Rythmik PEQ370 plate amp sub with OB shelf - anyone else tried it??

gooberdude · « **on:** 23 Jun 2008, 09:09 pm »

Over the last few months I have sold nearly all my gear....starting from scratch and tryin' to do it right!!!

My system consists of a pair of Hawthorne Sterling OB drivers and the bad-ass x-overs, a 25 wpc vintage CONN organ tube amp (7868 tubes) and an Imod with Revelation Audio Labs ipod cable.

The newest addition is a Rhythmik Audio PEQ370 plate amp for the Auggies. Previously I was using a 150wpc Parts Express plate amp (it had a remote control for the Cut-off freq and volume). I've also owned half a dozen other plate amps that were built into boxed subs I've owned.

Compared to all other plate amps I've owned or listenend to, the Rhythmik is in a class of its own. The power is relentless yet has a truly musical presentation. There is no one note thud. Somehow this amp is able to bring out MUCH lower tones from the Auggie's than the previous plate amp and it fills in some sonic gaps....gaps that i 'thought' were a natural part of OB augmentation. As it turns out, the gaps only existed in the PE sub amp.

I'm posting this here due to a special 'shelf' that the designer Briang Ding adds to these plate amps. In my case, with the Auggies, Brian added an 80Hz shelf specified for OB. In Brian's own words "the OB shelf helps to reduce any type of cancellation of the front and back waves"

I have NO idea what he's talking about, but this little add-on 'shelf' is clearly visible on the pcb, and when its little toggle switch is in the OFF position, the amp sounds terrible. With it on, however, a torrent of ultra tight and fast, fast, fast bass is unleashed. The amount of control that the amp exerts on the Auggie's is unreal. The way the music can start and stop so fast is new to me, and I've owned the Auggie's for well over a year now.

I have never enjoyed such low, low, low bass notes from the Auggie's... they sound like boxed subs now. Nothing is 'missing'!!

For under $300, I think this amp is a tremendous value. Also, the time and speed and monstrous musicality of the amp will make it a cinch to blend it into any system, mating with main amps of any quality. Even though i'm a tube amp fan now, if Brian Ding made a full-range solid state amp I'd give it a serious demo. The tone of this plate amp is 100% right on to my ears.

Currently I have the Auggie's in a parralel wiring arrangement. A speaker cable runs from the amp's output into 1 Auggie, and then a speaker cable running from that Auggie into the other Auggie matching + to + and - to -. According to B. Ding, this is the only way the PEQ370 will work correctly. Signal-wise, the plate amp gets its signal at speaker level from the main amp...

Last, the PEQ370 has an awful lot of flexibility. You can choose the Frequency and amount of damping, a Rumble Filter, choose from 1 of 3 x-over slopes and there's also an EQ. I sat next to the amp, about 6' behind the Auggie's, and set these levels by ear a few days after plugging it in. I don't know what any of it means, but it was clear by ear (even when behind the drivers) how to set the settings.

I cannot get the parametric EQ to do anything for me, I cannot even tell when its engaged, so I'm not messing with it anymore. BUT, this does not detract from the value or performance I perceive 1 bit.

My settings so far:

Rumble Filter ON
X-over 12/EXT
Damping Freq 20 Hz
Damping level High
OB 80 Hz shelf ON

Also, currently the cut-off freq is pretty high, at about 65 HZ before I hear the slightest bloat or overhang. With the Sterlings being only a few weeks old though, I'm sure they'll play a bit deeper as they age. Hopefully not too much though, the Sterlings pound....kinda weird!

For me, the coolest attribute of this amp is compatibility with multiple sources. My system has an Imod, digital cable TV box and the orig XBOX for DVD. All are 1V output devices... With the PE amp I needed the remote control - each source had to be set to a difft level. In the case of the cable box for example, the volume had to be set at 100% whereas it was good at about 60% with the Imod. The Imod luvs subwoofers.

