[Tyson]

Review of the Bolder Modded Logitech Duet - Updated 12/11/2008 (See Bottom of Post)

Background
We moved to a killer condo in the Golden Triangle area of downtown Denver.  Great location, great views, but no options for a separate, dedicated audio setup.  This meant I had to combine my audio and HT systems into one.  I kept my HP pre/pro, and my 2 channel amps, along w/my VMPS RM40's as mains.  Sold my 5.1 HT speaker setup, my center channel amp, and my surround channel amp. 

I was simply at the point where I was willing to accept 2 channel performance compromise in the name of domestic harmony and ease of use for the TV/DVD/Music setup.  It stayed like this for 2 years.  Then a couple of months ago I realized I am NEVER going to have a full HT 5.1 setup in my current location, it will only be a 2 channel setup, period.  Which meant I could ditch the mediocre HT equipment and focus on 2 channel audio performance.

During this entire time I'd been using a Logitech Squeezebox 2 for my music source.  Unmodded, and with the crappy digital wall supply.  Obviously this is the first thing that needs to be addressed!

Bolder Cables Modded Duet
I know that Wayne at Bolder has been modding the various Squeezeboxes for quite a while and I figured it would be a simple matter of giving him my squeezebox 2 and waiting a while for the mods to be done.  But as I talked with him about the specifics of the mods, it became apparent that the new Duet is a far simpler device, with less mods required, and a simpler internal layout and simpler power supply requirements, and the huge advantage of not having a continuous digital display always on and generating noise and grunge.

Duet ordered, no brainer on that.  Now, power supply, what about that?  There's some options.  Screw it, I'm going for the ultimate.  As someone once said, money is just a number in your bank account, you only get one life! 

So, ultimate analog mods and ultimate power supply are now in the works.  This is exciting!  I'd forgotten how addictive this whole process can be

For those curious about the actual mods performed and the specifics of the PS, here you go:

DUET has the analog only mod with V-Caps and WBT NextGen connectors. No Bybees were used in the analog output. I did do some work in the power supply distribution internally in the DUET. That is standard with that mod."

Power Supply has "cryo-treated, silver plated IEC, fuse holder, and fuse. All internal wiring is cryo treated solid core silver. It has a monstrous power transformer for the current, Fairchild Stealth HexFreds, Jensen four pole caps and FOUR Slipstream Bybee Purifiers. The circuit uses a current tracking pre-regulator and a "regular" voltage regulator. The DC cable is made with all solid core, 99.9995% pure silver."  And the circuit board is hand made from 1/8 thick fiberglass. I use the turret board technique for running point to point wire. This is the same sort of thing used in the hand built, boutique guitar amps. It ensures a quality mechanical and electrical connection with minimal susceptibility to vibration. The case is ... made from steel to deflect RFI and EMI. I line the interior of the case with a material similar to Dynamat to dampen the resonances. I also use some Ebony "pucks" on the capacitors, circuit board and transformer for resonance control.  The XLR connector uses silver for it's contacts."

To which I say "Holy Crap!"  God I love this stuff.

Getting the modded Duet
The mods were done first, the Power Supply took a bit longer, so I got a loaner of a CI power supply to use in the meantime while I was waiting for the Ultimate PS to be done.  Here are my initial thoughts, copied from the Bolder Forum:

The stock SB2 was OK, but hardly a world beater.  Actually, it was pretty poor if I'm totally honest.  Splashy, hard, harsh, lightweight, flat, all of these apply to the stock SB2 unit I lived with for a few years.  But I'd adjusted to that sound and it really didn't bother me so much.  Of course my daily music listening had dwindled to only a few minutes a day, if even that.  I simply didn't have much desire to listen to anything.

