Vacuum tube monoblockamplifier pair rated 350 watts each.
Here are my new amplifiers, not a relisting.And here they are!The pictures are stock photos of an older amplifier, the actual amplifiers have IEC connectors and silkscreened escutcheons and back face. They also come standard with KT-120 tubes. They reflect my latest thinking in amplifier design. The main new features are super extended bandwidth, and a special circuit that I invented which allows the amplifiers to \"listen to the room\". A normal tube amplifier is capable of listening to the room a bit, but this amplifier has a special circuit that allows it to listen to the room in spades. It works as follows: The loudspeaker that an amplifier is driving can operate as a microphone. Any loudspeaker can operate as a microphoneor as a loudspeaker. If we speak into the cone of a loudspeaker it will move back and forth and generate a voltage, just like a microphone. This passes througha specially dedicated current response loop in my amplifier, and combines in real-time with the incoming signal to make the room work for us. whereas other amplifier and speaker combinations cannot perform this feat, our amplifier uses the room acoustics to present a beautiful, deep, wide and more engaging soundstage with pinpoint imaging within on any speaker. It amazes even me.
Adamantine Steel - goodfor 450 watts maximum
I used a newexecution of my vintage, legacy output transformer design, wound on a huge,massive core made of Adamantine steel. Previously I had tried to clone them butwas not successful, but after ten tries I hit pay dirt. Not only that,but I designed it to increase the power output to 400 watts, and by using thepowerful new KT120 output tubes, I easily hit my design goal of 350 watts R.M.S.Efficiency and power bandwidth increased as well, yielding a rated power atclipping of 450 watts R.M.S. into one ohm.
The Heart and Soul of aVacuum tube amplifier, the output transformer
As mentionedabove, I\'ve designed a new output transformer using the best, modern layerwinding method as opposed to the classic, vintage technique of pie winding.When I first started building these transformers, I thought I would continue topie wind them. Though I have become pretty good at winding them myself, ittakes too long; I\'m finding that it takes me a whole day and a half to windone, and the rest of the day is spent finishing it up connecting all thesecondary and primary windings together without making a single mistake. Sincethere are two output transformers, one for each amp, it takes me four days toto build a pair. And because I have a day job, I\'ve been building them onweekends and in the evenings.
I had thethought of getting a commercial transformer company to make them for meaccording to my plans, but the cost was too high; they wanted over threethousand, six hundred dollars for the pair.
I needed a greattransformer to take apart and learn from to be in a position to wind my own(and do a credible job). I searched around and came up with five possibles: AMcIntosh 275, a Marantz 9, a Citation II, an EAR, and my own Silver Seven,which I DID wind myself during the early stages of production so long ago.
I couldn\'t finda 9, the McIntosh was designed for split cathode drive (not suitable for thisapplication), Tim is in England, leaving my own Silver Seven and the StuHegeman designed Citation. I have taken from both designs, incorporated the Adamantinesteel, changed the turns ratio, used thicker oxygen free wire (because of theextra space that opened up by not using all the insulation space required ofthe pie winding), made the core bigger, and let \'er rip.
After a lot ofwork I got them to sound the same, exactly the same, as the pie wound versions,not better, not worse, the same. I find it impossible to say which soundsbetter.
I love both ofthese transformers.
