Pass B1

[Hiten]

Strips on Wood faceplate looking like a magnified vinyl grooves

Bro, you dont know how close you are.
There is no limit to creativity. This designer made a turntable to read rings made by trees over the years. The Voice of the Trees by Bartholomaus Traubeck WWW.GOODNEWS.WS - YouTube
Not bad music at all.
Regards

 

[nraghunadh]

Bro, you dont know how close you are.
There is no limit to creativity. This designer made a turntable to read rings made by trees over the years. The Voice of the Trees by Bartholomaus Traubeck WWW.GOODNEWS.WS - YouTube
Not bad music at all.
Regards

Yes Hiten,

Those are called annual rings also call growth rings, by counting these rings we can determine the age of trees.

Thanks,
Raghu

 

[suraj]

I had a query about the OPS.
I read through Omishra's assembly guide pdf,and got confused about its current capacity.
it says

2This power supply can be used to take any output voltage from 1.5-37Vup to max 1.5A current.You need to match proper transformer for this and set output voltage
using above procedure. In case current to be drawn more than 500mA, heat sink will be required for regulator ICs.
3. From J1 or J4, to draw current in excess of 20mA ,please replace/short respective coils (L1-L6 ) in current path using wire jumpers. Otherwise it may get damaged due excessive current drawn. Its maximum capacity is 16mA with 10% tolerance.

So,to draw excess of 16mA load,one has to remove the inductors?
Assuming a load of around ~240mA,the inductors have to be removed?

 

[omishra]

I had a query about the OPS.
I read through Omishra's assembly guide pdf,and got confused about its current capacity.
it says

So,to draw excess of 16mA load,one has to remove the inductors?
Assuming a load of around ~240mA,the inductors have to be removed?

Hi Suraj, that guide was written when we had low current (16mA) inductors. That was case only durng first GB, not later. Now sachin got hold of better Panasonic inductors with ~240mA. So now its not required to remove those inductors.
Regards.

 

[suraj]

