Geoff gets a new Tube amp!

[Geoffcin]

Well not exactly brand new, but the output tubes, the Genelax KT88 re-issue are.

My first foray into the wild and sometimes woolly world of tube amplification.

[jrhymeammo]

Congrats Geoff,


looks like you got a Ming Da MC 368 B90.

http://www.pacificvalve.us/MD368B90.html

Do you still have a pair of 1.6QR? I would very much like to know how your new toy sounds with a pair of Magnepan.

Have Fun,
JRA


Edit: Looks like you got a pair of 3.6R. When did that happen?
Well, do you plan to drive 3.6R with your new toy?

[Geoffcin]

Thanks, and yes I've got the amp hooked up to my Maggies. It was late last night when I got it all put together so I've yet to put it through it's paces. Sounded pretty sweet though...

I actually never had 1.6qr's (I really like them though!) I went from the 80's vintage Magnepan III, to the 3.6 about 6-7 years ago. I've really got to update my sig as I've added quite a bit of stuff including some killer JM Labs monitors to my growing audio collection (my wife would call it by another name!).

[poppachubby]

Looks fantastic...you must be thrilled.

[Feanor]

Well not exactly brand new, but the output tubes, the Genelax KT88 re-issue are.

My first foray into the wild and sometimes woolly world of tube amplification.

Great to hear from you, Geoff.

Nice looking amp too. I'll want to hear you impressions after some burn-in and how well you feel it works with the Maggies.

[Geoffcin]

Thanks guys! Yes the amp looks even better in person. (weighs a freakin ton too!). I am one happy clammer too, especially since the amp had a long story getting here in one working piece. More on that in a future post.

I'll also post a short review soon, but my one word now review is "Phat!!"

(and yummy!)

[blackraven]

Beautiful looking amp! Gives us some specs!

[jrhymeammo]

Did you unit come with a acrylic cover?
There is nothing better than a new used toy.
Nice grab on power tubes as well. No personally experience, but have always been curious on the Genelax. As far as pre tubes go, what tubes are you running? We would love to see some pics!!!!

Have Fun,
JRA

[Geoffcin]

Did you unit come with a acrylic cover?
There is nothing better than a new used toy.
Nice grab on power tubes as well. No personally experience, but have always been curious on the Genelax. As far as pre tubes go, what tubes are you running? We would love to see some pics!!!!

Have Fun,
JRA

I had some time today to run the amp in and so far I've been impressed. I thought it would run out of steam driving the maggies, but I've yet to been able to push it into making anything but sweet sound. I'm really having a lot of fun with my gear again!

I'm running the amp without the cage, heck I don't even have it! The amp's tubes look cooler than anything so even if I had a cage I wouldn't use it. I've been in close contact with the original owner of the amp. He's got more than 20 years experience with tube amps and was the one who rolled the output tubes to the Genalex KT88 re-issues. He also rolled the other tubes to Tung-Sol 6SN7s and Sovtek 12AX7WA.

[GMichael]

Wow! I had to check the date on this thread. I figured that someone resurrected an old one. Good to see you post Geoff. Nice looking amp. I bet it makes those 3.6's sing.
I have heard that tubes sound better after a break in period. How many hours do you have on the new tubes so far?

[Geoffcin]

Wow! I had to check the date on this thread. I figured that someone resurrected an old one. Good to see you post Geoff. Nice looking amp. I bet it makes those 3.6's sing.
I have heard that tubes sound better after a break in period. How many hours do you have on the new tubes so far?

Yeah, I took some time off for bad behavior. This is really my first "new" piece of kit in some time too.

