45SET amplifier

[player77]

I own klipsch cornwalls and would like to get a 45set amplifier.

I wont build it specifically myself but i found a great guy who builds great valve amps locally to me.

Ive heard rave reviews of the Jeff Korneff 45 set amplifier and how the sound is the best you will ever hear.

I have found some information on some parts he uses and was hoping to buy similar parts and use a similar design. Can anybody help with what parts to buy and what schematic/design to use get a similar sound.

1 question I have is they say 80% of a tube amp is in the transformers, specifically the output transformers is that right. Or is it all the transformers including input?

The valve amp builder i found basically uses budget/medium range parts and the sound is quite good. I heard the 300b and not the 45 set as he didnt have 1 he had built to listen to.

He is happy for me to give him any specific designs or upgraded parts, transformers , tubes etc ,

Would the best option be to just get electra print transformers as that would give the biggest sound quality increase as I heard thats what jeff Korneff uses in his amps.

Or are there better for value money transformers out there for a 45 set .

Does anybody know exactly which transformers from the link Jeff Korneff uses?

http://www.electra-print.com/singleended.php

I want the best bang for your buck without going overboard on parts prices as some of the prices of the parts ive seen can be very expensive.

Any help is greatly appreciated.

[Panacea Engineering]

Player,

I'm not sure how much research you have done but you are certainly in for an adventure. I haev always wanted to hear my K Horns on valves and wanted to build an amplifier myself. I spent the better part of a year researching the various types of tube amps, looked at what was available, spent many hours just reading. It seems that everyone has the BEST tube amp so you have to be very careful in your choices. What does your local "builder" guy suggest? I finally decided on a 300B Push/Pull amp that was available in kit form a few years ago but is not to be found in kit form now. I took the plunge, did the research, ordered the parts and started building. It has been one of the most rewarding things that I have done in many years. Be prepared as this is NOT a cheap adventure at all. I have a build thread going on a European Forum called Audio - Talk. here is the link:

http://www.audio-talk.co.uk/phpBB2/viewtopic.php?t=3542&postdays=0&postorder=asc&start=0&sid=366af5756d7d1db8586c37ffe6f1e5fc

I am about 90% complete with the project and I had to take a short break due to my overdue retirement date and the construction of a new building. Not enough time to fit evberything in but I hope to finish the amp before Christmas (Present to Myself). I look forward to hearing the K Horns on valves. The "Iron" as they call it, is a very important part of the amp, but the quality of the other components, I. E. Capacitors, Resistors, Wire and the Valves are also very important, as they must all work together to provide the quality sound that you are looking for.

Good luck in your adventure, take the time to do the research, as it will pay off in the long run. Get out of the "Gotta-Have-It-Now" syndrome, as this requires a lot of patience. Don't just jump on something because someone says it is the best, there are a lot of BEST out there. Try to do as much listening to valve amps as you can before deciding. You will have to be the final judge in what you want with your Cornwalls.

Good Luck - W. C.

[Cut-Throat]

There is a Korneff 45 amp on the Audio Asylum Website for sale. This may be cheaper than building your own 'imitation'.

No, I am not the seller, or know who is.

http://trade.audioasylum.com/ca/listing/Amplifier-Tube/korneff/45-set-integrated/black-local-pickup-new-jersey-preferred./44217

BTW - I have 45 SET Monoblocks (Welborne Star Chiefs) and they are my Favorite Amps.

[mike stehr]

I own klipsch cornwalls and would like to get a 45set amplifier.

45 sounds great with Cornwalls...but if you a bit more oomph, 2A3 has a little more power.

1 question I have is they say 80% of a tube amp is in the transformers, specifically the output transformers is that right. Or is it all the transformers including input?

I can agree with that. A cheap ringy limited bandwidth output transformer ruins everything. I would go as far to say the the driver stage is right up there in that 80%. One wants a good linear driver stage, with low distortion and plenty of drive. What good is a fancy output transformer if the driver stage isn't up to the job.

