Duet Mods

Wayne1 · « **on:** 24 Mar 2008, 02:38 pm »

I have been receiving a bit of mail about this.

I though I would post to clear up any confusion.

I have two Duet systems on order. I have not yet received them. When I do receive them I will look them over to see if there might be any mods that will improve the performance of the unit. I will then try out various mods and listen to them. If they make a good improvement, I will offer them on the BOLDER Cable website.

The receiver is pretty much entirely new. It is NOT just a SB3 without a display. The power supply is different (higher voltage and no internal switchers). The DAC chip used is different. The analog output IC AND circuit is different. Sean Adams did say the digital output circuit is the same, we will will have to see to make sure.

If mods are possible, it will take some time to come up with them. Then I will have to evaluate them compared to a stock unit. The sound of the mods will change as the unit breaks in.

I do not expect to be able to offer ANY mod until 4/15/08 at the earliest.

Wayne1 · « **Reply #1 on:** 27 Mar 2008, 09:21 pm »

I just received the pair of Duets I ordered from my distributor.

Logitech did a great job on the packaging. Very 'Apple-ish"

Set up was a breeze. No problems at all. It took a bit longer than a standard SB3 in my system, but it required a minimal amount of input from me. The controller updated some software for it.

Everything is working well.

Now I have to finally finish the 9 volt power supply I have had sitting on the bench for some time. Hugh sent me a couple of "Nirvana" regulators for me to play with.

It looks like a fun filled weekend of experimenting coming up.

I also received the chassis and all the parts to build my son a tube guitar amp. LOTs of projects and never enough time

prpixel · « **Reply #2 on:** 27 Mar 2008, 11:40 pm »

Wayne,

My duets are in the house also. I like the controller a lot; more than the Sonos.

Wayne1 · « **Reply #3 on:** 28 Mar 2008, 09:17 pm »

I have spent a little time with the pair of DUETS.

First off, the external power supply used to feed the Receiver will make a VERY large difference to the sound of the unit.

There is no internal switching PS to mess with the DC. In fact the whole power distribution design inside the Receiver is very simple. What is fed to it is pretty much what you hear.

Changing to a linear PS WILL make a difference. A lot less switching noise. At the least a filter, such as a Felix, should be used both before and after the stock switcher.

Using a Felix or such like device on the PS for the Controller will also help reduce noise added to the AC line. Some sort of filter should be used an ANY device using a switching PS.

I did finish the built of a linear 9 volt PS. It is loosely based on the Ultimate MKII but using much less expensive capacitors. There was a LARGE improvement to the sound of the stock Receiver when I changed over to the linear power supply.

I have done some mods to the analog section AND the digital section of one of the Receivers.

The good thing about the Receiver analog section is that it is designed from the start NOT to use an op-amp after the DAC chip. The Wolfson DAC chip selected by Slim Devices can supply the voltage and current to run direct into amp without the need of any other device. So, any analog mods will NOT have low voltage or inverted phase.

I have just started listening to the modded unit with a linear PS. More time is needed to evaluate the mods and compare them to the stock unit. I will also need to compare the modded Receiver to a stock SB3 and one of my modded SB3. Unfortunately, right now all my modded units are out on loan. Hopefully I can get one back soon to do a comparison.

My first impressions of the Duet are very favorable. I do like the Controller. There are some features I would like to be included with it, but I am sure they will come, in time.

mountain1 · « **Reply #4 on:** 29 Mar 2008, 01:10 pm »

Sent you a PM

anthony a. · « **Reply #5 on:** 29 Mar 2008, 09:17 pm »

if you can do the analogue mods on par with your statement sb3 analogue (except without the invert phase issue) i think it will be a hit. the only thing holding me back from a statment analogue sb3 is the inverted phase.

Folsom · « **Reply #6 on:** 29 Mar 2008, 11:56 pm »

Quote from: anthony a. on 29 Mar 2008, 09:17 pm

if you can do the analogue mods on par with your statement sb3 analogue (except without the invert phase issue) i think it will be a hit. the only thing holding me back from a statment analogue sb3 is the inverted phase.

