[OzarkTom]

So the iTube is working out well then? no negative impact on detail retrieval?

The Itube works great, but it is not stock. A big difference was Cryo, special AC power cable by Reality Cables, and special 9V Astron Power Supply. This sounds twice as good as a stock Itube and will compete with tube pre's in the $2-3K price range. The extras adds $200 to the Itube.

[roscoeiii]

Good to know. My main concern with the Crown is overly bright highs and not enough meat on the bones for the sound. A tube solution like the iTube would make sense. But not sure what compromises that might involve.


Also Tom, have you compared attenuating the gain from the Crown vs. using the iTube attenuator to reduce gain? Curious which is more transparent.

[OzarkTom]

Also Tom, have you compared attenuating the gain from the Crown vs. using the iTube attenuator to reduce gain? Curious which is more transparent.

I have started to play around with that, but I still want to get more time on the Crown before any serious comparisons.

[jk@home]

I was just thinking all it needs is a tube buffer input, which would allow it to mate with a passive pre easily too. D amps seem to benefit from tubes feeding them. As is the 10k input impedance single ended is a little low too. A couple of 6SN7s would be great, I'm using the 5692 version in my preamp and they give a good full-bodied sound. The connectors could be upgraded but it would be better to find suitable PCB-mount replacements of high quality in the exact same form factor as the stock connectors. There are some options out there... The binding posts could be replaced pretty easy with std posts of higher quality.

That's what I was using with my 1500. Dodds tube buffer (with a 6H30P-DR tube) behind a Goldpoint 25k attenuator. I think the output impedance is around 100 ohms. I though about inserting one of my Jensen tranny converters in there, to use the balanced inputs of the Crown, which has double the input impedance. To see if it would make any difference.

I also could of done some tube swapping or even some digital EQing, and probably make the Crown work with my KEFs. I actually still have a couple weeks left in the trial period, and haven't sent it back yet.... 

[roscoeiii]

That's what I was using with my 1500. Dodds tube buffer (with a 6H30P-DR tube) behind a Goldpoint 25k attenuator. I think the output impedance is around 100 ohms. I though about inserting one of my Jensen tranny converters in there, to use the balanced inputs of the Crown, which has double the input impedance. To see if it would make any difference.

I also could of done some tube swapping or even some digital EQing, and probably make the Crown work with my KEFs. I actually still have a couple weeks left in the trial period, and haven't sent it back yet.... 

Look forward to hearing what else you discover if you take the time to tinker with the amp more. The LS50 is a great speaker,  though on the forward side of the spectrum in my experience. I  do think that highs do tend to be affected by amp break-in, or you could just be dealing with a characteristic of the amp (maybe other owners could weigh in here).

How lean was the Crown + tube buffer combo for you? And how did playing around with the amp gain affect things?

[Jon L]

That's what I was using with my 1500. Dodds tube buffer (with a 6H30P-DR tube) behind a Goldpoint 25k attenuator.

I think that tube buffer may actually not be "tubey" enough for our purposes 

I do have a souped-up Transcendent grounded grid preamp with nice, rich 12AU7 tubes sitting around, which should pair up nicely with Crown.  I'm thinking something like a SAS Labs tubed preamp will also pair up nicely with just enough tube harmonics but still transparent..

[jk@home]

Look forward to hearing what else you discover if you take the time to tinker with the amp more. The LS50 is a great speaker,  though on the forward side of the spectrum in my experience. I  do think that highs do tend to be affected by amp break-in, or you could just be dealing with a characteristic of the amp (maybe other owners could weigh in here).

How lean was the Crown + tube buffer combo for you? And how did playing around with the amp gain affect things?

Yes whether it is break in or just needing a warmer amp is the question. From what I could tell, it was the bump in the KEFs upper midrange/lower treble that was showing though. Just a little too etchy.

I think that tube buffer may actually not be "tubey" enough for our purposes 

I do have a souped-up Transcendent grounded grid preamp with nice, rich 12AU7 tubes sitting around, which should pair up nicely with Crown.  I'm thinking something like a SAS Labs tubed preamp will also pair up nicely with just enough tube harmonics but still transparent..

LOL, could be. I built this unit as an upgrade from a CI passive pre, and it really did improve the power amp's sound. Being "tubey" really wasn't the goal, but to use a passive on a lowish input impedance amp.

[roscoeiii]

JK,

How lean was the Crown + tube buffer combo for you? Meat on the bones there? I'm thinking of the resonance of a string instrument.

And how did playing around with the amp gain affect things?

[DaveC113]

AC power really has a lot to do with perceived forwardness and harshness and can make the difference between too forward and fatiguing and detailed but just right. If things being too forward, bright or harsh seems to be an issue it might be worth it to look at AC power.

That said the Crown is a forward sounding amp and combined with forward sounding speakers might be too much for some. My speakers are pretty forward too and while I don't think it's too much I could understand someone else preferring a more laid-back presentation. I think the main issue with the Crown amps is volume compression, it's better than when it was new but detail is presented with too much volume sometimes, which makes the amp sound forward.