I was pleasantly surprised how well the amp works with the maggies. I've got about a dozen hours on the unit and so far so good. I had heard about tube break in and asked the original owner about it. To make a long (and technical) argument short he's not buying it. He said if I kept the bias in proper spec the tubes should perform to the same level for at least a couple thousand hours if not more. One of the reasons he liked the Genalex KT88's is that they are very robust in addition to sounding great. He also said that the B+ voltage on this amp was 520v and the original 6550's were at the design limit under that load. while I haven't checked the voltages myself I can tell you that this puppy can swing a lot of current into the maggies, much more than it's rated 75wpc would lead you to believe.

[jrhymeammo]

I'm not too crazy on breaking in tubes, but the idea behind it makes sense. But I do think warmed up tubes sound better than cold tubes. I usually try to keep them on for at least 10 minutes before playing my first tune.

How does your Maggies sound when music become complex? My Chinese amp wasn't too happy with 1.6QR on large emsemble music. But It was very good with some string quartet.

Have Fun and welcome back!!!!
JRA

[Geoffcin]

Thanks, and yes I'm having fun with my gear again!

Oh there's definitely a difference between a cold and hot amp, The funny thing is I can hear that even with a SS amp. My old PS Audio 200c used to sound it's best after I got it really cooking. (think roasting marshmallows hot!)

The amp so far has been pretty much unflappable. I'm sure I was pushing it into, or close to clipping several times and it never barked at me like a SS amp would.

The amp has a switch to change from ultralinear to triode. It halves the power but supposedly is better for more intimate recordings. I've never used it yet, but I'll give it a shot soon.

I didn't know you had a Chinese amp too. Which one did you get? For me it was a toss up between this one and the MC34-AB with the 8 output tubes. When this one came up on the used market I jump on it.

[Geoffcin]

Beautiful looking amp! Gives us some specs!

Hi, sorry to be so long in posting the specs, but since I didn't buy it new, and all the documentation I have is in Chinese, it's been hard to really come by specs!

After talking with the former owner, a guy who currently has several tube amps, some of which he built himself, the amps nominal rating of 75WPC is VERY conservative. He would rate it more as >90WPC based on the plate voltages, with it easily able to reach 120W on the peaks. Speaking of which the amp's voltages were significantly higher than the supplied 6550 tubes like. Getting 1000 hours out of them would be pushing it at this voltage level. The Gold Lion KT88's that replace them are much more robust, and can take the higher voltages (and resulting output) without problem. He told me to expect 2000 hours or more from these tubes. He also said the closest American made tube amp to this design is the McIntosh 275. He also said that he had a MC275 for several months and on his bench it measured higher in distortion than the MingDa! I can't confirm any of this but I can tell you that the amp sounds CLEAN. I know what distortion sounds like, and this amp is easily under ~1% for loads that reach 95+ dB with my speakers. Speaking of which, my speakers are not the most efficient. Some have called them watt pigs. Certainly people have them hooked up to Musical Fidelity KW amps with good results, but as I write this I'm listening to the MingDa in Triode mode at 70dB-80dB and it's sweet as Tupelo honey.... So for better or worse I'm a "tube dude" now. My SS amps have been relegated to the HT system.

[RGA]

Hahaha - another convert to the music first side!

Gorgeous looking tube amp and for a nice price to boot. KT88 tubes are one of if not the most robust tube topology.

A fellow on another forum is running the Grant Fidelity Rita with his big Acoustats and he hasn't got it up to half volume (and the Rita is rated as 45 watts per channel) though its peak is 450 watts.

2000 hours on output tubes is fairly conservative and you could get anywhere from 5,000 to 100,000 hours from preamp tubes. Just like lightbulbs you never know.

As for distortion and power - unfortunately a lot of myths have pervaded into the halls of audio forums and magazines. Tube amps distort at volume - so what - at very high volume the ear no longer is able to discern quality regardless of distortion. At volumes the tube amp is capable of which is still quite loud, the amp is operating with its best measured results. Amplifiers are always measured at maximum volume where very few people ever play - SS typically measures best at maximum level and worst at minimum levels - guess where the solid state industry set the measurement standards - at max settings.

