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Tube vs Solid State Amplifiers

Celty

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I just bought a used, 10kg (22lb) single-ended 7wpc Musical Paradise MP301 Mk3 tube amp, and it's on the way from Florida to Panama right now, but for me, I really only decided to buy it for sentimental reasons. It will probably sound Just fine for most of my listening via my small speakers in a small room. My only source is mt Daphile/LibreElec (Kodi) "HYPC" via a Topping DX7s DAC with a volume control, so a preamp is not necessary.
View attachment 46605

I found it on USAudiomart for $425 including shipping to my forwarder in Miami. It has an auto-bias feature, and can accommodate 6L6, EL34/6CA7, 5881, KT66, KT77 and KT88 output tubes. Although those who talk about the amp on internet forums never mention it, I would assume that only one of those tube types are optimized for maximum performance, or perhaps none - as a compromise for easy interchangeability. Also, it is my understanding that how hard you drive the tubes (plate voltage?) changes the "sonic signature" and affects tube longevity.

The amp includes a pair of JJ 6L6 power tubes plus 6J8P driver tubes, and also a pair of Gold Lion KT77's that came matched and tested from Kevin Deal at Upscale Audio. I will probably also buy a pair of tested and matched Tung Sol 6550 power tubes from Upscale - just for fun.

In a couple of months when I buy the 200ASC/200AC ICEpower modules from Parts Express and finish my 70wpc (8Ω) Ghent/ICEpower amp, I will end up having three power amps to play with. In addition to the flea-power Musical Paradise MP301 SE tube amp and the 70wpc (8Ω) Ghent/ICEpower amps, I will also still have the BIG and heavy 1990's 70wpc (8Ω) Classé Model 70 Class-AB amplifier that is currently installed in my main system.
With those extra tubes looks like you got a great deal :)
 

cjfrbw

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I bought one of these. $120 delivered after various credits and discounts. "Compactron" tube i.e. both voltage and current driver pentodes in one tube. I bought three extra tubes on ebay for a grand total of $18 delivered.

3.5 watts of tube power. I have acquired an unusually robust and efficient midrange ribbon with active crossovers @ 300Hz-7Khz, and this guy powers them wonderfully well. It's a little irksome when you get a cheapo that competes with much more expensive stuff. Again, it probably measures like dog's breakfast, but sounds great because I still have perverted tube tastes. It has lots of gain, and doesn't need an additional gain stage in this use.
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cjfrbw

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Wow, living in California must have finally had a linguistic effect on me. I was able to read and understand this Spanish post without a translator. Weird.
I could understand bits and pieces of spoken Spanish on TV, and had some I used professionally for limited purposes.
 

Moretty

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[QUOTE = "cjfrbw, post: 310592, member: 1434"] Wow, vivir en California finalmente debe haber tenido un efecto lingüístico en mí. Pude leer y entender esta publicación en español sin un traductor. Extraño.
Podía entender fragmentos de español hablado en la televisión, y tuve algunos que utilicé profesionalmente para fines limitados. [/ CITA]


Lo importante es ayudar. Gracias
En California debes ser el único que no está equivocado.
 

Blumlein 88

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I understood Gracias, and California. Think I have a ways to go. I can maybe guess close on a couple more words.
 

Ron Texas

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Tubes, not for me in a place where the air conditioner runs 7 months a year. Tubes wear out, electricity is not free and bias has to be set now and then. They don't measure well. However, it it floats your boat, by all means have one.
 

Moretty

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[QUOTE = "Blumlein 88, post: 310846, miembro: 3"] Entendí Gracias y California. Creo que tengo mucho camino por recorrer. Tal vez pueda adivinar cerca de un par de palabras más. [/ QUOTE]

Your mother knows many languages ... give you some classes.
 

cjm2077

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This is correct, however THD or better say nonlinear distortion is not the only parameter to consider. Personally, I see no single reason why to use tube power amplifiers. I would especially address issues with frequency response modulated by speaker impedance and difficulties to design and manufacture a good output transformer, this part is always more or less a compromise and is never good enough.

I would say that should be possible to use all of the modern circuit design techniques and modern technology to build a very well performing tube amp, but it would take a lot longer, cost a lot more to produce, be much larger, be much less efficient, be less reliable, and have wear components you needed to replace on a regular basis, and it's also not clear that there is a customer base in existence for an amp like that. The audience that wants a tube amp loves it for the "character" they have, and the supposed superiority of 50 year old designs. So if you have the technical ability to make a cutting edge solid state amplifier, why would you wast time making very good tube amp that wouldn't really have a market? It's like giving a Michelin starred chef a butter knife, a metal tray, and a can of sterno and telling him to cook you dinner. I'm sure they'd deliver something tasty, but is it really the best use of their time?

I do have to admit some of them are awfully pretty though. And if you're building or repairing one as a hobby because they're easier to work with than trying to make or repair a modern PCB, I understand that too.
 

Celty

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Tube vs. SS is of course a matter of personal preference, but it's going a bit too far to question if there is a market for them. Obviously there is, or there would not be companies designing and manufacturing them. In fact the "boutique" tube amplifier makers who have strong reputations have far more orders than ability to turn them out, so the waiting lists can be lengthy.

