Low gain dac!

Is it possible for your pre to be sent back to the builder to have a separate gain control installed?  The reason I ask this,is myself and a few others here own Aric Audio tube preamps, and Aric installs a gain control on the rear of the unit. It is an awesome feature that I use whenever I swap in an amp with different sensitivity’s. 

I am experiencing same issue in my system as well. When first connected,  everything was great for about a year. Then I began to have the same experience as the OP has been having with the Volume Control.

Over the next few months the issue persisted and started to include the symptoms that Charles1dad described ".. poor L/R channel balance when the Volume Control is severely restricted to the very low positions." In fact I can only achieve L/R channel balance when the Volume Control is at the 5 o' clock position. 

I have sent both the CDP/DAC and Pre to their respective manufactures who swear, and I have confirmed, that they are working perfectly fine on their own. When connected - problems.  I thought that the problem might be the potentiometer on the Pre -TKD 2CP2511-MC/100K. Would changing this out resolve the issue? Any suggestion that may help the OP and myself would be appreciated.
  

Yes, the high output of many DACs and the high sensitivity (low V required) of many modern amplifiers creates this problem. Too much gain followed by too much attenuation.  Attenuators are best when not operated near full attenuation (<50%).  One reason passive preamps are popular. My system is built around a tube preamp with SS amp. Will likely add a tube amp as a alternative.  

My preamp has variable output gain. This requires two attenuators, one pre and post preamp gain. This is not ideal, a single attenuator would be better. However the gain control allows me to use use both attenuators within the best operating region. A compromise I am willing to enlist. 

Thanks for everyone replying I this thread, even the grumpy ones 😜 someone said that everyone should know that Supratek has very high gain, well maybe in the US or UK or Australia, but here where I live, you can be sure that no one knows the brand, I think the same would be the deal in Scandinavia and Europe.
I think maybe Mick didn’t notice the spec on my power amp as we exchanged quite a few emails, I always found him to be very forthright and patient with me.
Now I think some here are given the impression that my system is a total mismatch in gear, well if that’s the case, it sounds bloody fantastic!!!
With an upgrade to my dac with a lower output I think I can live with this, no problem.
Was listening to Tom Russel ( the man from God knows where ) what a fantastic sound and quite a good cd. Also The Modern Jazz Quartet ( Lonely Woman ) beautiful sounding, so much better with the Supratek than with other pre or intergraded amps I have had.So as you see, it is not the end of the world.
As I can see, many other people also have this problem with too much gain! To the more technical minded of you, where do you think the problem is mainly, are the sources the problem or is it the pre - power amps to blame, there must be a technical reason that designers choose to have high gain in their designs, maybe someone could explain for us more the reason and what in a combination of source, pre, amp would be best to have higher gain, I would think variable gain on a pre would be preferable, but maybe I am wrong.

Thanks for everyone replying I this thread, even the grumpy ones that Supratek has very high gain

Oh, ok!

You would have read the 6 moons review and others, before, during, and after your Supratek purchase, where it states that.

The "grumpy ones" don’t mind giving the correct answers when asked from those that ask questions as the title of a thread, that why they are here.

I look forward to giving you some more correct technical help.

Cheers George

OP,
You have made it abundantly clear that the addition of the Supratek improves the sound quality of your Audio system. Other alternatives you have tried were not as satisfying in your opinion. So you’re keeping the high gain Supratek. I understand that rationale. After all you wrote "it sounds bloody fantastic".

At this juncture since the Supratek is staying put, I do believe that acquiring a DAC with a lower output voltage (Probably 1.5 volt or less). I agree it would be nice if more amplifiers and preamplifiers had variable gain adjustment.
Charles

Don’t think I was talking to you.
But yes OP, just responding to your little digging slur. Just go with Charles he’ll give all the "correct" none technical answers

George,
 Sometimes you make no sense. OP has freely acknowledged he has too much system gain. He wants to address it by finding a suitable DAC with less output voltage.  This makes sense and is a reasonable solution. 

You like to frequently tout your tech expertise,  ok fine. Why so blatantly ignore his documenting  his'very' positive listening impressions with the Supratek?  You brush that aside because this result (Good sound, we are discussing audio) doesn't mesh with your version of tech dogma.

