New system/room, upgrade amp or preamp first?


Hi all! This is my first post here but I've been an active A'gon'er for many years.

I recently built myself a listening room in the basement. Nothing too exotic in terms of the actual room construction, but I do have 4 OC703 acoustic panels on the wall for front wall reflections and for first reflections. I had a friend build cabinets and I did the crossovers and assembly of Troels Graven's ScanSpeak 3-way Discovery monitors. Just got them done yesterday, they sound very good but need a while to break-in.

I am currently using Jriver set to DoP, out via USB to a Schiit Loki DAC, then on to a Marantz SR-685 5.1 receiver acting as a preamp, and finally on to a B&K AV5000 5.1 separate amp (5 x 105), obviously only using two of those channels. I have the sub out of the Marantz y'd and connecting to two BIC F12's, used only to fill in the lowend. They aren't the most musical subs obviously but they do a fine job to my ears for 45-50Hz and below. They provide a satisfying weight to the sound without dominating the room.

So, I'm pretty OK with the DAC and source. I'm basically using two repurposed home theater components so those are next on my list to upgrade. The room is small, 13 x 10 (speakers are 82" apart, my chair is 82" back from the center point, about 3' from the back wall). I have kicked around an integrated amp but I do prefer separates if I'm being honest. If I have a $1500 budget for ONE component, what should I be looking at first - addressing the AVR-turned-preamp, or the B&K amplifier? The item not chosen for upgrade at this point will be addressed in another 2-3 months.

It's tough to judge a system with such new speakers but so far, the sound is well-dimensioned for both width and depth, though depth is a bit shallow. Voicing is wonderful, thanks in part to the 4" ScanSpeak midrange (wired out of phase with the woofer and tweet).

My listening tastes are varied but primarily I prefer Rock, Metal, and am starting to get more into blues and jazz. I do some orchestral stuff here and there as well as instrumental concerts (violins and piano). Any and all opinions are welcome, I can clarify whatever is necessary. Thanks!
toddrhodes
i've always felt that a very good pre-amp is the soul of a system and mandatory to get right. There are others who feel differently. I'd say get a good tube pre-amp first although if you only have one source another good option would be a good passive like the Lightspeed which is only $500 new and then you can get a new amp sooner.
Todd-

the pre-amp is the heart-and-soul of any system. Start here and then proceed forward w/ other components/gear. Keep me posted and Happy Listening!
I would purchase the preamp 1st. I believe that would make the greatest upgrade given what you are using now is a HT processor. I own a Jolida Fusion tube pre and am happy with it driving a SS BEL 1001 MK5 amp. How demanding are your speakers for power?
Thanks everyone! We are on the same page, in fact I was eyeing an Arcam FMJ-C31 in the classifieds just a few minutes ago. It has everything I need and would at least get me into a more proper piece of kit for my purposes. I do not intend to start at the top, certainly, and $650 would definitely fit within my budget. With that said, I'll take a look for some other options and keep everyone posted. Mesch - the specs I have from the DIY site I built these from lists them as about 87dB sensitivity 1w/1m so... fairly hungry I'd say. I make up for that somewhat in that I have a pretty small space to work with at the moment.
There is a Bel Canto Pre1 for sale locally that I am very intrigued by; unfortunately I do need a remote based on where the preamp will sit, and this seems to be a very good Pre that allows for both sub hookup and remote control. Is $1k a reasonable price for a Pre1?
your pre-amp first ..... full stop

the receiver, particularly as a preamp, is your weak link
In that small room, the amp is probably fine for now.

If you must change one or the other sounds like the pre-amp is the one to change first.

Its hard to find any Bel Canto pre-amp in good working condition for much less than $1000 so the price seems fair off the cuff, assuming all else is in order.

Its worth checking Audiogon Blue Book on most items when you need to know what prices are reasonable based on prior similar sales. You might be able to justify offering less depending but $1000 does not seem out of the ballpark to start.

