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Toolshed Amps?


Shakeydeal

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12 hours ago, captainbeefheart said:

 

I am hoping for a confirmation but after some reading I am lead to believe these amps do not have any feedback. You just built a no feedback 300b amp for a member correct? Where were you getting your 1% THD at? And from memory you were around 5% THD with 6.5 watts or so correct?

 

In your experience have you been able to get 1% THD at 8 watts from a single 300b and zero feedback? Maybe I am doing something completely wrong but before feedback I was never close to getting that low distortion at that power and obviously I try and linearize an amp as much as possible even knowing I will use feedback.

300B @ 1% THD+N

 

This measurement was made of 2 different sets of 300B's with about 200 hours on each set. A newer set of 300B's (with only about 75 hours on them) had much higher distorion and lower power output based on 4 Watts as a refererence.

 

300B 1% THD.jpg

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59 minutes ago, Curious_George said:

300B @ 1% THD+N

 

This measurement was made of 2 different sets of 300B's with about 200 hours on each set. A newer set of 300B's (with only about 75 hours on them) had much higher distorion and lower power output based on 4 Watts as a refererence.

 

300B 1% THD.jpg

 

Have you measured the new W.E.300b at 1W ? It's an eye opener for sure, possibly due to the new proprietary filament coating.  None of the other 300b's are even close, although among the "other" high-end brands (EML, KR, Takatsuki), the Elrog ER300b (possibly due to the Thoriated-Tungsten filament) is closest, full disclosure, we have no EAT 300b to evaluate. Also, the Transcendence Amplifier uses a higher-than-typical primary on the output transformers, this helps to keep distortion lower at higher power as well. The amplifier was designed for musicality, not power. If a 3K primary OT was used at this operating point, the power would be in excess of 11W. This said, it really is a "dance" that numbers alone cannot quantify. 

 

Matt.

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1 hour ago, ToolShedAmps said:

 

Have you measured the new W.E.300b at 1W ? It's an eye opener for sure, possibly due to the new proprietary filament coating.  None of the other 300b's are even close, although among the "other" high-end brands (EML, KR, Takatsuki), the Elrog ER300b (possibly due to the Thoriated-Tungsten filament) is closest, full disclosure, we have no EAT 300b to evaluate. Also, the Transcendence Amplifier uses a higher-than-typical primary on the output transformers, this helps to keep distortion lower at higher power as well. The amplifier was designed for musicality, not power. If a 3K primary OT was used at this operating point, the power would be in excess of 11W. This said, it really is a "dance" that numbers alone cannot quantify. 

 

Matt.

I have not measured new (or even old) WE 300B’s. If someone was to lend me a set, I’d be glad to. 
 

For SE 2A3 and 300B amps, I prefer 5~6k OPT’s… for as you say “musicality” not maximum output power. 

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8 hours ago, ToolShedAmps said:

The design goal was musicality, everything else seems to fall into place within that context given sound engineering practices, a little luck, and mentors such as Gordon, Herb, JC, Joe Roberts... and countless unnamed contributors to MJ Audio magazine over the years.

Unfortunately, I have never had the pleasure to (physically) work with mentors in the tube audio field. I guess in a manner of speaking, reading countless hours of forums (with a grain of salt), books, periodicals and RDH4 (from front to back), I had mentors from afar. 
 

I am self-taught, which makes you even more focused sometimes when designing circuitry and amps. 

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6 minutes ago, captainbeefheart said:

 

That's the one issue with zero feedback type amplifiers, the performance of the amplifier is much more dependent upon the linearity of the tubes. It's a lot tougher to get consistent numbers.

 

 

Yep. When I build an amp without feedback I swap input & output tubes (after a good break in) until I get the best distortion and match output levels to within 0.5dB. Then those tubes are mated for life. 

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2 hours ago, captainbeefheart said:

 

That's great thank you.

 

I would change the specs on your website to what you just wrote here. Your website is misleading, it says no more than 1% THD and people are going to think that is at full output if not otherwise stated. This is the same thing that was just happening to the Crimson 275, they mislead on the specifications which got a lot of people fairly upset the product was sold under false pretenses.

 

Someone has to keep the manufacturers honest, hopefully you understand and not take this personal.

 

Noted, and adjusted....... FWIW, you'll notice that Silbatone doesn't list ANY specifications for the amplifiers on their website....., and believe me when I tell you that JC and Joe know what they are doing. ;)

 

Suffice to say that the amplifier sounds glorious, even at full power, banging out Highway Star at an absolutely absurd volume level, only fit for a teenager! ;)

 

Cheers!

 

Matt.

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1 hour ago, captainbeefheart said:

 

There is really no need to have a 'mentor' for amplifier design. All that is needed is good foundation of electrical engineering and time. Study and analyze circuits, build them and test them, listen, over time you make your own conclusions and not someone else's. You do not need a college degree although having a solid understanding of mathematics is extremely useful and will make life a lot easier.

