Balanced DCB1

[Domg]

Covid confinement has at least given me time to get on with projects that have languished in cupboards for a while. The dcb1 is working in balanced mode for the first time this morning and thankfully without any ground hum issues. Still quite a lot to sort out - some tricky metalwork for the volume display/controller and I still need to figure out the best way to get a 5V power supply inside the box (any suggestions? This is only my second build).
https://imgur.com/gallery/EcvOZWf

[Macca]

Separate box for the power supply?

[Puffin]

Stonking build there Dominic. I really like the enclosure. I can only access one pic from the Imgur link and it is difficult to see what sort of power supply you already have in there. I don't know if you ever heard of the Teddy Pardo Teddy Regs and Power Regs that were the rage about 10 years ago. There is info on the PFM forum.

I mention these only that as a result of enforced confinement I have been playing with these for the first time since I built them. I have just added a Power Reg to a DIY ClassD amp and the results are very impressive. The Teddy Reg (not Power) were for Dacs, Preamps and other less demanding stuff.

[Domg]

Separate batteries just now, but as 5V DC PS only needed for volume control and display I’d like to include it in the enclosure. The traffos step down to 12V AC - not sure if I could step down from these to 5VDC or if it’s best to keep supplies separate.

[Domg]

Tricky metalwork completed over last couple of days. Just the internal power supply for the display still to do.
https://imgur.com/user/hanoidom

[Domg]

https://i.imgur.com/I88yrTK.jpg

https://i.imgur.com/oPikPiV.jpg

https://i.imgur.com/x7gNy55.jpg

[grog]

awesome looking build, what was the incentive to go balanced?
i have the same board running SE, with a relay stepped attenuator,
if it's for non audio and low power, i use these, https://cpc.farnell.com/myrra/47152/power-supply-4-5w-5vdc-reg/dp/TF01429
you can get regulated and un-reg,
tiny, and direct mains to 5V DC,
great for control as they are so neat and self contained,
i just solder it to veroboard, and use the verobaord to mount the take off pins and mounting points.
they seem well made with no spurious interference etc. i guess a bit of copper tape over the top wouldn't hurt, or even a transformer can, but i'm using some without and no issues at all.

[Macca]

That is amazing, love the resistors on the volume pot.

[paulf-2007]

Looks very smart....what is it?

[Macca]

A preamplifier.

[Domg]

H
awesome looking build, what was the incentive to go balanced?
i have the same board running SE, with a relay stepped attenuator,
if it's for non audio and low power, i use these, https://cpc.farnell.com/myrra/47152/power-supply-4-5w-5vdc-reg/dp/TF01429

Thanks for suggestion, they look perfect.
Going balanced was partly just curiosity. My mono blocks are next to the speakers with the other components off to one side. It all worked ok, but did need 4.5m long interconnect cables and I wondered if these might work better balanced.

[Barry]

H
Thanks for suggestion, they look perfect.
Going balanced was partly just curiosity. My mono blocks are next to the speakers with the other components off to one side. It all worked ok, but did need 4.5m long interconnect cables and I wondered if these might work better balanced.

I use a pair of monoblock power amplifiers, each located directly behind the speakers (so the speaker cables are about 30cm in length). The monoblocks have balanced-line inputs and are connected to the preamplifier (which has true dual differential balanced outputs) via 15m of balanced-line cable running under the floor.

Works for me, so I would recommend you try it out in your system Dominic.

[bumpy]

A preamplifier.

With no overall gain?

[Wakefield Turntables]

Amazing build quality. Just goes to show what can be done in your garden shed!!!! ;)

[Macca]

With no overall gain?

Yes, zero gain. Which granted means it isn't technically a pre-amplifier, it's a buffer. But it's the common terminology.

[Lawrence001]

Yes, zero gain. Which granted means it isn't technically a pre-amplifier, it's a buffer. But it's the common terminology.I'd probably strictly call it an attenuated buffer. Or a buffered attenuator [emoji38]

[Macca]

Well whatever it is it's an outstanding bit of kit. The best 'Thing that goes in front of the power amplifier and lets you change the volume' I've ever had.