When I ran out of outputTransformers
You can imaginemy sadness when I ran out of the output transformers I had been saving my wholegrown-up life. I had only a single transformer left from my previously abundantstash, so I decided to take it apart and look inside, with the idea of copyingit down to every last detail. I had never looked inside, and what I found wasthat clearly it wasn\'t a commercial transformer design - it was way too good -it just had to have been wound for the military. It was amazing inside. It was\"pie\" wound with many separate pi windings, a vintage windinggeometry that is not used today; it\'s way too expensive, is a true art form,and besides, it is not needed anyway. The science of steel, in the vast gulf ofthe intervening 50 years or so has been developed to a remarkable degree. Steeltoday is not what it used to be; it is a zillion times better - less hysteresisloss, far greater magnetizing inductance, and vastly improved immunity tosaturation. Today, great transformers can easily be \"layer\" wound, andby using modern steel, superb performance may still be attained. Just the same,I copied the pie winding geometry down to the last detail, but was unable tolocate any vintage \"iron\" (steel actually). So I had to use modernsteel. And guess what happened! Well, I for one was not prepared for whathappened next. Losses dropped to almost nothing, power response went through theroof, and the power bandwidthincreased by about half an octave! I steppedback from my laboratory bench, and looked at the thing wide-eyed, scarcelybelieving my measurements. Not only that, but I found the maximum power outputhad increased by eighty watts. And here\'s the best part: they sound the same,exactly the same as my original output transformers did. I feel LUCKY!The picture shows me hand-winding the new output transformer. The finalversion increased by two hundred watts, which represents my latest thinkingregarding these new transformers.
This newest design has a bandwidth which extends almost all the way to 200kHz, a design requirement for an amplifier such as this in order to correctly integrate the functionality associated with its ability to listen to the room.
Tim de Paravicini and me
It was manysummers ago that Tim de Paravicini and I met in a small town (Sebastopol) inCalifornia. We spent three fascinating days discussing vacuum tube power ampsand the magic of our mechanical vinyl recording system that somehow, againstall odds, is able to deliver music with life and romance that no other systemcan.
We talked aboutoutput stages, phase inverters, front end amplifiers, output transformers, andespecially the dynamic characteristics of tube amplifiers playing music.
I will neverforget those fascinating three days as long as I live.
We mused thatthere have been only four basic designs that have been widely used since thevery beginning; the Williamson circuit, the Mullard 520 circuit, the Dynacopentode-cathodyne circuit and the Stewart Hegeman all pentode circuit. Asthe mornings turned into nights and we used up all the napkins on our tabledrawing amplifier diagrams, a remarkable circuit emerged as Tim held the penand drew a balanced current-sourced front end, followed by double balanceddrivers using a frame grid triode ultimately direct coupled to the grids of theoutput tubes.
The man with bigmuscles holding the amplifier is me, Bob Carver.
Tim designed theall important current sourced front-end. Together we designed the output stage,power supply, bias supply, and I designed the driver stage using the frame gridtriode. It’s simple, magically balanced with no offsets, and as it turned out,sonic performance that cannot easily be believed.
But I\'m gettingahead of myself.
I\'ve beencollecting vintage amplifier parts for a lifetime, always with the notion ofmaking a small museum someday. But after spending three fascinating days withTim, I had a change of heart and decided a much better use for them would be tobuild an amplifier. This amplifier is an updated version of that first vintageone.
There\'s more.
Every vacuumtube amp in the world suffers from shifting DC operating points, and this,unfortunately, has remained a functional limitation and maddening sore pointfor amplifier designers ever since the very beginning of vacuum tubes.Consequently, I had to invent a DC restorer circuit using a 6AL5 / 5726 tube;it eliminated every last vestige of DC shift, while simultaneously reducingdistortion three-fold and vacuum tube idle power by the same amount. AsTim would say, \"Nothing new under the sun\", just the same, it\'s neverbeen done before, and it works flawlessly.
Of the fourcircuits mentioned earlier, the Mullard 520 circuit is used in Marantz (8B andModel 9) amplifiers, as well as countless others by McIntosh, Eico, andCitation. Heathkit used Williamson almost exclusively, and Dyna used theubiquitous cathodyne circuit as did hundreds of others. Citation, Lafayette andRCA always used the Hegeman circuit in their best, most expensive units. Andthat was it! Only four!
This amp usesall vintage parts except for paint, the chassis, the big transformers, and someof the small circuit parts. Even the transformer covers, tube sockets, and theirdesigns are vintage. The front end is a superb vintage 12AX7, the tubefollowing is a five star military driver, and the DC restorer is a JAN 6AL5 /5726. Output tubes are new Tung-Sol KT120\'s, double tested, burned in for threedays and tested again. The best of the best. All are NOS except the front endtube and the new output tubes. The transformers are MASSIVE iron; eachmono-block amp weighs in at 44 pounds, 88 lbs in all. Power is an easy 350watts R.M.S. with a power bandwidth from 24 Hz to 45 kHz, frequency response 2Hz to 85 kHz, and distortion less than 0.15 % at 350 watts out.
