What is wrong with me? Addiction is real.

ICTWoody

Junior Member
Looking good's important, too. When Woody first sent me those pics, I wanted the amps back! Still kinda do... :)
Hey... I have a question that you and probably others can answer. But I'm asking you first. There is no problem running the AmpsandSound amp off the 2nd set of outputs on the Bent AVC-1 and just turning on the power amp that correlates to the speakers I want to listen to is there? Basically I want to run one front end and then just turn on the power amp I want to listen to, either the AAS with the Onkens or the Inspire with the Altec 614/414/802/32 speakers.

I don't want to blow anything up.

- Woody
 

paulbottlehead

Active Member
Your TVC will probably not appreciate the Miller capacitance of both amplifiers running at the same time, but it shouldn't be harmful if you leave one powered up but both connected.

Having said that, if you have a power amp with a 10K resistor across each input, it may sound a little better to unplug the cables between it and your TVC when running the tube amp.
 

ICTWoody

Junior Member
Your TVC will probably not appreciate the Miller capacitance of both amplifiers running at the same time, but it shouldn't be harmful if you leave one powered up but both connected.

Having said that, if you have a power amp with a 10K resistor across each input, it may sound a little better to unplug the cables between it and your TVC when running the tube amp.
Thanks for the advice. I definitely only plan on running one amp at a time. In my current configuration I have the TVC sitting on the floor in the open, so it would be easy to plug and unplug... but if it winds up on my rack...

- Woody
 

ICTWoody

Junior Member
Your TVC will probably not appreciate the Miller capacitance of both amplifiers running at the same time, but it shouldn't be harmful if you leave one powered up but both connected.

Having said that, if you have a power amp with a 10K resistor across each input, it may sound a little better to unplug the cables between it and your TVC when running the tube amp.
Since my AVC has a tape out, would I be better pulling the signal off that and running it through another high-quality attenuator like a Luminous Audio Axiom for volume control?

- Woody
 

SPL db

Junior Member
It's key here to say "OTL tube amps". For transformer coupled tube amps, there are usually lower impedance taps available.
Agreed, 6moons had the best review on these boxes in my opinion.

Quoted from - 6moons audio reviews: Zero Box by Paul Speltz

In essence, that's what the impedance transformers from AntiCables' Paul Speltz promise. That's especially relevant to OTL and low-power SET fanciers whose amps suffer high output impedances that interface poorly with low-impedance speakers. The Zeros are available as raw toroids with spade-terminated secondaries or encased in fancy Maple or Cherry boxes terminated in pure copper binding posts. They offer a 2 x, 3 x and 4 x impedance multiplying function to alter how your amplifier views your speakers. If your speaker is a nominal 4-ohm load with dips to 1.3 ohms, the Zero, depending on how its output taps connect to your speaker inputs, can turn your challenging speaker into a nominal 8, 12 or even 16-ohm load. That raises its undesirable minimum impedance value to either 2.6, 3.9 or 5.2 in our example, making most amplifiers, shy of the expensive load-invariant brutes who don't give a twit, happier campers.


It's obvious that this math works across the board. If your speaker exhibits wild impedance swings -- say from 3.8 to 30 ohms like an electrostat might -- the multiplier action widens the entire swing window. In a x 4 scenario, our example would create a crazy 110-ohm differential. Depending on what load impedance is encountered at what frequency, amplifiers whose high output impedances modulate their frequency response will naturally introduce off-the charts linearity aberrations with such exploded swings. But then, SETs with high output impedance are the most unlikely of all candidates to ever be leashed to electrostats and other speakers that exhibit such deviant behavior in the first place. It's a safe generalization then to say that most amplifiers will prefer a higher load impedance. The Speltz devices are an intuitive, elegant and simple way to accomplish just that.

The operative word is mismatch. The Zeros are not recommended or necessary without a mismatch. They're a cure for a particular ailment, not a maintenance vitamin for healthy amp/speaker marriages. A nominal 8-ohm speaker transformed into a 32-ohm load is not an automatic guarantee for mo betta sound. To a transistor amp which increases its output power into lower impedances (even if not doubling like the brutes), such a transformation could create rather than remedy a mismatch. And while more advantageous impedance matching should primarily benefit bass performance, improvements might materialize elsewhere just the same. Consumer audio has no impedance matching standards to create predictive diagnostics. Experimentation thus remains the sole solution.
 

paulbottlehead

Active Member
These would not be a good idea with low power SET amps. There will be some insertion loss, and this is no bueno where every watt counts. If you use these to increase the load the amp sees with these, you will decrease the available power to the speakers on top of the insertion loss. You may also run into issues where the output transformer resonance gets shifted lower as you increase the impedance of the load on the output. The SET amp should either be paired with a speaker that doesn't dip so low, or you just use a lower tap on the output transformer (or even better if you have dual secondaries that can be wired in series or parallel to get different impedances without wasting copper on the secondary).

If we actually look at the math for the example speaker that is 3.8 to 30 ohms and assuming that we will use the 4 ohm tap on a SET amplifier with a damping factor of about 3, then you can expect a 2dB difference between those extremes.

If we compare that to a solid state amplifier with very high damping acting as an almost pure voltage source that is able to double its power with every halving of impedance, then the power delivered to the speaker at 3.8 ohms is 19dB higher than the power delivered at 30 ohms. If you do the analysis for an OTL tube amp, this flip flops.

This is a very, very complicated question to answer and requires experimentation and measurement for any given situation.
 

SPL db

Junior Member
Luckily, I'm using mine with my OTL Atma-Spheres and have noticed a slight increase in power and dynamic range. I reached out to Ralph at Atma-Sphere before purchasing them. Ralph claimed that using these boxes would bring the wattage up from 60 WPC to almost 80 WPC which is what I attribute the slight increases to.

Not so much from the boxes themselves but more allowing the amps to breathe a little easier is my guess.
 

ICTWoody

Junior Member
These would not be a good idea with low power SET amps.
Before we get too far off topic, I should point out I have zero intention of using or owning a Zero Box. I think the originally got mentioned purely because of the similarity of the woodworking of their enclosures with maple and splines and the bases I built using the similar look for my Redbod SEP mono blocks.

Just to make sure you guys know I'm not talking about those at all.

-Woody
 

S0und Dragon

Junior Member
Not that I am going to run out tomorrow and acquire some. But my list leans to the classics I relented and picked up a once in a lifetime example for my Citation II. I would like a similar Marantz 8B and a Mac MC240. That would be my it I think.
 

SPL db

Junior Member
Before we get too far off topic, I should point out I have zero intention of using or owning a Zero Box. I think the originally got mentioned purely because of the similarity of the woodworking of their enclosures with maple and splines and the bases I built using the similar look for my Redbod SEP mono blocks.

Just to make sure you guys know I'm not talking about those at all.

-Woody
You would be correct sir, sorry for the hi-jack, back on topic. :cool:
 

mhardy6647

Señor Member
I don't know about addiction, but, according to the Louvin Brothers (at least), Satan is Real.

12581

Probably uses Class D amplifiers, though.
 
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