OP couldn't make it more clear that his audio system sounds better with the Supratek in the signal path. 
Charles 

Less source voltage will = even more hum/noise.
Inline attenuators to reduce the massive gain he has already will give impedance mismatch problems and more hum/noise.
Throwing a good dac aside for one with "at least" half if not less output to rectify this problem, is a sideways band aid fix with other problems that I've outlined.
As I said the amp with 0.7v for full output is the problem if the Supratek is to be kept

If you didn't know.

@charles1dad - Thanks, I don’t understand George either!

I am one that likes what tubes bring to a system, but have decided to have them in the pre amp as tube power amps would need more care and my speakers are 87db, so needs good power, not necessarily many watts, but a good power supply is a good thing, maybe some day I will have tube mono amps, Supratek makes a nice pair, so, maybe that would be a good pairing with my pre someday when I have gone on pension and have more time on my hands.
I made a post in the Supratek tread about when in Bangkok I was so lucky to hear a anniversary Supratek setup with Triangle speakers, the dealer had time for me, and we sat listening to music and talking about Hi-Fi, music and life in general, I think for 2 hours, as my wife was shopping, that was the best sound I have ever heard and today I can lister to even a better pre from Supratek.
Never expected to buy a pre amp all the way from a one man production shop in Australia, but it’s been totally worth it.

Just listening to this https://youtu.be/qsRLRmRogKU
wonderful music, it is YouTube but it sounds quite okey.

Hi @gryphongryph,
I do understand George’s concerns to a point. Your power amplifier is high sensitivity (Only requires 0.7 v input, same as my 300b SET). So obviously your DAC has a surplus of output voltage relative to your amplifier’s needs. But you know that.

I completely understand your decision. Once you’ve found a component that really pushes your music loving soul buttons why in the world would you discard it? You are very happy with your audio system sound quality and that’s a big deal. I believe that you’ll find an appropriate DAC that matches better (Gain/voltage) with your excellent Supratek.
Charles

OP your thread turned out to be an interesting topic for me, gain is something we don’t pay attention to when we assemble our systems, some of us new to this hobby assume equipment will just work alone with other equipment but that is not always the case.
I totally understand you love the Supratek, preamps in general if these are good provide a very satisfying sound on our systems, but other parts too, as an example in my system rotating equipment and such, for digital reproduction only I found that I cannot live without a piece of software which does all my digital conversio, we all have our preferences.

Now, about your issue, Charles understands what you are asking and it will be hard to find here on Agon someone as well intentioned as Charles when providing unbiased advice, he is a super helpful respectful individual, certainly he has my respect entirely.George on the other hand also tries to provide good advice but he is very direct and he is very strict with his own audio beliefs so most of the time he comes out as harsh, (English is not my native either so bear with me using adjectives here). George is somehow criticizing the Supra as having too much gain, George believes in passive preamps and simplification hence his comments, and he is right IMO on many of his comments. Nothing wrong on having your own strict beliefs but it is important how you present these to others.

Now I do believe not so much on passives but on simplification so in your case and as others have stated, if you must keep the Supra and as George said changing your dac is just a band aid IMHO so your Amp (again as George stated) would be a better replacement than your Dac, the Supra and Belles are just not a good match gain wise. And over the years the life cycle of a Dac on your system should be less than an Amp, you’ll be replacing dacs leaving the Belles there and your dac options will be mostly limited trying to create that match with your preamp and amps.

I myself would go into a completely different direction because there is something I would love to try and compare on my system.

There is this Dac (May) with resistor drift correction on the output analog stage (the analog output stage is IMO one of the critical parts for sound reproduction on any Dac because I, personally don’t use or care about the filters on the Dac’s digital stage so much, that’s why I use software for preprocessing) ,which happens to be also buffered, 5.8 V out on its balanced output (this will definitely won’t work on your existing system). I would love to connect this Dac directly to my amplifier and see how it sounds with no preamp (George might tell me now I'm creating the same effect as with a passive preamp and he would be kind of right but not exactly the same, this is no preamp at all) and I will be doing Dsp volume control on software.