This amplifierhas been designed with big Apogees in mind, the one ohm kind. It delivers450 watts into my one ohm Apogee Scintilla – I included a one ohm tap on theoutput transformer. And the mighty KT120’s do it with aplomb.
It\'s been soover designed that I expect it will last at least 50 years without need forservice. In twenty years the front end and driver tubes should be replaced,whether they need replacing or not. Here\'s the best part: even the output tubesshould last 50 years unless they have an unforeseen catastrophic failure. Noneed to replace them unless they won\'t bias up.
The sound
This amplifierstands with a small handful of the world\'s great vacuum tube amplifiers.
And beyond
It\'s elegantlybalanced, possesses huge energy storage that vintage designers (many of whomwere geniuses) could only dream of, a DC restorer, and twelve output tubes inall. Nothing can touch it.
The features
Four outputterminals, ground, one through three ohms, four ohms, eight ohms. A biascontrol that sets idling current. A switch that changes the response fromclassical (vintage) to contemporary.
Front panel meter:four functions.
It has a frontpanel meter that performs four important functions: It is used to set thebias, it’s part of the built-in tube tester that allows the output tubes to betested under actual voltage and current conditions, it allows the output tubesto be matched, though that is quite unnecessary, thanks to the DC restorer.Finally, it doubles as a VU meter, and is fun to watch, more fun than most, asit responds to output current rather than output voltage.
This amplifierhas built in auto-balance, and a volume control. A power switch with turn-oninrush current limiters is also included. And finally, a chrome roll barfor protecting the front end tubes.
Tim designed theall important current sourced front-end. Together we designed the output stage,power supply, bias supply, and I designed the driver stage using the frame gridtriode. It’s simple, magically balanced with no offsets, and as it turned out,sonic performance that cannot easily be believed.
This amp waslovingly hand crafted by Joey “Tubular Joe” Bonin, the best tube amplifierbuilder and craftsman of all time right here in the rain forest of the PacificNorthwest.
Hi, Tubular Joehere. Just wanted to let you know of a few aspects and features of theseamplifiers. They are hand-wired, point-to-point with star grounds. Thetagboards are military-style epoxy with bright silver-plated swaged turretterminals.
The transformercovers are lined with 3/16\" thick sound and vibration-deadening panels.
Hope you likethem. Enjoy!
Bob here. If oneever breaks, as long as I\'m alive I\'ll fix it free if you get it to me. Eventhe tubes. One last thing. I will autograph the amp to you withyour name on the champagne gold escutcheon. Example: \"To our friend Skip -Enjoy the music! Bob Carver\". Except your name, not Skip\'s, ofcourse. Or anything you would like. If you wish. Your choice.
Three morethings, the return period is for one year, not 60 or 90 days - the computer software will not allow me (for some reason) to change it in theintroduction above. Also the shipping from Canada is the same as shipping fromthe U.S., and I accept any form of rational payment.
Lifetime Warranty
As mentionedabove, it\'s my lifetime, and even the tubes are guaranteed for life. Theamplifier comes with a warranty certificate, an operating manual, and even labels.
Some of the pictures used above are stock photos. The exact amplifier you will receive is shown in the headlining picture with the KT-120 output tubes installed.
FRAUD ALERT
Severalfraudulators have downloaded my entire sale and posted it on several sitesaround the world, including and Alibaba. I have become used to peoplecopying me from time-to-time, but this is bizarre. They have copied my text andeven a photograph of me! To be sure it\'s really me, ask a question that only Iwould know the answer to - like my dog\'s name or a science question. Thissale is real, as you can verify my name \"Audioshopper\" in theupper right of this opening sale page. As a test, I recently ordered anamplifier from Alibaba, sent in my money, never received my amplifier, and Ihave not been able to get a dime of my money back. Don\'t send money to any website that offers these amplifiers for sale, used or otherwise, especially atbargain basement prices too good to be true - you will almost certainly lose itall.