With the Rhythmik though, the volume is always at 50% or so and I don't change it! I never get up from my seat to change the bass volume setting....i like this aspect a LOT. There is always bass, no matter the source or strength of the source material.

I have no relation with Rhythmik of course, but I am witness to their prowess and desire to get great gear in the hands of people like me who can only afford $300 amps. there is also a 2 year warrantly - not the norm with plate amps, ya know???

Custom driver x-over shelf, 240 wpc, loads of options, 2 year warranty and a musical plate amp???

highly recomended!!

matt

Brad · « **Reply #1 on:** 25 Jun 2008, 01:02 am »

Dang it Matt....

quit spending my money for me

I like the adjustable 12/24 xover and the selectable damping.
Plenty of power for a pair of Augies too.

dweekie · « **Reply #2 on:** 25 Jun 2008, 11:39 am »

Is it the same as the one GR Research is selling? Or is yours a bit dif?

http://www.gr-research.com/index.asp?PageAction=VIEWPROD&ProdID=142

I'll need something new to match my augies......

gooberdude · « **Reply #3 on:** 25 Jun 2008, 06:05 pm »

That is the same amp....

It is not a Servo amp though, but all the amps say that on the cover.

The tone of this amp goes perfect with the Sterlings and has really brought the Auggie's to life.

Even though I have been spending way too much $$ lately, the biggest surprise is the PEQ370.

of course the Sterlings are simply out of this world too, but i like bass and now think I own some of the best I've heard.

Some of my impression is certainly power based... The 370 has about 100 more wpc than the prev. plate amp.

I do think the magic of this amp goes way beyond useable power though. It seems to be a good design, and a good deal.

Brad, the x-over choices have ended up being the most crucial. Of the choices avail, the auggie's only sound good on the EXT/12 setting. I never printed out the owner's manual, but i do recall reading that this setting is for when a satellite system with sub is used...not my set-up. But, i could care less if its right or wrong. Using that slope and the extra OB shelf makes exquisite and tight bass.

I other thing I notice is that all user settings and options make a big difference...meaning every little adjustment to the amp is audible. I am mainly speaking of cut-off freq, the damping adjustments (clearly audible) and volume.

As i mentioned before, i can't get the EQ to do much of anything....but all other functions and options work 100%.

matt

KS · « **Reply #4 on:** 30 Jun 2008, 07:26 pm »

GR-Research has developed a 12" free-air servo driver for a special Rythmik servo amp. This is a 16 ohm driver, and can either be matched with a 16 ohm amp, or two in parallel with an 8 ohm amp, or three (or 4?) in parallel with a 4 ohm amp. Danny Richie of GR has designed servo drivers for special Rythmik amps in sealed or ported enclosures as well as the free-air driver--either the GR servo drivers matched with these special Rythmik servo amps, or regular Rythmik servo drivers with regular Rythmik amps.

http://gr-research.com/index.asp?PageAction=VIEWPROD&ProdID=141

On the GR-Research circle:
http://www.audiocircle.com/index.php?topic=56491.0
http://www.audiocircle.com/index.php?topic=47310.0

tyee · « **Reply #5 on:** 1 Jul 2008, 07:03 pm »

@gooberdude
I am very interested in this plate amp for my auggie's too. I have the basic auggie, not sure if you talking about the sterling silver auggie though??

So I can use this plate amp for stereo auggie's? I have two auggie's so was wondering if I had to purchase two of these amps. Looks like I don't have to?

tyee

gooberdude · « **Reply #6 on:** 1 Jul 2008, 08:15 pm »

I have 1 amp that runs both of the Auggie's.

Currently, the only Sterling Auggie's that exist are prototypes. In other words, only Bob from StL has them!!!

From what I read on the Hawthorne Forum, the Sterling Auggie's might not come to be. They would be more for Home Theatre anyways.

No issues though, the Auggie's are completely bad-ass.

My Auggie's are installed 1 per baffle (1 per side like the Duets) but they play in mono....the amp sums the signal into mono.

