RK3 and RK4

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metasonix
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RK3 and RK4

Post by metasonix » Sat Jan 14, 2017 12:03 am

Okay, they've been added to our website. We have also added owner's manuals for all current products. SUPPORT section, scroll down.

If you must purchase an RK3 or RK4, Big City Music has some in stock right now. Other dealers don't seem to have noticed yet. Isn't that strange.

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Post by albiedamned » Sat Jan 14, 2017 2:24 pm

Excellent! I'll put these on Modular Grid later this afternoon or tonight if someone else doesn't beat me to it.
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Post by albiedamned » Sat Jan 14, 2017 4:04 pm

https://www.modulargrid.net/e/metasonix ... ger-shaper
https://www.modulargrid.net/e/metasonix-rk4-filter-vco

I copied the images and description text from Metasonix.com. I also got the power specs from there. I put 31mm as the depth for both modules since it says all RK modules are no more than 31mm. I put $300 as the street price for both, although last I checked bigcitymusic.com only had the RK4 listed. I'm assuming the RK3 will be the same price.
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Post by sloth713 » Sat Jan 14, 2017 4:13 pm

Well some one has to be that guy so...

What are the hypothetical differences between the RK3 and r-53? Same question for the RK4 and R-54 (minus the vca and harsh switch)? I am sure we will get an audio demo comparison in the next 6 months but I want to hear Eric's thoughts on the differences

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Post by metasonix » Sat Jan 14, 2017 10:41 pm

albiedamned wrote:https://www.modulargrid.net/e/metasonix ... ger-shaper
https://www.modulargrid.net/e/metasonix-rk4-filter-vco

I copied the images and description text from Metasonix.com. I also got the power specs from there. I put 31mm as the depth for both modules since it says all RK modules are no more than 31mm. I put $300 as the street price for both, although last I checked bigcitymusic.com only had the RK4 listed. I'm assuming the RK3 will be the same price.
All the RKs are the same price. Thanks for putting those on Modulargrid.

(You could note that the R-51, R-53, R-54 are discontinued and the R-55 will be reissued sometime this year with a different front panel.)
What are the hypothetical differences between the RK3 and r-53? Same question for the RK4 and R-54 (minus the vca and harsh switch)?
None other than the RK3 not having that "Pulser CV" input (it was kind of useless anyway) and the RK4 not having the pentode VCA or "Harsh" switch. They sound exactly like the R versions.

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Post by albiedamned » Sat Jan 14, 2017 11:36 pm

metasonix wrote:(You could note that the R-51, R-53, R-54 are discontinued and the R-55 will be reissued sometime this year with a different front panel.)
Interesting... So is the R-52 still in production? Any plans for an RK adaptation of it? And will the R-55 front panel be the only change or are there other R-55 changes coming?

I just set R-51, R-53, and R-54mk2 to discontinued on Modular Grid. FYI, anyone can make those edits. It's like Wikipedia. :hide:
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Post by albiedamned » Sun Jan 15, 2017 12:01 am

FYI, some of the RK3 demo links on metasonix.com are messed up. The Demo 1 and Demo 2 links are merged into one link (which goes to Demo 2). Also the link for Demo 5 doesn't work because it's missing the .mp3 extension.
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Post by metasonix » Tue Jan 17, 2017 12:07 am

albiedamned wrote:So is the R-52 still in production?
yes, until it runs out, I think there's about 15 of them left
Any plans for an RK adaptation of it?
Seriously doubtful, dual pentodes of the types needed were never made. It could be done with two subminiature pentodes but they are becoming very scarce/expensive.

If I had a vast supply of 5840 pentodes, I could explode the sun. Unfortunately companies like Mojave Audio are using the damn things in their condenser mics. So presto, they are scarce because insane hoarders are buying all the old supplies up. Ha ha fuck me.
And will the R-55 front panel be the only change or are there other R-55 changes coming?
should be the same
some of the RK3 demo links on metasonix.com are messed up
fixed, thks.