Perfect!

~~~10chars

 

[omishra]

I have some spare B1 PCB's will be giving aff at Rs.100 each (postage extra)

I wonder how that comes under 100 Rs?

[Because size of original pass design, Fr4 material, gold/silver plated PTH for double sides PCB of pass b1 released by pass DIY comes Rs 3600 for 2 pieces, 2300 Rs for 3 pieces and 600-700 Rs of minimum 8.]

Can you please post some pics from both sides?

 

[sachu888]

I wonder how that comes under 100 Rs?

[Because size of original pass design, Fr4 material, gold/silver plated PTH for double sides PCB of pass b1 released by pass DIY comes Rs 3600 for 2 pieces, 2300 Rs for 3 pieces and 600-700 Rs of minimum 8.]

Can you please post some pics from both sides?

He has already posted here http://www.hifivision.com/diy/21036-pass-b1-69.html

Regards,
Sachin

 

[hydrovac]

Hi Sachin,
Can you arrange to ship one B1 kit for me. Please tell me the landing cost in Hyderabad.

 

[KiranPS]

Thanks Sachin,I have received the Pass B1 kit, Here is what I am planning for approach,
Gurus Please tell me if any of my assumptions are wrong.

I would like a pretty quiet preamp
so I am planning to use all metal cabinets.

1) I am planning to use two Cabinets one for power supply and one for the preamp.
The Powersupply cabinet will have one 22-0-22 transformer and the power board
dedicated for the preamp. One transformer 12-0-12 for Switcher etc to avoid the relay Back emf etc from affecting the preamp (assuming).

2) I am planning an Arduino board for Input Selector / Volume with IR Remote.
This way Instead of a rotary selector I can have a push button to switch the inputs. The Input can also be switched from the remote.
Arduino Board will be powered from the 12V Transformer with 7805 and will be in the power enclosure to avoid noise.

3) I am planning to get an APLS Motorized pot which can be controlled by the arduino
for IR remote.

What POT value is ideal for the B1 ?

I have got the Alps Pot for my Musical Fedility preamp from this german seller,
and the delivery was prompt and good.

familygate | eBay

Regds
Kiranps

 

[omishra]

I would like a pretty quiet preamp
so I am planning to use all metal cabinets.

That's good idea!

1) I am planning to use two Cabinets one for power supply and one for the preamp. The Powersupply cabinet will have one 22-0-22 transformer and the power board dedicated for the preamp. One transformer 12-0-12 for Switcher etc to avoid the relay Back emf etc from affecting the preamp (assuming).

"Two separate transformer" is unwarranted. People put 1N4148 kind of diodes across relay pins to protect from its back emf. also its not required if you have another 7812 regulator for relay drive transistor, if any.

2) I am planning an Arduino board for Input Selector / Volume with IR Remote. This way Instead of a rotary selector I can have a push button to switch the inputs. The Input can also be switched from the remote. Arduino Board will be powered from the 12V Transformer with 7805 and will be in the power enclosure to avoid noise.

You forgot- ulimbical cords connecting two boxes can acts as noise sources. Kepping regulators near load will more clean as DC supply from PS to its input could be cleaned there locally (automatically).
Push button switches using chips ( I remember some toshiba IC) does that job. But SQ is not of my liking.

3) I am planning to get an APLS Motorized pot which can be controlled by the arduino
for IR remote.

What POT value is ideal for the B1 ?

I have got the Alps Pot for my Musical Fedility preamp from this german seller,
and the delivery was prompt and good.

ALPS pots are good, B1 like 25K? pot.

 

[KiranPS]

You forgot- ulimbical cords connecting two boxes can acts as noise sources. Kepping regulators near load will more clean as DC supply from PS to its input could be cleaned there locally (automatically).
Push button switches using chips ( I remember some toshiba IC) does that job. But SQ is not of my liking.

Mr OMishra,

If the umbilical cords pickup noise, I was wondering why audiophile brands like NAIM suggest a separate unit for power ? Is it more snake oil or is there wisdom in keeping the power supply in a seperate box ?

Regds
Kiranps.

 

[omishra]

Mr OMishra,

If the umbilical cords pickup noise, I was wondering why audiophile brands like NAIM suggest a separate unit for power ? Is it more snake oil or is there wisdom in keeping the power supply in a seperate box ?

Regds
Kiranps.

Not if that cord is shielded or internally cores are twisted. That needs some mechanism to keep noise away. Also some ferrite bid at both ends need to be added to remove antenna effect of wires. (Remember antenna can transmit as well as receive.)

Keeping separate ps is not snake oil, it helps reducing mains born noises. In some cases transformer leakage magnetic fields cause EMI which can induce hum or noise in nearby signal cable. These noises compete with audio signal. Better to keep them away, shielded and get only DC exposed to circuitry. These magnetic interference not be stopped by thin metal sheets. By increase in distance magnetic reduces by square of it. Mechanical vibration could enter through TT cartridge. Transformer makes these minute vibrations.

 

[sachu888]

Our power supply has sufficient filtering so you can keep it with B1.B1 also has sufficient filtering and it looks immune to AC noise.
You can use 25k/47k/50k pot in B1 without any ill effect.

Regards,
Sachin

 

[sachu888]

Hi Suraj, that guide was written when we had low current (16mA) inductors. That was case only durng first GB, not later. Now sachin got hold of better Panasonic inductors with ~240mA. So now its not required to remove those inductors.
Regards.

Hi Om,
just checked the specification of Panasonic inductors and they are rated 160mA.Can we still use them for 240 mA load?

Regards,
Sachin

 

[omishra]

Hi Om,
just checked the specification of Panasonic inductors and they are rated 160mA.Can we still use them for 240 mA load?

Definitely NO! We have to limit its usage within 160mA.

 

[suraj]

So i see.Not an issue really.Thing is i want the OPS to do double duty as a PSU for a prototype ARM board that i am working on,when not powering the headphone amp(which doesnt need that much power)
It has multiple leds onboard to signal different states,and they draw quite some current.
Using switching supplies was no good either,its HF noise caused issues with the processor.
Will have to give an alternate supply for the leds.

 

[KiranPS]

Thanks Sachin,OMishra , You guys Rock.

Just Completed the B1 and Power Supply board. I wanted to give it a test run before putting it into the Cabinet.

One Word about the performance -> AWESOME !!!!.
Its better than my Musical Fedility A5cr Pre. Its better than parasound 2100, Its better than any onkyo I have heard.

In the tamil song "Muthan Murai Killi Parthen", For the first time I heard sound of wind in the background in the beginning of the song when using the B1.
I did not hear that before. When I Played the same song on MF A5, to check if its there, it is there , but not as pronounced as in B1 to notice it. Similarly "Old Fasioned Saturday Night" , "Allan Taylor - Colour To the Moon", "Somethin' Stupid" all sounded much better, with much more detailed, clear and neutral presentation. A5 was tending to be a little harsh and Bright.

Unless something really better comes along this is going to be my Preamp for a long time.
I will finish the Arduino with IR Remote for Channel Switcher tomorrow and Share the Sketch for others who might want IR Remote for the Pass B1.

I used NA7004 for source and Parasound A21 for Amp with Sonus Faber Luito Speakers.

Regds
KiranPS.

 

[captrajesh]

Quite interesting Kiran. Hope to audition it sometime.

 

[KiranPS]

Sure Captain. I should have the cabinet and remote done by next weekend.

 

[KiranPS]

Hi,

I am able to get only 10k,50k and 100k Alps Motorized pots, Which one should I go for ?

Thanks,
KiranPS.