VHT gig review

[Tetsuo]

The thing that I forgot about the VHT that no other amp I've played does is the clarity thing. I can have raging dimed out mayhem levels of distortion and play diminished chords - each note rings out fine. I can hear the difference in how hard I pick with full distortion, or if I hammer... what you give up is the ability to coast, or just kinda let your hands get pretty close to the notes you want and for them to come out ok. The VHT is just a strange beast, people either love them or hate them. There's nothing like them IMHO... and the Ultra Lead is even worse. At least the 50/CL has a little bit of give to it - the UL is so stiff you could use it to shore up a skyscraper.

Pete

Twas the case with my UL/ One hell of an amp for sure but man was it precise. It was basically what I call a clean clear Mark IV on roids

[akoch]

oh man, you are going just for the sake of it. Let's just wrap it. Just one last sentence:

"Again though, you aren't going to find a tube rectifier that is as efficient as a solid state device"

Where in my post did I argue this? I think I agreed like two or three times on this point with you, you are bring it up again. I'm wondering why. The tube recto is less efficient, no doubt about it - the whole 20-33% less than the SS. I also was saying at least twice - one 5U4 still provides MUCH more than a 50W amp requires, actually closer x2 to what the amp needs with all its inefficiency. Gave you the numbers to prove it. The power sag from it is VERY subtle on a 50W or less tube amp. Again - not absent, not non-existant, just hardly detectable. All that sag and saturation at full power really comes as a combination of the power supply performance and sag (yes, the SS-based still has it, just less of), tube saturation, transformer saturation, speaker load and compression. This is a much more complex picture than going for this simple explanation of the tube vs SS recto, which is at best is responsible for 10% of the result. Now, having said this let me bow out. Spend more time with you cat

[Twisteramps]

Where in my post did I argue this? I think I agreed like two or three times on this point with you,

Look at your results - they don't agree with me as far as voltage drops.

Results:
- green channel - identical readings on SS and tube rectifications, plate volrage 419V, output power readiing has not changed
- red channel, 5% reduction in power overtall in relation to the green channel, 6% reduction to for the tube rectifiction setting, but - no detectable plate voltage variation.

I don't observe any voltage and current drop on neither output, nor plate voltage.

So are you going by your agreement with me in the reply above, or your test data which refutes me?

[akoch]

Dude, get your results. There is no need to convince me.

[Twisteramps]

I'm not trying to convince you, just trying to get you to give the same answer twice in a row. You agreed with me, even when your amazing data test gave you different results. What the fuck is this, Schrodinger's Cat?

Pete

[akoch]

I think these are simply flaws in you logic. You seem to miss what's openly on the surface:
- the tube rectifiers are less efficient than the solid state ones (both of us agreed, like the theory of electricity really requires it)
- you stated that in the VHT 50CL you get a real difference playing SS vs tube recto mode, suggesting a significant plate voltage drop while using the tube recto mode. I disagreed and went as far as carrying out actual tests. I published the results intentionaly with minimal comments. I also believe that the any difference that might come from playing the tube recto mode, will come from the softenning the attack, and sagging the volume subtly when going wide-open and hitting the amp hard. You seem to go with a 'brown sound' theory, which is more about lower voltage and earlier breakup. Anyone sees the difference?
- you seem to believe that since the tube recto is less efficient it will result in lower plate voltage, pronounced compression effect etc. I demonstrated you at least twice that the power that the singe 5U4 provides is more than can be called for in a 50W amp, check the numbers, put them in a couple of formulas. I also showed that the rectified voltage on the tube recto can be significatly more than of the solid state rectifier. In fact much more. Man, I don't know how can I put it in a different way... will a BMW M3 go better/faster if you put a chevy big block in it vs its stock high-performance engine? The big block sure has twice more horse-power, more sag, and its sure less efficient. But it still provides more than adequate power for the car. This is where we seem to get stuck.

[Twisteramps]

Whether you can hear it or not, a tube rectifier SAGS versus a solid state one. It does not have to be underpowered to do so. Part of this is the internal resistance in the tube. You can duplicate some of these effects by putting a resistance in series with a solid state rectifier.

Whether you can measure it, a tube rectifier is NOT AS EFFICIENT as a solid state rectifier and WILL DROP VOLTAGE. I'd bet over 50v in the VHT.

No car analogies, no swinging around your degree like some magic wand... please, just answer YES or NO to the comments above. Which is it this time? Could I get just a plain answer minus the obfuscation?

Pete

[Shawn Lutz]

Pete said obfuscation...nice word

[akoch]

LOL when running out of logic and arguments, starting to use cats and rithoric? If unable to prove it, try to put the opponent on the defensive? Hope it will help you. Anyway, one very last time:

- I don't hear the a sag with the tube recto in my 50CL, certanly none on the green channel, a hint of it on the red; as described in the test conditions. Is this a clear NO?
- I believe in the numbers I got from the test, as described in the test conditions. Does this comes accross as YES???
- I believe that tube rectifiers are less efficient and exibit a higher energy loss during the conversion. A 50W SS-based rectifier will outperform a 50W tube-based rectified. Does it mean that the 50W amp is underpowered by the almost 100W-capable rectifier? Does a tube recto have to be of lower output (rectifed) voltage? Hell, NO.

Is this just me who can not understand why the same thing needs to be said 3+ times for mr Twister to take note of it? Look, I'm not asking you to comprehend it, just register the similarity between the three distinct answers.

[Twisteramps]

You didn't answer my questions directly, that's fine. Next time I build an amp maybe you'll be around to run an o-scope while I hand tune frequency response by choosing the coupling caps by type, voltage and value. Maybe you'll polish the glass on your degree while I'm changing the lead dress to get a subtle improvement. Hell, maybe you'll even get your degree out from the glass and sniff it while you stroke your oscilloscope... again, I'll be building or modding an amp. By the way, one of the websites I quoted for the rectifier internal resistance... was an amp designer who is a member of NAMM, makes awesome amps, and holds an EE degree. I guarantee he's forgotten more about tubes and tube amps than you and I will learn in our lifetimes.