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Post by YellowBlood » Thu Jan 26, 2017 12:01 am

Hey Eric, just had a quick question. Can the RK4 module be used as a single "pitched drum" like on the D-2000 or is there plans to release a dedicated pitched drum module in 8HP like the RK1? Thanks!
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Post by metasonix » Thu Jan 26, 2017 3:47 pm

The RK4 circuit is identical to the D-2000 circuits. Yes it can be used as a pitched drum voice.

Two RK1s and three RK4s and a controller or sequencer and you have a D-2000. Wazoo.

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Post by YellowBlood » Thu Jan 26, 2017 4:24 pm

Excellent, Thank you!
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Post by metasonix » Thu Jan 26, 2017 4:54 pm

Whups, a couple dealers have (finally) placed orders. Need to finish and ship. If you want quicker delivery, Big City still has a couple in stock.

Thanks for supporting us and don't shove 750Ts up your bunghole.

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Post by Kummer » Tue Feb 07, 2017 10:39 pm

metasonix wrote:The RK4 circuit is identical to the D-2000 circuits. Yes it can be used as a pitched drum voice.

Two RK1s and three RK4s and a controller or sequencer and you have a D-2000. Wazoo.
So then the R-54 is the same circuit as a D-2000 drum voice?

To echo a question from above, I am interested in the differences between the R-54 and RK4/R-53 and RK3. Obviously, there is a difference in the number of vacuum tubes... but what does that mean as far as differences in sound generation/processing?
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Post by albiedamned » Wed Feb 08, 2017 3:01 pm

Another question: the RK3 and RK4 have much higher +12V power requirements than the R53 and R54: 400 mA each versus 200 mA for the R53 and 150 mA for the R54. Do the RK modules truly require that much, or is that requirement for the initial power-up surge? If it's true, then do they really need 2-3 times as much for the initial power-up, meaning 800 to 1200 mA?
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Post by metasonix » Wed Feb 08, 2017 4:06 pm

Kummer wrote:So then the R-54 is the same circuit as a D-2000 drum voice?
yes
To echo a question from above, I am interested in the differences between the R-54 and RK4/R-53 and RK3. Obviously, there is a difference in the number of vacuum tubes... but what does that mean as far as differences in sound generation/processing?
There's not a big difference in sound quality or effects. The RKs have fewer CV inputs because of space issues.
Another question: the RK3 and RK4 have much higher +12V power requirements than the R53 and R54: 400 mA each versus 200 mA for the R53 and 150 mA for the R54. Do the RK modules truly require that much, or is that requirement for the initial power-up surge? If it's true, then do they really need 2-3 times as much for the initial power-up, meaning 800 to 1200 mA?
That's because we are limited by the tubes available. Yes, the RKs need more current, although it is entirely from the +12 line. The old R modules had two tubes, usually with heaters in series, so they used a lot of current from both +12 and -12v.

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Post by albiedamned » Wed Feb 08, 2017 5:18 pm

metasonix wrote:That's because we are limited by the tubes available. Yes, the RKs need more current, although it is entirely from the +12 line. The old R modules had two tubes, usually with heaters in series, so they used a lot of current from both +12 and -12v.
So do the RK3 and RK4 really need 800 to 1200 mA of +12 for their initial power-up surge?
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Post by Yes Powder » Thu Feb 09, 2017 11:58 pm

albiedamned wrote:So do the RK3 and RK4 really need 800 to 1200 mA of +12 for their initial power-up surge?
For simplicity's sake, yes.
Since metal has lower resistance when cold than when hot, they will naturally draw more current before they've heated up to operating temperature.
Depending on your PSU and how much you're overdrawing it, this may cause it to shut down and restart repeatedly as the supply tries and repeatedly fails to cope with the cold-surge power, or at worst (so I'm told) it can totally cook the poor thing.

