Pass B1

[omishra]

Re: Pass B1 - LDR Testing, sorting and matching

I took reference from this link

Only different I have to do is replace transistors by 2n2222 as BC546 burnt while testing with simple led. Somehow it crossed 200mA limit.

I tested for 0.392, 1.10, and 6.2 mA. Sorted for nearest match while low current and max resistance.
Ignored the odds ones on higher side as well as lower side. Totally it took 4 hrs to finish.

LDRs numbered for identification



This I tested with simple red LED and now ready for testing with LDRs.


After burning transistors, I replaced transistors and added from protection against accidental short circuit. Those three resistors were used for 3 different current measurement. [My DIY cheap switch using those open ended resistors ]



Done -



Uploaded with ImageShack.us

I got only two address from FM, please PM your address and phone numbers to me. I want these to be couriered within next two days.

Thanks.

 

[omishra]

Earlier before this GB idea, I bought 2 X 22-0-22, 30VA for me & Sachin, getting it today evening. My brother visiting there office today.

R-Core Transformer requirement -

22-0-22, 30VA

1. Gopib - 1 Nos
2. Stereorules - 1 Nos
3. Captrajesh - 1 Nos
4. AudioDoc - 1 Nos
5. Santhosh - 1 Nos
6. jetlag - 1 Nos

18-0, 30VA?
1. AudioDoc

34-0-34, 400VA
1. CaptRajesh

Please update if I am missing something.

 

[Audiodoc]

Just want to know the exact dimensions of the 22-0-22 r-core for the pass b1 kit. Will have to make changes with my enclosure drilling.

 

[omishra]

Just want to know the exact dimensions of the 22-0-22 r-core for the pass b1 kit. Will have to make changes with my enclosure drilling.

Get it by today if possible.

 

[cmsajith]

Please include me for the B1 transformer group buy

 

[gobble]

Earlier before this GB idea, I bought 2 X 22-0-22, 30VA for me & Sachin, getting it today evening. My brother visiting there office today.

R-Core Transformer requirement -

22-0-22, 30VA

1. Gopib - 1 Nos
2. Stereorules - 1 Nos
3. Captrajesh - 1 Nos
4. AudioDoc - 1 Nos
5. Santhosh - 1 Nos
6. jetlag - 1 Nos

18-0, 30VA?
1. AudioDoc

34-0-34, 400VA
1. CaptRajesh

Please update if I am missing something.

Add me to the list. The B1 requires 22-0-22 correct? How many amps? Is it better to get 22-0 22-0 instead?

Also please remember to insist that EMD puts in an electrostatic shield in the r-core. Can you also request better quality wire/leads from the Trafo?

How much does the Trafo cost? Can we include this amount in the payment to Sachin or do you want us to pay you directly?

Thanks
--G0bble

 

[omishra]

Add me to the list. The B1 requires 22-0-22 correct? How many amps? Is it better to get 22-0 22-0 instead?

Also please remember to insist that EMD puts in an electrostatic shield in the r-core. Can you also request better quality wire/leads from the Trafo?

How much does the Trafo cost? Can we include this amount in the payment to Sachin or do you want us to pay you directly?

Thanks
--G0bble

Wait...Wait...
Cost before tax is approx Rs 480 for 22-0-22, 1A (30VA), size is R-30. Let that bargained first. Now I purchased 2 pieces costing 960 + 250 Taxes (local pickup) + 40 Rs handling charges.

Payment will be decided later as my brother will be paying that in cash for the same, provided EMD agrees. It will save money and have some bargain.