Enter the modded Duet.  At first there was no difference between it and the SB2.  I plugged them both into my preamp and switched between them in real time (via remote), and I could not hear any difference at all.  Hmm, not so good.  How much did I spend on this?  But I know that Bolder gear takes a while to break in.  So the Duet goes on repeat for a couple of weeks.  Now we are starting to cook!  I've got about 200 hours on it now and it's starting to relax and open up.  Suddenly there is bass.  Real, textured bass.  Rich mids.  Relaxed highs.  I know that I've still got a long way to go for full breakin but already I'm listening for several hours everyday, it's a joy to listen for the first time in 3 years.  What a salve to the soul.  And resolution is outstanding.  How good, you ask?  Well, it makes 50 Cent's Lyrics intelligible (Get Rich or Die Trying).

Lest you think the Duet only does well with thug-gansta-rap type music, on goes Amy Mann's Magnolia disc.  This normally sounds awful, awful, awful.  Papery, splashy, indistinct, lightweight, white-noisy.  But, the modded Duet manages to make it not only 'listenable', but actually sound good.  Not 'great' mind you, as I am certain the original recording is fairly mediocre, but now it is very listenable and enjoyable, and that's one of the poorest modern recordings in my collection.

Duet with the Ultimate PS - Initial thoughts
Initial thoughts on the modded Duet with Ultimate PS are as follows:

I've had everything hooked up and running in again for a while now and I'm amazed at how the sound of the unit (and power supply) change over time.  When Jason was over on Sunday, it was quite relaxed sounding, very easy, almost tube-ish.  Honestly I liked it but I also though it was a slight bit boring.  Luckily, that was not a permanent state, as the Duet has changed yet again over the last few days. The sound has gone from somewhat soft to more detailed and dynamic, but without the glare normally part and parcel with SS based equipment.



UPDATE 12/11/2008 – Digital Mods

After living with the Duet for a while with my new audio-gd amp, preamp, and DAC (reviewed here - Audio-GD C3 Preamp, C1 Amp, and DAC8 ), I had the option of switching back and forth between the Duet and the DAC8 for my digital source.  I used the digital out from the Duet into the DAC8, and I also had the analog out from the Duet plugged straight into the C3 preamp.  Thus, I could switch between them in real time.  In the end I preferred the sound of the DAC8, it's a pretty spectacular piece of equipment.

So, I sent the Duet to Wayne to mod the digital output so that I could use it as a transport feeding the DAC8.  Turnaround time was very fast and I had the new mods back in hand in record time.  I hook it up the same way as before, analog out going to the preamp, and digital out going to the DAC8.  I figure the DAC8 will sound even better because the latest digital mods from Wayne really ameliorate jitter and give a much cleaner output than the stock unit.  And I was right, it sounded significantly better.

The BIG surprise was when I flipped it over to the analog outputs.  THE ANALOG OUTPUT OF THE DUET SOUNDED BETTER THAN THE DIGITAL OUTPUT VIA THE DAC8!!!  What the hell?  How could a digital mod affect the analog output's sound?  I fired off just that question to Wayne and his response was telling:

I changed out the voltage regulator circuits for the DAC chip and clock. This has been built on all the other mods I have done. Now the power is taken directly from the external PS and has separate regulators that are not getting their line corrupted by any of the data chips. The clock regulator is a very good shunt regulator from Paul Hynes. The digital out is the most "organic" that I have yet to hear from a SB type of unit.

I also replaced the digital out connector with a WBT and ran 75 ohm coax direct from the digital buffer. 

The changes do affect the analog section. I installed a different design of voltage regulator for the DAC chip. The Wolfson chip used in the DUET has an analog opamp built in. The change in clean voltage will change the sound. The new regulator is feeding a shunt regulator for the clock circuit. Cleaner digital signals will result in cleaner analog.

Now I don't pretend to understand all of that, but I do know what my ears tell me, and that is that the Duet is now outperforming the DAC8, and handily, despite the fact that the DAC8 is sounding even better than before as a result of the cleaner digital signal. 

In summary, all of the mods to the Duet have improved it at each step along the way.  But it was the last set of "digital" mods that pushed the Duet past a world class external DAC.  The good news is that the Duet is definitely capable of this level of performance, so I can listen to my PC based audio without compromise. 