Ghost questions fromthe past
Q: I have oftenread that an Ultra linear output tube connection is best for class AB amps. Yuramps are not Ultra linear, what is your opinion on this and what is thedifference? Thanks for your time, Tim
A: Hi \'t42, Longago when I first started designing tube amps I read the same literaturepromoting this same idea. However, an important series of convergingexperiments taught me that an Ultra-Linear output stage was not the bestapproach. I discussed this with the best and smartest tube amplifier designersin the industry. Each person felt that using an output stage with a regulatedscreen supply voltage yielded the very finest results. My conversation with StuHegeman (so long ago I was just a baby inventor), the designer of the HarmonKardon Citation amplifiers, confirmed my experimental results. He explainedthat when using an ultra-linear tap for the screen grids during full signaldrive, the screen voltage is unavoidably pushed so low that the maximum outputcurrent suffers substantially. Stu Hegeman, a genius, was right! I hope thishelps provided I haven\'t put you to sleep with my answer. Good luck, Bob Carver
Q: Hello Mr.Carver. I own Apogee Scintilla loudspeakers. I am interested in your amplifiersand love the sound of vacuum tubes. Every tube amplifier that i have tried withthese speakers has been unable to drive them to an adequate volume levelwithout distortion. Can you reassure me that these will work and, if so, how dothey do it? Thanks.
A: Hi \'113,Driving the Apogees is a matter of raw power as their impedance is about oneohm and their sensitivity is only about 72 dB SPL referred to one watt at eightohms. Pretty abysmal. But so what? They are among the most fantastic soundingspeakers of all time. I remember first hearing them years ago, and knew I wasin the presence of greatness! They were clearly designed by a person who lovedmusic and wanted his speakers to sound as good as he knew how. And never mindthe impedance or the sensitivity! He was a true artist, and that approach tookcourage because they were impossible to drive using normal amplifiers, and thatfact alone limited his market tremendously. He was truly courageous. Thisamplifier has six powerful KT120 output tubes, and can easily deliver 30 peakamperes into a one ohm Apogee load. That\'s a peak power of over 900 watts! Notonly that, but I own a pair of Apogees and have spent countless hours with thisamp, together with the Apogees, optimizing the whole system. I speak from firsthand experience - fear not, these amps will drive your Apogees with aplomb.Good question, hope this helps, Bob Carver
Q: How are theseamps different from the ones sold in the recent past? How do they differ fromone another? Thanks a lot! Chris
A: Hi Chris, Ijust knew someone would ask this! The main difference is the output powerbecause of my new output transformers and the new KT120 tubes. They sound thesame except for that. Cosmetic differences are a change from bright bottomscrews to shiny black ones, a shorter roll-bar for the tubes, and the chassisis infinitesimally (3/16 inch) longer to better allow the small tubes andvolume control to fit. That\'s it. Great question, and thanks for asking, BobCarver
Q: How can thetubes last for 50 years when most manufacturers recommend changing the tubes intheir amps in 3 or so years? Dave
A: Hi Dave, Thatis a very good question! The answer is the DC restorer. Here\'s how. Most ampsidle the output tubes at an average of 32 watts or so. Now the DC restorerallows the tubes to idle at about 9.75 watts. Since tube longevity is roughlyproportional to the plate dissipation raised to the 2.3 power, we have 32divided by 9.75 raised to the power of 2.3 = 15.4. Finally, 15.4 X 3 years = 46years. I have also noticed that many console amplifiers have 50 year old tubesright here on , and those tubes check out great. Great question, hope thishelps, Bob Carver
Q: Hello Bob.Beautiful amplifiers. I doubt that I\'ll have the coin to win, but I do have aquestion: How do you get so much power from such a small amplifier? Am Imissing something? Thanks.