For those requirement, aren't they standard? It seems like asking for extra topping on pizza


List updated -

22-0-22, 30VA
1. Gopib - 1 Nos
2. Stereorules - 1 Nos
3. Captrajesh - 1 Nos
4. AudioDoc - 1 Nos
5. Santhosh - 1 Nos
6. jetlag - 1 Nos
7. cmsajith - 1 Nos
8. gobble - 1 Nos

18-0, 30VA?
1. AudioDoc

34-0-34, 400VA
1. CaptRajesh

 

[Audiodoc]

My second transformer is a 0-18V, 1A only since it is also going to power my pass pre. The design is shown here:

http://www.ebay.com.my/itm/220721364063?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

 

[captrajesh]

Hi Mishraji,

Balance payment has been made for the B1/LDR/PS to Sachin's account.

34-0-34, 400VA1. CaptRajesh

The requirement as per Tom's website is for a 400VA trafo. Should I go in for a bigger one taking into consideration less than ideal performance of equipment in real world?hyeah:

do let me know.:sos:

Rgds


Rajesh

 

[omishra]

The requirement as per Tom's website is for a 400VA trafo. Should I go in for a bigger one taking into consideration less than ideal performance of equipment in real world?hyeah:

do let me know.:sos:

Sorry for troubling, I would be offline for next two weeks, hence wanted to finish everything by this weekend, (inclusive of settling CC bills).

For trafo, general thumb rule is use 20% more than required output of AMP. So if you amp a 320W then 400VA is more than sufficient.

I hope to get all packets couriered today itself. Fingers crossed.

 

[omishra]

Kits are shipped for below FM, please update here/send me SMS on receipt.

1. jetlag
2. stereorules
3. gobble
4. JosephJohnT
5. gopib
6. cmsajith
7. T Antony
8. Audiodoc
9. santhosh
10. Captrajesh

Instruction Document: I have pending kit of Sachin which will be shipped after I practice assembly instructions over it. Then I will post it here after verification.

Transformer update:
I am getting my transformers in hand on day after tomorrow. I talked to Mr. Arvind from EMD over phone. He confirmed - it has "electrostatic shield", 6" lead wires and obeyed standard size specification e.g. R-30 for 30VA. I am getting testing sheet along with these transformers.
This is the specification they follow. They procure core and bobbins from Shilchar Group itself. He advised me to test that r-core for a week and then confirm further orders. No talk on prices yet.

For transformer update - my brother pointed out this page. So if it is locally available why this running from pillar to post?

Please note still I am committed to complete above mentioned GB list of R-Core transformers.

 

[gobble]

Kits are shipped for below FM, please update here/send me SMS on receipt.

1. jetlag
2. stereorules
3. gobble
4. JosephJohnT
5. gopib
6. cmsajith
7. T Antony
8. Audiodoc
9. santhosh
10. Captrajesh

Instruction Document: I have pending kit of Sachin which will be shipped after I practice assembly instructions over it. Then I will post it here after verification.

Transformer update:
I am getting my transformers in hand on day after tomorrow. I talked to Mr. Arvind from EMD over phone. He confirmed - it has "electrostatic shield", 6" lead wires and obeyed standard size specification e.g. R-30 for 30VA. I am getting testing sheet along with these transformers.
This is the specification they follow. They procure core and bobbins from Shilchar Group itself. He advised me to test that r-core for a week and then confirm further orders. No talk on prices yet.

For transformer update - my brother pointed out this page. So if it is locally available why this running from pillar to post?

Please note still I am committed to complete above mentioned GB list of R-Core transformers.

This is interesting. Didn't know they have tied up with Silchar Group.

I have already "heard" their r-core transformer in the MyRef and it sounds like nothing so I am very pleased with the product.

PS: Did they mention the grade of steel used in the core? M4 or M5? Edit: the Silchar site says

M2H/M4 grade CRGO material used for all typed of cores

.

--G0bble

 

[omishra]

While building and testing I noticed supplying LDR board more than 12V making that 7805 regulator chip little hot. So using 330 or 390 ohm, >2W resistance in series to the wire from Power Supply board is advised to drop excess voltage across resistance itself.

Here are assembly instructions. These are for assistance and I verified it by following steps to build these kits. Please note these does not teach how to do soldering. But guides how to get accuracy in this context.