[denjo]

Tyson

Thanks for the great review - I like your writing style and approach!

I am headed towards the same direction; I have a stock SB3 but am looking at the Duet to send to Wayne to mod. But, if I do, it will probably be only the digital out mod, feeding an external DAC. I wonder if you did also have the digital mod and if so, how does it sound compared to the analog mod.

Thanks in advance,

Best Regards
Dennis

[mgalusha]

Back in the saddle again. Nicely done as always.

Regarding the buffer - yes and yet - meaning you will probably like what it does and it will cost you more money.

Still have to get together one of these days..

mike

[DSK]

...Wayne's offered to send me a Bolder Buffer to listen to, and I'm loathe to take him up on it because I've got a feeling that it will ramp up the Duet to that next level and it will cost me more money.  But for now, Wayne's on vacation and I'm enjoying the hell out of my incredibly good-sounding system...

Hi Tyson, glad to hear the Bolder/Logitech combo is working well for you.

The Burson Buffer, in a system using the analog output of a Bolder modded SB (or I presume Duet), is an absolute no brainer. The output drops to 1.1v due to bypassing the opamp in the output stage. Yes, the Bolder mods sound much better than the stock output despite this drop in output but when you add the Burson Buffer (which is extremely transparent even in stock form) you suddenly get improved dynamics and drive. Also, you get better inner detail and emotion, presumably that was being lost in the strain for the 1.1v to drive the pre-amp (or power amp if you go direct). Compared to what you have spent, the Burson Buffer is quite cheap .... just do it! You get to hear just how good those Bolder mods really are when not held back by the loss of output.  I was worried about adding another component and pair of interconnects into the signal path and the potential loss of transparency but these fears proved unfounded.

[Tyson]

Actually the Duet does not have the same voltage drop that the Squeezebox does, so from that standpoint it's less "required".  One thing I'm thinking is that a re-box is probably the ultimate way to go with the buffer, since Wayne could run the analog feed directly to the buffer circuit, bypassing a couple of sets of RCA plugs and a set of interconnects. 

[DSK]

Actually the Duet does not have the same voltage drop that the Squeezebox does, so from that standpoint it's less "required".  One thing I'm thinking is that a re-box is probably the ultimate way to go with the buffer, since Wayne could run the analog feed directly to the buffer circuit, bypassing a couple of sets of RCA plugs and a set of interconnects. 

In that case you may not get the same degree of improvement from the BB as the modded Duet may not be losing as much in the first place. I guess it partly depends on the Zout of the modded Duet and Zin of your preamp or amp that it drives. I haven't tried my BB on anything other than the Bolder modded SB2. Try one in your system first if you can as my "no brainer" comment may not be applicable in your setup. Good luck with it. 

[Tyson]

Well, it just so happens that I have one of the Buffers on delivery tomorrow.  I'll be able to say definitively whether or not it makes an improvement or not.  Problem is that this particular buffer is designated to be used on my very, very poor analog output from my Satellite TV (no digital output on the box), so its not a permanent solution for me, even if it's great.  If it does make a big improvement (and I think it will), a re-box w/a Bolder buffer is probably in my future.

[denjo]

Tyson

Any chance you could respond to my post above? 
Thanks,

Best Regards
Dennis

[Tyson]

Oh, sorry I got caught up in the other stuff.  I do not have the digital mod to the Duet, so I could not say.  Ultimately the external DAC you hook it up to will probably have a greater impact on the sound you get, but I don't see a reason to get an external DAC when the Duet can be directly modded, and thus eliminate the need for an extra digital cable and 2 connectors.  Unless of course you already own a top flight external DAC that you'd prefer to keep using, in that case getting the digital mod and upgraded PS is the way to go.  And (this is me completely speculating here, to take it with a grain of salt), if you ARE using an external DAC, you probably only need the mid-level PS, not the "Ultimate".  I think the Ultimate PS is going to have a more noticeable affect on the analog section than the digital section (tryin' to save you some $$   )

[denjo]

Hi Tyson
Thanks for your thoughtful reply! I hear what you are saying and must say that I have read many gushing reports about Wayne's analog mods and what it can do to elevate the stock SB3 or Duet and your testimony is another confirmation. Like what you said, I am very averse to extra cables and interconnects. Thankfully my amplifier is an integrated (-1 pair interconnects and -1 power cable  ) and has a built-in DAC so routing the digital out from the SB3 or Duet to the amplifier is just one digital cable.

