mfdu 1176 project

[Ry N]

mfdu
how's the diy 1176 going?
Is it together, did you you try the two different types of transformers (oep vs lundhl? is that what you werte testing? )
how did each sound?
I'm sure there's more than one out f the 99 intrested in your results?

:D :D :? :D
comments

[mfdu]

hi ry

ok, the 1176 projects came together great. ended up using OEP output trannies in both units, so i don't have anything to report re. difference b/w output trannies.

got a little bit of fault sourcing left - they are both working in 4:1 and 8:1 ratios, but not compressing in 12:1 and 20:1. haven't built the nuke switch yet - waiting till i've got all ratios working.

but they are juicy - having a ball tracking anything through them - vox, guitar or bass di, kik - whatever.
thats why i haven't tracked the faults down yet - too much fun using the bits that DO work.

got SSL mix-bus compressor pcb's and what? optical compressor pcb's on the way at present - just sourcing VCA's and opto-resistors and stuff. maybe i should start cancelling sessions so i have time to solder?

in short - the mnats 1176's are good projects, but they are challenging. if this is your first project, you might want to try a what? optical, or GSSL stereo mix-bus compressor first, as they are actually a little simpler.

:)
chris.

[Ausrock]

mfdu,

I've had pcb's for most of this stuff sitting here for around 18 months but real life and lack of spare dollars for these lesser priorities have held me back. This is also one of the reasons I don't frequent The Lab these days which is frustrating as I was there and semi-involved the day it was established while RO's TechTalk was melting down.

Out of curiousity, have you costed out the 1176 or the SSL Comp?

Cheers,

Chris

[mfdu]

hi there and nice to hear from you.

the 1176's using OEP output trannies (unshielded), altronics cheapo VU's and 2RU cases from jaycar came out at $220 each mono unit (using bal phono plugs, not xlr's). that would'a been down by $35 each if i had have built them into the one case.

i haven't done the maths on the SSL yet, but there is a bill of materials prepared by an aussie (kev, if you're out there you rock) which shows a total of $370 [edit : $341.42, according to kevs BOM]. but that's assuming a pricey meter, case, xlr's and VCA's.

a tip with the SSL - contact THAT corp in the UK (they do dBx VCA reissues). after chasing them for a month, they got back to me saying "sorry, would you like some samples of our 218X chips?" so they've sent three of each - as long as they survive the trip i now have VCA's for three stereo SSL's!!!!!

in terms of making the time to build, all i can say is i can afford the time to build more than the money the real units would cost me. thats how i find my balance.

there is a good crew hanging out at the lab - drop in and say hi sometime.

c.

[Ausrock]

Thanks for the info. I have the VCA's from THAT......arrived in a nice little plastic case with a complimentary THAT Corp pen and all........which like everything else have been sitting here for way too long.

What I've spent over the last year on upgrading workshop gear for working on instruments would have paid for most of these projects a few times (or more) over........like I said earlier.....bloody priorities :-).

Cheers

ChrisO

[mfdu]

i feel your pain.

but still, i'd rather work than not, and so if that means i have to juggle priorities vs. projects that's how it is. as you well know.

gee - i hope i get a nice THAT pen!!!!!!

chris.

(too many chris's)

[harry]

hi guys, i thought i'd let you know that the oeps are available way cheap from the uk.

it is interesting to note that RS components sells them for $39 aud here and 9.80 pounds ($23 aud roughly) at RS uk.

i found them from another supplier (canfords in the uk i think?) for about roughly 8 pounds each, cheap shipping (cheaper than rs courier) and they arrive in a week (royal mail is so cool)

i'll post the link soon (i updated my computer and forgot to save my emails - so i'll fo through my paper receipt)

m.f.d.u - sorry i forgot to reply - too busy. i finished one 1176, testing it showed that the voltages were correct, the needle was moving (compressing) but no audio was flowing! then i realized that i had soldered the output tranny where the input goes!

when i swapped it i had input and output gain (yay) but no compression!
i think the ic sockets i used for the BF245 (gain reduction fet) were intermittent!

before i could remedy this i fried the power transformer when i accidentally shorted the VU lamp terminals!!!

noticed that you have ordered the fabio boards (prodigy forum) that looks like a good project yeah?

it would be good to catch up and compare the units when they are done!
maybe in the next few weeks!

cheers lads.....

