sontec 1 RU build thread

[kambo]

thats exactly what understood from Igors post...
my individual band in/out switches are there... so, it must be it...

 

[syn]

Hi
    I'm oredering parts for the build, and have a couple of Qs:
No need for the 50k pots to be center detent if switches used for individual band bypass?
and
Could some one decipher this, please:
22R R-EU_0207/10
100R R-EU_0207/15
10k REU_0207/12
Thank you

 

[haima]

i'm pretty sure these would just be standard 1/4" metal film resistors (with part numbers for a distributor... like farnell?)

22R R-EU_0207/10 = 22ohms
100R R-EU_0207/15 = 100ohms
10k REU_0207/12 = 10k ohms

hope that's correct, and answers your question...

 

[kambo]

Syn, those are just European codes, not farnell etc codes...

center detent pot : no need if you use switch...

 

[boji]

Would someone mind explaining the difference between the Sontec 8 and the Sontec U19's  Input / Output signal flow?

Are they the same? I ask becuase the 2ch sontec has that pretty seperate amp card.

Would the Sontec 8's beneifit from using that?

 

[boji]

I suppose If I could find a copy of the sontec 8 schema I could compare it with the 2ch version, I just don't see the 8 build's schema floating around.  Any help would be appriciated, thanks.

 

[kambo]

8ch is 4band..
stereo version is 5 band mastering version...etc

 

[dagoose]

Today i added a nice dual pole on/off/on switch for the 6/12db/bypass per band and it works like a charm. So up is 6db, down is 12db and middle is bypass the band for left and right at the same time.
I ended up using 39k for the 6db and the standard 20k for the 12db.
So far only the low band and one mid band has a switch because i didn't have more switches in stock but it's a start and it looks quite ok as well.
The switch fits exactly in the middle of the purusha panel between the freq and gain pot, just drill a hole on the white line and your fine! (will take pics when done)

 

[kambo]

i have wired switches for boost_or_cut 

 

[boji]

8ch is 4band..
stereo version is 5 band mastering version...etc

I am asking about the inputs and outputs; I'd like a little explanation on the difference between the 1u and the sontec 8.

Thanks.

 

[zayance]

Just curious anybody build this one using stepped attenutor? Will it be risky, in terms of catching durt on the way, to put good quality wire from boards to pots? Like 3mm gotham or mogami cable.
I was thinking using the alphastat but could be cool doing this one with stepped attenuator, well for now, will see the fonds when there  
Thanks.

 

[bobine]

Has anyone from the U.S. ordered from Alphastat? How did you pay? What were shipping costs? How did you communicate?

sorry if I've missed this info elsewhere

thanks

b

 

[bobine]

I'd consider making a switched unit, but I think the cost of the Elma or Grayhill switches far exceeds the cost of the pots. I haven't seen any posts regarding the model Elma switches that have been used, just some basic specs: 24 pos, shorting... What model number Elmas will work? Is there a Lorlin equiv that could be considered?

again, apologies if this has been discussed...

b

 

[SIXTYNINER]

...for case ... any skeme about
cut-boost switch (as in "mazz-pazzive") ?

 

[muffy1975]

Hi Team Sontec,

Michael

 

[muffy1975]

Ok,

my last post was dumb. 1st one for this project.

Now here's a question for y'all.

Does the BOM suggest either mica or polystyrene caps for those 5 values?

3n3
2n7
100p
150p
330p

Can I use polystyrene here? Do they sound any good in these positions

Michael

 

[zayance]

Ok,

my last post was dumb. 1st one for this project.

Now here's a question for y'all.

Does the BOM suggest either mica or polystyrene caps for those 5 values?

3n3
2n7
100p
150p
330p

Can I use polystyrene here? Do they sound any good in these positions

Michael

Your choice, that's what the BOM suggests, any of both will do the job, some would prefer Silver Mica but the price is high tough, i'll go WIMA FKP series on my side....

Anyway here is PRR's tought on Mica i found some time ago...

>  impression that mica are probably the best for filtering higher frequencies...

No.

First: mica are only (usually) available in very small values. Too small for audio coupling or filtering. Maybe big enough for a treble tone-control capacitor.

When capacitor technology was very crude, mica gave the lowest losses in radio tuned circuits. This type of loss is usually unimportant in audio; sometimes (in supply bypassing) "too low" loss is actually bad.

Mica is a rock, found in odd corners of the earth, and much of the good stuff is already mined. Meanwhile very very good plastics and ceramics have been developed.

These days the main reason to go mica is "nostalgia".

While on the subject: "ceramic" is NOT one single type of cap. You can make flower-pots or engine-pistons with modern mechanical "ceramics", and the range of electrical ceramics is even larger. Below 1,00pFd "ceramic" is usually a glass-like mix, and so very very nearly perfect that it largely replaced both Mica and Glass caps. Above 0.01uFd they use some very different stuff, all doped with polar salts, very goofy electrical properties. I can hear a 0.02uFd ceramic coupling cap, whereas I can't hear most other cap-types. OTOH for many bypass chores, the exact capacitance does not matter and the types of losses are complementary to the needs of bypassing.

And here is something interesting:

http://www.reliablecapacitors.com/pickcap.htm

 

[muffy1975]

thank you broseph.

Am really considering polystyrene caps in these positions like those xicon styrene caps that Mouser do! We used them on the Ez1290 project. Any thoughts on those puppies? Order code 23PS110

Michael

( freaking out at the cost of them knobs)

 

[Igor]

Xicon styrenes are cheap price-wise, but should be good capacitors.
I love silver mica on highs, BTW, can post photo of 91nF/400V mica cap,
tell me they don't have high values
Polyprops or styrenes will work fine as well. All this is matter of taste.
Most people prefer styrenes versus mica soundwise. I prefer mica's.
To get right a/b test, you need some relays and good accoustic room
with perfect monitoring, converters etc.
Even in this case difference will be very, very subtle.

 

[muffy1975]

Thanks Igor. That's really clear now for me. Might just go Mica for the high end, but of course I have a dead room and £300 speakers and wool in my ears.

Now I have no need of relying on the I Ching/Oracle for his/her/it's opinion on capacitor choices. Maybe when it says 'move away' it's talking about audio in general. Who knows?

Oh I can't wait for my sontec pcbs ( said like fat kid starring a piece of cake )

Michael