As for your points about the power supply, I am a firm believer of "power supply is everything". Jitter is an absolute evil and must be avoided at all cost! A good DAC with anti-jitter characteristics will help but will not eliminate all jitter which should be addressed from the source. Paul Hynes and Wayne are now offering dual power supplies which as I understand will feed the Duet with two DC voltages (AudioCircler Kyrill has a dual PSU and hope that he will chime in with his views about a dual PSU for his digital out Duet mod). I think this probably explains why different transports will sound differently when feeding the digital out, suggesting that not all transports have the same jitter elimination capabilities.

Of course, if I can save enough $$$, it would be the best of both worlds to have Wayne's full analog and digital Duet mod. I am still undecided whether to go for the digital only or the full monty mods!

Best Regards
Dennis

[kyrill]

hy

The Duet does NOT need a dual pws
The SB3* ( which i am so in LOVE with, it makes "bad" recordings sound good, hey  i must have a very good sounding setup ) needs a dual pws (5V, 3.3V) but the Duet "only" a 9V pws.

I know Wayne ( also for the SB2/3) advises to listen to the analogue outs and so advises to do the analogue mods, next to a as good as can be pws, because of the very good dac inside and short internal links. But he listens to the digital out to his preferred stand alone dac(s) with  his digital modded units of course. What they miss I presume, is Pat's s/pdif out mods as Wayne is NOT doing this mod by himself. Look at Pat's scope photo's
before mod:

http://www.audiocircle.com/index.php?topic=45330.0

after mod, which still can be improved a bit while tweaking the assemblage of the mod:




 and notice how "horrible" a not s/pdif mod is looking. As i have done his s/pdif mod i can only say that my SB3 s/pdif out is better sounding than my modded TEAC VDRS1 CD transport with modded pws and super clock. And not a bit better but "3000 $" better.

So?  So i assume the digital out from the DUET needs Pat's S/pdif mod as well but, only when you really want to diminish digital "sound" as much as possible

[jhm731]

So?  So i assume the digital out from the DUET needs Pat's S/pdif mod as well but, only when you really want to diminish digital "sound" as much as possible

IMO, the stock Duet's digital output sounds better than a stock SB3.

Can Pat improve Duet's digital output, yes.

My Duet now has dual PSUs, 9v and 12v with a new internal regulator to run the SPIF/Clock chip.

[kyrill]

sounds good

[Tyson]

Updated with the latest Digital mods results.

[kyrill]

and?  aa

[Tyson]

See the bottom of my first post in this thread.

From a description of the sound quality, it really had the effect of improving midbass punch and cleaning up the entire treble frequency.  I'm convinced that a lot of the "digital" sound people don't like is really noise, and this noise flattens and washes out the sound.  All of the mods helped in these areas, but this final mod really made the biggest improvement in these 2 specific areas.

[Folsom]

Tyson before you go buying a Burson perhaps you should consider Borbely (depending on money too). They use the JFET setup that has been found to be probably the best possible in a line stage, and they do custom stuff. It might cost more but we are talking difference between really good and world class from what I have been reading.

http://www.borbelyaudio.com/pics/All-FET_325-259_Lineamp.PDF

[Tyson]

With the latest mods, the buffer is absolutely not needed with the Duet.  With the SB3 it might be, but not the Duet.  I know this because I have a buffer in house now and it does nothing to improve the sound of the current Bolder modded Duet.

[Folsom]

Cool