 and Siemens EL81 that Sonic send me sounds perfect. I've no inclination to swap to a different brand of the same type.
 
Dec 26, 2019 at 3:30 PM Post #238 of 1,415

SonicTrance

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You'll read a lot on other forums (especially the McIntosh forums) about how much power you'll need from amps to drive speakers well. I simply don't believe it. My speakers are low efficiency at 85db, and some people thought my tube amps at 75 watts (measure at 90 watts) might not be enough... Maybe if my listening room was very large it might be an issue, but with my current listening room and the preamp volume at half way, It's already starting to get uncomfortable to listen to.
Indeed! Some amps need more power headroom though (not sure about the McIntosch amps) for recovery after heavy transient peaks. These amps recover very quickly since they're open loop, no gNFB. So they don't need a large headroom.
 
Dec 26, 2019 at 3:38 PM Post #239 of 1,415

UntilThen

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I noticed your music on display btw…excellent gift... I have all the Beatles albums remastered. Tangerine Dream, Pink Floyd and Dire Straits are all favourites of mine. Have you heard Tangerine Dream Exit, Pink Floyd Pulse and Dire Straits On Every Street out of interest, I have these myself. Sorry if I've gone off topic a bit but I can't help discussing music, especially from the prog rock era lol!
:).

You are right up my alley. :) You have the same interest in those music.

With Yggdrasil > Oblivion > Verite, I'm on an exploratory journey with music. I'm listening to Mahler Symphony No.2 in C Minor. I could be listening to classical more now because the details, imaging and width and depth of soundstaging is tantalising. I just glance at the volume knob and it's at just 9am (a quarter) but the clarity and details shone right through.
 
Dec 26, 2019 at 3:39 PM Post #240 of 1,415

MrCurwen

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leftside, I'm going to let you in on a little secret, just between you and me here:

Output power wattage is not the most important factor in how you perceive the audible power (the physical sensation of power) of your system. Sure, it's a factor in there, but it's not the most important one.

What is the most important factor?

Transients.

How your amp handles transients is what determines if it sounds 'powerful' or 'weak'.

What you need to do is try out a 1 or 2 W amp with overkill transient control methods in place. 2W RMS is overkill in my personal opinion, I think my workhorse sims out at about 0.9W RMS bit more peak.
 

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