Good Class D amplification and Omega speakers are a winning combo

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pstrisik

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I've run the Bantam Gold for about 60 hours.  I listened over a couple of days through my Super 7 Alnico XRS.  I am quite impressed.  I switched back to my Dennis Had Inspire single ended amp for comparison.  I was thinking that the Bantam Gold was every bit as good but did find the tube amp brought back that extra bit of "liveness".  That extra bit of you are there quality.  Tonally they are equivalent.  The midrange is surprisingly smooth for solid state.  Imaging is quite good, just not quite as good as the tube setup. 

Now, the caveat in my informal review is.... I have been tube rolling for more that a year in my Inspire and have settled on dream tubes.  Vintage GEC KT77 power tubes, "Rocket" 6N23P driver, and Vintage British "fat bottle" GZ37/CV378/53KU rectifier.  If I compared them with anything less for tubes, the difference between these amps would be even smaller.  So, given that the tube amp is five times the cost with another two Bantam Gold's worth in vintage tubes, I would say that this little amp is quite remarkable and just mind boggling sound for the money.

Another factor:  I listened to both the Bantam and the Inspire fed by the Inspire LP-2 preamp.  I didn't think of it and probably will give a listen to the Bantam Gold without the preamp as it is sold as an integrated.  I think it will have gain enough.

A couple of niggles in design:  The blue power LED is too bright.  And, if you plug into a switched outlet, it will not power up without manually pushing the power button.  So it has to stay in an unswitched outlet to avoid that.  Other than the overly bright LED, it's really not an issue since it only draws a watt when idle.  I have some small, tinted mylar disks that I use to place over bright indicator lights, so that will take care of that.  The other minor issue is weight.  I have granite weight on top of the amp otherwise it will tilt back from the weight of the cables.  This amp is very small and light.  It might help to use a heavier faceplate and bottom plate to help counter this tendency.  But all niggles, particularly given the sound you can get for $300 (depending on current exchange rate - 189 british pounds).

I previously did try the Crown XLS1500 but it didn't do it for me.  I found it fatiguing with a bit of edge that I don't feel in the Bantam Gold.


......Peter

slefley

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I have the Fire Bottle 6L6 as well and would like to try the KT77 and 6N23P.  Can you recommend a good source for those tubes?

Steve

pstrisik

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I have the Fire Bottle 6L6 as well and would like to try the KT77 and 6N23P.  Can you recommend a good source for those tubes?

Steve

Hi Steve,

There are plenty of the 6N23P tubes available on ebay.  Those are the easy ones.  A guy in Washington State has created a bit of a buzz/possible mythology with his detailed testing and review of 6922 type tubes.  Among the Russian 6N23P, he claims the best are specifically 1975 gray shield, single wire getter post from Voskhod plant ("rocket" logo) and the 1974 silver shield SWGP from Reflector plant.  I don't know how true this is, but the price difference isn't great, at least for the 1975 rockets, so that it is worth it for the peace of mind.  There is at least one ebay auction right now for three of these these:  #161771267407 for $57 shipped and one for two 1974 gray/swgp: #231613856699 - $49 shipped.  There may be others.

For the GEC KT77's, you have to keep an eye out to find good deals.  I have gotten some on ebay for as little as $200-$300 / pair and they have been fine.  Just make sure there are test results posted, good seller feedback, etc., as well as returns accepted.  You can also find a pair from a reputable tube seller, Brendan Biever of tubeworldexpress.com for $650, which is the typical market price for good examples of this tube.  There are a few listings on ebay, some of which are very expensive.  There is a quad of Gold Lion labeled, testing as new, for $1600.  Best offer accepted, so you might get them for less than that, but more than about $1300 is getting high for a good quad.

For the KT77's, the buzz is that short brown bases are preferable to the bigger black bases.  I have a pair of each and can't tell any difference.  I've also heard that the ones labeled Gold Lion are preferable, but I don't think there is truth to that either other than they look cool.  Be wary of "Gold Aero" though.  I can't find anything definitive, but have heard that these may not be authentic.

As an aside, I bought some "tube saver sockets" since I've been rolling alot.  They are just like tube bases, but you can plug tubes into them.  They plug into the inspire's sockets and don't move.  I swap tubes in and out of the savers, so I'm no longer worried about wearing out the sockets installed in the amp.

I don't recall if I've seen you over in the big Dennis Had Inspire thread I started a while back on audioaficionado.org in the Cary section.  It's almost at 900 posts and has lots of folks with these amps.

........Peter

PS:  I guess this is a bit off topic for a thread on Class D amplification - sorry about that. 


DaveC113

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I previously did try the Crown XLS1500 but it didn't do it for me.  I found it fatiguing with a bit of edge that I don't feel in the Bantam Gold.


......Peter


They need a good 100 hours of burn in and better binding posts. After that, no edge at all... before break in is finished it's very fatiguing.

pstrisik

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They need a good 100 hours of burn in and better binding posts. After that, no edge at all... before break in is finished it's very fatiguing.

It was a used unit, so very likely hundreds of hours in addition to what I put on it.  Original speaker connections though.