A: Hi \'tss,Thank you, I think they are beautiful too. I spent a lot of time getting thecolor just right. I tried espresso brown, bright red, several other colors, andfinally metallic burgundy cherry red. I liked that the best. As for the power,it was pretty easy actually - all we did was use a lot of output tubes, a transformerturns ratio of about 19:1, a robust high voltage power supply, and the Tung-SolKT120 easily did the rest. And it\'s NOT so small-each one weighs almost 45 lbs!Good question, thanks for asking, Bob Carver
Q: Hey Mr.Carver---how do you have such a nice finish on the first amps? They look sonice and new. Thanks
A: Hi \'k67, Newfinish. Fresh paint, new champagne escutcheons on the front and new champagnetrim medallions on the transformer covers. There are some minor paintimperfections and some build-up around some of the small screws, but they arenot visible to the naked eye at one foot. Or when riding past on a horse at aslow trot. Good question, Bob Carver
Q: Dear Mr. Carver,I found the last question and your answer about bi-amping with a combination oftube [high end] and solid state [low end] amplification to be veryilluminating. As a solid state devotee for the past two decades--mainly Carveryou will be pleased to learn but Bryston too!-- I feel re-assured by yourstatement that tube amplification does not necessarily deliver a superior audioexperience. Am I going too far with this statement? I always warmed to theidea, in a tube-like way, that Carver \"TFM\" was a real technology,that solid state amps could deliver the warmth of tubes and then some. Don\'tget me wrong, I would dearly love to collect a pair of Reference Silver SevenTube amps (as you will likely be aware, a pair recently sold on for ashade under $19k). It is refreshing to hear, however, that solid state ampsshould not be discounted. I agree that tube amps are super cool -- I mean warm!Best, Marc + Maria + beagles Vancouver, BC
A: Hi \'oose,Absolutely! A great tube amp will sound wonderful, and a great solid state ampcan sound wonderful as well. But they WILL sound different. A tube ampgenerally will yield a more enveloping soundstage and a greater front-to-backdepth of field with tight imaging within that soundstage - a very romanticpresentation. A well designed solid state amplifier will usually deliver a nicetight focus together with a greater up-front presentation. With these tubeamps, a range of possibilities are possible, as the response switch and thebias adjustments allow the sound to be changed at will from very tube-like toalmost solid state. This emerges naturally as a by-product of the DC restorerand the fact that the bias is \"in the green\" over a wide range ofidling currents. Solid state amps are indeed not to be discounted - and thanksfor your thoughtful and on the mark comments - they mean a lot to me. Warmestand best, Bob Carver.
Q: Bob. You suregot that \"mad scientist\" look on your face while winding thattransformer! Thanks for sharing the pictures and your passion for audioexcellence with us! John
A: Hi John, Youthink? Now that I look at it again, I see the only things missing are bugs inmy teeth from the winding machine. The camera \"stopped\" the spokes -they are actually a blur. Bob Carver
Q: Hi Bob, hughfan! In a bi-amping configuration, would you use these mono blocks the theupper or lower end? What are the pros and cons for this approach?
A: Hi \'111, Iwould use these mono blocks for the high end and a solid state amp for the lowend, unless you had two sets of these amplifiers. A vacuum tube amp by itsintrinsic nature will yeild better bass because its output characteristicallows the signal to follow the impedance curve of the speaker system,delivering more voltage to the system within about an octive of its resonancefrequency. This usually delivers a more satisfying low-end response. However,what normally happens in the real world is that vacuum tube amplifiers lack theraw power to effectively accomplish this; typically a solid state amp is moreable to deliver the power needed and therefore works better. But NOT if we havefour of these very powerful tube amps. Good question, Bob Carver
Q: Is the rmspower pentode or triode?
