Tube Power Amps Comparison: Demeter VTHF-300M vs. Aguilar DB728

Discussion in 'Amps and Cabs [BG]' started by jokerjkny, Jul 25, 2005.

  1. jokerjkny


    Jan 19, 2002
    NY / NJ / PA
    FIGHT!! :D

    yes yes y'all... joker here with another mondo comparison of GAS'ed lovin'. after 3 months of spending time at rehearsal after rehearsal, a handful of small gigs, and too many sunday morning worship gigs to count, i think i have a handle on these big boyz, and its time to share the info with all y'alls. bottom line, is this too much tube power for one man to have?

    hell no! :p

    the hookup
    - Sadowsky VJ-5
    - Avalon U5
    - Acme B-2
    - Epifani UL310
    - Alessandro cabling
    - Canare speaker wire

    turn and cough!

    at first blush, the Aguilar is definitely heavier. beefy transformers make this suckatash a very bad dog to carry. supposedly the same weight as my DB359, but dont believe the hype. nearly pulled something on a 2 am loadout! the handles? they do nothing. the Demeter on the hand was surprisingly easy to haul around. sure, it has transformers from hell, but on a late night load out, i was actually quite surprised.

    build wise, the aguilar looks and feels like it could withstanding a megaton blast. feels about as stocky as michael chiklis, not that i've ever touched the man... but, the Demeter on the other hand has a flimsy steel cage that doesnt do nothing to protect the power tubes. also, while the cage is perforated for maximum cooling, pretty much open season for an errant beer bottle to kill the whole unit ASAP.

    fan wise, i like the fact that the aguilar has a nice two speed fan for optional use. the Demeter is one speed. both are kinda loud for recording, but fine for live even the quiet intimate stuff. the Demeter supposedly has factory tech only option of being able to turn the fan off, but i highly doubt i'd take that risk.

    FYI, after buying my aguilar used from a regional sales rep, i had it scrubbed down by the good gents at Aguilar. even got a free T-Shirt, too. ;) the Demeter, i rebiased myself as per the manual. once when i first got it, and a second time two weeks later once the tubes settled in. 300-305mV each power tube. which is an interesting point. The Demeter was a breeze to bias, and tinker around with. besides the pentode/triode switch and the nifty "feedback" trim pot, the Dem just seems that much more versatile. the aguilar just seems rather boring and workman like.

    I/O wise, both amps share a single 1/4" unbalanced jack for the input. but the output was another story. my particular 728 had two 1/4" taps for two cabs to run with the 728. also, the Aguilar can hit as low as 2 ohms. nice for when i finally talk myself into that second UL310. ;) on the other hand, the Demeter only has technically "one" output. the Demeter uses banana clips in a three in a row fashion, where the middle black/positive tap is in the middle, and depending on 4 or 8 ohm operation, you would plug in the red/negative lead in either the left or right side of the center tap. but this just means, its a "one cab" power amp.

    brown note?

    getting right to it, the Aguilar is all about muscle. like WWF wrestler muscle. fat, burly, "kick you where it really hurts" muscle. ampeg on steriods? sure, but with a side of creatine, and BALCO's victor conte as your man servant. no doubt, if you like to rock, the Aguilar will salute, than kick the crap out of you. no matter the preamp, cab, whathaveyou, the aguilar seem to have this furry, burly feel to the mids.

    the Demeter has muscle too, but more like lean, trim Bruce Lee style. more refined, hifi, and in some ways a bit more articulate and faster feeling. more than just a bass tube power amp, its also billed as a "audiophile" power amp to use with other gear. and heck, had i had the money i'd get a second for some stereo l/r lovin'! overall, the Dem imparts a halo of glossy sweetness that covered whatever was used with it.

    also, the triode / pentode switch made the power amp turn from a nice Dr. Jekyll to a most riotious Mr. Hyde. Pentode gives you that smooth glassy midrange, and big pillowy low end. but hit it into the triode mode, and the midrange becomes all squishy and almost aggressive like the aguilar! tho, there's a slight loss in bottom end, and not nearly as loud in this mode, was VERY fun to use.

