David have you considered trying a Rogue power amp with your set up. |
1439bhr, yure correct, only an order-of-magnitude estimate is possible. as i was told by the designer, but he suggested this was a good place to start. however, the cary, rated at 850 ohms output impedence, was at least an order of magnitude better (lower output impedemnce) in my testing, than the rogue. leafs, while yure correct that i started complaining *immediately*, after using my rogue, i had over 600 hours on it prior to selling, including over 200 hours on nos tubes i bought, to try & *fix* it. the nos tubes helped, but weren't enuff... regards, doug |
Gee David99, Don't you get it? duh!! :o) |
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The proposed method (place a resistor across the preamp output, listen for volume change) for measuring the preamp output impedance is a blunt instrument, at best, absent proper instrumentation. Here's why: Suppose that a preamp is able to produce an open cicuit voltage Vs. If its internal impedance Rs is much less than the load impedance Rload, then Vload = Vs. When a resistor Rtest << Rload is placed in parallel with the preamp output (and therefore, in parallel with Rload), then Rtest dominates the load seen by the preamp. Thus the voltage delivered to the load is Vload = Vs*Rtest/(Rtest + Rs). This means if Rtest = Rs, the voltage drops to 0.5 Vs, which is a 6 dB drop in power to the load (power delivered to Rload is P = (Vload**2)/Rload). Let Vratio = Vload/Vs, and we can rearrange the equation to get Rs = Rtest(1-Vratio)/Vratio. For a 3 dB drop in power, Vratio = 0.707, meaning Rs = 0.41 Rtest. For a 1 dB drop in power, Rs = 0.12*Rtest. So, depending on how sensitive you are in detecting a volume change, there can be very wide variability in your estimate of source impedance (in this example, a 1-6 dB volume range corresponds to an 8:1 range of estimated source impedances). Bottom line: to measure source impedance, careful instrumentation is needed. The proposed test, without measurements, can only given an order-of-magnitude estimate at best. |
Take Sedond view with a grain of salt.He did not even have 5 hours of breakin on his unit before he was complaining about it.i think he might have had 50 hours on it before he sold it.He did not give it a chance to break it in. |
my HT pro-silway mk2 are 1.5 meter |
dave, what's the length of yer interconnects? i tink this may have been a problem i faced w/my set-up. and, i *know* when i have good bass - w/a pair of vmps larger subs x'd over at 60hz, each driven by 900 watts, i get bass... ;~) and, interestingly enuff, the problem i had w/the rogue wasn't yust electronic/synth bass, but acoustic-upright bass was yust not there, & it was *this* that i missed the most. oh well... i guess it yust goes to show how important system-matching is... regards, doug |
Dud,you are none of the above,just telling it the way you see it.Im just a bit confuseds the 99 drives my Pass 3 with ease and the bass is KILLER!! I know people say the Pass 3's bass sucks but I know better.Sorry you cant make the trip.You can still buy me lunch sometime! |
hi david, interesting proposal. to be honest, i tink it'd be more reasonable to have the output impedence of the rogue tested by an independent lab - prolly a lot less driving inwolved, too! ;~) as for me, w/a wife, young children, the alfa club, & the pantera club pulling for my free time, i'm not sure i could swing something like this, yust to prove a point. the only reason the impedence-issue came up is because, when discussing the sonics of my rogue w/one of the most well-respected tube designers in the industry, he said it sounded like an impedence problem, & he said there was *no way* a mu-follower tube design could have such a low output impedence, unless it was a hybrid design. (rogue, in fact, doesn't publish the output impedence of the preamp, this designer obtained it from rogue by calling & asking if his amps would have any impedence-matching problems w/the rogue.) it was he who suggested i try placing resistors across the outputs of the preamp to check for actual volume-level change. doing so corroberated his beliefs, & testing of other preamps in this same manner, further corroborated them. lower output-impedence preamps, in fact, required lower-walue resistors to get an audible wolume-drop. as mentioned in my previous post, a 2.2k-ohm resistor casued a noticeable wolume drop when placed across the rogue 99's outputs. this same walue resistor caused *no* change in wolume when placed across a cary slp98 preamp - it took a 1k-ohm resistor to hear any volume