Status report. I have completed 001, which is my own personal unit. I've been listening to it for about four days. Please don't start asking pricing and details. It's too soon for that just yet. The initial sound quality far exceeded my expectations which were high. Now it's time to get some time on it and see how long it lasts against those expectations. Next step is to then make sure it's not a fluke by duplicating it so I will be building a second one next.
This is what I know so far...
It is the CSP3 circuit doubled up to create a fully balanced circuit. The only substantial difference in the circuit is that instead of the Hybrid AC/DC starved circuit design for the heaters, I chose to create a fully AC high current supply where the heaters of the three tubes per channel are in series. That means we're using an 18 volt heater supply. This is a trick I discovered before Decware on one of my own amps which is to say that something special always seems to happen when heaters are in series.
There are 3 XLR Inputs and 1 XLR Output per channel. The output level is adjustable via stepped attenuation. With 60 volts of potential output I have already found this to be a handy feature. Without getting into specifics, the preamp has taken what I previously labeled as "Animated" to a whole new place I did not frankly know existed, so that's always fun! It's going to be be really good.
The dual mono remote control is working well. Both motorized analog pots rotate at the same rate together because they share the same sensor. If you want to make an adjustment to one channel or the other to achieve a different channel balance, simply adjust one of the controls higher or lower and it will stay that way relative to the other channel as you continue to raise and lower both channels with the remote.
This is of course the best of all worlds, as you have infinitely adjustable volume and channel balance electronically ganged together on a single remote.
On the second unit, where I try to replicate the first and measure the specs to get a feel for how tight this can be made, I will be testing two options that I hope to offer; 1) Making one of the inputs a transformer coupled RCA jack so that non-balanced sources could be used. 2) Adding a transformer-coupled RCA output that can be used to feed non-balanced amplifiers. In this case, the preamp would have both XLR balanced and transformer coupled RCA outputs. Most likely only one will be able to be used at a time but it would make it possible to jump between balanced and non balanced amplifiers with ease.
So I'll report back when the second unit is done and let you know if the results are good. If so, I'll price it out, and start on the web page. IF not, I'll slowly figure out why and then work to make then match. Once done I'll then build a third one to confirm it can be done consistently.
Meanwhile, here is a large picture of it on my bench taken with the phone on the night it was completed. The sepia color pallet is just a teaser. This thing looks so good I want to wait to take the real photos before anyone sees what it really looks like. They will be initially available with either red or black face plates.
Oh, and since the original ZTPRE was a successful purist execution many many years ago, I have named this new preamp after it to take it's place and just like was the logic back then, not everyone in the world will go with a lower power Decware amp, but every system on the planet could use this.
In closing, so far I have only listened to it on my 6c33 13 watt monoblocks paired with Bob's HR-1 speakers. I have never heard the bass go so deep or the speakers hit like this. Never heard them sound this good before. That means that the stunning dynamics of the ZMA and even the more impressive dynamics of the Zen TORII Mono's were not as good. That means when I pair this preamp with either one of those, I'll probably be besides myself with amazement.
I've been listening to these HR-1's for years on everything we've ever built and never heard them sound like this. I expect this result to happen with all the speakers and amps because I think it's the fact that we have 60 volts of pressure to work with. If you thought the 30 volts of a regular CSP3 was a lot... consider that this is making a 13 watt amp hit harder than our 60 watt monoblocks do without it.
Guess you know what I'll be doing this weekend. It will be a nice contrast to last weekend which was pure hell since it took me 3 entire days to figure out why it didn't work right the first time I built it.
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NEW Decware ZTPRE Preamp (Read 42016 times)
