|10th February 2011, 03:49 PM||#1|
Another noob B1 question
I searched the forum in an attempt to find a nice first pre-amp build and stumbled across the seemingly simple to build for a noob B1. As I have read a great deal about Mr. Nelson Pass, I immediatley wanted to build one. BUT, my dilemma is this: I really want a remote controllable volume, and have been drooling over the DODD DIY remote-kit. Would it be possibly (most likely) and difficult to install this in the B1?
"If it ain't broken, don't fix it" seem to apply a great deal here, methinks.
Also gain would perhaps become an issue. I plan to use this on either a Hypex or SKA amp. With the Hypex, I have heard gain should be an issue, and with the SKA, a minor adjustment is required. Also the F5 seem incredible, is there a giud for the build somewhere?
ANY feeback, input and so on from more experienced diy'ers are most welcome
|10th February 2011, 05:32 PM||#3|
Not excactly sure about your pic.
But it's this one:
Whenever someone experience says "You -just- have to do this and this", I get a feeling it's not quite as simple
Thanks for your reply.
Maybe I'll leave the remote for another build, get some more experince in forst
Last edited by MagnumOpus; 10th February 2011 at 05:52 PM.
|10th February 2011, 11:47 PM||#4|
Join Date: Oct 2010
Location: Denver, Colorado
Don't be intimidated by that remote-controlled volume control. Integrating it into a B1 wouldn't be that hard. The biggest issue would be the 2nd power supply necessary to run the volume, but that could be easily accomplished with a wall-wart.
The B1 is a very nice project. You will not be disappointed with it regardless if you use a remote or not!
|11th February 2011, 09:13 AM||#5|
Ok, thank you. I've seen som goodlooking solutions for the B1 psu. Maybe I could even put both psu's in a standalone box and run to cables into the B1, perhaps without sockets even. But the alps the remote kit is 100k and Pass recomends 25k. What would be the difference?
I have decided to keep things simple the first time around, and leave the remote for mye nest pre build. There are so many great things (affordable, nonetheleast) in this forum I'm sure I'll find use for it. A nice tube pre perhaps.
I am working on the BOM for B1 and looking into the F5 a bit aswell.
I'll post my list later on and hopefully get som feeback on it
Thank you guys.
|11th February 2011, 09:42 AM||#6|
Join Date: Jul 2004
Location: Scottish Borders
A linear track pot can be converted to an approximate audio track by choosing a pot 10times too high and adding a log faking resistor of about 10% to 20% to the output of the pot.
You could implement a similar trick to the 100k log pot to bring down the effective output impedance over some of the volume adjustment range and gain a bit in softening the turn on of the remote, just in case it starts too loud.
The resistance that the 100k would need to bring it down to ~25k is 33k
You can add this resistor to the pot itself, from wiper to signal ground.
It would be worth experimenting with this resistor value.
You might not need it at all or it could work better at a high or lower value.
regards Andrew T.
Sent from my desktop computer using a keyboard
|11th February 2011, 11:11 AM||#7|
Mm, ok. I'll try and find a 25k one.
So I've snooped around the forum here and googled a bit aswell and I have come up with a BOM for my B1 build. It contains some alternatives, questions and all sorts of uneducated stuff I would be most appreciative if someone would look over it. Perhaps shed some light on the stuff I don't know. Perhaps even pimp the components abit as I am not sure if these are the recomended brands. They seem quite cheap, so if there are some more blinged out components out there it would certainly add to the cool-factor but within reason and most preferably -as stock First Watt B1- as possible.
Anyone who has built this before, or even anyone who knows this game better than myself are welcome to help me out I know it's a bit to ask, but I greatly appreciate your efforts, however small or big.