In order to let the Rhythmik amp see a true Parallel load, I have the speaker cables from one Auggie connected to the outputs
of the plate amp. Then, a single speaker cable runs from the 1 Auggie and feeds the signal to the 2nd Auggie.

In other words, both auggie's are not directly connected to the amp...just 1 of them. And the 2nd feeds off the 1st. Both Auggie's are connected to one another.

Guys, if this is the wrong way of wiring in parallel please let me know!!! I'm not talking the + to + OR - to - part of parallel (i got that part right), but rather how the speaker cables are wired up to the amp and to one another.

For over a year I had a parts express plate amp runing these Auggie's, but I had the speaker cables for BOTH auggie's connected to the plate amp's speaker level outputs. Not only would this wiring scheme NOT work with the Rhythmik amp (little or no sound came out), but I think i fried the power supply in the parts express amp by having it this way. Once I wired up the Rhythmik/Auggie's according to how Brian Ding explained, the bass poured out with exciting precision.

I have no clue what the consensus on running Auggie's in stereo (a plate amp for each channel) is at this point, but I've been led to believe that stereo isn't a benefit...most bass under 50Hz is recorded in mono (supposedly). I listen in mono and luv it...I know that much. I also like the simplicity of only having 1 plate amp.

matt

tyee · « **Reply #7 on:** 1 Jul 2008, 08:26 pm »

Thanks for the info gooberdude!

Have you ever tried the RCA line level inputs?

nicksgem10s · « **Reply #8 on:** 1 Jul 2008, 08:54 pm »

Hi Matt,

I will be joining you with owning this amp and using it on a pair of Hawthorne Audio Augies. I will also be running them with Sterling Silver Iris coax drivers.

I was already planning on this exact same setup when I started reading some of your threads on Hawthorne.

I can't wait to get my speakers built. I am ordering my drivers in the coming days.

I already have the PEQ370.

I am ready for high end OB done right

Darrel & Diana Hawthorne have been awesome in answering all my questions along the way. That forum is really cool with friendly knowledgeable folks helping out.

Thanks for all your help Matt.

-Nick

gooberdude · « **Reply #9 on:** 1 Jul 2008, 10:58 pm »

Tyee,

I have used sub amps with the line level (RCA) signal....and I've hated the sound each and every time. Through RCA signal I would always get the classic 1 note thud..with speaker level inputs, subs seem to become much more musical, faster, tighter...

No clue why this is, but many seem to agree that for music listening purposes, sub amps run better when fed the speaker level signal.

I've read that this way the sub amp can benefit from a bit of the sonic character of the main amp, which normally is a better quality amp. I use Blue Jeans Cables 10 gauge wiring for all Auggie wiring.

Hey Nick! Good to hear you pulled the trigger on the PEQ370 and the Sterlings. In a few weeks you are going to have a smile on your face that's going to last for many years. The Sterlings are just ridiculous! so much fun.

tyee · « **Reply #10 on:** 1 Jul 2008, 11:36 pm »

Gooberdude
What do you notice about the Sterling Silver Iris's that you like assuming you had the regular performance grade Iris's before?

gooberdude · « **Reply #11 on:** 2 Jul 2008, 05:18 pm »

I've owned the Performance Grade Silver Iris drivers for over a year...and like them a lot. About 4 months after purchasing them, I replaced all the x-over resistors and capacitors with the help of Jeff at SonicCraft with the hope of taming the stock tweeter's performance.

With the Sterlings, no tweaks are needed. Its as if Darrel Hawthorne took every SI owners 'wish list' and created the Sterlings.

That said, it is difficult to compare them. Each system is designed for a specific price point and performance level.

So far I haven't come across any music material that the Sterlings can't reproduce amazingly well. There doesn't seem to be any compromises with the Sterling design, and to my ears this equates to an ultra smooth and silky top end, perfect midrange, voice reproduction that is SO addictive, 3-D freaky imaging and deep, fast and righteous bass performance.