decrease. the melos, with *very* low output impedence, had no volume drop w/even a 500-ohm resistor across the outputs. this test is wery easy to try at home - all ya need is a small "y" interconnect hooked up between your amp & preamp - then take a resistor & hold one end on the center-connector, the other end on the outside-connector of the free rca plug. the lower the output impedence of your preamp, the smaller-value resistor it will take to perceive a wolume-level drop. you mite wanna try this on yer preamp at home before taking it *anywhere* to be tested! ;~) i don't need conwincing that the rogue 99's output impedence, whatever it is, is much higher than the cary slp98, the version of which i tested, was rated at 850 ohms - i audibly tested both, as described above. (i mistakenly said 600 ohms previously - i believe that this is correct for cary's most recent production, the unit i tested was older.) i suggest ewe do the same, prior to driving a day, to have this checked. and, as i said before, i'm sure there's a qualified tech (much closer then at rogue audio), that could test this for you w/proper equipment, if ya don't wanna try the audibility test. regards, doug ps - i noticed i have gotten an inordinately high number of negative feedback on my posts here. i guess it's due to my hostile, inflammatory, uncivil manner, & not due to the fact that some of ewe may not like my opinions... ;~) |
Duddy,I have an invitation to extend to you.Meet me in Pa.we will go to the Rogue joint and Mark can run his "tests" on a 99.If his tests show his specs are correct you can buy me lunch.If you are correct you can still buy me lunch.Mark has offered to prove to me his specs are dead on.I have faith in his E.E.ability.I live 6 1/2 hours from Rogue's plant.Your drive is probably closer.At the least we could have a chat and a meal.You can order crow! Let me know :) |
hi dave, yure rite about the price of the s/f line 3 - sorry, dunno what i was thinkin' - mebbe i was tinking about the retail price of the rogue, w/fono... $2750, shipping included, was the lowest price quote i got on this prior to buying the melos (it was also a preamp i was considering). as far as cost goes, music-directors' last retailed for $4600 new (line-stage only - $7400 for l/s & fonostage). but, i paid only $2k for my line-stage. i'd love to try a bat vk 50se, but as i can't afford one even used, it's kinda a moot point for me. if yure tryin' to say that the melos *should* out-perform the rogue cuz its retail price is more than double the rogue's, well yure right - it should, & it does, imho! :>) but the cary slp98, which is comparable in price to the rogue, also outperforms the rogue, imho, & is more flexible, at least for me. as far as mark & the rogue, i'm not sayin' anyone's lyin'. all i know is that 100 ohms output impedence means that placing a 100 ohm resistor across the outputs should correspond to a 3db drop in volume - which is the change in level that's generally considered to be the smallest change audibly distinguishable by a casual listener - anything smaller becomes gradually more difficult to perceive. well, i placed a 2.2k-ohm resistor across the outputs of the rogue, & the drop in level, while not measured w/a db-meter, was *easily* noticeable - it was *at least* 3db, indicating a much higher output impedence. as i said before, it could also be the 17'-long interconnects that were contributing to the problem in my system. i'm glad you enjoy the rogue, i know there are others out there who think it's great, too, & i'm sure y'all's hearin' is yust fine. not to be disrepctful, but i yust tink there's others out there that are better, for the same money, especially if yure willing to purchase used. regards, doug |
Duddy,I still dont know why you had an impedence prob. with a 99,it drives my Pass just fine.Also,I think you may be mistaken about the cost of a line-3.The cheapest used I have seen is $2500.New dudes go for $5000. As far as your music-direct besting the 99? Whats the new cost of a music-direct? Would the price ratio be similar say to your direct verses a BAT VK 50SE.Which do you think would be better? As far as Mark not being upfront about the impedence.Why would he lie about it? Ihave spoken to him and he has assured me his specs.are correct.He designed it,he should know.My 99 sounds killer! Very quiet unit,and superb bass.Im sorry you didnt have a better match.You really are missing out on a great pre-amp!! |