So here goes, my BOM:
FIRST WATT B1 BOM
*B1 PCB + 4 matched JFETS Pass DIY: Order Form $53,- (incl.ship)
*6stk Digi-Key - CMF1.00MHFCT-ND (Manufacturer - CMF551M0000FHEB) NOK.6.48,-
*4stk Digi-Key Part Search NOK.4.08,-
*2stk Digi-Key - CMF221KHFCT-ND (Manufacturer - CMF55221K00FHEB) NOK.2.04,-
*2stk Digi-Key - CMF10.0KHFCT-ND (Manufacturer - CMF5510K000FHEB) NOK.2.04,-
*1stk Digi-Key - CMF15.0KHFCT-ND (Manufacturer - CMF5515K000FHEB) NOK.1.02,-
*1stk Digi-Key - P1.0W-3BK-ND (Manufacturer - ERX-3SJ1R0) NOK.3.89,-
*1stk Digi-Key - BC2076-ND (Manufacturer - BFC241671005) NOK.16.50,-
*2stk Digi-Key - P6890-ND (Manufacturer - ECO-S1EP153BA) NOK.42.82,-
*1stk Digi-Key - 1N914BCT-ND (Manufacturer - 1N914BTR) NOK.1.02,-
*1stk Digi-Key - CP-037A-ND (Manufacturer - PJ-037A) NOK.5.03,-
*1stk Digi-Key Part Search NOK.53.02,-
(other options ? )
@parts-express.com: (can this be sourced elsewhere ? )
*2stk Jantzen 1.0uF 400V Crosscap Capacitor | Parts-Express.com $3.44,-
*2stk Jantzen 10uF 400V Crosscap Capacitor | Parts-Express.com $11.76,-
*1stk DPDT Mini Toggle Center Off | Parts-Express.com $1.75,-
What are these ? :
Precsion Resistive Products PR9372 audio series reesistor
Dayton Audio DFFC-0.47 0.47uF 400V By-Pass Capacitor | Parts-Express.com
Where to get Volume pot 25k?
Enclosure, knobs, RCA, feet/isolation device etc.
(Needed? : VAMPIRE BP-.5 ground post, $9.00,- each)
*RCA: 3 pairs (2 in / 1 out) http://www.partsconnexion.com/product7493.html
*Feet 4stk VIBRAPOD Cone-shaped Isolation Device (Sold as Each) $32.00,-
*( Wooden knobs, perhaps? Wooden knobs )
* http://www.partsconnexion.com/product3570.html $15.95,-
* Knobs ConneX 28mm D, Champagne Anodized Aluminum $11.95,-Knobs ConneX 28mm D, Clear Anodized Aluminum
Enclosure: What size would be sufficient?
*DPDT Toggle Switch for Input. What is this? Instead of knob?
Power Supply: (options/suggestions)
Velleman 1A POWER SUPPLY KIT: Designnotes.com $14.30,-
Where to get 1x24V 35VA trafo for the Velleman PSU? Other options?
Universal Power Supply PCB ?
Amazon.com: Energizer XP18000 Rechargeable Power Pack for Laptops: Electronics
Will this work? Other suggestions? If this is good enough (9-12v and 16-20v output) what would I need to connect it to the B1?
Aluminum Project Box Enclousure Case Electronic DIY_Mid - eBay (item 250597854445 end time Mar-10-11 17:14:50 PST)
What types of cords/plugs and such would I need to go with this solution?
If I have broken any forum rules (some of which, sadly enough, are often forgettable) by linking to the suppliers, I appologize aforehand.
So, any suggestions?
|11th February 2011, 01:01 PM||#8|
|11th February 2011, 02:46 PM||#10|
Join Date: Oct 2010
Location: Denver, Colorado
Looking at your BOM, it looks good so far.
A couple of things -
25k pot -- Digi-Key - KKA2531S28-ND (Manufacturer - KKA2531S28)
DPDT switch for input selection -- Digi-Key - 450-1304-ND (Manufacturer - MTA206N)
Poly caps for signal (if you want to source something appropriate from Digi-Key) -- 10uf -- Digi-Key - EF2106-ND (Manufacturer - ECQ-E2106KF)
1uf -- Digi-Key - EF2105-ND (Manufacturer - ECQ-E2105KF)
Also, the Jantzen caps are Danish - Jantzen Audio Denmark - Leading coil and inductor manufacturer in Europe They also have many grades of capacitors, it's worth a look.
You asked what are these - "Precision Resistive Products PR9372 audio series"
It is a series of 1/2 watt 1% metal film resistors. I used them in my Pearl project, they are very nice.
My B1 thread may give you some ideas about powersupply. - However, know that there are many good answers, not just mine! B1 preamp build thread
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