Enjoy reading. [Please point out error, I tried my best and human error is possible.]

Power Supply Instructions

LightSpeed LDR Volume Control Instructions

Above documents are verified by using them for below construction.

 

[sachu888]

Excellent write up,very easy step by step instructions.

Regards,
Sachin

 

[captrajesh]

Great job by Mishra.:clapping: Could we have similar instructions for the B1 as well?:sos:

While building and testing I noticed supplying LDR board more than 12V making that 7805 regulator chip little hot. So using 330 or 390 ohm, >2W resistance in series to the wire from Power Supply board is advised to drop excess voltage across resistance itself

You mean we need to purchase an additional 330 or 390 ohm, >2W resistor and connect it in series to the wire from PSB to the LDR?

 

[omishra]

Great job by Mishra.:clapping: Could we have similar instructions for the B1 as well?:sos:

Thanks! I think that is very simple and does not require any setup/tuning. So starting with smallest part and moving towards bigger one is simplest strategy.

You mean we need to purchase an additional 330 or 390 ohm, >2W resistor and connect it in series to the wire from PSB to the LDR?

Hmmm.. Unfortunately yes. Because lower the voltage chip has to drop, cooler it runs.
Or let me check it tomorrow by using actual transformer how much it heats after an hours use. If not much then okay. Definitely we can get that solved easily if take voltage from 317 chip for +15.

 

[captrajesh]

let me check it tomorrow by using actual transformer how much it heats after an hours use. If not much then okay. Definitely we can get that solved easily if take voltage from 317 chip for +15.

Oh do let us know the outcome so that we can incorporate all the changes that you recommend.

 

[cmsajith]

Nice to see the group buy is proceeding smoothly.

I had received the parts for B1 from Sachin last week and yesterday I received the CNC parts from Element14. Need to start assembling them.

Please clarify my few doubts:

- Since B1 is a Passive Pre (w/o any gain) and volume control, it can be connected to active Preamps (w/ B1 volume to max) to get more dynamics. I am planning to connect it to my Acoustic Portait PM1 tube pre to get a tube flavor. Can the effective gain of the PM1 preamp can be reduced by adjusting the volume pot in B1?

- Can we replace the current volume pot in PM1 with a lightspeed attennuator? If so, what are the changes required?

- Can we make a direct connection to an active preamp (w/o any interconnects) from B1 PCB?

- Can we bypass the volume control in B1 by adjusting it to max?

 

[omishra]

Sajith, Thanks.

- Since B1 is a Passive Pre (w/o any gain) and volume control, it can be connected to active Preamps (w/ B1 volume to max) to get more dynamics. I am planning to connect it to my Acoustic Portait PM1 tube pre to get a tube flavor. Can the effective gain of the PM1 preamp can be reduced by adjusting the volume pot in B1?

Yes, it could be done. Better you keep volume max on PM1 and control volume with LightSpeed Volume Control. This is most favored in all volume control solutions.

- Can we replace the current volume pot in PM1 with a lightspeed attennuator? If so, what are the changes required?

Yes provided you can supply 7.5-12V DC or regulated 5VDC and your PM1 has analog volume control. I already mentioned that diagram in some post here while connecting CCW, W and CW point of volume control with LDR Volume Control.
- W is connected to middle terminal of volume pot
- CW is connected to terminal of volume pot which contact with middle when turned clockwise direction.
- CCW is connected to terminal of volume pot which contact with middle when turned counter clockwise direction.

- Can we make a direct connection to an active preamp (w/o any interconnects) from B1 PCB?

Yes, connect shielded cables from PASS B1 PCB, OUTPUT to your another amp.

- Can we bypass the volume control in B1 by adjusting it to max?

Yes! Short CW and W pads of each channel on PASS B1 PCB. you B1 is without any volume control. LightSpeed Volume Control is redundant.

 

[sachu888]

I am learning new things everyday here:clapping:

Regards,
Sachin