i had a hot-rod version of the rogue 99, & yes, it's coloured. besides, nice as mark o'brien is, he ain't up-front about the output impedence of his preamp. he states its 100 ohms - real-world experience told me 2400 ohms is more likely. i, too, had extremely poor bass response, most likely due to a long cable-run between the 25k-ohm input-impedence of my active x-over, and the high output-impedence of the rogue. i, too, had noise problems w/this unit - ewe could hear any rheostat-light in the house being adjusted thru my speakers! took a while to figure out what *that* was! ;~) while the rogue had better soundstage depth than the linn kairn it replaced, the kairn bested it in all other areas. not satisfied w/the rogue, but still wanting that *toob* sound (those colourations *were* kinda nice!), i then tried the cary slp98. ($1300, used). better than the rogue in all areas, especially in accuracy & frequency extension. (and this was their stock wersion - they, also, offer a *hot-rod* wersion.) no impedence problems w/this unit, which is rated at 600 ohms output impedence, which my field-testing confirmed. i'd have stopped my preamp search here, but yust after i got the cary, i came across a melos music-director at a reasonable price, & i yust had to try it - i *loved* a melos sha-gold i'd heard several years ago, but couldn't afford it then. well, the melos is in another league all-together, imho. at ~$2k used, i don't see how it could be beat. (regarding s/f pricing, btw, i dunno about the s/f line-2, but the line-3 can be had brand-gnu for <$2.4k, delivered...) oh, one more thing - both the cary & the melos have a tape monitor, which the rogue doesn't have. i like this for my dbx-3bx, which i can now keep out of the signal, except when in use. not possible w/the rogue, so i dint have it hooked-up. also, the cary & the melos have balance controls, which the rogue doesn't have... and, regarding the rogue 66, if ya get the built-in fono, don't ya have to lose the balance control? |
also is the Rogue "colored" or is it that the SF signature has the well reported "uninvolving emotional"
traits as the "regular" line 2? |
how much is the SF line 2 signature? The Rogue is just under $2000 |
I just replaced my Rogue 99 with a SF Line 2 Signature (just released). Wow! I didn't realize just how colored sounding the Rogue actually was. The SF has far superior sound staging, better extension and articulation on both extremes. It also mates much better with my amp due to the fact that it has far lower output impedance than the Rogue. Oh, it's also much quieter. |
I have a 99 which has been by far, the biggest sonic improvemnt my stereo has seen ever.The 99 uses an all tube mu-follower circuit.It is a bigger and heavier pre than the 66.Both use nobel volumn pots.The 66 has a balance control,the 99 doesnt.The 99 has a headphone jack located on the back right of the unit.The 66 doesnt have a headphone jack.The 99 has a slow turn on to lengthen tube life.The 66 doesnt.Both come with a heavy,machined,aluminum remote but its an option with the 66.Both are avaliable with a phono board which I have.They both are avaliable with NOS tubes but I recommend getting the stock tubes then rolling with NOS.Kevin Deal of Upscale Audio is up on Rogue and knows what sounds the best in them.I have found BDR cones #4 to be mandatory with my 99.I havent heard the 66.Audio Musings has a review of the 66 where it was put against the A.I.mod.3A Overall the reviewer liked the 66 better.In other threads here the 99 is discussed.One owner of the S.F. line 2 has decided to get rid of the line 2 in favor of the 99.In my opinion either the 66 or the 99 will give complete satisfaction as an addition to an already excellent system.The only written review of the 99 I am aware of was in Listener mag. a while ago.I didnt read the review.I heard it was very good though.Mark O'Brien designer and prez of Rogue is very attentive to customers needs. |
VAC has a new Preamp that retails for $2100.00. It has remote and a killer. It's called the Auricle. |
I can tell you here and now the 66 will never be a 99 even after I `ve done the Hot rod on it, the 99 is another animal altogether. I love my 66 and wouldn`t trade for the world, you would have to buy a 99 to beat it.I can`t think of a better buy than the 66 for the money. the 99 is better still. But if you can`t get a 99, a 66 with the mods is more than half way there, the 66 images like a demon and has really good base. I`ve had mine a year now and decided to do the mods on it ,so I called Mark and sent it to him, boy this thing Kicks ASS. I just love the way it sounds now. there are other people who have them, David 99 has one and swears buy it. the 66 is a very good unit and when you mate it with the model 88 amp you get MUSIC. greg |
