[Wayne1]

Does it have to be 9 volts coming in or will it work with a higher DC voltage?

The reason why I ask is because I have seen pictures of the internals of the receiver on the net, and someone mentioned that it already has 3 voltage regulators on board. So,,,,,,,, in other words, I don't want to regulate to exactly 9V if it's not necessary.

Sorry to highjack the thread . . .    I hope someone can answer.

with LARGE heat dissipation You will need regulators or heat sinks bolted to the case to remove the excess heat, Large resistors are also good at this. Any larger voltage and you would have to do deal with the exrts heat created

[Quiet Earth]

Thank you Wayne1. I think I understand what you're saying about the heat.


But are you also saying that the receiver doesn't need exactly 9 volts DC input to work properly?

[jman66]

Buy the Acopian and strip a power cord and DC cord and hook it up - it's easy and Acopian has the exact match in amperage that you need.

I ordered an Acopian and arrived today: 9EB150 - 9V/1.5a 
All I can say is WOW! I had no idea the vast improvement it would bring.

[mr_bill]

I have a different Acopian than you - larger model, can't remember the part number, except it is rated at 0.5A which is what the Duet power supply is spec'd.  The 1.5 should be fine.

[jman66]

Perhaps you have the B9G50 (Gold Box), that's rated 9V / 0.5A. But the stock switching supply is rated at 1A.
Regardless, eliminating that switching PS worked wonders for me...

[Quiet Earth]

Does it have to be 9 volts coming in or will it work with a higher DC voltage?

Well, I have submitted the question to Logitech. We'll see if they reply. Meanwhile, I decided to put my money where my mouth is and I picked up the little Mastech power supply for a bench test supply. It's a very nice little power supply and brand spanking new.

I hooked it up to the Duet receiver to see how low in voltage I could go and still keep working. Just below 5.9 volts the receiver shuts down completely. There's not enough voltage to turn it on. Between about 5.9 and 7 volts it works just fine, BUT, the white front panel light is either very dim or purple. I think purple indicates it is in a "trouble" mode of operation. Anything above 7 volts and up to 9.1 volts seems to be the perfect working condition. All testing was done using the digital outs into an outboard DAC, so I can't comment on the sound of the analog outs. Also, I have not taken it above 9.1 volts because I don't want to damage my receiver.

The current drawn at 6 volts is 540mA (0.54A) and it steadily goes down as you increase the voltage to 9 volts, where the current drawn is only 380mA (0.38A).

[Bob in St. Louis]

Does it have to be 9 volts coming in or will it work with a higher DC voltage?

Well, I have submitted the question to Logitech. We'll see if they reply.

I would be shocked if they reply with an answer other than "you shouldn't be playing in there. Therefore you don't need to know". 
The Logitech folks don't like "modders".  But let us know what they say anyway.
I would not recommend increasing the voltage to a piece of electronics. 
You can't put the smoke back in.
As far as turning the voltage down to the point where it shuts off...Not sure I'd do that too many more times either. It can't be good for it.

Bob

[Kirk57]

Hi jman66--

Could you elaborate a bit on the improvement seen using the Acopian Linear PS?

I'm hoping to eliminate a slight grain I'm hearing and would like an increased sense of air in general (compared with my vinyl setup)

Thanks

Kirk

Digital: SB Duet -> Valab NOS DAC (newest one)
Analog: Systemdek IIX/RB300/Cardas wiring/Audio Technica AT150mlx
The rest: Modded Superphon Revelation Dual Mono pre -> Superphon DM200 amp -> Anti-cable speaker wire -> Van L Speakerworks Quartets

[Quiet Earth]

I would be shocked if they reply with an answer other than "you shouldn't be playing in there. Therefore you don't need to know". 

Right you are Bob. The reply that I received from customer support mostly said "It is highly recommended that you use the adapter that was designed for the player.".

If I was selling a mass produced product and I wanted to keep the variables to a minimum, that's exactly the answer I would give too. Fair enough.