[mfdu]

be happy to hear from you. yes i got the fabio boards - a lot more complex than the 1176 or GSSL (lots more options) so i'm scoping the schematics prior to starting.

i've got a small identical problem with both 1176's - i think theres an error on the ratio board. but before that, i gotta get the GSSL mix compressor running - only hearing what i suspect is the sidechain at present!

chris.

[tim]

Hi guys,

Good to see some fellow DIY'ers in Melbourne. :D

I have built the SSL comp. clone and the dual channel G9 valve pre- amp. 1176 is half done.

All great projects. The G9 especially is a winner, for the cost of approximately $600. Try buying something equivalent sounding for that ! :D


Keep us updated with how you going.

Is that SSL finished yet MFDU? What do you think of it?

I just recently added a switchable HPF to the sidechain in mine, nice !

[mfdu]

been lonely for so long. where'd everyone else go, tim? i'm impressed u found this thread!

chris.

[Seedysea]

Hi diyers,

I have been (mainly) lurking over at prodigy-pro and getting back into making stuff. I found this forum by accident and I enjoy the local flavour.

I have nearly finished some of the green pres and loving them. Next up is a gssl and an 1176.

mfdu

[Ausrock]

Seedy,

Altronics in WA are the "budget" meter source.

[Seedysea]

Thanks Ausrock, I'll jump on the site and check it out. I remember seeing that they were opening an outlet here in Melbourne somewhere.

[mfdu]

if altronics are opening in melbourne thats cool.
thanks for jumping in on that Ausrock - you were the one who gave me the Altronics tip so you deserve thanks!

the altronics meters work a treat on gain reduction mode. but me and another chap who have used them have found they dont work in output mode - i think they may need bridge rectifyers.

but for $20 a pop thats ok - i happily leave it in GR mode and observe output on my console buses, channel meters in protools and the tape VU's

all the best with the build.

chris.

[harry]

hey thats right - princess highway springvale! altronics!

sorry i have been out of touch chris (mfdu) although schools out in a little over a month.... i predict a big diy summer.

hey seedysea, what i have found out thanks to chris is that semiconductors especially transistors are really cheap (sometimes 1000% cheaper) from 'mouser' in the states, and it costs $12.00 to send to australia.

for oep transformers, get them from canfords in the uk and they will be closer to $20 each rather than $39 over here. the post from the uk is as cheap or cheaper than the rs courier! (i LOve 'royal mail' - i bring in vinyls all the time cheaply and fast - sometimes 3 days! door to door)

for everything else i'd try altronics or rs (very expensive) especially rs if you want to use name brand capacitors.

i am definently gonna support altronics though now that they are in melbourne - finally i'll be able to get what i need when i need it!

hey chris - how did the fabio what comps go?...... i've been thinking about doing the G9 and also the SSL but with the sidechain thrust thingy - what do you think?

[tim]

[quote="harry"]hey thats right - princess highway springvale! altronics!

sorry i have been out of touch chris (mfdu) although schools out in a little over a month.... i predict a big diy summer.

hey seedysea, what i have found out thanks to chris is that semiconductors especially transistors are really cheap (sometimes 1000% cheaper) from 'mouser' in the states, and it costs $12.00 to send to australia.

for oep transformers, get them from canfords in the uk and they will be closer to $20 each rather than $39 over here. the post from the uk is as cheap or cheaper than the rs courier! (i LOve 'royal mail' - i bring in vinyls all the time cheaply and fast - sometimes 3 days! door to door)

for everything else i'd try altronics or rs (very expensive) especially rs if you want to use name brand capacitors.

i am definently gonna support altronics though now that they are in melbourne - finally i'll be able to get what i need when i need it!

hey chris - how did the fabio what comps go?...... i've been thinking about doing the G9 and also the SSL but with the sidechain thrust thingy - what do you think?[/quote

G9 is goodun. Well worth the build.

