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Discussion Starter · #1 ·
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.
 

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And this info is based on what?

- Personal experience?

- TechNote from manufacturer/distibutor?

- Friend of a Friend?


What's the part number for this so called digital cable from REL?
 

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Quote:
Originally Posted by westcoastman /forum/post/15577733


And this info is based on what?

- Personal experience?

- TechNote from manufacturer/distibutor?

- Friend of a Friend?


What's the part number for this so called digital cable from REL?


"TechNote from manufacturer/distibutor"


Actually, phone call and email exchanges with Sumiko, themselves.



They make the cable there, in house. I don't know if there is a "part #" attached per se. It's more like a "per request" type of deal.
 

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So does this mean I could potentially have a problem using the Neutrik Speakon High Level Interconnect when connecting my REL R205 to my amp mains according to the instructions in the manual (page 10)?


I only use my R205 for music so I have nothing connected to the R205's LFE or.1/lfe inputs.
 

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Discussion Starter · #5 ·

Quote:
Originally Posted by westcoastman /forum/post/15581655


So does this mean I could potentially have a problem using the Neutrik Speakon High Level Interconnect when connecting my REL R205 to my amp mains according to the instructions in the manual (page 10)?


I only use my R205 for music so I have nothing connected to the R205's LFE or.1/lfe inputs.

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

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Discussion Starter · #6 ·
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.
 

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Discussion Starter · #7 ·

Quote:
Originally Posted by westcoastman /forum/post/15577733


And this info is based on what?

- Personal experience?

- TechNote from manufacturer/distibutor?

- Friend of a Friend?


What's the part number for this so called digital cable from REL?

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.
 

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Quote:
Originally Posted by Thebarnman /forum/post/15601022


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

I am using an Arcam A90. I don't know what class type that would be. I maybe OK after reading one of your post on the other thread. I agree if this can cause damage people should be made aware of quickly.
 

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An A90 should be fine - it is a regular single ended class A/B amplifier with the black speaker terminals connected to ground.


I suspect the problem occurs with full H-bridge amplifiers, which are very common in higher power class D designs, where it is not permitted to ground either speaker terminal (e.g. by connecting it to the high level input of a grounded subwoofer). This would be true of most "bridged mono" conventional class A/B amplifiers too, but that configuration is relatively uncommon.


If there is another explanation I would be interested to hear it.


Sincerely,


John Dawson (Arcam)
 

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Discussion Starter · #11 ·
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.
 

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Discussion Starter · #16 ·

Quote:
Originally Posted by Fanaticalism /forum/post/15707304


Are they charging for this cable?

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!
 

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Discussion Starter · #17 ·
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.
 

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So only Rel issues such warning but no other subwoofer makers?
 

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I don't know of another manufacturer whose subs are available here in the States that uses this type of connection. There is another in the UK, but I don't think they import them here to the States. So, in the world of subs, this is a pretty rare application.
 

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The connection type of the cable is not the issue, it's still a speaker level input, which is used universally by most other MFRs as well but with the regular speaker cable. The point is REL is either having ground issues on it's own and try to put the blame on others, or just want to sell some cables. Improper grounding may cause noise, but it isn't cause any damage, and since we are talking about low voltage audio signal it won't pose any shock hazards either.
 
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