Would the best option be to just get electra print transformers as that would give the biggest sound quality increase as I heard thats what jeff Korneff uses in his amps.

Well, if you want to copy the Korneff design, then Electra-Print would be the ones to use.

Or are there better for value money transformers out there for a 45 set .

Does anybody know exactly which transformers from the link Jeff Korneff uses?

http://www.electra-print.com/singleended.php

More than likely the 5K primary/50 milliamp SE output xformers for 45. But who knows...there is options with the Electra-Print iron. You can have them wound with silver wire, or have multiple secondary taps, or multiple primary taps. You can have them wound to one's specific needs and budget.

There is plenty bang for the buck output transformers for 45. I have a pair of James universal OPTs, they sound great to me. You can go hog-wild on the output transformer budget...Magnequest, Hashimoto, Tamura, James, Electra-Print. The list goes on and on...from cheap to downright rich.

I want the best bang for your buck without going overboard on parts prices as some of the prices of the parts ive seen can be very expensive.

Don't cheese it on the output transformers. Get the highest quality you can get within your budget. Consult with your amplifier builder about this.

You can use cheaper parts like caps and resistors at the start, and set the amplifier up so you can upgrade these parts as your budget allows down the road.

Mike

[Marvel]

Don't cheese it on the output transformers. Get the highest quality you can get within your budget. Consult with your amplifier builder about this.

The Edcor trannies are supposed to be pretty good, too.

[Panacea Engineering]

SP Wound in the UK provided the Iron for my amp. Geoff Budden is the greatest and will work with you to any extent that you want. He is a true fountain of information when it comes to winding. The Mains in my amp is 35 pounds by itself, total transformet weight of all seven was better than 55 pounds. FWIW, here is the Web Site:

http://www.spwoundcomponents.co.uk/

Email him with your questions and he will get right back with you. As mentioned above, the transformers are the Heart of the amp. Not the place to cut corners. JMHO

W. C.

[tube fanatic]

You will find as many opinions about what the best components are as there are amp designers/builders! When budget isn't a concern, I always use the Hammond 16--SEA series of single ended output transformers. To my ears, and those of the the folks I build amps for, they are excellent and provide great value for the money. 45s are nice tubes and tend to sound lovely in the right system. But, there are other tubes which can do a just as good, or dare I say better, job. So, you really need to have a long conversation with your amp guy and ask for recommendations based on his experience. I've used many triode connected pentode designs for owners of Cornwalls. Depending on the size of your listening room, how far you sit from the speakers, and how loudly you listen those can often be a very cost effective way of achieving the sound you want without incurring a considerable expense. Is the local fellow willing to "voice" the amp for you in your listening room? That refers to adjusting the operating parameters of the amp to modify the resulting sound to some degree. It seems that you're on your way to a great listening experience. Just take your time and ask lots of questions before committing to a definite plan of action.

[Mike Lindsey]

I had a Jeff Korneff 45 that I sold a couple of years ago. It just didn't have enough oomph for me, but it sounded marvelous. Jeff is one of the premier amp builders in the country and you can't go wrong with one of his amps.

Mike

[erik2A3]

FWIW:

Another amplifier in the same power range as the 45 triode is one that subtracts one of most important aspects of its (or any transformer coupled amplifier's) performance is one that does not rely on one (an output transformer). They're referred to as an OTL, and many who have heard them have come to prefer them for a number of reasons to more conventional single-ended amps that use more conventional air-gapped output transformers for impedance matching between amp output and loudspeaker. I own several single ended amplifiers using the 2A3 and 300B triodes, and also find myself using one of the two OTLs I own from Transcendent Sound.

The OTLs referred to above do not use hollow state rectification (vacuum tube diodes), but rather solid state counterparts with significant filter and storage capacitance. There was a time I wouldn't consider anything that did not rely on vacuum tubes, but thankfully stepped away from that notion.........which, just speaking for myself, was ignoring some potentially highly sophisticated circuitry with outstanding sonic performance.