All audio is essentially a hobby, be happy ;)
 

cjm2077

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Tube vs. SS is of course a matter of personal preference, but it's going a bit too far to question if there is a market for them. Obviously there is, or there would not be companies designing and manufacturing them. In fact the "boutique" tube amplifier makers who have strong reputations have far more orders than ability to turn them out, so the waiting lists can be lengthy.

All audio is essentially a hobby, be happy ;)

Oh, I was questioning the market for a "State of the art" tube amp. Obviously, people still buy tube amps, there is a market. But I doubt any of them do it because they see a really nice graph of data. A really high tech one won't have all the buzz words they're used to, and will sound quite a bit different. The reviewers will probably call it "Sterile" and "Clinical", or "joyless". It would be a niche inside of a niche, and I don't see that as very profitable as compared to making a cheaper version of the Benchmark amp let's say.
 

JRG

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I think that today doesn't make sense to design a tube amplifier to measure best as possible.

If we want very good performance (SINAD, damping factor,...) the logical way is to use modern technology, because at best with valves we could achieve the same result (up to a limit), but at a much higher cost.
What is better? a 100 dB SINAD achieved with semiconductors or with valves? If they measure the same they are the same.

That said, nothing prevents designing a hybrid amplifier where the valves are used in the final stage of amplification (the push-pull for example) while the previous stages and the power supply are designed in solid state. Or even go beyond adding some type of FeedFordward type correction system that minimizes error of the valve stage to the best possible. The valves amplify the signal and the solid state fixes the error.

The question is: Is it worth that trip? People who buy valve amps want that distorsion of "valve sound"... that is the reason to choose valve amps: valve sound.
A tube amp with the performance of the AHB2 would be quite a technical achievement (almost magic :cool:), but does make NO sense, because the AHB2 do the same much cheaper and reliable in every aspect.
 

cjm2077

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Transformers all suck. Some just suck less than others. Inductors too. If you can figure out how to make a design without them, it always helps in terms of size, bandwidth, losses, and accuracy.
 

SIY

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Getting either the output impedance or wide band low distortion with output transformers would need magic not engineering :)
Depends on how low for distortion. 0.00x is doable with good design- low source impedance to the output transformer primary, low turns ratio, lots of nested feedback loops. If memory serves, Krohn Hite did this commercially back in the 1960s.
 

Blumlein 88

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http://www.wolcottaudio.com/WA_presence.htm

http://www.wolcottaudio.com/WA_Pres_specs.htm

Wolcott tube amps probably do better than your general run of the mill tube amp. Different circuit design and some feedback around the transformers, very low output impedance. Their specs aren't quite up to best SS, but pretty good and unlike specs quoted by most tube designs are at full power. They also will happily power the hard to power Soundlab ESLs.

http://davidberning.com/products/zh270

David Berning amps are a different kind of tube amp. Not normal OTL, though an OTL that works something like a switching amp. Berning patented it as a ZOTL amp. Not super low distortion, but wide bandwidth, low noise, and tubes last about 10 times what they do in normal designs.

Linear Tube Audio make amps based upon his designs.
https://www.lineartubeaudio.com/power-amps
 

Xulonn

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Linear Tube Audio make amps based upon his designs.
Case design allows just a bit of the tube to protrude through the top of their 50wpc, $6.8K "ZOTL40 Reference" power amplifier. I didn't read the design details, but getting 50wpc vs the typical 35-40wpc of ultralinear push-pull designs that use transformers - while reducing current by 50% is interesting. And being transformer-less, it weighs only 15lb (or 6.8kg, making the price $1 per gram).

ZOTL.jpg


Fortunately, although most EL34s have top "getters" (the partial silvery coating inside the tube), the tubes stick up high enough to display the glow that is visible between the getter and top of the plate (as long as the particular brand of tube has a "high" filament - photo of high vs low filament below)

EL34 Filament Glow.jpg
 

Blumlein 88

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The Wolcott's have a ventilated cage or can be run sans cage for tube viewing glory. Nice auto-biasing circuit too.
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Severian

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I was highly skeptical before I built it, but it turns out that I adore my Bottlehead Crack OTL headphone amp. I wouldn't try to convince anyone to go this route over a cheap, capable solid state amp for the sake of high fidelity, but it adds an unmistakable, pleasing character to the sound of my HD6XXs and looks great.

Since I'm already interested in high-efficiency speakers, I'm sure eventually I'll tackle a DIY tube power amp project for the fun of it.

What I won't ever do is spend thousands and thousands on high-end commercial tube gear under the delusion that it's better than solid state.
 

cjm2077

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Case design allows just a bit of the tube to protrude through the top of their 50wpc, $6.8K "ZOTL40 Reference" power amplifier. I didn't read the design details, but getting 50wpc vs the typical 35-40wpc of ultralinear push-pull designs that use transformers - while reducing current by 50% is interesting. And being transformer-less, it weighs only 15lb (or 6.8kg, making the price $1 per gram).

View attachment 47106

Fortunately, although most EL34s have top "getters" (the partial silvery coating inside the tube), the tubes stick up high enough to display the glow that is visible between the getter and top of the plate (as long as the particular brand of tube has a "high" filament - photo of high vs low filament below)

View attachment 47107

So for about $7k for state of the art in a tube amp you can get the specs of a $270 crown amp that puts out 6 times as much power. I'm not saying I don't admire what they're doing technically to some extent, talking about the circuits with the designers would probably be very fun, and it does look pretty. But as a buyer, I don't see the appeal.
 
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