A: Hi \'4t, Thisis one of those simple questions with a very complex and extended answer. Theanswer here is pentode, but that\'s only the beginning of the story. Long, longago, in the \'30s and \'40s the only way to build an amplifier without notchdistortion was to build it class A. Many talented amplifier designers workedand worked on the this problem until at last a genius by the name of Williamsonarrived and taught the world how to build a class AB output stage that wascompletely devoid of of notch distortion. This was late \'40s - a breakthrough,and the hi-fidelity industry took off. However, to work right, triodes wererequired which limited power efficiency - still, the leap in efficiency fromclass A to class AB was huge, completely overshadowing the fact that troideswere not as power efficient as pentodes. Triodes were still needed to makenotch distortion go away as the the art of output transformers had not yet beendeveloped to their fullest. This was was because triodes had a characteristicknown as \"low output impedance\" and could easily overcome the problemsof leakage inductance in the output transformer. It took the genius GordonGow,a founder of McIntosh to teach us how to build a high efficiency class ABoutput stage WITHOUT notch distortion. Others followed suit at Marantz,Citation, Scott, Fisher and on and on. Today it is not difficult to build aclass AB amplifier without notch distortion, thanks to the amazing pioneeringwork of those early guys. So - we see we went from triode class A to triodeClass AB, and finally to pentode Class AB as the years trolled by. Often oldideas die hard, and to this day a false belief sometimes exists that triodesare still preferred in class A. It IS easier to design with triodes, but asuperbly designed pentode stage will easily out-perform even a well designedtriode stage. Any difference in sound is associated with the circuit itself,not the choice of pentode or triode. Thanks for the question, Bob Carver
Q: I own aSunfire amp and the Current Source outputs are 1 ohm (I think). Curious to whatthe output impedance is for your new tube amps?
A: Hi \'310, Thatis a very deep and important question - more than you might imagine. Let meexplain. It is the details of the output impedance that convey so much of themusical romance we hear when listening to great amplifiers. The non-zero outputimpedance and its variation with frequency give rise to a large romantic andbeautiful soundstage. It helps deliver deep front-to-back depth of field,together with sweet imaging within that extensive sound-field. It allows theamplifier to \"listen\" to what the room is doing acoustically; thisroom-amplifier interaction provides a sense of believable ambiance and acousticspace that is thoroughly realistic and quite enjoyable. All this for a numberof technical reasons beyond the scope of my missive here. My latest thinking onsource impedance is 1.70 ohms, my very most favorite number, and sure enough,Zout = 1.70 ohms for these amplifiers! One more thing, it may be changed frommuch lower than that to much higher by changing the idle current, and is readon the front meter. Great question, hope this helps and that I did not put youto sleep with my long answer. Thanks for asking, Bob Carver
Q: Wow two ofthe worlds best tube amp designers, one amp - must be AMAZING! I will offer formy Stax F81\'s, that need limitless juice to open up. I use a Luxman M6000 rightnow, but the promise of tubes like this on the Stax, I have to offer!
A: Hi \'att, Hey,I have only stood on the shoulders of the truly greats - Sid Smith, FrankMcIntosh, Stu Hegeman, and foremost Tim de Paravicini. I\'m lucky to be livingnow, and was able to rub shoulders with Tim and some of the other greatamplifier designers. These amps DO have almost limitless juice to get anyspeaker to show its true self! offer away, and if you should win and live withindriving distance I\'ll deliver them myself. offer away, happy offerding! Bob Carver
Q: Youramplifiers are beautiful. I love the dark red color, very classy. I have a pairof Apogees and I have been using a solid state amp and would like to switch totubes. A friend of mine brought his tube amp over and it sounded great, but itcouldn\'t drive them well. Do you think your amps would be able to drive them?Also, how is it possible that the tubes in your amps could last 50 years? Ibelieve you, but it just seems to good to be true. Thank You, James.
