MS, Pultec, 1/2-BA283 boards support thread!

[Harpo]

Axel, use non-shorting or BBM or break-before-make switches, else you might have a 3rd cap in parallel for the blink of an eye.

 

[Axelerator]

thanks harpo !

Maybe  i have enough unshorting ones at hand !

axel

 

[Axelerator]

still looking for the value of R1 when using the 10648 input ..
pacemaker, did you find the right value ?

axel

 

[Axelerator]

so i have to use 600 ohms for r1 on the freq.makeup.board if using the 10468 backwards ?
thank you people !

 

[pacemaker]

Hi guys and hi Harpo !
i was too struggling about the MBB or BBM switches,
i thought for Pultec style build , shorting was necessary other wise clicks might be heard ?
can you explain me better to understand why non-shorting is better in this build ?
Igor , i also noticed that in your partlist C6 is 4n7 while PCB and schematics state 5n6 ?
thanks for the help,
Francois

 

[Harpo]

i thought for Pultec style build , shorting was necessary other wise clicks might be heard ?
can you explain me better to understand why non-shorting is better in this build ?

For most lorlin-type switches in this build, a connection is already established and this switch connects a 2nd. cap in parallel.
FI low-cut section, C6 is always in circuit, setting the highest cut frequency and either C4, C3, C2, C8 or non is switched in parallel to C6. If this switch would be MBB, a 3rd. cap would be in parallel in between switch steps, FI C6+(C4+C3) when switching from 1st. to 2nd. step or C6+(C3+C2) when switching from 2nd. to 3rd. step ...
FI hi-cut section, C13 is always in circuit and either C14, C15, C16, C17, C18 or non is switched in parallel to C13.
FI low-boost section, C5 is always in circuit and either C12, C11, C10, C9, C7 or non is switched in parallel to C5.
Hi-boost is different with no fixed value part in parallel to the switch, so this switch better would be a MBB type. Don't forget to displace the end-stop washer to pos.11 for this switch.

 

[pacemaker]

ok now that's clear !!
as a non native english speaking guy,
i was wondering about your "3rd cap ion a blink of an eye"
thank you so much for the explanation Harpo !
good to have some help to understand how things work!
regards,
Francois

 

[Axelerator]

..little bump here about r1 on the filterboards.
i understand that here is the termination for the input tranny. i have to use 600 ohms here for the ea input trannsformer ?
i would have to desolder a lot of connections before i couls swap the resistor out , so i would like to have the correct value from the start.
thanks alot

axel

 

[Axelerator]

bumpedy-bump ;D

 

[mitsos]

probably not many people have used neve mic inputs reverse for a pultec line input.... you might have to be the guinea pig... I don't know if you'll see much difference between 1K and 620R.  How are you wiring it? Series:series would get you the most inductance.  That would mean about 4K8:1K2, so you'll need a bit more gain than with a 1:1 trafo.

 

[Axelerator]

hi mitsos, thanks for chiming in. as on igors drawings i read the primary is in series and the secondary in parallel (?) , the trafo reversed so it would have a 1:1 connection.
drawings on page 3, don´t know how to embed posts here..
i cannot find it again but i remember somebody suggested 600 ohms here.my understanding of the math is still not enough to figure it out.
Igor says this combo sounds awesome and igor normally don´t like sound talks so i think this is worth a try !
what about your second pultec variant, my 511x slots are filling much to fast this days ;D 8)

greets
axel

 

[mitsos]

The reason I suggested going series on the secondaries (primaries in this situation) is to get the most inductance and therefore the best bass response.  Not to say that the other ways won't work, of course they will.  In the end, if it sounds good, that's the important thing.  The resistor is the load on the trafo so it will reflect that impedance to the other side as the load on the previous circuit driving the pultec.  I hope that makes sense?  This resistor also affects the circuit, if you look through older pultec threads there were some people putting 10K in some Gpultecs and not getting enough boost or cut IIRC. 

Try this: put a 1K in that spot, test the circuit and see how it works.  Then solder a 1K5 on top of that one (1K || 1K5 = 600R) and retest. If you prefer the 1K just cut the 1K5 off.

 

[Axelerator]

will do this !
thank you !
axel

 

[skal1]

anyone know how to wire a VTB 9046 correctly to the ba238 board , no ms pcb and what load resistor would i have to use .


thanks

skal

 

[gareth33]

hi all

i am looking to buy 1 x BA 283 board from Igor, if anyone has one for sale, please message me 

regards

gareth

 

[dribro]

Hi
Can you guys link me or upload me the pult2010 _ms_wiring.PDF please
I have this project lying around and would like to finish it

Regards

Edit: a fellow diyer just sent me the file, thanks!!!

 

[ravachol]

Does anyone have the original docs for this project? I think a few people hanging on it could need some outside opinions.

Right on!

 

[letterbeacon]

Does anyone have the build docs for the BA283 boards?

 

[Whoops]

Does anyone have the original docs for this project? I think a few people hanging on it could need some outside opinions.

Right on!

Please, would be possible if someone helps with the docs for this project?

thank you so much

 

[gareth33]

Does anyone have the original docs for this project? I think a few people hanging on it could need some outside opinions.

Right on!

Please, would be possible if someone helps with the docs for this project?

thank you so much

If you PM me your email address I can send over everything I have, I think its pretty much everything.

As a bump, if anyone has a spare Igor BA283 board I would love to buy one! Thanks