    also, the feedback trim pot added another dimensionality turning one way made for a looser feel, which really heightened the tube aspect. like bathing in a pool of corn syrup. great for some diggin' pickstyle action. while the other way made for a tighter stiffer, jabbing feel in the upper mids that almost made the sound woody and throaty. nice for my usuall fingerstyle stuff, and any jaco impersonations i may feel up to at the moment.

    also, interestingly, with the volume all the up on the Dem and Aggie, the Dem wasnt nearly as loud no matter what i did. didnt know 100 watts could make that much of a difference, but it was there.

    when i first started gigging, i found that the Aguilar seems to be "voiced" in a certain way down in the middle lows. that low end burly attitude that in some venues made for a very boomy sound. thus with my DB680, had to be dialed out. whereas with the Dem, i didnt really have to do much. but overall, it seemed like the all tube power sections werent as tight as i usually get with my SS power amps. more on that later.

    preamp wise, dem on dem, aguilar on aguilar sounded best to me, and they complemented one another nicely. my Kern preamp was just too muddy, tho it did sound pretty darn good with the Demeter. the gloss of the dem seem to ride atop the kern's midrange fatness, and actually lend a touch of hifiness to the tone. quite fun. had the EQ section been parametric, the Kern just might have ousted my HBP-1.

    a third contender crashes the ring?!: Kern / Stewart!

    now, all this might seem rather obtuse for those who have never experienced the all tube party, so i also did some comparisons with my Kern IP777 / Stewart World 1.2 setup.

    overally, the stewart made for a punchier sound. crazy 1200 watts nonwithstanding, there was even more refinement and hifi air that the stewart had. also, that rig seemed a bit more articulate. faster runs seem almost blurry on the all tube rigs compared to the stew. there was a nice dalloup of tubieness that the Kern lent the Stewart's proceedings, but its tube flavor wasnt as rich complex or as rich as what the power tube sections can do to a bassist's rig.

    and while, going from the all tube world to harsh reality of SS world was nothing short of taking a bite out of a moist caramel laden brownie then having a waverly cracker shoved into your mouth, the sound of an all tube power amp does seem rather messy and almost boomy compared to the tighter more regimented feel of an SS power section.


    there you have it. while, its pretty ridiculous to have two power amps, i think in this case, its not such a bad idea. the powerful, beefy feel of the aguilar is a nice ying to the yang of the hifi sweetness of the demeter. also, the aguilar seems to be made for the road and gigging bassist. and while the Demeter has much more going for it in terms of versatility, a few more minor basscentric touches would make it unstoppable.
  2. You do realize that different makes of tubes change the whole equation, right? I expect full reviews for both with NOS Genelex KT88's, vintage and new Tungsol 6550's, GE 6550A's, EH 6550's and KT88's, Svetlana 6550C's and KT88's, JAN Philips 6550A's, Ei KT90's, EH KT90's, and the new Ruby 6550's and KT88's. You can try swapping preamp tube types later... ;)
  3. Kurisu


    Nov 19, 2003
    Saskatoon SK
    Oh man, I just busted a gut!!

    Great review Joker, thanks for putting in the time!
  4. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    The Republic of Texas
    Why do your reviews always make me hungry?

    Great fun! Thanks!
  5. inazone


    Apr 20, 2003
    Great review and at the right time for me. Im going to pull the trigger on either the 728 to go with my 680 or just get a db750.
    Thanks again.
  6. smperry

    smperry Moderator Staff Member Gold Supporting Member

    Nov 3, 2003
    Bay Area, CA
    Endorsing Artist: Martin Keith Guitars
    Nice review!

  7. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    Great review, Joker! Unfortunately, the folks at Demeter still haven't gotten back with me as to why my 201s and 300M won't play nice together (all I get is a hum, no signal, and it's independant of the volume setting of either unit). The weird thing is, my 201s works great with my 728, and my 680 works great with my 300M! :confused: I tried a bunch of preamps with the 300M, and in addition to the 201s, the only other pre that exhibited similar behavior was my F-1X. I think I'm just going to retube the 300M (which I bought used from Dan Lakin) and see where that gets me.

