Pass B1

omishra · Nov 18, 2011

Re: Power supply

sachu888 said:
Hi all,
I have ordered 12 pairs of matched JFETs from Spencer(DIY audio member,Hong Kong).I will order remaining parts for B1 and LDR tomorrow from Element14.Om/Prasad has also designed a regulated power supply for B1 and LDR.It will cost INR 700(approx) with locally available components.Please let me know how many members are interested in power supply as I need to order PCBs for this.

Regards,
Sachin

Sachin, is that 12 pairs (12 X 2) or 12 quadruplets (12 X 4)?

sachu888 · Nov 18, 2011

Re: Power supply

omishra said:
Sachin, is that 12 pairs (12 X 2) or 12 quadruplets (12 X 4)?

Sorry Om,
Its 12 groups (12X4).

gopib · Nov 18, 2011

Re: Power supply

sachu888 said:
Hi all,
snip snip .Om/Prasad has also designed a regulated power supply for B1 and LDR.It will cost INR 700(approx) with locally available components.Please let me know how many members are interested in power supply as I need to order PCBs for this.

Regards,
Sachin

Hi Sachin,

Will help us make a decision on the powersupply if you let us know what it comprises. I have quite a collection of trafo's and the like. Want to use some of that. However for the sake of uniformity I may want to use the kit too. I am sure there would be others in the same boat as me, and information
would help,

Thanks

josephjohnt · Nov 18, 2011

Re: Power supply

sachu888 said:
Hi all,
I have ordered 12 pairs of matched JFETs from Spencer(DIY audio member,Hong Kong).I will order remaining parts for B1 and LDR tomorrow from Element14.Om/Prasad has also designed a regulated power supply for B1 and LDR.It will cost INR 700(approx) with locally available components.Please let me know how many members are interested in power supply as I need to order PCBs for this.

Regards,
Sachin

I will take one.

captrajesh · Nov 18, 2011

Hi Sachin,

I'm for the power supply as well.

Regards

Rajesh

omishra · Nov 18, 2011

Re: Power supply

gopib said:
Hi Sachin,

Will help us make a decision on the powersupply if you let us know what it comprises. I have quite a collection of trafo's and the like. Want to use some of that. However for the sake of uniformity I may want to use the kit too. I am sure there would be others in the same boat as me, and information
would help,

Thanks

In continuation from here.
We reffered Elliot Preamp power supply and LM317/LM337 datasheet, application notes for hints. Also we put some of experiences into this.
This power supply based on low noise linear voltage regulators LM317 (2 numbers for +24V and +15V) and LM337 (1 number for -15V).
It take input voltage from transformer, any from (18-0-18) to (32-0-32). (minimum 500mA for PASS B1, LDR Volume Control and CNC phono stage). More current is not an issue as regulators can provide upto 1.5A but heatsink will be required for regulators and output filter coils need to be rechecked.
Output is designed to provide (+24, 0) and (+15, 0, -15). Output voltage it set using trimmers in each power line which could be adjusted with small screw driver. You can settle at any preferred value but need DMM for this voltage reading.
If you plan to power up CNC phono stage then please use r-core or EI transformer without overlapped winding. This will couple less noise from ac mains power line. (as it is understood that toroidal transformer have more capacitance between primary and secondary, hence more noise coupled through it)

Please feel free to ask more questions.

Audiodoc · Nov 18, 2011

I also want the power supply. Kindly pm me the total cost as your account has already been added to my list of beneficiaries.

A post describing the kits in a gist will be helpful so that everyone doesn't have to go through the entire post to check for any changes down the line.

sachu888 · Nov 18, 2011

Audiodoc said:
I also want the power supply. Kindly pm me the total cost as your account has already been added to my list of beneficiaries.

A post describing the kits in a gist will be helpful so that everyone doesn't have to go through the entire post to check for any changes down the line.

Hi Audiodoc,
Final cost should be in between INR 3500-4000(B1+Lightspeed kit and power supply).

Regards,
Sachin

gobble · Nov 19, 2011

The PSU is not the transformer right? OK then I want one.

@Sachu I will make the payment tomorrow.

FYI: The Great Capacitor Shoot-Out

--G0bble

santhosh · Nov 19, 2011

Sachin/Om/Quad: sorry I am catching up on this thread after a long time. Thanks for the efforts you folks are putting in for this.

@Sachin: I will transfer the money in 1-2 days. Include me for the full kit.

sachu888 · Nov 19, 2011

santhosh said:
Sachin/Om/Quad: sorry I am catching up on this thread after a long time. Thanks for the efforts you folks are putting in for this.

@Sachin: I will transfer the money in 1-2 days. Include me for the full kit.