 

It really boils down to effort and time, you get out what you put in. I never had a mentor of any sort, just lots of books and many files of circuits to study. Then the time to build circuits and test them, listen and evaluate, this is how I made correlations between what I am hearing and what I am measuring. If you learn from a mentor only you not only pick up their good habits, you may also pick up their bad habits as well.

 

 

As for this.......... I somewhat agree, you can find and read, and disseminate as much information as you can get your hands on, develop a more-than-passable working knowledge of advanced mathematics, crawl down the rabbit-hole of endless forum "suggestions" until you become part of your computer chair, then order up $20K worth of resistors, caps, power transformers, chokes, output transformers, signal tubes, power tubes, rectifier tubes, vr tubes, solder, switches, tube sockets, wire, etc........... and solder together all of the circuits you've read about and see how they sound................. so about 5,000hrs and two marriages later you can be somewhat satisfied? Maybe if it were a hobby. Certainly not the suggested methodology if you've got four kids to feed.

 

I feel eternally blessed to have the help I've been given...... and express it every chance I get. The "help" is usually in the form of not wasting precious time chasing a topology that's been tried by others and is ultimately not good enough. This kind of direction is most welcome. 

 

Bad habits..................... Hmm.... well, everyone knows that audio designers have the capacity to grow like any other human being. Changing one's perspective is part of the human condition. I welcome change................ as long as it sounds better. ;)

 

My recommendation for those wanting to DIY, is to find a topology that several people have used, build from a valid schematic, then rub on it till it shines. You'll learn much in the endeavor. I absolutely believe in empirical evidence to support what I'm hearing. Word of advice: buy the best iron you can afford. There is a difference.

 

Good Luck!

 

Matt.

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Hi,  Matt is building my 300b right now....    It will be loaded with Hitachi Fine Met OT and vintage main PS and chokes.  Lots of other good stuff in there , NOS Rectifier and input tubes and new production Western Electric 300b’s

 

Can’t wait,  will post pics and impressions soon

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“If you were to hand me your amplifier and not allow me to look inside it or anything, just allow me to measure some in and out characteristics I will build you an amplifier that sounds identical and nobody would be able to tell the difference in a blind test. Your amp could be tubes and my amp could be solid state but still have the same sonic attributes, by nature of course I will try and accomplish this as inexpensive as possible too.”

 

I call “ BULLSHIT” here.  One of the funniest things I think I’ve ever read

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36 minutes ago, Steve. said:

“If you were to hand me your amplifier and not allow me to look inside it or anything, just allow me to measure some in and out characteristics I will build you an amplifier that sounds identical and nobody would be able to tell the difference in a blind test. Your amp could be tubes and my amp could be solid state but still have the same sonic attributes, by nature of course I will try and accomplish this as inexpensive as possible too.”

 

I call “ BULLSHIT” here.  One of the funniest things I think I’ve ever read

Bob Carver did that very thing 40 years ago and it pissed a whole lot of people off! 

 

https://www.bobcarvercorp.com/carver-challenge

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11 minutes ago, Steve. said:

I would like a Marantz Model 8b please, with all the tube goodness in a solid state 1/2  1RU size ......  I had a Carver 1.0 , was supposed to sound like tubes....it didn't.    Wasn't bad but not a great amp by any metric.

 

 

Yeah rumor has it the clone wasn't reliable enough to put into production so the M-1.0t was basically a watered down version. I've got the tube bug myself have had a half dozen or so amps / integrateds over the years there is definitely something special and engaging about tubes-- I'd love to hear one of these ToolShed amps someday, congrats on having yours built! 

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The closest SS amplifiers that sound like tubes to me are the ones like Nelson Pass builds using mosfets on the outputs and simple circuits. Listening to my PP V-fet amplifier at the present time and it has a very tube like character. The advantage of tubes is cost. Tube amplifiers with our speakers can produce outstanding sound for less money then a class A SS amplifier. Mystic character also with those glowing tubes to look while listening to music. Adds to the entertainment experience which is what our hobby is all about. Transistors have been trying to mimic the tube sound since invented. Mosfets have curves like pentode tubes. V-fet transistors have curves like triode tubes so they have a triode tube character. 

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15 hours ago, ToolShedAmps said:

Word of advice: buy the best iron you can afford. There is a difference.


Price (money) does not equate to the best. The boutique transformers are always much more just because they don’t have the sales volume. That doesn’t make them better. Take Hammond transformers for example, if you listen to the “experts” Hammond is pure junk. My first tube amp I built 23 years ago used 1627’s and the amp sounds wonderful. Especially if you use an 8 Ohm speaker on the 4 Ohm tap for a 5k load. 
 

However, a lot of people will spend money on “the best” to make themselves feel good. 

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3 minutes ago, Curious_George said:


Price (money) does not equate to the best. 
 

However, a lot of people will spend money on “the best” to make themselves feel good. 

This can be said about any product. Reputable companies do build better products for a higher price that are more reliable, last a long time, and sound better. Sounds like Heritage speakers doesn't it. 

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