I highly recommend biamping with Nelson's 6-24 active crossover and powering your Altecs or Faitals with their own dedicated amp.I have 15" altec 416 8b at the moment and a pair of faital 15PR400 standing by. I have played with the latter very briefly and I have the impression they integrate much better with the 2002 in the midrange due to their very low inductance. They may not go to 24Hz like the altec but whatever. The crossover is passive so single amp is used.
I have thought about that. I have an SHD studio and I could use that and all I would need is a second DAC. I have had mixed results with analog active xovers in the past and some practicality issue. At the moment, I really like my passive xover. Some exploration is needed.I highly recommend biamping with Nelson's 6-24 active crossover and powering your Altecs or Faitals with their own dedicated amp.
After scrounging extra parts, I was able to put together the VFET amp this weekend. Thanks to 6L6 for his build guide that made it very easy and quick to assemble. Getting a late start, I was able to take advantage of everyone's experience. It worked immediately. No turn-on/turn-off thumps. No hum or background noises. The sound has lots of musical details. The VFET is now my favorite amp. I set the voltage before connecting a source or speakers. Then ran it for 45 minutes, streaming music, and then made a minor adjustment to the voltage. Thanks to all you have had a part in the design.
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The source of this picture is not revealed.One impression from this years ETF (European Triode Festival) image copied from here
I bet there aren't many of us that would pass up the chance to take a listen to Franken amp.Who would do such a thing to a Sony VFET amp? They turned it into a Frankenamp! That is the beauty of DIY!
So this is a curiosity. I've measured my P-ch amp temperatures assiduously since I started using it, and I've never seen TO-3 case temps (with an IR gun, through the slots in the top lid) on either device higher than 42C. 39-40C is more typical. And another thing, the fins near the middle of the heat sink consistently read ~2C higher than the TO-3 case tops, which seems like witchcraft.150-160ish. Uncomfortable to touch.
It's biased at 20V, so it's not running under spec.
It is mine! the amp fits well the mandarins (joke). The driver is a folded PCC88 that is choke loaded - the big trannies, in fact 10K:10k that I wired in series. Great clarity. The driver goes 25Vpp with ease. Without a HV!One impression from this years ETF (European Triode Festival) image copied from here
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The red cables from pre- to main are Isoda cables. [These are wires made up of a selection of many metals to give a harmonical transfer funtion; acqired from advice by J Hiraga.]
There are two plates with the drives and a faux bottom under which I have the power supplies (40V, 12V), filter structures and power buffers.
I have the 1.27 amp idle current and never go beyond the First Watt at home.
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Here some innards of my build. I deviated and designed my own driver with as constraints: 1) Must have Tube. 2) Must run on the Vb of output stage = <40V. 3) Must allow > 8Watt. 4) Must have good bandwidth. I succeeded. Less than 5 Hz to >50 KHz. or so. Yes it is still inverting, but my preamp also inverts.
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