The Performance Grade SI's is a good speaker system. The world needed the SI's

IMHO the Sterlings are a great speaker system and represent an incredible bargain for us folks.

For the best info Tyee, frequent Hawthorne's forum. There is a good community of folks there who know a heck a lot more about OB and these systems than i do.

gooberdude · « **Reply #12 on:** 14 Jul 2008, 09:04 pm »

I just wanted to post a follow-up to this thread...

Darrel Hawthorne has been in contact with Rhythmik and is planning to begin selling a version
of this same Non-Servo plate amp that has a newly designed OB shelf just for the Auggie's (Hawthorne's OB subwoofers)

I have the normal PEQ370 and think the 'OB Shelf' is the cat's meow...my Auggie's sound insane now.

If Brian Ding is going to improve upon this, it should be something really special. aa

Over the weekend I used the PEQ370 amp to run in the Sterling mid-woofers. A hilarious exercise! The Sterlings truly pound like nice subs when asked. The PEQ370 is an excellent Hawthorne driver break-in tool, in addition to the perfect mate for a pair of Auggie's.

No affiliations

matt

tyee · « **Reply #13 on:** 14 Jul 2008, 11:37 pm »

Just received a 370 amp! Waiting to tryout!

gooberdude · « **Reply #14 on:** 15 Jul 2008, 03:54 pm »

Good move tyee!

Your Auggie's will be thanking you nightly for many years to come...

Be sure the OB shelf is turned ON and you might copy the settings that I listed in my original post if only initially to get used to what the PEQ370 has to offer. With so many adjustments its important to get music playing right away. My 1st night with it was a bit frustrating due to no instruction manual.

I think i stated that I had the Damping Freq set at 20 Hz before...now its set at 28Hz and sounds better.
And i have to admit I don't know what the heck this adjustment does!!

Brad · « **Reply #15 on:** 15 Jul 2008, 05:01 pm »

I think I'll wait a week or two on my order to see what Darrel and Brian cook up.

Good stuff! thx

gooberdude · « **Reply #16 on:** 15 Jul 2008, 05:36 pm »

The really nice thing about this development is that the 'OB shelf' is a little add-on to the main pcb.

I haven't looked into this, but my guess is that existing PEQ370 owners will be able to get this new little shelf and
install it at home. the existing one is tightened down by 4 screws, should be a simple swap requiring no soldering or anything (hopefully).

I just saw that Brian Ding occasionally posts here at AC...maybe he can share a few thoughts??

From reading the info that Darrel H has shared on his forum, it appears Mr. Ding has heard this amp power Auggie's and likes it.

tyee · « **Reply #17 on:** 15 Jul 2008, 07:29 pm »

I have to pickup another add on shelf board today. Brian sent the wrong one he said. I don't know if this newer one is more suited to the Augie's or not. I'll have to email him and ask.

willyspuddle · « **Reply #18 on:** 16 Jul 2008, 01:13 am »

I contacted Darrell and am going to help start his first buy on this amp. He wants to order 5 in and has 3 pre sold. Not sure if Brian can optimize the shelf any more for the Augie other than what gooberdude already has in place. Currently I have a 300W BASH amp that is a 175.00 class D product. It works well enough but seems to be missing something.

It is a leap of faith, but based on this feedback, and the Rythmic reputation I think it will put a big grin on my face.

Oh I am running Duets with PSI's.

Cheers!

gooberdude · « **Reply #19 on:** 16 Jul 2008, 04:33 am »

its exciting!

I can't wait for a few others to be able to compare the typical plate amps to this sucker, and this is a good way for Rhythmik to grab a firm hold in this new OB bass niche.

Just going by direct experience, the OB specific circuitry makes OB subs sound much more box-like...w/o any nasty attributes. Deep, thorough and musical, lightning fast, rich and all that.

A high power plate amp customized for use with Hawthrone Auggie's, capable of righteous output & being a studly wing man for the Sterlings, for less than $300.

"seems like something is missing" BINGO!!