FWIW I am a BC fan. It's one of the lines I track regularly. I have Bel Canto amps but not pre-amp, though I might someday.
I appreciate the feedback! I had considered going to the BlueBook to check it out, I just may do that. Thanks again!
I've initiated contact with the seller. I just can't find a bad word about this thing unless it's being compared to units several times its price. It checks all the boxes, BlueBook reveals it is priced well... I believe it shall have a new home soon.

Todd
I agree with the many suggestions of preamp first, not on philosophical grounds related to the importance of preamps generally, but because the AVR appears to be the weak link in this case.

I took a look at the possibility of impedance incompatibilities arising with the various replacements that have been suggested, given the 33K input impedance of your power amp and the 75 ohm output impedance of the DAC, and I don't see any likely issues, even with the passive Lightspeed.
04-24-15: Toddrhodes
There is a Bel Canto Pre1 for sale locally that I am very intrigued by; unfortunately I do need a remote based on where the preamp will sit, and this seems to be a very good Pre that allows for both sub hookup and remote control.
I took a look at some rear panel photos of the Pre1, and I don't see that it provides a suitable means of connecting to your sub. Even if that's the case, though, your subs provide speaker level inputs which you could use, connecting them to the amp outputs. That shouldn't be a problem given that it does not appear that the B&K amp's outputs are bridged or balanced. But when you eventually upgrade the amp, you'll want to keep in mind that with that connection arrangement you should avoid choosing a new amp having outputs which they are bridged or balanced. The negative output terminals of bridged or balanced amps have signals on them, rather than being grounded, and connection to those outputs of the high level inputs of a powered sub could short those signals to ground, depending on the design of the particular sub.

Keep in mind, also, that you don't need heavy gauge speaker wire to connect the power amp outputs to the subs, since essentially negligible current will be drawn by the input impedance of the amps in the subs. Anything in the range of 18 to 24 gauge, or even higher, should do fine, assuming that the main speakers are connected to the amp separately, via heavier gauge cables.

Finally, you might consider adding another acoustic panel, in this case to the wall behind the listening position. The three foot distance to that wall will result, to some degree, in a suckout of frequencies in the vicinity of 282/3 = 94 Hz. Perhaps reflections from that wall are also contributing to the slight lack of depth which you mentioned.

Good luck. Regards,
-- Al
Al - thank you so much for that response, it truly is helpful. The plan all along has been to treat the rear wall, I just haven't gotten to it yet but the concern is heard and will be handled post-haste. I have plenty of material left to make another 4" trap - my other thought was to put up a GIK Monster trap (7" thick IIRC) with a diffuser panel on the front of it to treat that space. A friend of mine also turned me onto a bass trap idea using upholstered 12" pipe insulation from OC to sit in the rear corner of the room. I just need to find a source for the insulation.

Regarding the Pre1, I noticed as well it does not have a pre-out, however I found a few references to people using the tape-out to drive the sub inputs. I unfortunately don't know what this terminology means but it is a buffered output that basically is identical to whatever source input is selected on the front panel. The manual suggests I can use both the XLR outs and RCA outs simultaneously as well, so a simple XLR-RCA adapter could fill that need as well.

Again - thank you for your effort and time in digging up that information, I really do appreciate it!

Todd
You're welcome, Todd.

Tape outs are not usually suitable for connection to subs, because they are almost always "ahead" of the volume control in the preamp's signal path. So the volume of the signal sent to the sub would not vary as you vary the setting of the volume control. The alternative of using the sub's volume control and continually having to coordinate its setting with the setting of the preamp's volume control is probably impractical as a long-term solution.

