Warning to REL owners with Class "D" amps and/or receivers

of damage due to improper ground.

The following situation can cause damage to your audio equipment. If you use regular "High Level" cables connected to any of the main outputs on a Class "D" amp or receiver, there is risk of damage due to improper grounding. However there is no risk of damage if your using the RCA type connection while hooked up to the low level connection.

If your using a newer REL sub bass system that's designed for both music (high level input) AND movie sound (.1 LFE Channel low level RCA type connection) while connected to both connections at the same time, AND your using a class "D" amp or receiver, you risk damage to your audio equipment with only the High Level Input connection.

Again, the issue being proper grounding. Hooking the black wire of the "High Level" cable to a phono ground will not help. Hooking up a RCA type connection to the black wire and attaching it to any of the unused RCA connections on the back of your amp/receiver will also not help.

The way to properly hook up your REL to a class "D" amp/receiver (while using the high level connection) is to use a "High Level Digital Cable" available through your local REL dealer. This is a "new" situation and the "High Level Digital Cables" are only being manufactured on a case by case basis. The word "Digital" is not to be confused with the type of signal being sent through it, it only describes the type of cable to be manufactured. Many local REL dealers may not be aware of this and will have to contact Sumiko for further information.

Only if your amp is Class "D". What Brand is your amp and model number?

My "High Level Digital Cable" arrived last Thursday. Unfortunately the "Speak-on" connection was of the newer type, not of the older type I need for my older REL Stadium II.

Not a problem as it was easily sent back to Sumiko by one of my local REL dealers for a replacement.

So as part of this update, it's also important to provide the model of the REL sub bass system you have as the connections are different on the newer models.

Once I get the correct replacement, I will provide images so everyone can see what the "Digital High Level Cable" looks like.

To describe by words, it does not look any different then regular high level cable connections except for the fact that it does have a RCA type connection on the black wire. Again, REL says there's more to it than that, as there's more that helps provide a proper ground.

This was based on both "Personal Experience" AND from the "Distributor". Also, the Distributor mentioned they were working on getting the word out to their retailers. However because this is "currently" an unusual situation, and not many know about this, I felt it important enough to post a warning as a service to fellow AVSers who could benefit from such information and help prevent damage to their equipment.

According to Sumiko, this is a fairly new situation as class D amps have been getting more popular in recent years. Retailers selling class D amps and receivers who are not REL dealers would not know about this situation. And as I mentioned earlier, the "High Level Digital Cable" is only made on a case by case basis. As far as I know, there is no part number. That is why the advise was given (by the distributor) when ordering it, to stress the word "Digital" in describing the "High Level Digital Cable".

AVS is a fantastic source of helpful information from friendly pros and enthusiasts I normally would not be able to easily meet..locally or anywhere else. For what it's worth, I help whenever I can, and not sharing this information would be a real disservice. In my many years of this audio and video hobby, I've never ran across anything like this.

I finally received the replacement "High Level Digital Cable" two days ago...it had all the enclosed equipment for the proper grounding, unfortunately the RCA connection that was suppose to be on the black wire was noticeably absent.

My local REL dealer got back on the phone again with Sumiko where it was admitted they did not look at the wire for final approval before it was shipped out. Since the wire had all the components needed for the proper grounding, all that was needed this time was the RCA connecter on the black wire.

My local REL dealer could have easily connected one on, however I felt it was not the responsibly of my local REL dealer to do that, so back out to Sumiko it went.

I was told Sumiko's electrician/technician...or the person who would connect the RCA connector is only there once a week. I thought fine, I just wanted it to be done correctly. And besides, I noticed on the last wire from Sumiko had a RCA connector that had Sumiko printed right on it! So I thought hell, if it's coming from Sumiko, I want it to say Sumiko!

I also learned I may be the first person to actually order and use the new "High Level Digital Cable". So I can understand the mishap.


So I wait another couple weeks. No big deal.

When I do finally get the wire, I will take an image of it to share on this site.

Yes, I had to buy it from my local dealer, and they had to contact the people who supply REL equipment. (Sumiko). Here's something that might be important, if no one at Sumiko knows what this is about, Kendra at Sumiko will know what's going on.

Remember to order it from your local REL dealer and they need to contact Sumiko for further information. Also, it's called the "High Level Digital Cable"...with the word DIGITAL distinguishing what cable needs to be made to order. This is made on a case by case basis...and I did in fact, end up being the first customer to have ordered and use this "new" cable.

I would have to say, this was a very odd FIRST in my video/audio hobby! And it was only by chance, that I found out about this. I'm glad to be able to share!

Sorry for the delay. About a month ago, I learned about the passing of someone I knew and spent all this time in another forum talking about him.

The new REL cable works. The levels still seem to be a bit lower than what I was used to with my other amp, (same effect as the older wire) (simple matter of re-adjusting the audio to correct level...if in fact it is different) however it seems to be operating smoother...(maybe).

Now if there is a real difference or not, I'm not positive about anything at this point. It's been a real long time since I had it connected with the older cable and it was only like that for a very short period of time.

What I do know is it is now connected correctly and I have no worries that I would be doing any damage to my equipment.

Here are some images to show the differences between the old wire and the new one....

OLD WIRE...


NEW WIRE


You can clearly see on the new wire, the white "housing" is bulky, evidently helping to provide a proper ground for a Class D amp. And notice instead of a simple black wire, the black wire now has a RCA male connector. That male RCA connector is connected to a unused RCA jack on the back of the SC-07. I'm told ANY unused RCA jack on the back will do.

Hi! Yes, I'm still watching, however only now and then. Yes, I have all that info your asking for. I'll be sending it to you in a PM.

Yes, I paid for the new cable and if I remember correctly, it was around $140 or so. I don't remember the exact price.