If you do the gssl, yep...definately do the thrust filter. A must for 2 buss stuff. :D

[mfdu]

hiya harry. we should catch up again sometime.

fabios what? optical compressor is sounding great, but not working 100% to spec. much the same as the 1176 and the ssl.

whilst building gear is fun, it is also time consuming . . .

re. VU's - i forgot to mention that jaycar have small round blue-lit VU's. not small enough to fit in a 1RU case, but nice and compact if doing a dual 1176 into a 2RU case! $20 can't hurt that much, huh?

the next pair of 1176's i build (have the pcb's ready to go) will be lundahl input trannies instead of oep's.

and yes, i should try the thrust filter for the ssl.

but before that, i gotta open up my console and replace the left +4 xlr main output - it's a dirty little bugger and keeps dropping 6db.
the gssl (fault = no make-up gain) needs +4 - the gain drop means that -10 just ain't hot enough! and thats after dropping the output trim resistors. 15k = +4, 20K = -10 but i'm running 8K to boost output. and i'll be whipping them out and trying 4K instead.

just don't get me started!!!

:)
chris.

[Seedysea]

Thanks for the tips guys.

mfdu - I agree about the meters. I never use output metering on compressors anyway. All I ever want to know is how much signal is going in and how much GR I am applying. $20 is better than $100 for a Sifam at RS. I'll have a look at the JAycar ones also, they are my local supplier.

Harry - thanks for the canfords tip for oeps. I contacted them. They are very helpful and way cheaper than anywhere else. I'm about to order some trannys. Also, I have looked at Mouser and I agree that they seem better for components. It is a pain to get name brands here in Aus.

[mfdu]

seedysea,

would you get better pricing for trannies if you buy bulk?
i'm thinking i might build the next pait with input and output OEP's rather than going the lundahl path - OEP's are supposedly crunchier, and i built my boxes for colour over clarity (don't spit - i know what i'm doin)

so i could maybe be interested in four OEP's if a bulk order tickles your fancy. . . maybe six (install output trannie in the current pair - maybe that'll give me a slightly hotter output?)

edit - remember to use sockets for your trannies so you can safely remove them or whatever. my first build, i mounted them straight onto the board. wont be doing that again. by a strip of IC sockets and cut to length is the cheapest way.

lettuce know.

chris.

[Seedysea]

mfdu - thanks for the tip on using sip sockets, that is a great idea.
I don't mind buying some extra OEPs if you want some. There is a price break at 10, but it really isn't a huge difference, so the numbers don't really matter (except more freight cost I imagine). I was going to get four myself, so let me know if you want some.

[Seedysea]

mfdu - I forgot to mention. The oep's I am looking to get are the A262A2E

[mfdu]

seedysea

sorry it took me a while to get back to you.

i was kinda hoping maybe some other folks would jump in on a group buy of OEP's suitable to the 1176 (that's the product ID you quoted)

if we aren't reaching the bulk rate, then i'll just leave it be. funny thing about money - regardless of how great the saving is, it is only a saving if you have the money at the time.
and i dont.

but cheers and thanks, and i'm looking forward to hearing how your build goes.

chris.

[Seedysea]

mfdu - thanks for letting me know. It will be easier to just get what I need. The less than $20 postage charge makes it easy for anyone to order these direct anyway.

I think it will be a while before I finish this project (money and time constraints allowing), but I'll report here and at groupdiy when I do. I'm especially interested to compare a feww differerent trannys.

[mfdu]

yeah - easiest just get your own. group buys can be torture.

one thing i can say is this - the trannies for the 1176 are a 1.1:2.2 where as the optional input trannie for the what? opto compressor is 1.1:6.25 6.25

the gain difference is immense - believe it or not i have been able to use the what? as a mic pre (chain = sm57 > XLR > 1/4" TRS > what?) and it sounded grand.

so now i'm thinking of swapping out the 1.1:2.2 and trialling the 1.1:6.25 6.25 in the 1176 to see how fully sik that is, maaate.

tee hee.

chris.