I did notice that the Pre1 provides a pair of jacks labelled "loop," but I'm not sure what they do. And I note that the RCA input of the sub is adjacent to a switch selecting which of two receiver types is providing the signal to that input, a Pro-Logic receiver of a Digital SomethingOrOther (I can't tell what it says) Receiver. I'm wondering if that MIGHT be suggestive of the need to provide the sub's RCA input with an LFE (low frequency effects) type signal, rather than a full-range signal. And, finally, most XLR-to-RCA adapters short the inverted signal on XLR pin 3 to ground (XLR pin 1), and the XLR outputs of some equipment cannot tolerate that without the possibility of misbehavior or even damage. I suspect that modestly priced solid state equipment such as the Pre1 may be particularly likely to have that difficulty. I'll mention, though, that relatively expensive Cardas adapters can be ordered with pin 3 left open, as it should be for actively driven XLR outputs. Or a cable supplier could customize an adapter cable which does the same. (Pin 3 SHOULD be shorted to pin 1, btw, when adapting RCA outputs to XLR inputs).

So while it's possible that line-level connections from the Pre1 to the subs could be successfully implemented, there are a considerable number of uncertainties involved, at least as far as I've been able to determine. But as I indicated earlier I see no problem with speaker-level connections, as long as when you upgrade the amp you avoid those having bridged or balanced outputs.

Regards,
-- Al
Al, hopefully this pastes well, but the text of the Pre1 manual reads:

XLR Output Jacks for Left and
Right Channels
These outputs go to your power amplifier or
active crossover if it has XLR inputs. They
use the standard Male XLR pinout pattern of:
1 - Gnd
2 - Plus Signal
3 - Minus Signal

• RCA Output Jacks for Left and
Right Channels
These RCA outputs can be used instead of,
or in addition to, the main XLR outputs to your
power amplifier, active crossover, or
sub-woofer

Since neither my amp nor my sub accept balanced ins, it looks like your observation of using the adapters is probably still in play so I would likely just go with the speaker-level option for the subs. The subs operate in a very narrow window and are just there to troll the depths, so to say. I don't expect much if anything out of them above even 50 Hz, roughly.

The loop feature is listed as being useful for sources which have their own internal volume control, the preamp is bypassed entirely. Specifically useful as a HT-Bypass mode of operation.

Thanks Al!
I will throw this out there, just to get feedback - am I loony for thinking a simple single-ended Y out of the preamp would be doable until I (ideally) find a balanced amp so as to use enable both sets of outputs concurrently? Not dismissing the high-level input option, just curious.
Seller and I have agreed on $950 plus shipping. Can't wait for it to show up!
04-24-15: Toddrhodes
I will throw this out there, just to get feedback - am I loony for thinking a simple single-ended Y out of the preamp would be doable until I (ideally) find a balanced amp so as to use enable both sets of outputs concurrently? Not dismissing the high-level input option, just curious.
Not a loony question at all. In fact, given the 50 ohm output impedance that is specified for the Pre1, I suspect that would work well, if perhaps not completely optimally. (I'm assuming that the sub can accept an input covering the full frequency range for at least one of the two positions of the switch I referred to earlier).

One thing that has to be considered with respect to that approach is the possibility that the combined input impedances of the sub and the power amp may be too low for the preamp to drive with good results. Particularly because the line-level (RCA) inputs of most powered subs tend to be low. There doesn't appear to be a spec on that for your BIC F-12 (the 8 ohm "input impedance" value that is indicated would be for its driver, not for its amp), but I wouldn't be surprised if it were in the 5K to 10K area. The combined parallel impedance of 5K and the 33K input impedance of your amp would be (5 x 33)/(5 + 33) = 4.3K. That would be too low for many preamps to drive with good sonic results, including some solid state preamps, most tube preamps, and probably all resistive-based passive preamps. But it shouldn't be much or any problem for the Pre1, given its 50 ohm output impedance.