A: Hi\'tro, Mymother taught me that if something seems too good to be true, it probably is.Forget everything thing your mother taught you about moderation - the tubesWILL last 50 years - here\'s why. First of all a good output tube that isoperated well below its maximum dissipation (heat) level will last a long time,substantially longer than three or four years. They have been designed by ourforefathers to do that. Take a look at all the vintage stereo amps listed on - the ones from consoles - their output tubes are about 50 years old andusually check out fine. As for the small tubes, my own experience as a T.V.fixing man in my youth taught me that video pentodes and sync splitters seemedto last forever. They were not quite 50 years old of course, but close. It\'sthe D.C. restorer that allows this extreme longevity, as it reduces thedissipation to about one fourth or one fifth normal practice. Longevity iscalculated as related to the 2nd power of the dissipation ratio; 4^2 ~ 16.Finally, 16 X 3 = 48 years. I think the color is nice as well, it\'s a darkburgundy strawberry with a touch of metallic. Looks better in real life than inthe pictures, if I may say so myself! As for driving your Apogees: If you haveone ohm apogees, no problem - these amps can deliver over four hundred wattsinto one ohm. If you have four or eight ohm Apogees, driving them becomes supereasy and a walk in the park for these mighty KT120\'s and powerful output transformers.I specifically designed them to be able to deliver lots of current by having aseparate high current supply voltage source for the screen grids. Stu Hegeman(my hero) taught me how to do this long ago. Good questions. Bob Carver
Q: holy crap!are you really the bob carver?! if so you ROCK!!! anyways im a young audiophilevintage collector, are you on audiokarma.org? if so i want to add you to myfriends list over there!!!!!! thanks! stereo rob.
A: Hi\'hi fi,Holey Moley Rollers! I love your out-of-sight enthusiasm! I\'ll pinch myself tosee if I\'m really Bob Carver. Ouuuuccchh!! Yep, it\'s me, so count me in.Thanks, Bob Carver
Q: Hi Bob, Greatpair of amps you have there. May I ask, (if it isn\'t an old family secret),what ingredient(s) you use to make the output transformers, that you arewinding for these amps, that you are selling now, superior to the originalsthat you used to use? They certainly are beauties!!! Best of Regards,\"jay\"
A: Hi Jay, Nosecrets at all. I\'m using oxygen free(well, almost oxygen free)copper wire, thehardest steel known to man, non flammable nitrate transformer varnish, and lotsof love with tons of attention to winding geometry detail. Good question, BobCarver
Q: Thank you sovery much Bob! I am in awe of you as an amp designer and even more as a humanbeing. I am star-struck by you. You are a real star in the audio world. I evenkeep these emails so I can show my friends, like an autograph! My buddies won\'tbelieve I actually conversed with THE Bob Carver! You are the best and I am soappreciative. I am going to enjoy building this amp more than any other. I lookforward to our future correspondence. Please don\'t ever stop doing what you do.I grew up with your name on amps and I remember how big it was. Then in the 80\'stubes lost a lot of appeal. My dad had some really big collections of tubes andold tube radios and tube test gear, and I look back today and wish I would haveknown then what I know now. I try to spread the word about tube gear toeveryone I can because I feel like tubes almost became extinct. I would be solost without them. They are what keeps me straight in the mind and gives me somuch joy, after 3 tours in Iraq and now a
A: Hi Sarge, asI mentioned earlier, you have made my day. It is you who deserve the hi-five.Thank you. Best wishes and warmest regards, Bob Carver. And thank you for yourservice!
Q: Hi Mr.Carver. What\'s your conclusion about using output tubes in parallel? It seemsto me very dificult that two or more tubes in parallel (or push-pull with tubesin parallel) will going getting old synchronously even considering that theywere absolutely equal when new. The developed lazy, unequal, or non-linear tubewill cause overloads in the other tube/s increasing their aging, this also affectsthe effective load impedance of the output transformer and distortion will bepresent. Have you experienced this issue? In my opinion, if this occurs, thehi-end performance collapses and the result is a guitar amplifier! Thanks inadvance and sorry for my poor english. Jose.
