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sbelyo

2018 PCB Group Buy with TKD pots

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Thanks Kevin I thought so.

My question really was about the GB sheet. If I opt for 1, do I get enough for a stereo set (so two bal/unbal boards and one power supply board)?

or should we even use one power supply per channel (seems overkill to me)

i vote megatron style btw

steef 

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On 2/26/2018 at 7:32 PM, Skooby said:

Cheaper than WE300B reissued ! :rolleyes: 

JAC Music got  a pair for ~500usd, still pretty steep for a set of four.

My bad. Price was per pair.:angry: 

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collecting all the gerbers tonight.  Will update the first post tomorrow with the list so everyone can double check 

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17 hours ago, sbelyo said:

collecting all the gerbers tonight.  Will update the first post tomorrow with the list so everyone can double check 

thanks so much for your work on this!

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my pleasure...  

Hoping to offer several options with the that340 adapter boards

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I'm thinking to join gb too.

When you plan to close GB? Do I have time to figure out  abbreviation in google spreadsheet? I'll do reading this weekend. If any one can make short description of it it'll be appreciated. 

Also can you give an idea of build cost without transformer and enclosure and a PCB cost. I need to plan my budget.

 

 

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17 hours ago, Pars said:

Steve,

Here are the gerbers for the SOT23 Linear duals and for the original Toshiba 2SJ109/2SK389 duals. Note that this board is not compatible with the BJT 7 pin package (2SA1349/2SC3382 IIRC).

 

Thanks Chris

I'd say we'll keep it open for the next two weeks or so.  I'm planning on sending the files for a quote next week so after I receive them back I'll update the prices.  I figure we'll wait a week after that and close it up

32 minutes ago, vladco said:

I'm thinking to join gb too.

When you plan to close GB? Do I have time to figure out  abbreviation in google spreadsheet? I'll do reading this weekend. If any one can make short description of it it'll be appreciated. 

Also can you give an idea of build cost without transformer and enclosure and a PCB cost. I need to plan my budget.

 

 

what abbreviation did you need help with?

As far as costs, the boards will be relatively cheap.  It's hard to say as far as total costs go it's hard to say.  For my dynahi as an example I'd say I have around $1000 usd in it so a balanced CFA is going to be around there I think.  A dynalo mini with a case from the other group buy would probably run you $350.  Maybe others can comment on their costs

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had added my name for a set of CFA boards and a GRLV as well

edit: changed to 4 CFA, 2 GRLV, Dynalo Mini & TKD pot. 

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Steve,

Is the GRLV version you are doing the one with the dual output blocks? This is the one I would prefer as I've had to modify a couple of mine for greater output capability. I attached the gerber file for this one (6d version). Not sure what your noted "v6 combined" in the signup spreadsheet refers to.

goldenreference6d.zip

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30 minutes ago, Pars said:

Steve,

Is the GRLV version you are doing the one with the dual output blocks? This is the one I would prefer as I've had to modify a couple of mine for greater output capability. I attached the gerber file for this one (6d version). Not sure what your noted "v6 combined" in the signup spreadsheet refers to.

goldenreference6d.zip

Does this version have the big caps on it? 

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Don't think so. The one I posted above is the same as goldenreference6, but has dual outputs.

The version with 35mm caps is goldenreferencelargecap.zip? That one has the 35mm caps, dual outputs. It is only setup for 1 bridge (center tapped) and TO-220 SiC diodes only. That one would be fine with me, but others may not want that one.

Edited by Pars

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Here are gerber images of goldenreference6d:

goldenreference6d.png

 

and goldenreferencelargecap:

goldenreferencelargecap.png

6d may be closer to what people were looking for. The largecap version does not support the rectifier boards, but the TO220s rectifiers it uses are SiC diodes (which are schottky as well).

Edited by Pars

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How much is the price estimate for TKD 4CP-601 10K and TKD 4CP-2500 10K?

Edited by penmarker

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Thank You for the group buy!

I'm excited to try the GRLV +  CFA 2.

May I ask someone links the GRLV and the CFA 2 build docs, like schematics and layout, which transistors should be matched etc?

I did found some jpg schematic, but not 100% sure it is the version on the GB. The links from Kevin does not work for me for a few days now.

Also, how do you guys match transistors? With a simple low current beta meter or you make a simple circuit and simulate the current in the application?

Thanks a lot!

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This is the schematic. As for your other questions, look at the golden reference LV thread and the "And now for something completely different" thread. That thread devolves into discussion of two or more amps. As far as build threads, there aren't any, nor are there guides, etc. You have to read the threads and take your best guess on some things.

Kevin retired from Northwestern University, so none of those links work. The current archives are here:

Documents: https://drive.google.com/drive/folders/0B7egryukiT7_TFlEQlBRejdVdDQ

Gerbers: https://drive.google.com/drive/folders/0B_iJFfZStuVhSE5nOHBVdTByR1k

 

cfa2cmirror.PDF

Edited by Pars
  • Like 1

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Thank You!

So, for layout drawing, I can create from the gerbers.

As I see the GRLV is the goldenreference6d.zip, the CFA2 is the cfp2hmt.zip linked earlier here.

I did read through the "And now for something completely different" thread, but the base doc links are pointing to http://gilmore.chem.northwestern.edu/***

I thought the cfa2cmirror.pdf is used for simulation of the CFA 2. Is that accurate to create the BOM based on that? Is that the schematic used to create the layout?

On the schematic of the GRLV, I assume it is the latest : goldenreferenceboard.pdf, can I use that to create the BOM and start ordering components?

Thanks a lot!

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Oh ghost...I hate it when parts are out of order for 6-9 months.  Anyone has any spare pzta56 :D ? This is a nightmare

maybe fzt593ta ?

Edit** I got them ordered from 

http://www.newark.com/

thanks Pars

Edited by Whitigir

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The links I posted above will take you to the current files.

cfa2cmirror is the schematic and the latest edition of the CFA2, and is the basis for the boards in the GB. Kevin changed the servo layout and how it feeds back into the amp as some of us found the servo in the original to be audible.

I've attached the original CFP2 BOM, and a BOM for the GRLV. I don't recall whether I updated the CFP2 BOM for the latest, but it should be close. The original 1 ohm resistors were wirewound; this BOM has the 3W Vishay metal film in it which is a better choice.

CFP2 BOM.xlsx

GR LV BOM_Sep26.xls

  • Like 1

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Reading the dynalo mk2 thread the consensus seems to be that 1oz copper should be sufficient for the boards, anything more seemingly presents some challenges. I know it's already been changed from 3oz to 2oz, but wanted to bring up the thought of going with 1oz. Would help those of us with limited smd soldering experience, especially with troubleshooting. Don't mean to sound unappreciative, thanks for the doing the group-buy.

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