And as always, there is not a single audio component that fits everyone. Some have tried OTLs and ultimately returned to their comfortable single ended triode amps (which I do from time to time too......depending on my mood, and depending on what music I'm listening to, etc. The human element constitutes a very significant part of the equation, IMO.

I'd like to suggest too, that as much of a fan I am of the lower powered OTLs and SET amps, there are also some not just good, but extremely good sounding higher powered tube amps using EL-34s, 6L6s, etc.

And then there are also the very high powered designs from Transcendent Sound (with whom, by the way, i have not a single connection other than for owning some of their amps and building, or in three cases completely rebuilding, them for others). You might check the website and forum for more information. Interesting stuff! The single ended SEOTL, which is the one in the same ball park in terms of power as single ended 45s, is IMO staggeringly good for such a low power amp, and I far preferred it to any 45 amplifier I have heard. If I'm not mistaken, Korneff's 45 is of a shunt (aka parallel) feed output topology, which is different from the usual output transformer that has to deal with both DC current and music signals, and I have built a couple of this type of amp using both the 300B and 2A3. They ARE different, and about as close as you can get with an output transformer to not having one at all................but not quite.

Try to listen to as many as you can, enjoy the process.

Erik

[erik2A3]

I may be thinking of someone other than Korneff as far as the parallel output design topology. Been such a long time since I've poked around at those amps, but there are a number of such designs, including Bottlehead stuff (formerly Electronic Tonalities, for those of you that remember that...) The Horus, which I also built, was one of these amps. Users of Moondogs and other common SETs can also subjectively easily (just time consuming) replace the existing OPTs on their amps with a high quality parafeed design from MagneQuest, as well as the necessary large plate choke for the DC component. This is an extremely WORTHY modification, at least from what I heard. There was another forum member and Moondog owner that used to contribute here that performed this precise modification to his Moondogs, and never turned back.

Again, all subjective, and capable of being changed back if one wants or is interested enough in the investment of time and money to complete the task.

[erik2A3]

BTW: If you're still reading this thread -- I also happen to very much like the Electra-Print transformers. This is another entirely subjective element, but I've heard the EP and another brand of also highly regarded output iron, and preferred the Electra-Print.

My Moth Audio 2A3 amplifier also uses Electra-Print output transformers. The Moth 2A3 circuit is the best I have heard in terms of a conventional SET amplifier, and very close to a parallel feed output configuration, which is distinctive.

erik

[Guest " "]

1 question I have is they say 80% of a tube amp is in the transformers, specifically the output transformers is that right. Or is it all the transformers including input?

there are a lot of cumulative contributive factors involving various components in a tube amp. But on the transformer question, if inductance is too low....low end frequency response suffers because the tranny acts like a low pass filter and shunts to ground needed bass response....example....a 26 Henry coil on a 600 ohm load will shunt frequencies below 3.5hz to ground...which is not a problem since there's no real music at 3.5hz. Lower the the inductance and now your lo pass to ground frequency creeps up....it's difficult for a small tranny to operate above 30hz.

But high inductance is usually associated with high impedance. A KT-88 might operate ideally with a 2500 ohm primary. A high inductance primary might be 5000 ohms. So you saved you bass response...but now you cut your power in half.

Then you have the issues of capacitance, course windings, air in the laminates, etc which hurts high frequency response.

[erik2A3]

Yup. That's why it can be very nice to get rid of the OPT altogether. OTL, well designed, is rather spectacular, IMO.

[jcmusic]

Player77,

I have a Jeff Korneff 45 SET amp with upgraded khorns, see my signature or PM me for more info.

Jay

[JBryan]

The Korneff 45SE is a great amp, I owned one for years and it held its own against quite a few other 45-based SET amps I put up against it. As others may have mentioned, 45SET amps put out 2 watts or less and if your room is any larger than say, 10' x 12', you'll have to listen at fairly reasonable SPL's, probably below 85dB or risk some compression and distortion. In other words, if you like to ROCK OUT!, you may be disappointed.The Korneff amp in particular has very low gain and has a difficult time pushing those 15" woofers. I tried the Korneff on both C'Walls and Khorns and the amp was much more compatible with the Khorns - very smooth and detailed.

