2254C build/support thread

[MikoKensington]

http://www.groupdiy.com/index.php?topic=29771.0

 

[303monkey]

Cheers Miko

 

[jplum]

Hi Guys

For those that only ordered boards and not kits(!) i've put together a BOM based on Mouser (delete the .txt extension)
Please verify against the BOM before use

cheers

[edit]
File upload corrupted file. RTFM'd and so here is the URL to my BOM.
http://twin-x.com/groupdiy/displayimage.php?pos=-3173

 

[SIXTYNINER]

please check xls doc
it is empty
6T9R

 

[Igor]

Strange...Seems, 47n diasappeared due to eco crisis, but this for 220p will work fine:
Mouser Part #: 81-RPE5C1H221J2P1A03
Mouser Part #: 81-RPER72A221K2P1B03

 

[jplum]

Thanks Igor

I obviously didnt look hard enough!
I found this for 47n from Mouser: 75-MKT1822347254

here is the updated BOM
cheers

http://twin-x.com/groupdiy/displayimage.php?pos=-3173

 

[RightOnMusic]

10368 is equivalent to 31267, correct?

 

[MikoKensington]

The data you seek...

 

[jplum]

Hi Guys

Just wondered how everybody is getting on with their build ?
I'm about 80% complete on stuffing the boards

I'm hoping that Tat's case will be here sometime later this month.

Has anyone got to point of testing yet ?
I wonder if we need to nudge Igor for an update on page 1 yet ? 

 

[Igor]

Yes, I still have to prepere some files, hopefully this week they will be uploaded.
Too busy these days.

 

[jplum]

Thanks Igor, much appreciated.

I noticed one thing, the BOM for R"19 says 1K but both the schema and PCB are at 820r
I dont think it will be a problem as it looks to be in series with the gain trim pot, but wanted to check to make sure.

cheers

 

[Igor]

Actually, R"19 can be in range between 750-1k2.

carnhill transformers are closer sub to originals

 

[SIXTYNINER]

What OEP's can be used to substitute the 31267/VTB9046 and 10468/VTB9045?  I've been looking at the usual suspects around here, but the impedances look off compared to the St. Ives/Carnhills.  

$350 for Carnhills hurts.

HI
I Don't know if the links still working,
1-
http://www.sototo.com/build/items/00/69/091.html
but the info of the link are this:
Carnhill VTB9045-Equivalent to Neve number L10468,
low level impedance matching input tx 1,200 ohms to 4,800 ohms
2-
http://www.sototo.com/build/items/00/69/095.html
Carnhill VTB9049 AKA VTB1148 -Equivalent to Neve number LO1166,
line output tx handles 24d/c current
3-
Carnhill VTB9045 -Equivalent to NEVE L131267

Any further info/help , it's wellcome.
6T9R

 

[matta]

Hi Igor,

I'm in the process of stuffing the PCB's and an noticing quite a few differences between the BOM and the PCB, which is correct?

Many of them are legending things, like certain resistors have a * next to them, see R54, R47 and so forth, what do these mean?

A few components also have N/A on them, in my mind that means not applicable, in which case do we NOT stuff them?

Is it also safe to assume that 33r and 33R are the same values? The BOM shows R71 as 33r but then R16 & R18 are 33R? Why the differentiations?

R7 - 0R and J' = 0, I assume these are both 0R resistor or jumpers?

Also RZ is designated as 1K5, surely this value is dictated by the transformers used?

Do any of the diodes need to be matched at all?

Lastly are the rotary switches make before break? I assume so, but want to check... desoldering DS boards is never fun  ;D

Cheers

Matt

 

[Igor]

Hi Matta!

Many of them are legending things, like certain resistors have a * next to them, see R54, R47 and so forth, what do these mean?

R54 and R47 forming the load of input trafo. Assume, R47 will be allways 2k2 as you use 2:1 10k:2k4 input trafo.
But R54 and C19 forming Zobel network for trafo secondary. Vlues shown are good for TF100XX and 31267.
In case of Lundhall for example, they may be different. Search forum for Zobel network, you will find a lot of info there.

A few components also have N/A on them, in my mind that means not applicable, in which case do we NOT stuff them?

You mean C10/R10. There's a option to make HPF as resonant type filter, but after listening I changed it to way it done now.

