PRR-176 Vari-Mu REV 2 - *Group Buy 7/13!*
- Thread starter abechap024
- Start date
Help Support GroupDIY Audio Forum:
astroschnautzer
Active member
the 8027-WF 1mA needs some melting of the glass, and additionally some melting of the meter enclosure, its not beatiful but it keeps inside the box (so you don't see it) and you have to be careful not to melt too much so that the meter mechanism is affected..... with the 8027-B 1mA you might not have to do melting. (?)...diylan said:
Abe has a Mod for the meter to work. We decided on that meter and its placement for the look of it in the panel and function. Its a pretty easy little mod. I think Abe explained it in a post some place.
Edward
Well-known member
Edward said:
I found a site about zener diodes as voltage regulators and it had a calculator for finding out the power rating of the zener diode. I entered 100V as Vout, 115V as Vsource and 50mA for Imax. The result is 5W. Could it be D14 which in my case is 100V/1W that is failing? Even if Vsource is dropped to 100V the result is still 5W for the zener.
Sorry for my noob questions...
abechap024
Well-known member
Edward said:
Your forgetting to put the 3k in series before the voltage drop in that calculation i believe. You also have to have the power supply loaded for it to read 100v
Edward
Well-known member
abechap024 said:Edward said:
Your forgetting to put the 3k in series before the voltage drop in that calculation i believe. You also have to have the power supply loaded for it to read 100v
Thanks Abe. It's the same answer to all my questions, loaded the measurmets will be correct.
Kinda like saying during soundcheck that it will sound better when the crowd shows up.
Got it.astroschnautzer
Active member
Yep, but it needed some additional cutting (melting) atleast for the box I have, it has a bent front edge so its abit higher there, maybe earlier boxes didn't have a bent front edge (?)dandeurloo said:
ethervalve
Well-known member
Hi astroschnautzer,
I ordered one of the Collective Cases enclosures too (still in transit).
Do you mean the top panel of the enclosure has a 'lip' that curves down and meets the front panel?
If so, I wonder if it would be easier just to grind that part down with a dremel or file? I've had to do that a bunch with 'Circuit Test' brand enclosures (which seem to be the cheapest option here in Canada).
I ordered one of the Collective Cases enclosures too (still in transit).
Do you mean the top panel of the enclosure has a 'lip' that curves down and meets the front panel?
If so, I wonder if it would be easier just to grind that part down with a dremel or file? I've had to do that a bunch with 'Circuit Test' brand enclosures (which seem to be the cheapest option here in Canada).
abechap024
Well-known member
ethervalve said:
no, well actually you could gind and gain about 1/16" but you would still need to cut off some of the meter.
ethervalve
Well-known member
Cool--sounds like it's no biggie.
Thanks for the details.
Hey, if you ever have the chance to create that calibration doc you mentioned earlier, it would be much appreciated! (The threshold adjustment is really the main thing I'm confused about).
Thanks for the details.
Hey, if you ever have the chance to create that calibration doc you mentioned earlier, it would be much appreciated! (The threshold adjustment is really the main thing I'm confused about).
astroschnautzer
Active member
It might just be that if you gain the 1/16 you wouldnt have to cut the body of the meter just the front cover part wich is easier, have to be careful with the body part that you don't destroy the whole meter....
tommypiper
Well-known member
ilfungo said:
Just curious, what apps are you guys using to create these colorful wiring guides? Some of them have cabling drawn out in curves and elipses very nicely.
abechap024
Well-known member
ethervalve said:
Its really not that big of a deal. I mentioned how to do it in an eairlier thread (check the rev 1) The 2 trimmers closest to the base of the 6bc8 tube adjust thump, the one near the tip of the tube adjusts the meter (adjust till meter reads "0")
The threshold is just were you want your compressor to start compressing. Make it some arbitrary value, -10db or +4db, depends on how much you want the unit ot be able to compress. Something that I personally can't answer for you.
Some people want to be able to have a huge range of compression and therefor would set the threshold lower, others want to just barely grab 5-10db, those people would logically probably set the threshold higher. If your looking for a "do this" answer, I'm deliberately not giving you one, your going to have to sit down and experiment and hear for yourself
There is no big secret. Ps really dig your studio/band. very cool 60s vibe.
abechap024
Well-known member
tommypiper said:
I just used Photoshop, the really talented people here that turn everything into amazing artwork i bet use adobe illustrator. I've tried to get my brain around the curve tools and just can't do it yet!
ethervalve
Well-known member
Hey thanks Abe, that actually clears matters up for me. I hadn't had any luck finding a service manual for any vari-mu comp; I'm glad to hear it's a 'to taste' sort of adjustment (as opposed to, say, the q bias step in the 1176 or some of the adjustments for a gain brain). My console's inserts are -10dBu so I'll try splitting the difference between that and +4dBu line level for the onset of gain reduction.abechap024 said:Its really not that big of a deal. I mentioned how to do it in an eairlier thread (check the rev 1) The 2 trimmers closest to the base of the 6bc8 tube adjust thump, the one near the tip of the tube adjusts the meter (adjust till meter reads "0")
The threshold is just were you want your compressor to start compressing. Make it some arbitrary value, -10db or +4db, depends on how much you want the unit ot be able to compress. Something that I personally can't answer for you.
Some people want to be able to have a huge range of compression and therefor would set the threshold lower, others want to just barely grab 5-10db, those people would logically probably set the threshold higher. If your looking for a "do this" answer, I'm deliberately not giving you one, your going to have to sit down and experiment and hear for yourself
Ps really dig your studio/band. very cool 60s vibe.
BTW great job getting this project happening and making it so flexible in terms of configuration (i'm going for chip I/O). I'd always thought a vari-mu comp would be out of reach money-wise.
(and thanks for the kind words RE band/studio).
abechap024
Well-known member
prh said:
Good point. I was thinking the same thing. You could do it and even have it replace the input pot, or not. Would probably make it more flexible in some instances.
I have some Carnhill VTB9046 line input transformers. Could these be used either input or inter-stage with the Vari-mu?
Data from the AML Carnhill guide:
Series 1° Parallel 1° Series 2° Parallel 2° Gain dB
10k ohm 2k4 ohm -6
10k ohm 600 ohm -13
2k4 ohm 2k4 ohm 0
2k4 ohm 600 ohm -6
Thoughts?
Data from the AML Carnhill guide:
Series 1° Parallel 1° Series 2° Parallel 2° Gain dB
10k ohm 2k4 ohm -6
10k ohm 600 ohm -13
2k4 ohm 2k4 ohm 0
2k4 ohm 600 ohm -6
Thoughts?
Snapshot:
ethervalve
Well-known member
nice! If you don't mind divulging your shop secrets, how did you label the illuminated switches?