Thanks Santhosh ,

Regards,
Sachin

gopib · Nov 19, 2011

Sachin/Omishra/Quad,

Thanks guys for all the hard work. It is going to be one good kit!!!:yahoo:

cmsajith · Nov 19, 2011

Me too for the full kit

captrajesh · Nov 19, 2011

So what is the amount Sachin. 1K + 700/- = 1.7K ?

captrajesh · Nov 20, 2011

The DIYers seem to have improvised the B1. This guy on another forum has collated the info available on some other forums here: DC-Coupled B1 Buffer Build

I'm quoting him here:

The DC Coupled B1 Buffer (DCB1) is a DIY project designed by Salas and others on the diyaudio.com forum. It based on the popular B1 Buffer Preamp by Nelson Pass, also from the diyaudio.com forum. There are several threads on both projects with hundreds and hundreds of pages, so I decided to do tutorials on both for those who would just like to roll up their sleeves and build.

The DCB1 takes caps out of the signal path and uses a shunt regulated power supply; the goal being greater transparency and improved sound quality. There are many testimonials to the success of this design and personally I have found it to be a worthwhile upgrade to the original B1. Plus all the pretty lights from the LEDs.

Would love to hear comments from DIY gurus of this thread Omishra, Quad, Sachin. Other gurus are also welcome to chip in.

omishra · Nov 20, 2011

captrajesh said:
The DIYers seem to have improvised the B1. This guy on another forum has collated the info available on some other forums here: DC-Coupled B1 Buffer Build

I'm quoting him here:

Would love to hear comments from DIY gurus of this thread Omishra, Quad, Sachin. Other gurus are also welcome to chip in.

Yes, Initially I thought against caps in PASS B1 which are costly and effect on audio. We have considered modified version. But requirement of PS was critical in modified version. Discussion with Sachin, preference was given to original design from Mr Pass. It is time tested and all data available with lot of options. Caps are added for stopping gate bias of 1/2 supply voltage. But that bias make it running w/o crossover distortion. Here caps show effect beyond 100KHz square wave. Definitely beyond audio frequency band. Its like class A amp.
Modified design has part matching is one critical requirement. It uses dual regulated PS, no gate bias. Means input signal directly at part's gate. Still is not clear if anyone measured any DC offset at output due to mismatch of JFETs and what about lots of risks involved into that design? Also many resistors in power line of JFETs control biasing and currents. This is not required in original PASS B1.
With modification, no published improvement claim with data.
So we put efforts to Original Pass B1 - short and sweet.

Please pardon me about my ignorance but I do take audiophile reviews with pinch of salt (if not backed by technical analysis.)

Anyway more thoughts are welcome.

sachu888 · Nov 20, 2011

Pass B1 parts update

Hi all,
I have ordered all parts (except 10uf PP caps)from Element 14(kitnspares.com),JFETs have been ordered from Spencer HK.Total cost for Parts=8300(Element14 with Tax and Rs 400 shipping)+ 12 groups of matched JFETs=3000(Spencer Hk.)
I will order 24 X 11uf PP AXON caps from part connection AXON True Cap Metallized Polypropylene Capacitors
I am waiting for a shipping quote from partconnection.

Regards,
Sachin

jetlag · Nov 20, 2011

> Please pardon me about my ignorance but I do take audiophile reviews with pinch of salt (if not backed by technical analysis.) <

+1 to that.

A cap free design would be great, but as said before would require lot of matching. In fact, there is another cap free preamp design in diyaudio. It sort of ran into controversy for not publishing design details and test results.

The original B1 is still an excellent product as is!

Later
Jetlag

gopib · Nov 20, 2011

I have been following the discussions on all Pass creations over time and have
found them all very well received. Whatever I have seen of his designs, based on my limited knowledge of electronics are fundamentally sound designs. Very difficult to critique. His loyal fan following is a testament to it.

That said N P also advocates experimentation, however the benefits gained from such mods have to be balanced against the improvement.

Ofcourse YMMV.

sachu888 · Nov 23, 2011

10uf pp caps

Hi all,

All parts have been ordered except 10uf PP caps.Can someone suggest a good source for 10-uf-12uf PP caps.I have narrowed down two options:
Jantzen 10 UF PP caps
Jantzen 10uF 400V Crosscap Capacitor 027-932 ($120 for 24 caps+$35 shipping)

11uf Axon PP caps,same caps used by Nelson Pass AXON True Cap Metallized Polypropylene Capacitors ($69+$40 shipping)
I feel above Axon caps are VFM but they ship by Small packet air mail which doesn't provide tracking no.
Kindly suggest.

Regards,
Sachin

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