Mezmerize DCB1 Building Thread

[HiFi Rookie]

I have ordered the board now through DIYaudio. Ordering parts I find the Jfet is no longer carried with Mouser. I will look at other sites, any preferred?

What is "matched" vs. "unmatched" N-jfet?? How do I know which I am ordering?? I need 4 of one and 6 of the other.
Thanks!!

 

[Salas]

Thanks! what are a couple sites you would recommend for purchasing RCAs?
Will I need any additional components (other than the diyaudio parts list) to set up volume control?

Beyond the Alps pot itself, extension shaft and some knob.
Try Ebay USA stores for Neutrik Rean NYS367.

 

[Salas]

I have ordered the board now through DIYaudio. Ordering parts I find the Jfet is no longer carried with Mouser. I will look at other sites, any preferred?

What is "matched" vs. "unmatched" N-jfet?? How do I know which I am ordering?? I need 4 of one and 6 of the other.
Thanks!!

Matched means same IDSS parameter. They bias with small offset voltage that way.
Ask in the swap meet forum here, maybe some members can offer.
Or ask this guy:
Store | FET Audio

 

[kop89]

Volume pot connection

About the volume pot terminals on the PCB, can anyone confirm which holes are for input, ground, and output for each channel?

I could have found out by looking at the back of the PCB, but forgot to do that and the PCB's already mounted with IRFPs greased to the chassis

Thanks!

 

[Salas]

Top view

 

[HiFi Rookie]

mezmerize build

So I have ordered everything I can from Mouser, Farnell, DIY HiFi audio supply... etc.

I need help, if someone would be soo kind, finding where to order the correct parts for my mezmerize build:

-Decoupling A 150nF/63v
-12v Relay 2 poles
-05v Relay 2 poles
-Fuse 115V (not sure which one to get)
-Fuse 230V (not sure which one)
-Jfets matched/unmatched

Thank you to the person that can help the newbie out (Salas)! Also, a link to your preferred transformer for this build would be greatly appreciated!!!

 

[HiFi Rookie]

Oh and
how about a link to your preferred pot for this build (volume control).

 

[Gooch]

Oh and
how about a link to your preferred pot for this build (volume control).

I just bought mine from here 10K, Blue Velvet - STEREO

I got my jfets for here Resistors, MOSFETs items in AudioFET store on eBay!

Relays from mouser 551-EA2-12NJhttp://www.mouser.com/ProductDetail/NEC/EA2-12NJ/?qs=%2fha2pyFaduhXUwPPWNR4NtsWKfVW%2frJA%2fd8lQuuTyhNbIv%2fFWinIjg%3d%3d

 

[Salas]

For primary inline fuse you may divide your transformer's wattage by your wall voltage.
Prefer 12V relays and put a wire jumper where it says 'note' on the PCB, they heat the 7812 less.
Decoupling you will most possibly not need if you got the BC517 relay driver transistor.

 

[HiFi Rookie]

Thanks Gooch! That helps a lot.
Is this 5v relay ok? I picked up the NEC 12v relay you recommended.
Mouser # 653-G5V-2-H1-DC5
http://www.mouser.com/Search/Produc...5virtualkey65300000virtualkey653-G5V-2-H1-DC5

 

[kop89]

Also, a link to your preferred transformer for this build would be greatly appreciated!!!

I got an ANTEK 100VA, 2x15V trafo:

Antek - Transformers - Grid View

 

[BackinBlack]

You should only need 12V OR 5V relays, not both. As Salas notes 12V are preferred.

 

[HiFi Rookie]

For primary inline fuse you may divide your transformer's wattage by your wall voltage.
Prefer 12V relays and put a wire jumper where it says 'note' on the PCB, they heat the 7812 less.
Decoupling you will most possibly not need if you got the BC517 relay driver transistor.

Salas. The build materials ask for 12v and 5v relays. Are you saying I only need 12v relays?? And that this is better? So should I have 14 12v relays then?

 

[HiFi Rookie]

You should only need 12V OR 5V relays, not both. As Salas notes 12V are preferred.

Ah. Gotcha. Thanks.
And so all I will need is 7 12v relays.

 

[HiFi Rookie]

Kop 89. Doesnt the B1 asks for a 50Va transformer 2x12v. You use 100Va?

 

[kop89]

Oh and
how about a link to your preferred pot for this build (volume control).

I use a 4x24 Elma switch with these resistor values for 25K ladder (Dale RN60 1/4W resistors):

http://www.hificollective.co.uk/pdf/ladder_r_values1.pdf

 

[kop89]

Kop 89. Doesnt the B1 asks for a 50Va transformer 2x12v. You use 100Va?

I hotrodded my build, so use 100VA with 2x15V secondaries. Going to bigger VA never hurt.

 

[Salas]

Salas. The build materials ask for 12v and 5v relays. Are you saying I only need 12v relays?? And that this is better? So should I have 14 12v relays then?

Yes you only need 12V relays of the specific characteristics and form factor.
Asks for 12V or 5V. Not both.

 

[Rush]

Going to bigger VA never hurt.

I think it sounds better too!

Rush

 

[kop89]

It's alive!

It came alive this morning - this is an "emergency" build, I will finish the details later (top cover, add inputs, wire dressing, tighten all the nuts/screws, etc)

The 25K ladder pot works OK.

My build is hotrodded using 10R resistors in place of 68R - wondering if I can hotrod it some more by soldering another 10W in parallel to make it 5R?

The ground of the PCB is floating and isolated from the earth and chassis - any suggestions on what to do with the PCB ground? Is there any star ground hole on the PCB?

My electronics chain are all now DIY
Pearl 2 (or Opus DAC) - Mesmerize - Aleph 2

This project is relatively low-cost and low-effort compared with my other projects, but it sounds like ten thousand bucks. My Conrad Johnson PV10 and Adcom GFP750 will go into storage. The Mez sounds very transparent and detailed but neutral.

Thank you Papa and Mr. Salas for sharing this project and make it easily accessible for all of us