In any case, the Crown amps aren't perfect (neither is my SET amp) but the value you get is pretty amazing. Based on what I'm hearing I'd put all my budget into source and speakers and just use these Crown amps if I was buying a new system. I think you'd get better bang for your buck than spending less on source or speakers to buy a different and more expensive amp in most cases.

[Folsom]

That's a reason I spoke about modifications to the Crown. There might even be some simple $2 mods that'll bring the forwardness down.

[Freo-1]

I have started to play around with that, but I still want to get more time on the Crown before any serious comparisons.

Tom, how does the Crown compare with the Ncore?  The best Class D I have heard to date is the Yamha MX-D1, slightly more dynamic than the Ncore (but both are very good).

[DaveC113]

That's a reason I spoke about modifications to the Crown. There might even be some simple $2 mods that'll bring the forwardness down.

I think the forwardness is primarily a result of the compression, which can't be fixed... but could also be AC power. I'm not so sure the issue with AC power is in the amp though, I'd bet it has to do with other components. The Crown amps PS are supposed to be designed to handle dirty AC power although I have not tested it with or without my PLC yet... it is possible some improvements could be made there.

[roscoeiii]

I think the forwardness is primarily a result of the compression, which can't be fixed... but could also be AC power. I'm not so sure the issue with AC power is in the amp though, I'd bet it has to do with other components. The Crown amps PS are supposed to be designed to handle dirty AC power although I have not tested it with or without my PLC yet... it is possible some improvements could be made there.

Interesting thoughts about the potential contribution of AC. Though I think I'd be OK in my place with it through my Equitech 2Q or my Audience one outlet power conditioner.

And good to know that it is a forward amp. That should help folks decide whether it is for them or not, and whether it would work with their speakers or not.

[Folsom]

It's hard to say with compression. There's what we think we hear etc... but also the compression if dynamic at all, is a response that can be changed.

Their filter looks decent, albeit very low capacitance. But that doesn't mean there isn't a complication created by the filter itself. Also the proximity of the diodes (if I'm even sure what I'm looking at) is a good distance from any AC capacitance that could help with their probably bad RF production.

It might benefit from some PFC too.

Anyway, if you want to PM me maybe we could investigate, not hijacking the thread.

[jk@home]

JK,

How lean was the Crown + tube buffer combo for you? Meat on the bones there? I'm thinking of the resonance of a string instrument.

And how did playing around with the amp gain affect things?

I don't really feel it was a lean sound, as much as it is what Dave was describing. I had turned my subs off, and un-plugged the KEFs ports, and got decent bass out of them. I didn't feel adjusting the gain on the power amp really changed much, except limiting the volume adjustment on the preamp. But I could only go so low as my setup really doesn't add gain pass what the DAC is putting out (2.2 volts if I recall).

Maybe using something like the Benchmark DAC or a high gain pre would allow a lower gain setting.

[roscoeiii]

Thanks. Very helpful.

[OzarkTom]

Tom, how does the Crown compare with the Ncore?  The best Class D I have heard to date is the Yamha MX-D1, slightly more dynamic than the Ncore (but both are very good).

My system has changed so much, it would be unfair to compare. Both amps are very neutral, so garbage in-garbage out as for the quality of the recordings. They both have great bass.

The Ncores never gelled here on my bad AC, so I took them to Rex's. He ran his AMR tube DAC straight in through RCA inputs and the sound was just OK. Then we hooked his AMR balanced to the Ncores and they came to life. I would be curious on how the Crown sounded running balanced.

Is anyone here running their Crown balanced? I would run my Crown up to Rex's, but he and his wife moved back to Hawaii last week.

[guest61169]

I broke in my crown for months unbalanced in my video system but always used balanced inputs when in my audio system (where it currently resides).  So can't give an accurate sound quality assessment between unbalanced vs. balanced. 

My Benchmark DAC-1 which I use as a preamp has (true) balanced outputs and I prefer running balanced.  The Benchmark even has jumpers to adjust the gain (which also affects output impedance) inside the unit. 

With unbalanced, preamp/power combinations I've used in my listening room over the years would amplify noise from power switches (popping sounds while turning on/off nearby bathroom light switches, bathroom fan switches, etc.) but all fully balanced preamp/power amp combinations I've used in my listening room have conversely been dead quiet.  If you have a preamp that has true balanced outputs and your electrical environment is less than ideal, that would be the way to go IMHO...not just with the Crown but with any amp that offers those inputs.

[OzarkTom]

Well, I learned something tonight. I was getting a severe edge coming through the system tonight, I was getting very frustrated and fatigued. I was blaming my AC. I decided to crank the ITUBE wide open and use the gain controls on the amp. Voila, the edge totally disappeared. 

Now to find my balanced cables and hook up my Sony balanced using the gain controls on the amp. Tuesday I will report back on what I find out.

[roscoeiii]

Yeah, some of the threads on this amp suggest better performance with gain at lower levels. 12 o'clock IIRC was mentioned by more than one person.