Anyways, I ran a voltmeter on the thing in tube and solid state rectifier mode. Measured a drop of about 30 volts, which is much less than it should have been, but still a difference. It was surprising, but still is a difference that should be noticable. Yes, the tube rectifier dropped voltage. And I also changed channels and the same thing occured.

And again, just because your golden ears can't hear it doesn't mean the sag and tonal difference doesn't exist. If you have horrible vision and can't see a car crash 1/8th of a mile ahead of you, it means you can't see well, not that the car crash never happened. It certainly is subtle at regular levels - at my gig I could hear it a little bit. If you're playing in your basement at very low levels, you very well may not hear anything. I use my amp at gigs, maybe that's the difference.

Enjoy your amp, I'm going to enjoy mine.

Pete

[jgcable]

Here is what I found in my intense studies of these theories.
My Stilleto sounds different when I switch between the Silicone Diode setting and the Rectifier setting. The Stiletto uses big bottle rectifier tubes. I believe they are 5u4's. My owners manual says that the tone difference is due to the voltage sag exhibited when using the Rectifier tubes. The Silicone Diode setting is mure constant and thus exhibits a tighter attack.

[Twisteramps]

Hey John, do me a favor - measure plate voltage in SS vs Rectifier modes. That's the same family of rectifier that the VHT 50/CL uses... I'm betting you see a bigger difference. I'd appreciate it, and am curious. Thanks!

Pete

[akoch]

the degree thing really got you Heck, take it easier, consider the benefit of not having to kill 6 years of your life to go through that. Don't forget you initiated a harsher response by accusing others of "you don't know what you're talking about", and "cat's algebra". You don't know what you don't know. I just paid you back your own medicine, no other intentions. Nevertheless - peace man, just maybe don't jump the gun so quick next time, at least on me

I knew from the very start where you were coming from, and the actual answer to the recto thing for the 50CL. The answer would have been different for some of the other amps. And quite a few people on the board understand a thing or two about the amps, tubes and amp design. The 50CL is probably the amp I happened to like and use the most, well... the Soldano is another one for me.

Your results are practically identical to mine: you got 7% difference. This is well under the 10% tolerance level and I can bet my money it will vary from amp to amp, year of production/circuit revision and settings. Hope you will not say this is a principal alteration of the tone and response of an amp. Wether you can hear it.... I will not argue, it is personal. I admitted that I sort of can, but it is REALLY subtle and more pronounced on the red channel, I doubt that if you are not intimately familiar with the amp you can identify it. Sounds like you are not too far from this opinion as well. Still, there is a huge myth going on in the industry about the tube rectification. For me this is mostly marketing. There are though some amps where it effect is pronounced. Hint: look for dual tube recto amp of 160-200W output. And good getting it to sweat even at the stadium levels. Or some of the older designs of 80+W output stage with singe tube recto.

Again, no need to accuse others of sitting in the bedroom, not building/fixing amps, or stroking a scope etc. Many are still gigging or gigged in the past, can/do work on electronics, or just enjoy music.

Peace, enjoy your amp(s).

Alex

[Twisteramps]

Alex, don't be so reasonable, makes it harder to flame on here.

Regarding the voltage drop - what is weird is that it should be a LOT more. I need to send Fryette an email and see what's up - the VHT has a fairly complex PCB so I can't just poke around on it as easily as I can a Plexi or old fender and just trace the power and signal paths. He has something weird going on there, probably some sort of voltage regulation, because at the voltages I was seeing for the SS rectifier (fairly close to 500v!) There should have been more of a voltage drop for the tube rectifier.

Sorry about the shots on your academic credentials, but I've seen guys with Master degrees in electronics not know their ass from a hole in the ground regarding tube amps, and come out swinging on other threads here and at other boards. I'd really be surprised if any college taught much about tubes beyond historical footnotes after the mid 70s. The best textbooks that I own are from the 50s - everything after that is polluted with transistor information and theory - "the wave of the future!"

Pete

[akoch]

Alex, don't be so reasonable, makes it harder to flame on here.

Regarding the voltage drop - what is weird is that it should be a LOT more. I need to send Fryette an email and see what's up - the VHT has a fairly complex PCB so I can't just poke around on it as easily as I can a Plexi or old fender and just trace the power and signal paths. He has something weird going on there, probably some sort of voltage regulation, because at the voltages I was seeing for the SS rectifier (fairly close to 500v!) There should have been more of a voltage drop for the tube rectifier.

Sorry about the shots on your academic credentials, but I've seen guys with Master degrees in electronics not know their ass from a hole in the ground regarding tube amps, and come out swinging on other threads here and at other boards. I'd really be surprised if any college taught much about tubes beyond historical footnotes after the mid 70s. The best textbooks that I own are from the 50s - everything after that is polluted with transistor information and theory - "the wave of the future!"

Pete

Oh, flaming - that we can Just say 'go' LOL

Regarding the voltage drop, I would love you to ask Steve. I did in the past, it came to an interesting discussion with him going over how Mesa emulates the tube recto sag using transformer characteristics and some intersting tricks. For a simple reason - it was not possible to get one with two recto tubes and 100W power rating. But since "Recto" is a big selling feature for Mesa, they go an extra two miles to emulate the effect. He wanted to stay away from this path, and achieve the natural sag. That's why the 50CL has so little of it... because this is what you really going to get without silicon implants . And this is the reason he dropped this option for the 100CL version - two tubes would jsut provide lots of power and the sag will be undetectable.