[corndog71]

This may be a stupid question, but how do these amps get the input signal?  Do you need a preamp with two sets of outputs or can you use a splitter near the amps?

If you only have one set of outputs from your preamp then you can use splitters otherwise it’s probably better to have a preamp with dual outputs. You can also go off of your amplifier speaker outputs if you have the A370PEQ.

[mikeeastman]

I use a Jensen Iso-Max thats connected to the binding post of my amp and outputs  either RCA or XLR depending on what you need.

[ketchup]

If you only have one set of outputs from your preamp then you can use splitters otherwise it’s probably better to have a preamp with dual outputs. You can also go off of your amplifier speaker outputs if you have the A370PEQ.

Thanks.  Is there any consensus on what sounds better (using a preamp's 2 sets of outputs, splitting a preamps single set of outputs, or using high level speaker inputs) or is it one of those things you just have to try?  Is there a manual somewhere for the A370PEQ?  That's probably what I'll use because I'm thinking a pair of dual 12s may be enough for my current room [18.5' x 13.5' x 7.5' with two openings on one end (2.5' and 4.0' wide)], but I'd like to be able to step up to a pair of triple 12s at some point if I end up with a bigger room.  Will a pair or dual 12s work okay in this room?  If this isn't the appropriate place for these question, feel free to delete them.

[Captainhemo]

I use a Jensen Iso-Max thats connected to the binding post of my amp and outputs  either RCA or XLR depending on what you need.

As you  know Mike, I'm doing the same thing here. 
IIRC, you  were at one time  high passing  your main amp for the Super 7's.....   did you remember to remove that inline cap  ?   

jay

[emailtim]

Thanks.  Is there any consensus on what sounds better (using a preamp's 2 sets of outputs, splitting a preamps single set of outputs, or using high level speaker inputs) or is it one of those things you just have to try?  Is there a manual somewhere for the A370PEQ?  That's probably what I'll use because I'm thinking a pair of dual 12s may be enough for my current room [18.5' x 13.5' x 7.5' with two openings on one end (2.5' and 4.0' wide)], but I'd like to be able to step up to a pair of triple 12s at some point if I end up with a bigger room.  Will a pair or dual 12s work okay in this room?  If this isn't the appropriate place for these question, feel free to delete them.

I would place them in this order, best to worst, but deltas maybe small.

• using a preamp's 2 sets of outputs
• splitting a preamps single set of outputs
• using high level speaker inputs

#2 Will have 3dB lower output than #1, but can be compensated either on the pre/pro's side (sub out volume control) or the plate amps volume control.
#3 High level outputs are usually the last or convenience resort.

More information can be found here:  http://gr-research.com/a370peq.aspx

Manuals can be downloaded from here:  http://www.rythmikaudio.com/amplifiers.html

[Captainhemo]

Duals will work    well in a room of that  size... prety close to mine and   have  had  duals  in one form or another in here for ages.


jay

[mikeeastman]

 Jay, yes I remover the caps. Had no choice, as I no longer have any interconnects in my system with my new PM and the caps were in a XLR splitter cable.

[Captainhemo]

Right,  forgot you had the  new   integrated, duh on   my  part   LOL
Enjoy, it's a great  piece

jay

[mikeeastman]

Yes, it's only got about 50 hours on it and it blowing my away, can't wait till it's burned in.

[ketchup]

Thanks for all the help so far.  Here's my room right now with no real tuning at all.  The only acoustic treatments I have are absorption panels (3" of OC 703) at the first reflection points on the walls.  The speakers are Magnepan 3.6Rs.  Adding a pair of dual 12 OBs is about $2500.  Is it worth it?  Is gaining extension down to 15hz or so going to add enough to the music to justify the expense?  I listen to jazz, classical, and rock.  Talk me into it.

[Tyson]

Thanks for all the help so far.  Here's my room right now with no real tuning at all.  The only acoustic treatments I have are absorption panels (3" of OC 703) at the first reflection points on the walls.  The speakers are Magnepan 3.6Rs.  Adding a pair of dual 12 OBs is about $2500.  Is it worth it?  Is gaining extension down to 15hz or so going to add enough to the music to justify the expense?  I listen to jazz, classical, and rock.  Talk me into it.