    But thanks for giving me some justification for keeping both! :D Now, who can I get to help me lug that deep, 8U SUS-4 shock mount rack (which I do have!) back and forth to my gigs... :p

    Again, excellent review!
  8. jokerjkny


    Jan 19, 2002
    NY / NJ / PA
    lol, and you're gonna send me all these tubes, right? :p

    still, interesting point you do bring up. FYI, both power amps come with Svetlana 6550C's. so, all else being equal, any differences in tone go beyond tubes and are a factor of company voicing et al.


    that really sucks you're dealing with that problem. have you tried tinkering with the internal gain trim? maybe that has something to do with it. if your other preamps work fine with the Dem power amp, maybe its something with the VTBP preamp.


    in the works, i'm also umpalumpa'ing my butt off on a DB359 vs. DB680/728 comparison, AND, a sweet little comparison of the parametric Demeter HBP-1 and DB680. stay tuned!
  9. Joelc73

    Joelc73 Supporting Member

    Nov 13, 2000
    New York
    Great review - nicely done. I'm not sure that I agree with your point though about the Demeter having a "flimsy" steel cage. It's definitely not as thick as the Aguilar but I'd hardly consider it flimsy. If you can throw a beer bottle hard enough to get through that cage I'll send you a new one for free! I've toted mine around quite a bit and have had zero trouble.

    That's odd about the fan also. There should be a switch on the front that turns the fan on and off.... I'd be amazed if they removed that from the spec. Stranger things have happened though. Let me know though.

  10. jokerjkny


    Jan 19, 2002
    NY / NJ / PA

    time for some "joker must get off the crack, and not reviews while on it" corrections. :p

    FYI, yes, there is a fan switch in front, but oddily, its not marked! fiddled around with it. and whaddya know, it does control fan speed. stranger things indeed. guess i'll have to pull out the ol' labeler. ;)

    as for the cage being flimsey, compared to the aguilar, its just not nearly as sturdy as i'd like it to be. but then again, all this is moot, since mr. skb 4 spacer is guarding the velvet ropes.

    now, back to your regularly scheduled thread. :)
  11. metron

    metron Fluffy does not agree

    Sep 12, 2003
    Lakewood Colorado
    thanks a ton joker. :crying: :D im in the throes of gas right now with no clear direction. this has complicated it for me for sure. i really want a 728 to go with my 680. quick question about that rig... i love my old ampeg v-4b. in the clean range its thick and fat but turned up a little more it growls before it reaches complete distortion. can a similar thing be achieved with the 680/728 rig?
  12. jokerjkny


    Jan 19, 2002
    NY / NJ / PA

    good question. short answer, i'd say, "yea, why the heck not?" the EQ and gain structure of the 680 is sooo flexible, that i'm sure you can get that sound. pump up the upper midrange, and pull out lots of the airy hifi air, and VOILA, aggro-ampeg-o-land!

    still, an old ampeg from the sulfur laden depths of middle new jersey is hard to cop, and quite addictive to say the least.

    but if you want something closer to the ampeg sound, the DB728 is more the way to go, IME.
  13. Joelc73

    Joelc73 Supporting Member

    Nov 13, 2000
    New York
    Agreed - The 728 is definitely more SVT-esque than the 300M. The Demeter is really more of a hi-fi amp that just happens to be tube based. It can get soggy like an SVT but it's forte is big, thick bass.
  14. cabcreaser

    cabcreaser Supporting Member

    Feb 12, 2005
    Great Comparison.

    I believe the speaker output on the Demeter is black (middle position/common) = negative; red or blue (8 ohms or 4 ohms) = positive. Perhaps I misunderstood your description . . but just in case.

    thanks for the review
  15. metron

    metron Fluffy does not agree

    Sep 12, 2003
    Lakewood Colorado
    sulfur laden depths of mid nj... :p LOL thanks for the comments guys!
  16. Jokerjkny has once again proven his ability to write excellent and objective reviews that manage to capture all of the salient points. Nicely done... and thanks for the GAS. :)
  17. jokerjkny


    Jan 19, 2002
    NY / NJ / PA
    its obvious i'll never write a proper manual. :p but yea, your description is spot on.