Babelfish M25, SissySIT - general building tips and tricks

[Juntuin]

you didn't read this thread from start ?




contact : https://www.diyaudio.com/forums/members/pras1170.html

both THF51S and 2SK182ES are proven parts , if you ask for 2 pcs with Ugs adequate for SissySIT

also watanabetomoaki on fleabay , choice is yours

what's important is that Ugs is no greater than [-3V8] with 24Vdc rail and 2A for Iq

Oh, like 10 times all the way from beginning It just seems that young mind can’t remember everything.

 

[Zen Mod]

I should postpone any info , asking for Benelli pics as condition for my reply

 

[Juntuin]

Thanks, and you got something in Da Pub!

 

[Ylab]

Finally received my boards Thank you Zm!

Question : is there a reason for using 0r resistor instead of a piece of wire? It’s been puzzling me each time that I saw one of those on a pcboard.

Hubert

 

[Zen Mod]

nicer

several reasons , depending of circumstances - with automated insertion , robots like more resistor form factor than wire form factor

when ZM insertion is in case , I like more that I don't need to think about additional insulation ....... besides, less work than stripping isolated wire etc.

also , when 0R or something else is going to be in 1-pin holders (sockets) it's sorta nicer and easier to manipulate with resistor form factor

 

[Ylab]

nicer

several reasons , depending of circumstances - with automated insertion , robots like more resistor form factor than wire form factor

when ZM insertion is in case , I like more that I don't need to think about additional insulation ....... besides, less work than stripping isolated wire etc.

also , when 0R or something else is going to be in 1-pin holders (sockets) it's sorta nicer and easier to manipulate with resistor form factor

Great so since it’s me doing the insertion.. will go for the jumper

Another question : is 1/2w resistor ok for all the 100r in the sissysit? I’m sure it’s ok for r1 but nut sure for the other. Not enough knowledge to compute

 

[Zen Mod]

100R resistors - size (them all!!!), mistakes and mishaps

all resistors in Sissy and Babelfish M25 are regular 0207 size , meaning - your plain old good Metal Film resistor ...... nowadays being more like 600mW , not 250mW as in Yore

yup , I got several bags of 100R ones from my Vendor , sized more like 1W (somewhat bigger than 0207) , but I didn' made a fuss about that , simply because they are not too big - right enough to be put through holes without awkward bending of da legz

however , and this is important:

as I'm informed ( twice !) in last few days , it seems I had some strangers in my 100R bags , so please check all 100R buggers you got from me

blame is on me (as always , and I'll blame Papa , as always) , that I didn't catch that and packed them and labeled together ...... but primary blame is on my Vendor - I know that they all were in same plastic bag , prior to opening it and pouring in plastic drawer ......

 

[ItsAllInMyHead]

yup , I got several bags of 100R ones from my Vendor , sized more like 1W (s
as I'm informed ( twice !) in last few days , it seems I had some strangers in my 100R bags , so please check all 100R buggers you got from me

I got one sneaky one...

Not a worry ZM. Thanks for letting us know. Great reminder to measure EVERY resistor before stuffing...

Is it brown, black, black, brown, brown... or brown, brown, black, black brown? Hmmmmm?

 

[Zen Mod]

as far as I know - no surprises with any other resistor value !

just damn biggie 100R

dooh!

 

[Juntuin]

I had one sneaky also luckily I’ve learned from here to measure everyone.

Btw, VFET’s ordered and paid.

 

[cal3713]

Is a 1/2watt resistor enough for r2? I was going to move it up to 200k to decrease the cost of output caps on my preamp, but didn't have any 600mW ones...

 

[Zen Mod]

all resistors can be/are regular 0207 size

just don't think about power

 

[dBel84]

Greedy Boyz who need keratherm are in luck - swap meet

now I can swap out my out of spec SITs for the ones that will make the Sissy work as designed.

..dB

 

[Zen Mod]

I already wrote before - Conrad.de is having nice assortment of Keratherm thingies

it is on other side of Pond to you US guys , but you can't have all



though , SITs in case are sooooo big ( comparing to dissipation) , no need for Keratherm ...... even blanket is good enough

 

[dBel84]

but we WANT it all

 

[ItsAllInMyHead]

Finally got the chassis. Test fit of SITs. I have determined that I have zero skills for tapping. Went through 2 bits and a tap for 4 holes. Learning as I go...

If all things go well, I should have a dual mono PSU and new chassis set up for it tomorrow or Thurs .

 

[rhthatcher]

Use WD40 for drilling and tapping. Take it slow and gentle on tapping, back it out and remove the dreck often. Summary: slow, gentle, lube.



I learned the hard way on re-purposing some Rawson amp chassis by breaking a few taps.


By the way, tap jokes never get old (to me).

 

[Zen Mod]

for M4 - go full depth drill - just eyeball ( with calipers! ) holes to go exactly between fins

tap or no tap , put Allen bolt from fins side (head between fins) , then all necessay bits on SIT side , ending with nut.

that's sexy

 

[rhthatcher]

I cut out the R13’s after I saw the big note

Phillips caps installed.

Waiting for Cinemags...

I saw the note about 100R - it looks like a few stray critters made it into my shipment! One on each board. My habit is to measure first one I pull from a bunch. Oops. Easy fix, glad I caught it now. Early is much better.

 

[rhthatcher]

Amp 1 fixed with 2 x 102R 1% from my stash in R1 and R3 position.

I checked amp kit #2. It seems 2 impostors are hidden in the mix.

Measure all the 100Rs!