Is it also safe to assume that 33r and 33R are the same values?

Yes, they are 33 (Ohm)

The BOM shows R71 as 33r but then R16 & R18 are 33R? Why the differentiations?

Sticky CAPS

R7 - 0R and J' = 0, I assume these are both 0R resistor or jumpers?

Yes, both are 0R jumpers.

Also RZ is designated as 1K5, surely this value is dictated by the transformers used?

Here is the place for discussion As long as output is single-ended, we should supply some load.
I use allways 1k-1k5 at output of 1166. This way, it terminated, sounds right, but when low impedance load connected
(like Pultec for example), it operates still not on heavy load. If 1k2 used, load output on additional 1k2
to make total load 600 ohm when adjusting symmetry (quiescent curremt), RV1 5k.
If 1k5 connected, use 1k in parallel to adjust quiescent current.

Do any of the diodes need to be matched at all?

Yes, sure, D14, 15, 16, 17 should be matched by Vf.

Lastly are the rotary switches make before break? I assume so, but want to check... desoldering DS boards is never fun

 
Yes, all Lorlins are MBB. Farnell CatNr's:

Order Code: 1123699
Manufacturer Part Number: CK1059 

Order Code: 1123700
Manufacturer Part Number: CK1060

 

[SIXTYNINER]

MATTA
i got a transformers offer
but 31267 don't appear as a code
that i see is :
VTB9046 Equivalent to NEVE L131267 (Is this right code?)
VTB9045 Equivalent to NEVE L10468
VTB1148 Equivalent to NEVE LO1166

(ok for output transformer model in case to use 1u rack case)

cheers
6T9R

Again, NEVE NEVER made transformers, the companies who did with the 10 series were Gardeners, Marinair and St Ives.

The Marinair were stamped L1.31267 / S, so I can only assume that is what you are referring to, that transformer is a LINE transformer.

Cheers

Matt

Matta i never said Neve build transformers (i know Neve give a custom code to transformers)
only asked if you are making a 2254c with original transformers
and
if someone know the right code of transformers used on the original 2254
please post , as "public domain info/help".
6T9R

 

[Igor]

Guys, PLEASE. As long as we already discussed the options for trunny's, let's leave it.
Just imagine you have to read 30-40 pages of stuff after 3 month!

Let's discuss here more usefull issues. Anyone get to soldered PCB's stage?

 

[SIXTYNINER]

Guys, PLEASE. As long as we already discussed the options for trunny's, let's leave it.
Just imagine you have to read 30-40 pages of stuff after 3 month!

Let's discuss here more usefull issues. Anyone get to soldered PCB's stage?

hi igor the 2254c project you done is probably one of the best done in this "posse",
i'm soldering parts on pcb , and found same "doubts" as matta
also checked main pcb pictures you posted , and i found differences
if i can .......i suggest you to post some picture
(a picture can say more then 20000..words and avoid many discussion pages,and reduce time for get "making of " informations)
Pictures have to show info about :
R7 - 0r , resistor "RZ" , R54 -11k* ,C19-100p* ,
D14 D15 D16 D17 Match,
belclere or carnhill - wiring option with resistors and value if required,
(or the 30/40 pages links about, i think pages you mean are about 33609)
A picture about lorlin rotary switches and resistors pcbs finished with all parts ,
*
in my 2254c set i received ,
the 47k resistors are normal metal film type ,
not the
Metal Film Resistors Flameproof like this
Mouser Part No: 71-CPF1-B-1.2K
Manufacturer Part No: CPF11K2000BEB14
6T9R

 

[jplum]

I'm all soldered up 
Just waiting for 1 or 2 out of stock items from Mouser and also clarification on some BOM/Board Layout questions, which have been answered.
BTW I'm using Carnhill's for the transformers as mentioned previously earlier in the thread

Just need to fix the camera and i will post some pics.

Igor, if you could manage it, it would be great to update page 1 with calibration/test steps sometime soon that would be great!

cheers
John

 

[TomWaterman]

1 question, the board has quite a few 80uF caps on it. The kit provided 100uF/25v, I take it these are cool in those spots?

Also the big cap C17 just under the relays, PCB says 100uF, but the large radial caps in the kit I have left are 1000uF?

-T