A second issue that should be considered is the ability of the preamp to drive the combined capacitances of the cables to the main amp and to the sub, without perceptible rolloff of the upper treble resulting (the capacitance of the cable to the sub, as well as the capacitance of the cable to the main power amp, can potentially affect the high frequency content of the signal to the main power amp). The likelihood of that being a problem increases in proportion to the output impedance of the preamp, to the lengths of both of the cables, and to the capacitance per unit length of the particular cables. For most reasonable cable lengths and cable capacitances an output impedance of 50 ohms is low enough to make any such issue unlikely.

Finally, ground loop hum is a conceivable issue, but I suspect that the chances of that occurring with this configuration would not be particularly greater than in most other situations involving unbalanced interconnections to a sub.

Good luck. Regards,
-- Al
I've learned more about audio in general, and system considerations to a more specific degree today than any single day I can remember :) You are a very kind person to spread the knowledge you have to anyone willing to take it in. Thank you Al.
Todd, 87dB is middle latitude sensitivity. Hope the BC pre proves to be all you hoped for. Al is a great asset here, I have learned much from him. I have considered the use of Y splitters also and knew of reactance issues however with now a better understanding. Thanks to you for your thread and again to Al.
Todd and Mesch, thanks very much for the nice words.

Regarding my earlier comments about connecting subs at speaker-level to amps having balanced or bridged outputs, I should add that it is often (although not always) possible to accomplish that. As I indicated, the negative input terminal of the sub should not be connected to the negative output terminal of that kind of amp. But connecting the negative input terminal of the sub to a chassis screw on the amp will often work well, depending on the amp's internal grounding configuration.

Also, there are some cases where the amp provides a circuit ground terminal, and connecting to that would work. Or if the amp provides both XLR and RCA input connectors the sub's negative input terminal could be connected to the ground connection of a connector that would mate with whichever of those inputs is not being used.

But my point is that there may be some cases involving amps having balanced or bridged outputs in which there is no practical solution for connecting a sub at speaker-level.

Best regards,
-- Al
I would go with the preamp first as I feel thats the foundation of a system. I would spend the most I could as I would like to keep if for a while. I don't think you can do it new but used, with some help, you can have some fun. I'd be willing to help with a really good price I would give you on an older Innersound preamp. Check it out on line )now sanders sound). It was $4 grand new and is solid state, black as night and makes the grand canyon seem narrow. dynamics are awesome. It gets out of the way so you can hear everything else. If you're intersted, I will make you an offfer you can't refuse.
Sorry! Just saw you got one! Best of luck! GREAT unit!
Thanks Cerrot, no worries at all! If somehow anything falls through on the BC, I may look you up, so I appreciate the heads up regardless.

I'm about 1/2" short of having enough wood to build the last hanging acoustical treatment for the rear wall. This one will be 6" thick, OC703 in a wood frame, upholstered with the same type of stuff I used on the other "wall hangings" in my room. Had a buddy over last night who is almost as much into 2-channel as I am and he was very happy with how the room is coming together. I did also figure out I can A/B the Marantz I currently have with the Bel Canto using its Loop function. Should make for an interesting experiment, to be sure.
Test, Test, Test
I found success with both components from the same manufacturer. You get the company's preferred sonics and no surprises. Get them at the same time.
Installed the Pre1 tonight, running y-adapters from the line out section to both the B&K and both subs. So far, so good. So, so good :) The soundstage feels like it's a foot deeper and maybe I'm just imagining things but I swear I'm hearing more detail now than before. Little things like a guy hitting his guitar with his hand (or something that sounded like that) and increased instrument separation, even in complex/loud passages. I always like to crank the opening of Money for Nothing (SACD) as a simple test. If I can play it loud, as in 90-95 dB (guessing here) and still here all of the individual sounds during the opening sequence, I feel good. No regrets there at all.

I think I'm good now for awhile. I'll save up my coins for a SET amp, most likely. That's the nice thing about having such a small room, it won't take much :)

Thanks again for all the feedback!
Todd
Update!

