Tascam 788 and Zoom drum machine MIDI clock sync problem

[ejm]

I'll try to make this brief, since I've done a lot of troubleshooting/experimenting on this problem and have had no luck.

I have been using the 788 and a Zoom RT-223 for about a year and a half. I record a basic drum pattern/song to tracks 7/8. I then add other instruments to other tracks. As things progress I go back and add more patterns/rolls/etc to the drums and re-record them to 7/8. I sync up the Master 788 to the Slave Zoom drums. I use the Sync clock, since that is all the drum machine will accept (no MTC). I use the standard selections: 788 Master, Sync clock, 30ND frames, etc.

(Editted 12-10-2014) I noticed from time to time that between takes things didn't always line up and play in time between instruments, and for a while I thought my playing/timing was off on the other instruments. Long story short: The Zoom drums do not always play in sync, in other words in time, consistently. It is definitely repeatable, but when and where it occurs is random. Sometime you will get two drum recordings/takes that play in sync (time), but about 50% of the time they do not. All of the other instruments on the other tracks (guitar/bass/etc) play in sync (time) with each other. Only the drums are out of sync (time).

To verify all of this, I have recorded a mono drum pattern/song to one track, then repeated the process on another track. Using the Scroll function on the Tascam I can measure how far out the timing is when it starts to go bad. I have measured anywhere from 30-60 milliseconds between points in the recordings, which is a lot. It makes it sound like "the band" is not all playing in time.

Here's the kicker: Before getting the newe RT-223 I used a Zoom RT-123 the same way for about 10 years. I never had a problem. And.........A couple of weeks ago, as a backup as well as for this experiment, I found another RT-123 on CL and bought it. It does not have this problem.

The RT-223: This step did not use the MIDI clock sync function. I manually started the drum machine during recording. I chose a preset pattern, let it repeat, and recorded it for 3-4 minutes. I then did the same thing, recording it to a different track again manually. I did this four times, so I had four tracks of the same pattern repeating to compare to each other. However, since I started the recorder manually, they were out of alignment with each other. Using the editor functions in the Tascam 788, I lined up the tracks to make them all start at the same time. Result: The tracks all played in time for their duration. This tells me that the internal clocks of the drum machine are OK. The problem is in the circuitry and/or processing of the MIDI sync clock.

So:
The old Tascam 788 and the old Zoom RT-123 drums play together using the MIDI sync clock.
The old Tascam 788 and the newer Zoom RT-223 do not play well together using the MIDI sync clock.
Also, the internal clocks of the RT-223 drum machine are OK. The problem is in the circuitry and/or processing of the MIDI sync clock.

I found the following post recently. It seems that other users had a similar or the same issue between a Tascam 2488, an old Alesis SR-16, and a newer Alesis SR-18. The fix was to put another MIDI device (a Midiverb II) in between the 2488 and the SR-18 to act as sort of a MIDI "buffer".

I use an old Lexicon LXP-1 reverb that has jacks for MIDI In and Thru. The In and Thru ports have active circuitry inside; It's not simply a direct wire. I tried this set up with my 788/Lexicon/Zoom RT-223. It still does not play in sync.

https://homerecording.com/bbs/gener...2488-mkii-midi-using-alesis-sr-18-a-275244/2/

Thoughts/Tips/Advice?

Is the 788 bad? I don't think so, since it plays fine with two (older Zoom) drum machines.

Did I get a lemon with the newer Zoom RT-223? Zoom will exchange it for $95, but what if I spend the extra money and things still don't work?

Does the Zoom have a design problem common to all s/n's of the RT-223? I suspect not. Why? If this unit doesn't work with a 788 clock, then anyone using any other device as the clock source (a keyboard, a PC card, etc) may have this same problem. That means that Zoom would be getting returns by the truckload. Keep in mind: If you are using the RT-223 to simply play along with, and are not using any pre-recorded tracks or other instruments that you are syncing to, you most likely will not notice a problem.

Have MIDI specs changed over the years so much that older devices no longer work with newer ones?

I have not tried any of these drum machines with a newer DP24 or DP32. I could do that since I have access to a couple of them. However, this would take even more time. Plus, it still wouldn't solve my 788 problem.

A company called MIDI Solutions makes a Thru box that appears to be a MIDI "buffer". Has anyone used one?

Any thoughts/suggestions would be appreciated.
Thanks in advance.

 

[ejm]

An update to my previous post. BE FOREWARNED!!!!!!!

If you are using this machine to jam along with and practice, it will be fine.

If you are using this machine with the MIDI Sync Clock, BE FOREWARNED. It may not work correctly. I have since come to find out that this drum machine seems to miss a clock occasionally, for lack of a better term. If you are using it as a slave and driving/syncing/sequencing it with a clock from another master, IT MOST LIKELY WILL NOT WORK CORRECTLY.

The internal clocks when not using the MIDI sync clock appear to be fine and stable. The problem is when using the RT-223 as a slave to some other clock source.

It is a very subtle yet noticeable problem. That is why it took me so long to realize and find it. I always thought that it was MY timing that was off when playing the other instruments. It seems to occur about 50% of the time.

I use this DM with an old Tascam 788 8 track recorder. I use it as a drummer to develop/record songs. The 788 is the master clock source and drives the RT-223. Occasioanlly, the RT-223 will seem to miss a clock and the "drummer" will start to play out of sync with any other pre-recorded tracks. It is definitely enough to be noticeable.

I did a boatload of tests/recordings to try to narrow things down.

I tried my old Zoom RT-123 with the 788 again. (Note that I used the RT-123 with the 788 for about 12 years with no problems......ever.) It still works fine sync wise.

I bought another RT-123 off of CL for $50. No problems.

I had Zoom tech support arrange an exchange for another RT-223.

I tried using another device (a digital reverb) with MIDI In/Thru jacks as a sort of MIDI clock "buffer".
The RT-123 is OK.
THE RT-223 DOES NOT WORK (did not fix the problem).

I tried both the RT-123 and the RT-223 with a newer Tascam DP-24 recorder.
The RT-123 is OK.
THE RT-223 DOES NOT WORK (did not fix the problem).

I have e-mailed Zoom engineering about a month ago detailing what I did. I have yet to hear from them.