CAV 45 S2 and Rel Subwoofer

[midniterider]

Hello All,

Just joined this forum as I am in the process of owing a CAV 45 S2. I heard is a few months ago in my friend's system and was absolutely smitted by the sound. I am really looking forward to using it in my system though this my first foray in fully tubed integrated though I have owned many hybrids previously - BAT, Unison, Pathos, Vincent...

Also have searched the forums but couldn't find the answer I am looking for. So here goes...

I own a REL subwoofer and want to hook it up the CAV 45. I would like to know if anyone has done this previously. The connections reco from REL is in the link below.

https://rel.net/blog/2015-07-23/how-to/ ... jN68AljNG5

Thanks much
MR

[Big Dog RJ]

Nice one on the CAV45, great control amplifier. Remember it's not an ordinary integrated amp... it doesn't have an active gain stage on the level control like ordinary integrateds do. Rather, it's only a Passive level control, hence the term "Control Amplifier."

The CAV45 has a single input gain stage, which is directly coupled to its output stage, so there's no Active line-stage or any buffered gain stages between input and output. Just one gain stage that's it! Very simple in design and uses a Passive volume control, that's why it's super quiet.

Re. To connecting a Sub woofer system, it doesn't have main outs for a sub. So, in this case you'll have to use the High Level Outputs going from your CAV45 directly Into your sub. Then from your sub Outputs and into your main speakers.

In this case, you'd need to make sure that your sub has two sets of stereo Inputs and two sets of Outputs, for L and R channels. If your sub has just one set of each then you can't use one sub... you'd have to get another sub in order to form a stereo config comprising of Separate L & R channels. I hope your REL sub accepts this type of stereo config, otherwise its a mono-sub.

As far as I'm aware, that's probably the only and best way to connect a sub woofer system to the CAV45. I also owned both versions of the CAV45 & S2, both were an absolute joy!

BTW, two questions:
1. Which CAV45 series do you have? S1 or S2?
2. Why do you need to connect a sub?

Cheers, RJ

[admin]

Adding to (reiterating) RJ's comments, a lot of subs have speaker cable connectors so you just put the sub in-between the speakers and the amp in a serial fashion. You can also potentially do a similar thing between the source and the CAV45 via RCA connectors if the sub has both input and output RCA connectors. Most likely it's going to be the first option in your scenario.

Which specific sub model is it, I can take a look at the connectors and tell you what the specific options are in your case.

And congrats on the CAV45, a very nice unit.

[Big Dog RJ]

Yes, that's correct Admin and good suggestion.

Only thing is based on my rationale, the CAV45 does not have any further active gain stages nor an active Linestage... hence the mv signals are quite low. If going trough a source component then using that onto the subs RCA's will still be a low level signal... unless that source had a very high mv output.

Therefore, to get the full effect of that source signal going into the CAV45, best is to use its High Level Outputs, which basically goes directly from its higher voltage Output stage (provided his REL sub has two sets of connections for stereo L & R channels / Inputs & Outputs).

The CAV45/ S2 even though on its own is a wonderful amplifier to use, it's a very low signal all way, which is one of the reasons it's extremely quiet. Other than the special driver/ phase inverter tubes it uses, are a very low noise type A7 series tube.

Hopefully, based on your advice and other findings, he'll find the best way to connect the sub.
Cheers mate, RJ

[admin]

Some subs will have RCA input and output for both stereo RCA and speaker connections.

Here is an example of one for example: https://www.reddit.com/media?url=https% ... 2d9aaf58f0

There not common but I just wanted to mention it as I don't know what specific model of sub we are talking about. This would potentially allow for a between source/CAV45 connection.

With all this said, I'm typically not a big fan of subs in non-hometheater audio setups so I think RJ's question of whether a sub is really needed in the first place.

[midniterider]

BTW, two questions:
1. Which CAV45 series do you have? S1 or S2?
2. Why do you need to connect a sub?

Cheers, RJ

Thanks for the background RJ - very helpful.

To your questions:

1. Its the S2
2. I have always loved the bottom line extension offered by my sub along with Fritz Carrera BE bookshelves.

FYI I have a Sumiko S10 sub - which is very similar to a Rel sub in the connectivity it offers. Specially this sub integrates so well with my current setup as I have dialed it just about perfectly to satisfy my listening tastes. Also in my original post I have attached a link to how the connectivity is suggested by REL and plan to connect using the speakon cable.

sumiko-s.10-6.jpg (160.85 KiB) Viewed 3441 times

[midniterider]

Which specific sub model is it, I can take a look at the connectors and tell you what the specific options are in your case.

And congrats on the CAV45, a very nice unit.

Thanks admin! My sub is the Sumiko S10 which I have linked to my earlier post. I have always used the speakon connectors and intend to do so with the CAV as well. This is inline with the speaker terminals connectivity as I have linked in my original post. As I do this way, maybe a different question,

Is there a ground terminal I can connect to on the chassis or do I need to sand a screw down to get the same effect? Basically I need to know where I can connect the ground - black cable...

[admin]

The CAV45s2 is grounded (ie 3 prong plug design). You could ground it to the chasis or any other component in the system that has a ground.

You can also get a grounding plug like this: https://www.amazon.com/Aomitop-Shielded ... 68&sr=8-12

[midniterider]

awesome - i will ground it to the chassis

[admin]

I would also test it with a continuity meter once you have it all hooked up. Make sure that sub ground is on the main ground.

[midniterider]

Good call out. Will take care of that and report on the outcome

[Big Dog RJ]

Ah, OK that makes sense now. Thanks for your clarifications.
Let us know how it all goes. CAV45 S2, very nice!

Cheers, RJ