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Post by albiedamned » Fri Feb 10, 2017 4:49 pm

ElectricNoises wrote:
albiedamned wrote:So do the RK3 and RK4 really need 800 to 1200 mA of +12 for their initial power-up surge?
For simplicity's sake, yes.
Since metal has lower resistance when cold than when hot, they will naturally draw more current before they've heated up to operating temperature.
Depending on your PSU and how much you're overdrawing it, this may cause it to shut down and restart repeatedly as the supply tries and repeatedly fails to cope with the cold-surge power, or at worst (so I'm told) it can totally cook the poor thing.
I would like to hear from the horse's mouth (aka Eric) about what the actual inrush draws of the RK3 and RK4 are. I've also emailed Doepfer to try to understand the capacity of the PSU3 to handle inrush demands, given that it's a linear reuglator fed from a switching supply. I really want to swap out my R53 for an RK3, and maybe my R54 for an RK4 too, but I'm worried that my PSU3 won't handle the inrush even though I'll be well below the overall 2000 mA +12V limit.
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Post by corduroyflipflops » Fri Feb 10, 2017 6:43 pm

A minor thing, but it affects quality of life, things just aint right.....

I miss yellow :help:

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Post by albiedamned » Sun Feb 12, 2017 8:24 pm

Eric, I'm still hoping you'll answer my question above about how much inrush current the RK3 and RK4 draw on power up.
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Post by metasonix » Tue Feb 14, 2017 2:26 am

albiedamned wrote:Eric, I'm still hoping you'll answer my question above about how much inrush current the RK3 and RK4 draw on power up.
It's about 2.5 times the operating current; it varies slightly from tube to tube so we can't make it a "rating". I doubt the Doepfer PSU3 will have a problem running that load.

Just don't be another one of those guys who tries to run our products off a Tiptop uZeus, has problems, then "upgrades"....to a Synthrotek supply. Which isn't any better. I've had TWO of them this week alone. Do I have to keep screaming DO NOT USE THE CHEAPEST POWER SUPPLIES YOU CAN FIND?

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Post by albiedamned » Tue Feb 14, 2017 2:19 pm

metasonix wrote:It's about 2.5 times the operating current; it varies slightly from tube to tube so we can't make it a "rating". I doubt the Doepfer PSU3 will have a problem running that load.
Actually the PSU3 will have problems. I got a reply from Doepfer, from Dieter Doepfer himself. Here's what he wrote:
as the A-100PSU3 is made of a switching supply (followed by linear
regulation) it's not possible to obtain inrush currents beyond the specs of
the power supply. We know this as there are e.g. problems with the new
digital Roland modules which consume high inrush currents during power on.
The A-100PSU3 should be more than sufficient to drive these modules based on
the current specifications. But the PSU3 does not turn on when more than 3
Roland modules are connected. These should take only about 3*450mA = 1350mA.
But they obviously consume more than these currents during power on. On has
to connect one module after the other to the PSU3. Then it does work but
that's not a practibal solution.
I'd recommend to keep the A-100PSU2.
So the PSU3 can't handle inrush draws that push it beyond it's total rating of 2000 mA +12V and 1200 mA -12V. I know you said 2.5x is not an exact thing, but let's just use it for an example. An RK3 and an RK4, at 400 mA +12V each, would combine to require all 2000 mA of +12V for their inrush current draw. You wouldn't be able to connect a single additional module to the PSU3.

Dieter says to keep the PSU2, which is linear. But it's total capacity is only 1200 mA of +12V. So it's a trade-off: higher total capacity with no ability to handle inrush (PSU3), or lower total capacity with ability to handle inrush (PSU2).

I know what the correct answer to the problem is: RKP.
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Post by metasonix » Thu Feb 16, 2017 3:52 am

Tubes are EVIL, tubes are awful, they hate you and your mother, they want to chop your nuts off and eat them, etc.....

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Post by metasonix » Wed Mar 29, 2017 8:33 pm

BCM demo of RK4


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