But of course this is something I would like to try personally, I done it before but with dacs with no output buffered stages and low output voltages and in all cases I preferred the included preamp sound to dac alone so I understand why you keeping the Supra.
BTW have you tried the DHT stage with EML 45s?
Cheers

Luis

+1 Charles

The OP's opening statement was the desire to replace a high gain  DAC with one having less gain.

Well, The OP has a DAC with 4.3V output, far more than needed. Also a high gain preamp and high sensitivity amplifier which on technical basis may not be ideal, however how these play together with the speakers satisfies the OP who only is looking to reduce gain to take better use of volume control. Seems to me that replacing the DAC with one having less than 2V output would reduce the gain by close to 10dB at the source with the least alteration of the sound quality of the system and allow greater degrees movement on volume control.

@mesch thanks for your input, yes this was my thinking too, when I got the opportunity to buy the Belles for a very good price, I could not pass it, must admit that gain was not in my thoughts.
The Sonnet Morpheus https://www.sonnet-audio.com/Morpheus.html
looks very intriguing with 2v output and also a pre section that I can use when watching tv, thereby bypassing the tubes, the price is a bit too high at the moment for me, but later in the year it could be an option.

@gI use a Audio Mirror Tubadour III DAC which also has 2V output. Hard to find a DAC with lower output voltage. The only possible issue is it's 2K output impedance, which like many specs in not a problem if understood. I really like this DAC.

I am not familiar with the Sonnet Morpheus DAC. Will have to research that one, likely out of my budget.   

@gryphongryph somehow the address on my last post did not take.

@luisma31,
I sincerely appreciate your very kind comments. I’m in complete agreement with you that the importance and influence of the DAC analogue output stage is overlooked. Same applies to a DAC ’s I/V conversion and power supply. Yes the chips play a definite role but too often overemphasized.

@gryphongrtph, I believe that the Sonnet Audio DAC you linked and the Audio Mirror Tubadour (Recommended by mesch) are very viable options. Their 2 volt output would be much preferable to the 4.3 v of your current DAC.

Obviously you’d need to hear them to know for sure but in terms of system gain management, a move in the right direction.
The Tubadour consistently receives high praise. The Sonnet is unfamiliar to me. It sure looks interesting on paper however.
Charles

Isn't 4.3V out on RCA from the dac against the normal specs/standards?

I thought they were supposed to be 2V on single ended outputs and 4V on balanced. I think some DACs have higher output when they also contain a volume control, the idea is that they can work without a pre-amp in the system. If your amp has a volume control you can just lower that and try how it sounds.

Yes it is true that the gain on my Primare Dac is higher than the industry standard of 2v.

The dac does not have a volume knob or any way to adjust the output.

 I don’t know why Primare decided to do this, maybe most of their customers normally use the balanced out on systems with more than one Primare component?

My thinking is just to get the gain a bit down with a source that has the standard 2v output.

Isn't 4.3V out on RCA from the dac against the normal specs/standards?

I thought they were supposed to be 2V on single ended outputs and 4V on balanced.

Yes the Redbook standard was 2v back in the 80's but since 2000 it's crept up now and the norm is 3v or more, which is good, as the higher the source voltage, the less end noise/hum/distortion there is because of less amplification needed down the line.

Nelson Pass,
"We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.
Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.
Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.
What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.
And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp."

Cheers George

If you want to keep all of your gear, then try reducing the signal level between your DAC and preamp by using an autoformer with a fixed attenuation.  Technically speaking (and in practice), an autoformer will sound much better than reducing the signal level by means of any type of resistive attenuation.  In fact, it may actually improve the sound overall (making it more detailed and dynamic).

Contact Dave Slagle.  For $200, you can pick up a pair of AVC (autoformers) and have them wired for any fixed reduction you would like (let's say about -10dB to -15dB might be useful for your case).  If you are feeling ambitious, you can get these transformers wound with silver wire at a cost.  I believe the transformers are about 1.5" tall, 2.5" wide, and just over an 1" deep.  You will need a pair of these to fit.  If you're not experienced, have someone who is help you out with this DIY.  Ideally, you can get these to fit within your preamp chassis and wire up directly.  Otherwise, maybe you can fit them within your DAC's chassis.  If not, then this solution probably won't be convenient.  Good luck.

http://www.intactaudio.com/atten.html

Buy a Chord Qutest, it has three selectable output levels. 1v, 2v, 3v

That is a nice feature on the Qutest.  