.......Peter

wellpleased

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For Class D amps, look no further than Nuprime. The new IDA-8 should work wonders with any of Louis' models.

vinagunner

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« Last Edit: 15 Mar 2016, 03:50 am by vinagunner »

oskar

I'll chime in on the Bantam Gold although I'm not using Omega's. Yet.
When the box arrived from Canada Rob I thought there was a mistake. I knew the amp was small but I wasn't prepared for how small!
After a good laugh I strapped it to my 95db speakers. I've been playing it a lot in the last ten days and it is really a sweet piece of kit.
Recently I switched it over to high gain mode and definitely prefer it with my set up.
Still using the supplied SMPS but will pick up a linear soon.
Since Rob represents Omega and Bantam I can believe the two would make a great match.

mrvco

For Class D amps, look no further than Nuprime. The new IDA-8 should work wonders with any of Louis' models.

I'm definitely interested in trying the IDA-8 now that I have the 7XRS MKII's.  I currently have a Musical Fidelity M3i Integrated and a Schiit Bifrost Uber DAC which I've been happy with, but I can't help but wonder if the ISA-8 might be better suited to the Omega Speakers.

sruffle

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I have been using a Rogue Audio Medusa with my new Super Alnico monitors.  The Medusa is a hybrid with a tube input and Class D output of 200 watts per channel.  Combined with a passive preamp this gives a really great midrange and bass with loads of detail and no fatigue. 

I bought the Alnicos with the intention of trying a SET amp but this is a great combination and may stay.  Despite all the examples I read about,  I am really concerned about going from 200W to potentially 2W.  I mays try to get a used or cheap SET amp to see if it works in my room and then sell it. 

In any case, the Rogue  hybrid is a very nice combination with the Alnicos.

roymail

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In any case, the Rogue  hybrid is a very nice combination with the Alnicos.

I'm thinking the same thing about the Rogue Sphinx.  Tube front end, class d amp, integrated with volume control, 100 watts output.  Should sound great with Omegas.

sruffle

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I bet the Sphinx would be great.  It is also a very good value.

mrvco

I'm thinking the same thing about the Rogue Sphinx.  Tube front end, class d amp, integrated with volume control, 100 watts output.  Should sound great with Omegas.

I had forgotten about those guys, there is a shop that is "sort of" on my way home that sells Rogue Audio.  I guess I'll have to stop by and take a listensee :)

vinagunner

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v
« Last Edit: 15 Mar 2016, 03:48 am by vinagunner »

mrvco

I had forgotten about those guys, there is a shop that is "sort of" on my way home that sells Rogue Audio.  I guess I'll have to stop by and take a listensee :)

Apparently Sphinx are few and far between around here... there should be one showing up sometime next week.  While it does cost an extra ~$500, I do like that the Sphinx doesn't include an integrated DAC.  We shall see.

mrvco

I listened to a Sphinx and decided to order one.

roymail

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mrvco, tell us more...like what speakers were used for the Sphinx audition and your thoughts about what you liked about this amp.  I read some very good reviews about the Sphinx.  Would love to hear one, too.

mrvco

A pair of $2k'ish Tannoy 2-way floor standers and a sub-$1k Pro-Ject turntable.  That was my first experience with Tannoy speakers so I'm hesitant to attribute specific sonic qualities to the Sphinx independent of the Tannoys or Pro-Ject turntable, but the Sphinx had everything well in hand (excellent build quality, very quiet, very strong and consistent from low volume and up).  Nothing about the Sphinx contradicted the reviews that I've read, so I'm definitely looking forward to hearing the Sphinx w/ my Omegas and Rega turntable (and DAC).

This will be the new v2 model.  I do like the look of the new grooved front panel better than the v1 version.  My only concern was with the new "skeleton" remote which is plastic instead of the previous metal remote.  I'd prefer something with less (or no) plastic and more heft to it, but it worked very well and it includes a Mute button now in addition to the Volume Up and Down buttons.  I'm not too concerned about it since the local dealer is throwing the remote in w/ the deal.

edit - It should be arriving late next week.
« Last Edit: 18 Sep 2015, 11:34 pm by mrvco »

mrvco

I picked up my Sphinx this afternoon.  Initial impressions after having it powered up and playing for ~4 hours now are outstanding.  The Sphinx is definitely a good match w/ Omega speakers.  I didn't realize how much the M3i was struggling to keep up with the Omegas.  I assumed the lack of clarity and harshness that became readily apparent as the volume increased was a DAC issue.  The Sphinx is definitely not getting between the DAC and speakers like the M3i was; sound stage, detail, musicality, etc., it's all definitely there and I'm not getting the harshness / listening fatigue that I was getting with the M3i as the volume increased.  The Sphinx has absolutely no problem keeping the Omegas under control.  I read somewhere that the M3i's "damping factor" is 36, while the Sphinx is rated at greater than 1000 (I get it now :)).  I'm spinning a couple of records and the phono stage sounds great as well.

I had high expectations going in and they've definitely been met so far.

roymail

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How does the Rogue Sphinx sound in your system without a DAC?  How would describe the sonics?