[Quiet Earth]

I'm hoping to eliminate a slight grain I'm hearing and would like an increased sense of air in general

Kirk,

FWIW,  I've used both a 15 volt Acopian supply with aditional 9 Volt regulator, and a Mastech variable DC supply set to 9 volts. I think both of these linear DC supplies are an improvement over the included wall wart. They move you toward the direction that you are describing, reducing a slight grain and giving you an increased sense of ease.

However, for as much of an improvement that a linear supply brings,  I don't think that it transforms the Duet into something that it is not. To be more specific, I think my CD transport sounds better than the Duet does playing into the same DAC. I don't know why, but the CD transport sounds like the CD, and the Duet sounds like a copy of the CD. A very good copy mind you, but still a copy. This is just my opinion, and I know that results will vary for a multitude of reasons.

I like the Duet for what it is, and I like my CD player for what it is too. Same goes for vinyl  . I'm just trying to keep that perspective during all of this experimentation. 

[evan1]

above is a link for a power supply somebody posted on one of the circles.5 volt 2 amp, item number tm93pws2476. This power supply has made me change my mind for an external DAC. The sound from my SB Classic is now more opened and detailed and nice bass response. The best part it only costs 9.95.

Link did not work. Go to Herbach.com and search for the item number above

[Kirk57]

Evan1-

So far I've been unable to find a linear power supply for the Duet (9v) that's as cheap as the one you found for the SB Classic (5v).

a bit over $100 for the Acopian 9v is the least expensive linear power supply I've seen for the Duet; anybody else find anything?

Kirk

[jman66]

Sorry Kirk, just saw your question...

In my setup, the Acopian cleaned up the highs and added a greater level of air and separation that was immediately noticeable. Improvements in soundstage and imaging too, perhaps on a more subtle level.
Those improvements now have me rethinking sending the unit to ART (Pat) for his mods.
If you don't mind large and clunky, go with the HP unit recommended earlier in the thread.

-jim

[Kirk57]

Found this:

http://www.mcmelectronics.com/product/DISTRIBUTED-BY-MCM-MW122A-/28-2200

Description is

Multi Voltage Regulated Power Supply
Ideal for any device drawing up to 2A
Fully regulated to deliver constant DC power
Rotary selector switch selects 3, 41/2, 6, 71/2, 9 and 12V
Power projects or small battery operated devices
Color coded binding posts makes connection easy

I sent a mail to MCM and they comfirmed it is a linear supply.

Cost is $27.95 plus shipping

Kirk

[jholtz]

Hi Kirk,

Thanks for the great find. I googled the model number and found it's sold by many vendors. The least expensive was at http://www.altex.com/default.aspx for $21.95. They also offer an optional cable for a little over $3.00 that'll save hacking up the one that came with your Duet.

Thanks again!

Jim

[MerlinWerks]

Found this:

http://www.mcmelectronics.com/product/DISTRIBUTED-BY-MCM-MW122A-/28-2200

Description is

Multi Voltage Regulated Power Supply
Ideal for any device drawing up to 2A
Fully regulated to deliver constant DC power
Rotary selector switch selects 3, 41/2, 6, 71/2, 9 and 12V
Power projects or small battery operated devices
Color coded binding posts makes connection easy

I sent a mail to MCM and they comfirmed it is a linear supply.

Cost is $27.95 plus shipping

Kirk

Unfortunately I believe you overlooked these two features:

# Built-in surge protection allows for safe car start-up and shutdown
# Low battery shutdown when DC voltage falls to 10.5V or less

It appears this is made to regulate battery supplied voltage.
Or it could very well be that I'm the one overlooking something 

Edit:
And I was overlooking something, if you search for the MW122A part # on the site Jim linked to, that one is AC powered 

[jholtz]

Unfortunately I believe you overlooked these two features:

# Built-in surge protection allows for safe car start-up and shutdown
# Low battery shutdown when DC voltage falls to 10.5V or less

It appears this is made to regulate battery supplied voltage.
Or it could very well be that I'm the one overlooking something 

Here's the description from the Altex Computer page:

http://www.altex.com/Philmore-Multi-Voltage-2-Amp-DC-Power-Supply-MW122A-P143093.aspx

 ITEM# MW122A
Description: This compact sized regulated power supply is ideal for all devices drawing up to 2 amperes. It is fully regulated to assure that a constant, accurate DC power is delivered to different kinds of electronics and electrical appliances.