It IS worth using that cable for the simple fact I know there is no more possible damage to any of my equipment...receiver and/or sub bass system.

In my situation, using the class "D" amp/receiver...with this sub was the combination that warranted the switching of cables.

As far as any improvement in the sound quality, I thought the over all bass sounded smoother...however I want to strongly caution that I only had the old cable on it for only a few moments before being told to remove it because of possible damage. And because it took a while to get the new cable, it was hard to do any real A/B testing. Even with both wires in my possession, I was in no way going to start hooking up the older wire to try it out. I was just glad to get the new one and move on with music enjoyment!

As far as I know, Sumiko has been in the process of letting their dealers know of this situation. In my case, I have a much older REL sub bass system and at that time, class "D" amps/receivers were not common. Class "D" amps/receivers still not being too common today, though currently growing in popularity...this has given more concern to this situation than even just a year or two ago.

REL still being a very fine sub bass system. While exercising a little caution by using the correct wires (based only with the high level input using a class "D" amp/receiver) the equipment will be fine and give fantastic performance.

Talking about class "D" receivers and my older REL sub bass system, here's a little story about the performance of the two put together!

On Jeff's first visit Sept 2008, he did a full calibration on my 60 Pioneer Pro-151FD Kuro and an audio calibration. At that time, he pointed out a problem I was having with the lower audio frequencies and how it could be corrected with a second subwoofer and/or additional audio equipment. Even though I still don't have a 2nd subwoofer, I did however buy a new receiver...the Pioneer SC-07. Being aware of the adjustability of my new receiver, I couldn't wait to see what adjustments Jeff would do with my new equipment during his 2nd visit.

With my highly anticipated late December 2008 purchased of the Pioneer SC-07, I knew I would be getting closer to the audio performance I desired. Even so, reaching maximum audio performance didn't come without a hitch. I first had to deal with getting the correct wiring from REL to get a proper ground for my new class "D" receiver.
http://www.avsforum.com/avs-vb/showt...1#post16599598

That took about two months. After that, I let the Pioneer SC-07 set up it's own audio calibration via it's MCACC program and the supplied microphone. I felt that the audio sounded "better" and the sound stage was much more "solid", however it sounded overall too bright particularly when compared to my older pre-amp amplifier combination.

Now I was ready for Jeff's arrival. When I checked his schedule, I saw he was already booked for my area. However, I did notice he was taking requests in case of cancellations so I sent him an email. It turned out he was able to fit me into his schedule so I was set.

On May 27th, 2009 9am sharp, Jeff came by for a 2nd visit to do a "simple" audio calibration...at least that was his first impression. What ended up being an issue (and taking up more time) had almost everything to do with how my REL sub bass system was hooked up. To correct most of the problems I was having, Jeff suggested an RCA to XLR (three pin) converter so I could take advantage of the SC-07s crossover (I hope Im saying that right!) And to make sure we were getting the correct connection/equipment, we called around and both ended up traveling to a local music store. I bought the converter and back to my place we went. Overall, his visit was about five hours (about two or three more hours than he anticipated).

When the work was done, I was thrown back into amazement. I've never heard my audio system sound as good as it does today. With a term I like to use, it simply sounds like showroom quality! And what's amazing, is how great it sounded in a room (my room) that is about as bad of a listening environment as it can get. Jeff would never tell me (his client) how much my listening environment sucks, however I took his well meaning descriptive words while he was listening to the differences of the much improved audio and could tell he was surprised how good it sounded in such a bad acoustical environment. We looked at each other at the same time and just started laughing! All I knew, is that the audio was smooth, (something I'm not used to hearing) balanced, detailed, open, realistic, much more depth in the low end and not colored in anyway. On top of that, I was really impressed on how Jeff was able to improve the performance of my older model REL Stadium II. Older yes, however still a fine product and it simply just needed a little help.

If you checked out the link in this story, I want you to know, that the digital cable from Sumiko is still hooked up (for proper grounding) along with the RCA to XLR converter (for the low level hookup).

The bass is now much more detailed, smooth, much more even and the bass produces the same audio levels throughout the lower audio range (there was a lot missing before he worked on it) and I hear much more liveliness in the music.

Jeff put a lot of work into my system. Like I had mentioned when I contacted him, he was simply figuring on a simple calibration, something that would normally maybe only take a couple hours. He ended up being here for five hours because of the audio problems he encountered. Jeff wanted to make sure that all the audio equipment could be brought out to perform at their maximum ability.

The improvement in audio quality was worth much more than I paid. Even though the price ended up being a little bit more than was quoted, it was more than well worth it. There were problems along the way and a lot of time spent sorting them out. HOWEVER, the improvement was as if I had just spent tens of thousands of dollars on new audio equipment. It sounds like I have new speakers, a new subwoofer and I can tell for the first time that the purchase of my new Pioneer SC-07 was well worth the money.

I'll definitely be having Jeff over again when I purchase a new subwoofer and/or center channel speaker. He even said by that time my Pioneer Pro-151FD would be ready for a quick calibration update. And that he would (at no additional cost) go ahead and do that for me. Since he had already calibrated my Kuro and is familiar with this Pioneer product, he assured me that the differences would be small and would not take long at all. It would be interesting to see if my 60 Kuro would need any adjusting at all since I rarely have time to sit and watch TV anymore.

In any case, for those sitting on the sidelines wondering if a TV and or Audio calibration is worth the money or not, I cannot say in enough words how much more value you will get from your equipment when it's set up properly. My own abilities with this hobby can get me further than mosthowever no matter how much I keep up, I simply don't have the background, education and knowledge that Jeff has. His visits to my home has given me lots of confidence in knowing when I listening to music and/or watch a movie, either by myself or with friends, the performance will be better than most have experiencedalmost anywhere!

http://www.accucalhd.com