So it's been nearly a month now since I got everything up and running. Where to start... first of all, these DIY speakers are something special. They are hyper-resolving, tonally they are very accurate. Drums sound like drums, pianos sound crisp but not sharp or glaring, bass guitars sound incredible. Playing a 35 Hz test tone, these things have prodigious output down that far. Turn on a 20Khz test tone? I can hear it plain as day. They paint a deep, wide, and rock solid stereo image, dare I say 3D-like. They are faithful to the source, now that I've upgraded my DAC and Preamp. Still rocking a bargain-bin, used B&K amp too! And yes, I did end up finding a used power cable, plugged directly into the PS Audio outlet. The rest of the gear runs through a Tripp-Lite ISOBar.

The room. I've done a lot since my last post. Put in rear absorption just behind my listening position, put up a curtain over the wall to the right of my listening position to tame some reflections that liked to collect back in that corner, and threw down an area rug. All of which have made steady improvement, resulting in the imaging and spacing I alluded to in my first paragraph. The room seemed quiet enough with everything turned off. I used an app on my phone to see just how quiet - 18 dB is the final number. As soon as I turn on the TV and PC, that number goes up to 26 dB. Obviously the TV is simple - turn it off and pick my music from my phone, duh. The PC, I thought, was going to be a challenge. Turns out, going back to integrated video (bye bye PC gaming, hello future new console?!), turning off both case fans (don't worry, temps are fine), and spinning the HSF down a little resulted in a huge decrease in noise. It doesn't sound like much, but I'm now at 18 dB noise floor with the computer on, so that's good. Next up is a fanless PSU.

I can't overstate this - the quieter the space, the better everything sounds. Little details in music you've never heard suddenly come to life. This is across every recording I've tried. I just had on Wish You Were Here and thought... "Is that someone breathing?" during the intro. Turns out, yes it is. I'm not talking about the cough or the sniff, it's someone breathing. Maybe others have heard it, but I hadn't, even on this exact same system three days ago. It's there now, though. Little guitar notes during solos, performers hitting their hands on the guitar unintentionally, it all comes through.

So, to sum up, I'm enthralled, and enjoying the shit out of this room and system. My new routine is to kiss the wife and daughter goodnight around 10, then go downstairs and enjoy a little bourbon, some tunes, and a very dark room. It's enriching, I assure you. Money and time very well spent, and I've learned an unbelievable amount about sound and playback systems in the last month.

Oh, and from someone who had not given Radiohead - OK Computer a fair shake in my previous attempts to listen to it, it is now one of my favorite albums to turn on. Also, Black Sabbath - War Pigs, in the right system, is a lesson for how to record drums.

Edit - thought it would be fun to list some of my favorite stuff to listen to in here:

Dire Straits - Brothers in Arms (the song, but the whole album is good too)
Pink Floyd - Time, Comfortably Numb, anything from Wish You Were Here
Rush - YYZ, Vital Signs
Jethro Tull - Aqualung
Hank Mobley - Soul Station
Rodrigo y Gabriela - *
Yo-Yo Ma plays Enio Morricone
Radiohead - Paranoid Android, Let Down, Lucky, Karma Police
Black Sabbath - War Pigs, Paranoid, Planet Caravan, Iron Man, Rat Salad
Titanic Score - Death of Titanic
Hans Zimmer - Gladiator - the long one, it's 10:30 seconds, don't remember the name
John Williams - Duel of the Fates
Pearl Jam - Ten.*
Parkway Drive - Atlas.*

There are more, but those are my gotos.

Edit 2 - shit I knew I'd forget a bunch. My favorite part of the room? Listening at low to mid volume. On a scale to 100 with 85 being *loud*, I do most of my listening between 48 and 60. Doesn't wake up the ladies of the house but the sound is full and rich. This is a direct result of a much better preamp than what I was using initially. Also, I took the metal/glass stand out of the front of the room and all of the equipment sits on the floor. Well not really, I can go into detail if anyone wants to hear about that whole setup.