This might do you justice if you have a powerful enough computer (my laptop 2ghz Centrino does not cut it). You can try this without a modded SB it would just reverse the phase to out of phase, but you would know right away if this would work well for you.

http://www.audiocircle.com/index.php?topic=52374.0

Analog mods with a linear power supply (some argue switcher) and power filtering are really amazing.

The other option is running the old firmware which is what I do and it works good enough. The difference between unmodded and modded makes the slightly less good firmware MORE THAN OKAY with me. The only think really not good about the old firmware is it scrolls kind of funny and it responds slightly slower from waking from what I can tell. I have not had any real issues. The worse thing has been because I send .wav over wireless is once or twice it has stalled due to network or computer, not firmware related. Anyways there are options! Although you could always get digital mods and use a hot DAC with pace car or not.

BRN · « **Reply #7 on:** 15 Apr 2008, 05:45 pm »

Wayne,

Any update on the Duet? It sounds like at a minimum it would be good as a transport.

Brad

Wayne1 · « **Reply #8 on:** 15 Apr 2008, 10:21 pm »

Sorry I haven't posted any updates.

The power supply is VERY important to the Duet system. There are some rather large differences depending on what power supply is used.

I have built a couple of PS for the Receiver. One is a "standard" PS using all high quality parts. The other raises the bar quite a bit by having a "Felix" type CLC filter built in. I also used a "Nirvana" regulator designed for 9 volts. There is an improvement in dynamics and a lower background "noise" level with the more expensive PS.

The sound of the Receiver when run digital out (modded) compared to a modded SB3 is very close. The only modded SB3 I had on hand was just modded today. There was a slight lack of dynamics in the SB3, but I will put that up to the fresh mod.

A digital modded Receiver using a GOOD linear PS will sound at least as good as a digital modded SB3. It may even sound better.

I do have a couple of modded SB2 on hand. I will try to compare those to the modded Receiver later in the week.

Digital mods for the Receiver should run around $150.00.

I have not yet compared the analog mods to a modded SB2 or 3, or even the stock Receiver.

As I said at first. the power supply will make a HUGE difference. All linear PS are NOT the same.

There may be another Aspen Audio/BOLDER offering for a PS for the Receiver. It will not be cheap.

I am also looking at a less expensive, lower sound quality PS for those who don't want to spend quite so much.

Wayne1 · « **Reply #9 on:** 21 Apr 2008, 06:14 pm »

I have completed my evaluations of the mods.

I am VERY pleased with how they have turned out.

The mods are now listed on the BOLDER Cable website. I should be able to turn the mods around in about 7 days once the units arrive here.

I have added a linear power supply at a very special introductory price, including DC cable. I have enough parts on hand to build FIVE of them. When they are gone, there WILL be a price increase!

Hugh is working on a power supply designed just for the Duet system. He is expecting the circuit boards this week. I have no idea what the selling price will be, BUT IT WILL NOT BE CHEAP!

In my evaluations, there was a very obvious improvement using the Nirvana regulator on full range, dynamic program material.

I'll post more later. I also have some updates on the digital mod for the SB3 and a "new" inexpensive power supply for the SB2 or 3

mr_bill · « **Reply #10 on:** 21 Apr 2008, 09:26 pm »

Wayne,
How does the Duet with analog mods and your linear power supply sound versus a stock Transporter or an SB3 into a higher quality dac?
Inquiring minds want to know! I suspect straight into amps and bypassing a preamp is still the way to go with the Duet?
Thanks Wayne,
Bill

Wayne1 · « **Reply #11 on:** 21 Apr 2008, 09:36 pm »

I do not have a Transporter on hand to compare it with. I have compared it to a Statement level modded SB3 with an throughly outrageous power supply. The Statement was just a bit better.

The power supply in the external DAC and what it is using for an analog section will have more of an influence on the final sound than the difference between the DUET system and a modded SB3.

I would still take take the modded analog output of a SB3 or DUET with a good power supply over any external DAC.

