Some transformer manufacturers specify the output voltage of the transformer unloaded (and provide a regulation spec), others specify the output voltage at some rated load current. The FSP presents a very light load, and a very consistent load. A 32V transformer will give you a 45VDC power supply once rectified and smoothed. There is no need to drop the voltage further.
1R RD/Link is good for a 32V Antek. Mainly forming an EMI RC filter with the reservoir capacitor. Tiny voltage drop. 27R is good for 36V transformer to keep the rectified DC safely below 50V when loaded with the UBiB 1.3S running standard 100mA CCS setting (R1=5.6R).
However I don't remember subjective impressions feedback here for UFSP on hot running UBiB 1.3S. Like with 3.9R R1 at 150mA or with 2.8R at 200mA. Its probably satisfying enough already so nobody tried my more heat for possibly bit better sound evaluation suggestion.
However I don't remember subjective impressions feedback here for UFSP on hot running UBiB 1.3S. Like with 3.9R R1 at 150mA or with 2.8R at 200mA. Its probably satisfying enough already so nobody tried my more heat for possibly bit better sound evaluation suggestion.
It's been a while but wanted to again thank you Salas (and Teabag, for all the parts and PCBs), your design is still bringing me enjoyment and I'm always amazed at it's capability to make vinyl come alive! I've slowly upgraded to an entirely JFET chain: Simplistic NJFET, Mesmerize DCB1 and a First Watt J2.
I still have 2 UFSP's to build - the last year was consumed with work, family and covid but I have listened to a lot of vinyl to stay sane. I've had a couple cartridges rebuilt (Benz Ruby 2 and Soundsmith Otello) and replaced the AT VM540ML stylus. I gave up on my tube amp as the primary amp, it was fun but too much maintenance and tinkering for it to be the in the primary sound system for the family. The UFSP, Mezmerise and J2 with the Altecs are pretty amazing - family is happy too and I don't worry about things being inadvertantly left on overnight.
How concerned should I be with everything DC coupled other than the UFSP? I've checked for DC at both speakers with everything cold and warm and it's <10mV - the tube amp of course was AC coupled so I previously didn't give it much thought.
How concerned should I be with everything DC coupled other than the UFSP? I've checked for DC at both speakers with everything cold and warm and it's <10mV - the tube amp of course was AC coupled so I previously didn't give it much thought.
Not too much concern with the specific designs, because not with a prone to failure record, but best insurance policy is to simply install a DC sniffing protection relay system at the power amp's output. Especially when connected with irreplaceable vintage loudspeakers. There are very cheap modules on offer. See examples
I would like to try a step-up transformer with my folded simplistic pre-amp (built for 40dB gain), I would like something with multiple taps to allow 2 or 3 gain settings. I would like to use it with an Ortofon Quintet Blue (specs below). I was thinking of the Lundahl LL9226 on a custom pcb to allow switching of the gain. What do I need to look for to know if this would be a good match for my cartridge and the FSP? Other suggestions? Thanks!
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Your cartridge's resistance is safely below all lowest Ohmic recommendations for ratios and good frequency response in the particular step up transformer's datasheet.
It is also useful to remember each transformer's setting divides the MM phono's input load resistor by a squared ratio i.e. 1/10 divides by 100 so 47k/100=470R reflected load at the primary as seen by the cartridge. If you want 100R load on 1/10 ratio for the cart use 10K R1 in the FSP and so on and so forth.
It is also useful to remember each transformer's setting divides the MM phono's input load resistor by a squared ratio i.e. 1/10 divides by 100 so 47k/100=470R reflected load at the primary as seen by the cartridge. If you want 100R load on 1/10 ratio for the cart use 10K R1 in the FSP and so on and so forth.