Meanwhile, the Anniversary mods for CSP3 are going great. I've done enough to get good at it, and have fine-tuned the mod for both Type I and Type II beeswax caps. Here is Lon's CSP3 with the mods.
The mod is an option now in the shopping cart for anyone who wants to purchase a new unit built this way. It can be found in the shopping cart under the signal-cap section where you choose what type of signal-caps to have your CSP3 built with.The one pictured is a CSP3 built with copper foil (type II) beeswax caps and then updated further with the Anniversary mod. There are a total of 12 Jupiter Cryo-Treated beeswax caps in this modded unit, several poly film caps and two miniature solder-into-place voltage regulator tubes that will last the life of the preamp if they're not shorted.
The headphone section is also bypassed with the copper foil beeswax caps.
All of this takes a preamp / otl headphone amp that already sounds better than all of it's competition and punches it through the stratosphere.
For the techies that want to know what is different, while we have a picture to look at... the standard CSP3 is built with a novel power supply design. It features a simple pie filter using two caps and one resistor. Very Zen. To negate the need for a choke, regulation, or anything else the power supply transformer is rated at 170 mA while the circuit draws only 30 mA. The other novel part is that it is a signal node supply, meaning that all the B+ comes from a single point for all three tubes. No attempt to segregate whatsoever. This kept the timing the same for all three tubes which promotes cohesiveness.
The Anniversary mod takes the 10K 6.5 watt dale resistor in the pie filter and adds another 10K to it, dropping the value in half and doubling the wattage rating. Heat drops in half. Voltage increases. Then it is sent through an added 1K 6.5watt resistor to a pair of miniature VR tubes which drop the voltage back down to the original value but without heat, and segregate the voltage between the two channels, so each VR tube serves 1-1/2 audio tubes.
Once the voltage gets through the VR tube, which acts like a miracle filter being in series with the supply, it then is accumulated in the cryo treated beeswax caps using a .47uf for each channel because it is big and has to supply 1-1/2 tubes. Then we bypass that with another cryo beeswax cap at .022uf to balance out the speed for high frequencies. These caps then feed the plate resistors of each tube.
The main filter caps also have to be bypassed with film caps, and the same applies. There are two bypass caps for each filter cap to maintain a balance of speed to properly feed the VR tubes.
The performance went up, the distortion went down (it was already super low) and the noise floor that was also super low dropped even further. The VR tubes can offer in some cases ten times the ripple reduction as an equivalent resistor with the same voltage drop and do it with no heat... so this mod is basically like running your CSP3 off high voltage batteries with bottomless current. It doesn't get any better than this... but it's not cheep unless you put it in the perspective that nothing retail is available that does this, and a power re-generator for 6 grand or more isn't going to be half as good.
On a side note, someone is going to ask, so the cable I use from and to the input/output jacks is MOGAMI from Japan. It's copper, with a copper shield, no foil. On the inputs the stereo shielded cable is used from each pair of input jacks which works well for the lower voltage source signals generally 2 volts or less. From the output tubes we use a stereo cable for each channel, paralleling the conductors. This prevents crosstalk when the unit is set to the full 30 volts of output and even when it's set at unity gain the dual conductors sound more juicy.
Steve
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csp3 25yr anniversary mods (Read 59198 times)