I do hope to get together with mgalusha and TweekGeek soon and compare the DUETS in their systems. mgalusha is using a VERY highly modded DCX2496 for a DAC.

mgalusha · « **Reply #12 on:** 4 May 2008, 01:11 pm »

Thanks for bringing your duet of Duet's over yesterday Wayne.

After listening to various combinations starting with a stock Duet and PS to the fully modded unit with BOLDER/Aspen Nirvana plus (I think) power supply and Wayne's statement SB3 I have to agree with Wayne that his SB3 is just a bit better though not so much better as just a little different. Both were very good and like the Squeezeboxes, the Duet really benefits from a good power supply.

As Wayne mentioned I'm using a DCX2496 crossover which can also act as a DAC. For our listening we fed all the sources through the analog inputs of the DCX so we could evaluate the analog outputs of the various boxes. The analog section of my DCX has been replaced by one of the units available from Linear Audio and is transparent enough to easily show the differences in source components. I did want to try the digital out from the Duet but we ran out of time and never managed to get to that, ah well, another time.

Lastly, I was surprised by just how small the Duet receiver is. About 1/2 of an SB3, very cool!

mike

Wayne1 · « **Reply #13 on:** 4 May 2008, 04:12 pm »

Thanks for the comments, Mike.

The DUET really benefits from a better power supply. Not just a linear. The "standard" linear I used on the DUET yesterday was all hand built. No printed circuit board. 1/8" thick FR Epoxy boards drilled out and turrets installed. Point to point Nitro wiring. 60,000 ufd + of Nichicon Muse caps, with Black Gates and Sonicap Gen 2 bypasses. Acme Audio silver plated, cryo-treated IEC connector, fuse holder and fuse.

There was an amazing improvement when switched from the stock switcher to the linear. Mike's AC power is all on separate runs. The switcher was on a completely different circuit than the front end electronics and that was separate from the amps. The low end improved quite a bit with the linear. Highs were less harsh, etc.

The Statement SB3 powered by my Ultimate Nirvana Plus prototype PS had a bit more "tone". Slightly fuller and richer. I just may have to eat my words about that PS

It is more full sounding than the other PS. IT IS a lot of money, but it may just be worth it to continue to explore this design.

At some point, I would like to compare the digital output from the Duet system to the modded SB3. I would also like to compare the modded Duet analog output to that of some different outboard DAC's. If there is anyone in the Colorado front range that has a Benchmark, Bel Canto 3, LessLoss, etc and would be willing to lend it to me or host a meeting, I would be very interested in getting in contact with you.

I will be getting more parts in shortly to build more of the Standard Linear PS. Price will be around $450-500.00 for this supply. Hugh Dean will be sending me a Duet version of a Nirvana PS. I will try that out and report. I will also be building an Ultimate Duet PS as a prototype. I didn't think there would be as much difference between different PS parts with the DUET, but there certainly is. My new goal is to try to get the Duet system closer to the sound of the Statement SB3 with Ultimate Nirvana Plus supply. There is not a great deal of difference, but the final few percent of difference will be very expensive to bridge.

s_cervin · « **Reply #14 on:** 17 May 2008, 02:14 pm »

Please keep us posted. Looking at getting the Duet and if you are able to get that very close to the Statement SB3....I'm sold.

SC

jr1414 · « **Reply #15 on:** 10 Jun 2008, 08:13 pm »

I haven't heard anything about using the optical digital connection. Would you recommend using the optical connection over the coaxial connection in any cases? (Possibly to avoid any ground related issues and/or de-couple?). Would the digital mods have any affect on the optical output?

Thanks.

Wayne1 · « **Reply #16 on:** 10 Jun 2008, 08:19 pm »

The digital mod is just for the coaxial output.

I do not recommend using the optical output, ever.

jr1414 · « **Reply #17 on:** 12 Jun 2008, 06:48 pm »

Wayne,

Don't take this as a shot, I value your opinion or I would not ask it here. Please view this as an inquiry to determine factual information from which to make an informed decision.

Here is an excerpt from an article on Audioholics that seems to indicate contrary to your suggestion.

Quote

Q: Between optical and coaxial, which connection is going to give the better sound quality, and why?