On the other hand, I can't agree more with Eric's recommendation of the SEOTL amps. I have a pair and they really sing with CW's - dynamic, super fast and lots of oomph in the bass compared with the Korneff. I'm working off memory but I preferred the Korneff with Khorns - nice detail and you can't duplicate that 'you are there' sensation of SET, especially the 45 and a pair of SEOTL's with the CW's - great transients, excellent bass and more open presentation on the top.

Your ears will tell you more than any of us can but I'd suggest a minimum of 8-10 SET and SS Class A watts (300B or equivalent) to adequately drive the CW's, double that minimum for Push/Pull and triple that for Class A/B SS. Have fun!

[player77]

Thanks to everybody for all the great replies and advice.

Would running a solid state pre amp affect the sound coming out of a 45 set amplifier in any way?

Or would it totally destroy the 45 set magic sound and make it sound solid state doing this?

[tube fanatic]

Thanks to everybody for all the great replies and advice.

Would running a solid state pre amp affect the sound coming out of a 45 set amplifier in any way?

Or would it totally destroy the 45 set magic sound and make it sound solid state doing this?

It's hard to determine what effect it would have. You would need to try it yourself. Remember that your sources are, I assume, all solid state anyway. Why not go with an integrated tube amp so you don't need a preamp at all?

[seti]

Personally I think it would defeat the purpose of going 45 SET. I've never run a 45 but have run a 300b. I've been using a passive preamp or autoformer volume control and really dig it. http://www.intactaudio.com/ This is really minimal but depending on your source it could be all you would ever need. Intact Audio makes a really good one and they sell kits as well. These have been done by western electric luxman and quad in the past.

[mike stehr]

Personally I think it would defeat the purpose of going 45 SET. I've never run a 45 but have run a 300b. I've been using a passive preamp or autoformer volume control and really dig it. http://www.intactaudio.com/ This is really minimal but depending on your source it could be all you would ever need. Intact Audio makes a really good one and they sell kits as well. These have been done by western electric luxman and quad in the past.

Which version of the Intact Audio AVC did you purchase? Fully assembled in a steampunk box, the modules with the autoformer wired to a couple potentiometers, or the kit with just the autoformers?

I've been using just a pair of 60K Allen Bradley type J pots mounted in a box for years as a passive attenuator...and pontificating over buying the Intact Audio AVC for just as long. I don't need the extra gain from a tube pre-amp, and always been happy with attenuating using the AB type J pots.

The kit seems nice, but I'm not too thrilled about wiring 100 or so wires to a multi-tapped switch. The modules are what I want...it's all just a matter of figuring out how to pony up the cash.

I even have a old vintage dovetailed mahogany box picked out for the modules. It'll match my turntable plinth and entertainment center.

Mike

[seti]

Personally I think it would defeat the purpose of going 45 SET. I've never run a 45 but have run a 300b. I've been using a passive preamp or autoformer volume control and really dig it. http://www.intactaudio.com/ This is really minimal but depending on your source it could be all you would ever need. Intact Audio makes a really good one and they sell kits as well. These have been done by western electric luxman and quad in the past.

Which version of the Intact Audio AVC did you purchase? Fully assembled in a steampunk box, the modules with the autoformer wired to a couple potentiometers, or the kit with just the autoformers?

I've been using just a pair of 60K Allen Bradley type J pots mounted in a box for years as a passive attenuator...and pontificating over buying the Intact Audio AVC for just as long. I don't need the extra gain from a tube pre-amp, and always been happy with attenuating using the AB type J pots.

The kit seems nice, but I'm not too thrilled about wiring 100 or so wires to a multi-tapped switch. The modules are what I want...it's all just a matter of figuring out how to pony up the cash.

I even have a old vintage dovetailed mahogany box picked out for the modules. It'll match my turntable plinth and entertainment center.

Mike

I have a steampunk drug through the hudson Slagle box The simplicity of the AVC blows me away.. You know sometimes less is so much more.