A: Hi Flash\',You know, that is a very good question - I don\'t know the answer. I never eventhought about it. I must have figured it couldn\'t be a big deal and never gaveit a second thought. But I can do an experiment whose results will teach us theanswer. I have a big quantity (27) of old Sylvania 6550\'s in my tube stash thatI\'ve been buying on (for my audio museum) these past two years. They aregood vintage tubes, varying in age from 30 to 50 years old, and they are quiteused, but still test well into the green. It will take me about 45 minutes todo the experiment, so I\'m going to get up from my computer, go perform theexperiment, and return as soon as I have some results. Stand by.,,,,,,,,,,,,,,,,,,,, Okay, I\'m back. It took longer than 45 minutes. What I didwas I removed all six output tubes from the amp and installed six randomlychosen Sylvania tubes in their place. I adjusted the bias after they warmed upabout 30 minutes and then measured the power output, frequency response,damping factor and power bandwidth. Here are the results (compared to brand newNOS GE 6550\'s, also from my museum stock): The output power was down by fourwatts, the frequency response was unchanged, and the damping factor was changeda tiny amount, so small I had trouble measuring it, even with all my cool labequipment. The power bandwith was changed by exactly the same relative amountas was the output power. Guess what? The amp still sounded great! Now I knowthe answer to your question; my conclusion is that it\'s nothing to worry about.Clearly and with no ambiguity! Super question! Bob Carver
Q: Hello, Bob!!! Beautiful amplifiers !!!! I live in Europe. Is it possible to switch thepower to 220-240 volts? Best Regards KOnsatntin
A: Hi KO\', Thankyou, and absolutely! These amps have split windings on the power transformer,so it\'s easy to do. I\'ll do it for you if you win my sale (if you wish).Otherwise it is a standard operation for a technician who is skilled in the artof working on electronics that has 120/240 volt capability. Move some wires,install a new fuse, and \'viola! 10 minutes per amp. Thanks for joining mysale. Warmest and best, Bob Carver
Q: Are theseamps built with love ? My wife used to say the meals she made me were made withlove. Hey ummm I got a job with some guy named Tom and he has this shop calledVintage Hi-Fi Pittsburgh. I\'m the repair/modify guy and there\'s a guy gushingabout my mods to a C-19. We have both sets of these amps bi-wired on yourribbon speakers. Hard to believe how loud and clean they play. I look forwardto seeing you at Carverfest. Anders
A: Hi anders,You are making my day! Yes, these amplifier are built with gobs of obsessivelove. However you can tell your wife you can\'t eat them. I look forward toseeing you at Carverfest as well. See you there! Bob Carver
Q: Hey Bob, I amhaving some difficulty finding information on using adamantine steel for outputTransformer use. It seems like you\'re the only one to use it. Why adamantinesteel? What are the advantages?
A: Hi \'ber, Thefirst time I ever heard of Adamantine steel was as a young child when I watchedthe classic science fiction movie, “Forofferden Planet,” the screen adaptation ofWilliam Shakespeare’s “The Tempest.” William Shakespeare loved Adamantinesteel. It appeared in several of his plays, most notably “A Midsummer Night’sDream” in which a sword of Adamantine steel was forged. In recent times,Adamantine steel was used by the minor wizard Xolotan (sp?) in the Marvel comicbook Conan The Barbarian. Although I can’t remember what Xolotan used it for,it was likely to try and best Conan and his broadsword. He failed. The mostenduring image I have of Adamantine steel is when the krell “Monster From TheId” in “Forofferden Planet” broke through an impenetrable steel door crafted ofAdamantine steel. It seems that more than one audiophile has used the Krell ofShakespeare’s forofferden planet to define amplifiers. In truth, Adamantine steelis an actual steel developed early in our century (I think in the 1930’s or1940’s) to define the hardest steel known to man. And it still is. At least asearly as 1952, U.S. Steel had a catalog including Adamantine steel with ahardness rating at the top of the list of all the steels they produced. As faras me being the only designer to use Adamantine steel in the outputtransformer, as far as I know, I guess I am! I chose Adamantine steel for myoutput transformers because to this day it is the hardest steel known tohumankind. And the harder the steel, the lower the induced eddy currents andthe better the transformer. Good question, Bob Carver
PLEASE ASKQUESTIONS! THE MORE THE HAPPIER! NO QUESTION TOO SILLY!GOOFY QUESTIONS ARE AMONG THE BEST, SO DON\'T BE RELUCTANT. I LOVEQUESTIONS.
Bob Carver