A: " Better" is relative. In a harsh environment, optical may have advantages. By "harsh" I mean:

Cable runs over 10ft
Cable runs in close proximity to video and power cords emanating RF noise
In most cases, the above conditions would result in negligible impacts on the signal quality since the signal being transmitted (PCM or bitstream) is sampled at low frequencies (44-48KHz) and thus are more immune to noise impairments.

However, using optical cables can minimize the potential of the above mentioned problems and thus may help to reduce common mode noise. The only negative about using optical cables is the connection is not always as secure as a coax one, and can sometimes be compromised easily by moving components frequently. In addition, optical cables are usually more expensive than coax ones.

Bottom Line: Using optical cables for your digital connections may help minimize susceptibility of coupling RF noise into the line and reduce loss for long runs (10 feet or more). However, optical cables tend to be more costly and sensitive to abrupt external forces, which may potentially weaken the connection over time. In any event, either connection method should yield excellent and comparable results in most cases.

I've read where people have done double blind tests and after setting them to comparable volume levels, could not tell a difference between coax and optical. I haven't done this myself, but will surely give this a try soon, just for my own satisfaction.

The business about RF/EMI noise makes sense, the elimination of ground loop hums, etc and it is a widely known fact that the cable companies use fiber optics (optical) instead of coax cables which has resulted in more bandwith available and better error rejection over long runs. When you take into consideration how many cable manufacturers insist that shielding interconnects (DISCLAIMER: primarily analog interconnects) is detrimental to an "open" sound, it makes sense if you can eliminate this shielding by using an alternate signal path.

Now, let it be known, I've always used coax where possible as I understand electrical connections much more than optical. I also prefer a connector that will be less succeptable to damage over time, but honestly how often do we connect/disconnect our equipment. In light (no pun intended) of the information in front of me now, I might be forced to reconsider optical connections.

My only thought is that there may be errors induced in converting the digital signal (1's & 0's) to an optical signal and back again. But it's hard to argue with quantifiable real world results.

Do you know of any technical reasons to prefer coax connections to optical? Anything quantifiable that can demonstrate higher bandwith, better noise rejection.. In essence a purer digital signal? I understand you have much more experience than I do (obviously), so I value your input.

Thanks.

Wayne1 · « **Reply #18 on:** 12 Jun 2008, 07:28 pm »

First off, what you are asking about is TosLink, not fiber optic. The two are quite a bit different. TosLink was developed by Toshiba

TosLink actually has a narrower bandwidth (6 Mhz) than coax (500 Mhz). The apature of the laser in TosLink is wider than most fiber optic systems, resulting in the narrow bandwidth. The optical output is quite a bit lower than fiber optic systems, thus making it a poor choice for really long distances. TosLink Signal cables are usually limited to 5 meters in length, with a maximum length of 10 meters, for reliable transmission unless using a signal booster. Depending on the actual material used to carry the optical signal, there may be large amounts of reflections in certain lengths.

There is no real set standard for the construction of TosLink cables. TosLink may use inexpensive 1 mm plastic optical fiber or it can use higher quality multi-strand plastic optical fibers or even quartz glass optical fibers depending on the desired bandwidth and application.

In the real world, there are no 1's and 0's. There is an analog waveform changing from high to low. Usually this will equal 3.3 volts for high and 0 for low. If there is noise on the low end or any delay on reaching the high side, the signal will not be correct. The actual TosLink transmitter and receiver modules used in the SB and most inexpensive home audio units are rather noisy.

I have also found the mechanical connection of TosLink to be vastly inferior to coax. I do use TosLink from my cable convertor to my HT receiver. The connection has broken and will not hold the cable correctly. I have never had that happen with an RCA or BNC connector.

(Note: I did pull some of this info off of Wikipedia)

brj · « **Reply #19 on:** 12 Jun 2008, 08:01 pm »

I've also read that there can be some variability in the quality of the optical/electrical converters. If you like the "simpler is better" approach, then this added signal conversion probably wouldn't be considered helpful. That said, an optical connection will break an electrical ground loop, so if that is your greatest audio problem, there might be a benefit.