IME it's not really about extension, it's about power.  Panel speakers, even large ones, have good, tuneful bass.  But visceral, punchy, MEAN bass?  Uh, no. 

Before the servo OB subs came along, the only way to get powerful bass was with a box.  And boxed bass is crazy hard to integrate with a planar main speaker.

The beauty of servo OB subs is you get all the power and punch while not losing any detail or musicality.  You truly can have your cake and eat it too.

[Captainhemo]

Yup ,  brings  Ray Brown to life   

jay

[Kalali]

This may be a stupid question, but how do these amps get the input signal?  Do you need a preamp with two sets of outputs or can you use a splitter near the amps?

I have a similar question but more around the impedance matching between the preamp output and the amplifier input. My tube preamp does have two outputs but they're in parallel, probably like most preamps with dual outputs, and has an output impedance of 600Ohms (@ 1KHz). One output is already driving a tube amplifier with 100KOhms input impedance. The Hypex amp appears to have an extremely low 1,800Ohm input impedance which on paper should be a (very) poor match for most tube preamps. The A370PEQ is much better in this respect with a 30KOhm input impedance but most 12" Rythmic subs appear to only come with the Hypex. Is this impedance matching something to seriously consider when picking the right subwoofer model or this is an example where the real life application does not support the measurements. Thanks.     

[ketchup]

I love the look of exposed drivers, but the no rez, in my opinion, looks terrible.  Has anyone ever made a grill frame like they are typically built but with a wider perimeter and cross piece in the center?  The idea is that the wider frame will cover up the exposed edges of the no rez.  The frame can then be painted the same color as the cabinet.  Will this have a negative effect on performance or will it be purely cosmetic?  It should improve the appearance considerably if not using grills.

[Peter J]

I love the look of exposed drivers, but the no rez, in my opinion, looks terrible.  Has anyone ever made a grill frame like they are typically built but with a wider perimeter and cross piece in the center?  The idea is that the wider frame will cover up the exposed edges of the no rez.  The frame can then be painted the same color as the cabinet.  Will this have a negative effect on performance or will it be purely cosmetic?  It should improve the appearance considerably if not using grills.

The foam on the NoRez is  mostly acoustically transparent so if you cover its edges it effectively changes the sonic characteristics of the cabinet. Essentially puts a semi-back on cabinet.
There are some alternatives. Here's one:

https://www.audiocircle.com/index.php?topic=139529.200


I think that photo sort of highlights the NoRez.

[mlundy57]

If you make the frame out of 1" x 3/4" hardwood (I've used both poplar and oak, you don't need a cross piece.

[emailtim]

The foam on the NoRez is  mostly acoustically transparent so if you cover its edges it effectively changes the sonic characteristics of the cabinet. Essentially puts a semi-back on cabinet.
There are some alternatives. Here's one:

https://www.audiocircle.com/index.php?topic=139529.200


I think that photo sort of highlights the NoRez.

I really like the compound bevel look of this NoRez build.  It gives it a very finished look.

FWIW, I rotate my drivers by 45 degrees (so the posts are in the corners, NW/SE or NE/SW versus E/W or N/S) to give my big mitts some more room to access the speaker binding posts.

[mlundy57]

I really like the compound bevel look of this NoRez build.  It gives it a very finished look.

FWIW, I rotate my drivers by 45 degrees (so the posts are in the corners, NW/SE or NE/SW versus E/W or N/S) to give my big mitts some more room to access the speaker binding posts.

Yes it does. I've built two pair like that. However, when you miter the NoRez it takes twice as much compared to straight cuts.

[ketchup]

I really like the compound bevel look of this NoRez build.  It gives it a very finished look.

FWIW, I rotate my drivers by 45 degrees (so the posts are in the corners, NW/SE or NE/SW versus E/W or N/S) to give my big mitts some more room to access the speaker binding posts.

I agree.  That's a very nicely done pair, but I would still like to cover up the norez, but not if there's a sonic penalty.  Does anyone know specifically how covering it up as described above will change the sonics?

[Sonicjoy]

Seem like if you wanted to get real creative you could wrap the NoRez with grill fabric. (that would be a challenge to implement) That should not affect its performance significantly. Personally I would use grills if for no other reason but to help keep dust out.