Yes agree, all dacs with digital domain volume should have this selectable output max voltage feature, then there’s no risk of "bit stripping" at all when using it direct if the volume is too low (<70%).

Wadia I think did it first with 6 x different levels on their top line dacs https://ibb.co/30WXsC1 but with user adjustable links inside. But if this option isn't there with a dac, then same can be done using a $49 Schiit Sys as max preset between dac and poweramp. 

Cheers George

manthik - I am considering replacing the potentiometer in my preamp with a  Slagle Autoformer. I have read about new projects/preamps that utilize his products, however have not seen anything on swap out/ replacements like I am contemplating. Are you able to point me toward some information other than their own website...

georgehifi - I have a Wadia with the adjustable gain. I have turned it down to the lowest voltage setting and still have the same issues. This is why I think my issue is with the  potentiometer, but the preamp manufacturer insists that there is nothing wrong. 
And Yes, I can connect the Wadia directly to Power amps and it works, however it sounds significantly better  when connected to the preamp - when its working...

Benchmark DAC's have internal pads that can be moved to lower the gain by 10 or 20 db. I have an older DAC1 and I use this feature when switching from a tube amp to a solid state amp. The DAC1 actually has a -30db pad as well. The pads lower gain on the balanced XLR output only but I use a custom cable that has an XLR connector on the DAC end and an RCA connector on the preamp end. (My tube preamp only has unbalanced input.)

@ggc, hello, sorry.  I think your best bet is to contact Slagle himself.  He has a variety of options that might work in your case.  He could probably help you figure out if his AVC would fit in place of your existing pot.  Another option is to bypass the existing pot in your preamp and use his EMIA passive remote AVC preamp as volume control for your preamp.  Only downside here is you will need an extra set of ICs.  I thought to do this (or at least have the flexibility to do this), but realized I like the AVC as its own standalone preamp better.  My EMIA preamp is wound in silver.

Not a cheap solution but one that will solve your problem with no sonic penalties. 

http://www.thehornshoppe.com/the_truth_pre_amp.html

Thanks for all the replies, a question to George, Charles and others, if I move the Belles to an other system and were to get me an other power amp, preferably class A or heavily biased into class A, what would you guys recommend ?
Your suggestions would be appreciated.

gryphongryph OP
what would you guys recommend ?

If your asking up to 50w Class-A only

There’s not much around that is just 30w Class-A
Pass Labs XA30 or XA25 https://www.passlabs.com/products/xa30.8/
My pick would be a Gryphon Essence https://gryphon-audio.dk/shop/power-amplifiers/essence-power/

Then if you want high biased Class-A and big A/B wattage
Parasond John Curl Halo JC5 https://parasound.com/jc5.php
Gryphon Integrated Diablo 120 or 300 https://gryphon-audio.dk/shop/integrated-amplifiers/gryphon-diablo-300-integrated-amplifier/

Cheers George

Hi @gryphongryph,
Solid state, Valvet Audio A4 mono blocks. Pure class A 55watt into 8 ohms/90 w at 4 ohms.

Tube, Line Magnetic 805ia class A SET 48 watts.
Both of these amplifiers would in my opinion easily drive your 8 ohm impedance speakers. Caution, if your listening space is modest the 805 tube will generate heat.

Either will contribute to providing beautiful sound quality given the make up of your Audio system. . I believe that the Gryphon recommendation from George is a good option as well.
P.S.
Luxman 590 AX MK II pure class A. Intergrated but I believe that the preamplifier section can be bypassed.
Charles

Chord Qutest has variable line level output that can be set at 1v, 2v or 3v. If you can use single ended connections only it’s a pretty good DAC.  

I agree with checking out the W4S dacs.  I had 2 tube preamps in series and used the DAC to set the volume controls at 12 oclock.  It is easy to attenuate the dacs output.