The rotary selector for choice of 6 voltages (3, 4.5, 6, 7.5, 9, 12VDC), with any currents not more than 2000mA e.g. portable TV sets, video games, tape recorders, radios, scanners, boom boxes etc. The red and black binding posts enable easy connection. In addition, an optional cable is available for easy hookup to devices with a DC input receptacle.

Features:

    * Operates on 110/120VAC
    * Multi-Voltage Output: 3, 4.5, 6, 7.5, 9, 12 VDC
    * Provides constant current from 0-2000mA
    * Fully regulated, low ripple
    * Short circuit protection
    * Automatic thermal cut off
    * Automatic overload protection
    * Heavy Duty Red and Black Binding Posts
    * “LED” red lamp indicates power
    * 3-3/4” Wide x 5-1/4” Long x 2-5/8” High

I have one on the way. I ordered this morning and they shipped this afternoon.

Jim

[jholtz]

Ok, an update on the linear power supply from Altex Computers. It is exactly as advertised and seems to be well made. It gets warm just like the Acopian I had for my SB2.

Now the sound. I'm working from memory of listening to the CI power supply that my friend has but the Altex seems to have the same qualities. The background hash goes away which adds to the presence of vocalists and the black background we seek during quiet passages. In other words, it works well and for $21.95, I consider it a steal.

The optional wiring ($3.25) was easy to install and other than the slightly loose fit of the end that plugs into the Duet Receiver, it was very easy to hook up. There are two ways the end will plug into the wire. There are no instructions so I winged it a bit and found the way that worked was to match the word "tip" imprint on the end of the wire with the + sign on the tip that plugs into the Receiver. I took care of the slightly loose fit into the Receiver by using a bit of clear packing tape to hold it in place. I hide the Receiver behind my DAC anyway so it's not visible unless you crawl behind my audio rack.

Anyway, I think this is a very good and very inexpensive linear power supply for the Duet. Thanks to Kirk for running it down! 

Jim

[Kirk57]

Jim-

Glad to hear that it's an improvement; I'll order one myself...

BTW since you don't mention one, I assume you aren't using a DAC, just the analog outputs of the SB, is that right?

My understanding is there is a greater difference with the linear supply when using the analog outputs.

I'm using a DAC but for the price of this supply it's worth trying it just for the heck of it.

Plus I can use it as a tool to help me fix my recent acquired Magnepans, but that is most definitely a different thread...

Kirk

[jholtz]

Jim-

Glad to hear that it's an improvement; I'll order one myself...

BTW since you don't mention one, I assume you aren't using a DAC, just the analog outputs of the SB, is that right?

My understanding is there is a greater difference with the linear supply when using the analog outputs.

I'm using a DAC but for the price of this supply it's worth trying it just for the heck of it.

Plus I can use it as a tool to help me fix my recent acquired Magnepans, but that is most definitely a different thread...

Kirk

Hi Kirk,

Actually, I am using a DAC. It's a Pacific Valves Lite Audio DAC-62 which is a DAC-60 with mods. It is a tube DAC, BTW. I love the sound! The linear power supply made it better. I can hear a difference in the background hash and presence of vocalists even using the Duet as a transport rather than the analog outs. I find the Duet to be an awesome transport but an average CD player using the analog outs. Not bad but easily bettered with a good DAC.

The downside is the power supply is heavy so shipping isn't cheap. I paid $39 delivered from the east coast to the Midwest for the power supply and wiring kit via FedEx express shipping. Altex was excellent to do business with. Very fast shipping and no hassles.

Jim