*For most UFSP builds on available JFETs Idss & when set in highest gain mode, usual readings are about 34V rail and 9V at C4's input. Allowing circa 16V peak to peak uncompressed output capability. Or 5.6-5.8V RMS. For the 0.3V RMS nominal output spec with a 0.25mV LMC cartridge that's 25-26dB overload margin (headroom). In other words plenty.
Didn't manage to take more measurements, but, yes, I 've tried it a lot. I 've read the comments of other people comparing it to the FSP, and in all honesty I believed that great part of the praise was due to the enthusiasm of the new build.
Well, that unitl I 've built the UFSP. There is a great improvement and I didn't expect that. The UBIB is an obvious difference, but other than that more or less it's the same circuit. Another difference is that I used the clarity cap CMRs this time instead of MR and Jupiter copper foil for the signal capacitors and nichicons instead of ELNA Cilmic II for the lytics. All in all, the differences in caps should make a small difference if any.
So what's the difference? The striking one is bass. As more both in quantity and quality. Compared to the FSP (which I really love and has been my main driver for many years), if one word can describe the sound of the UFSP, that is: solid. A solid foundation in the low register, while remaining airy and detailed in the mids and highs. I feel very sad that I will have to part with it, since I 've built this for a very close friend, but I have already the second unit under construction, so I guess that will be a small gap.
Well, that unitl I 've built the UFSP. There is a great improvement and I didn't expect that. The UBIB is an obvious difference, but other than that more or less it's the same circuit. Another difference is that I used the clarity cap CMRs this time instead of MR and Jupiter copper foil for the signal capacitors and nichicons instead of ELNA Cilmic II for the lytics. All in all, the differences in caps should make a small difference if any.
So what's the difference? The striking one is bass. As more both in quantity and quality. Compared to the FSP (which I really love and has been my main driver for many years), if one word can describe the sound of the UFSP, that is: solid. A solid foundation in the low register, while remaining airy and detailed in the mids and highs. I feel very sad that I will have to part with it, since I 've built this for a very close friend, but I have already the second unit under construction, so I guess that will be a small gap.
Nice to know. Success on all fronts then. No noises and very good sound. Congratulations. 
Surely the 1.3S (special) Ubib section, also the layout architecture and proposed build level as a whole, proved a quality step up in the UFSP. Despite the gain switching facilities new complexity. In my attention to counterbalance possible signal degradation from facilities I pushed the goal posts beyond FSP it seems.
Surely the 1.3S (special) Ubib section, also the layout architecture and proposed build level as a whole, proved a quality step up in the UFSP. Despite the gain switching facilities new complexity. In my attention to counterbalance possible signal degradation from facilities I pushed the goal posts beyond FSP it seems.
Lets not also forget Mike's handpicking work in preparing such a difficult & delicate obsolete components balance for a repeatably correct result. Predictability helps version differences to shine through in each individual build. So everybody could tell. This is not a given bias values circuit due to the JFETs Idss spread spec nature. Not an exact gain figure circuit either due to the JFETs also varying transconductance spec. No loop feedback in this to fix figures. Thus a lot is based on sorting, matching, and preparing.
We used more basic resistors and caps in the initial prototypes with basic UBIB. It seems the matched caps .1% resistors play a bigger role. Was able to get a much deeper soundstage with this circuit and aggressive matching. The Nichicon KZ and KG caps are going away via End of Life, so hopefully that is not what makes them great.
After a very very, VERY long journey in turntable-prep, I finally dusted off all my courage and plugged everything in for a first little listen.
It is working.
Journey isn't finished yet, as unfortunately I only have one channel.
I suspect the cartridge to be faulty, as I've swapped input channels of UFSP, output channels of UFSP, Cables, and Input channel of DCG3, and controlled continuity of the tonearm-wire (from an empty headshell to the RCAs) as well as the single headshell-wires from cartridge to headshell-connector, all is good. Last possible suspect seems to be the cartridge. argh.
BUT: UFSP is good. Just had a 5 minutes listen, I already really like what I heard!
It is working.
Journey isn't finished yet, as unfortunately I only have one channel.
I suspect the cartridge to be faulty, as I've swapped input channels of UFSP, output channels of UFSP, Cables, and Input channel of DCG3, and controlled continuity of the tonearm-wire (from an empty headshell to the RCAs) as well as the single headshell-wires from cartridge to headshell-connector, all is good. Last possible suspect seems to be the cartridge. argh.
BUT: UFSP is good. Just had a 5 minutes listen, I already really like what I heard!
Bummer! To confirm you could measure the suspect channel's output pins with the Ohmeter directly on the cartridge without any other connections. Some will say don't do that because you may fry the thin wire inside because the multimeter applies DC to measure resistance. Who's worried could use 100Ω resistor in series current limiter for MC or 1kΩ for MM I would say. Can even delta this out automatically on some DMMs with a REL button. In any case its possibly already gone plus I have done that test to some of my MC and MM cartridges and nothing bad happened. 
But its your decision.
But its your decision.
You may also check DC by switching one DMM to Ohmeter and another DMM to DCVmeter. Put the DCV's probes measuring ends in the Ohmmeter's empty sockets. One will read DC the other will read its own load impedance. Usually 10-11 MΩ for digital meters. Say you find 0.2V for the Ohmeter. That would create 20mA in a 10Ω cartridge's coil when measuring its resistance. But only 2mA with a 100Ω resistor in series. Because you just created a 1:10 L-Pad in essence.
In other words by knowing your cart's Ω spec and what voltage your DMM puts out as an Ohmmeter you can scale the current limiting resistor's value safer. Because DMMs have no standard DCV they use for Ohm metering. It may vary significantly between brands and models. Depending on their main chip inside and their general design.
In other words by knowing your cart's Ω spec and what voltage your DMM puts out as an Ohmmeter you can scale the current limiting resistor's value safer. Because DMMs have no standard DCV they use for Ohm metering. It may vary significantly between brands and models. Depending on their main chip inside and their general design.