Tube amps consistently sound better than SS amps at very low volumes. A couple of nice tube articles

http://www.stereophile.com/features/357/index.html

This one is more about negative feedback so it applies to certain SS makers but in general tube amps - not that in the blind session the manufacturers of even top solid state companies chose an old no longer made $100 tube amp over their own $3000 SS amps. http://www.stereophile.com/reference/70/index.html

[Geoffcin]

FWIW; My "conversion" is more like an evolution. The very first time I heard the Magnepan 3.6's they were driven by uber-powerful Audio Research tube amps. That system was truly stunning. My most recent amp, the PS Audio HCA-2 also doesn't sound like your typical SS amp either, so I'm no stranger to using different sounding amps, or making judgment calls based on what I hear with my own ears.

My choice to go with this amp though was mostly a leap of faith. I had never heard it, nor was there much written about it. Like some of my best stock picks I had a feeling and went with it. Sometimes you get lucky, and sometimes you don't. This time I not only got lucky with a good sounding amp, but the former owner is much more knowledgeable about tube amp design than just about anyone I've ever met. For about two years this amp sat in his reference system, and now it sits in mine!

[thekid]

Geo

Nice piece!

Someday when budget,time and space permit I'd love to get my hands on a real quality pre-amp/amp tube combo.

[Geoffcin]

OK, got it to noticeably distort. On the track "Low" by Flow Rida the bass line distorts if played above a moderate level. A powerful SS amp wouldn't have given up on the bass line so quickly. No it's NOT my choice in music, but there it is. To be honest the maggies aren't the first choice (if it even was my choice) for Hip-Hop/Rap in the first place. That being said, I'm sure if I reconfigured the system the way I used to run it with the dual 15"' subs we could get "Low" to blow the walls out!

[Geoffcin]

Geo

Nice piece!

Someday when budget,time and space permit I'd love to get my hands on a real quality pre-amp/amp tube combo.

Thanks!

I got this piece on the used market. These Chinese amps are pretty affordable to begin with, and now that they have been out for several years you can bet a lot more will be rotating out of peoples systems and onto the market.

[Geoffcin]

Just to allay my fears that there's something wrong with the bass response of the amp I played Copeland; Fanfare for the Common Man at a pretty realistic level. The tympani strikes are really quite startling and shake the place up good. Had the goose bump thing going on too. Always a good sign things are working right.

[E-Stat]

My first foray into the wild and sometimes woolly world of tube amplification.

Congrats! I'm sure you're loving it.

rw

[Geoffcin]

Congrats! I'm sure you're loving it.

rw

Thanks! And yes, I am.

Now I've got an idea to go revisit my old vinyl collection.... Perhaps I'm loosing it!

[nightflier]

Congrats.

How would you compare the sound between the HCA-2 and the Ming Da?

[Geoffcin]

Congrats.

How would you compare the sound between the HCA-2 and the Ming Da?

That's a good question, but since I smoked one of the outputs in the HCA-2 a few months back, and have been using my Musical Fidelity A3cr amp to drive the maggies it wouldn't be easy to give you a good definitive answer. I can say that I was very happy with the PS Audio amp. If it didn't fry I wouldn't have even gone looking for anything else.

[nightflier]

Just FYI, PS Audio will still repair it. I purchased a non-working one about a year ago for $25 at a garage sale (I don't think the guy knew what it was), and had it repaired and brought back up to speck in less than a month. They are very good about this.

On the sound, I'm not a tube guy, really. I have an Odyssey Candela preamp, and that's it. But I've been told more than once that the PS Audio class-d amps sound surprisingly similar to tube amps, but I have no way of testing that (right now).

I've also been intrigued with the tube gear coming out of China from companies like Shanling, Bada, MHZ, etc., but I've never taken that plunge. I'm a bit swamped with gear & projects now, so I'm not quite ready to buy another amp, but it's always interesting to read about the experiences of others.