I just got my FSP ultra finished this morning and of course couldn't wait to house it properly before having a listen. First impressions are that its fantastic superbly detailed, musical and with real punch, drums never sounded so good, bass so articulate.
I am using it with an Ortofon Kontrapunkt B, the FSP is in high gain (S5, S6 and S9 on, all others off). Load is set at 100R with S1 on, all the others off). The FSP feeds my DCG3 preamp (gain set at 3X) and then Pass F5 and speakers are 95db/W.
I do notice one issue though, in that the FSP gain doesn't seem to be very high, I have to turn the volume pot almost to max to get it to go loud. I don't really mind this, but am concerned that if someone in the family uses the streamer and I have left the volume way up it will be deafening. My question is, does it sound like i have made a mistake and is there anything I should check?
Overall delighted but would love to make it integrate better into the rest of the system.
Thanks Teabag for the kit and thanks Salas for a great design.
Ian
I am using it with an Ortofon Kontrapunkt B, the FSP is in high gain (S5, S6 and S9 on, all others off). Load is set at 100R with S1 on, all the others off). The FSP feeds my DCG3 preamp (gain set at 3X) and then Pass F5 and speakers are 95db/W.
I do notice one issue though, in that the FSP gain doesn't seem to be very high, I have to turn the volume pot almost to max to get it to go loud. I don't really mind this, but am concerned that if someone in the family uses the streamer and I have left the volume way up it will be deafening. My question is, does it sound like i have made a mistake and is there anything I should check?
Overall delighted but would love to make it integrate better into the rest of the system.
Thanks Teabag for the kit and thanks Salas for a great design.
Ian
Hi
I wouldn't think there's a mistake in your build when with so good audio results. But to verify gain you can build a 1/1000 divider cable and use 1kHz test signal. Two male RCA with metallic bodies, a length of coax, 10k series 10R shunt small resistors Lpad inside one RCA. So they are shielded from noise.
1V sinewave signal in the straight end coming from a lab gen or some digital device ends up 1mV at the Lpad end, it goes to the phono input. The gen's noise is also divided.
Confirm 1mV entering the phono with DMM in mV AC mode (losses can happen, up the gen's output a little if so).
Now measure the phono output in ACV. Divide this output figure by 0.001V. Translate this ratio to dB.
*Also confirm your correct input load value by measuring Ohms across the phono's input female RCA when free from connection and the power is off.
*62dB gain from a 0.47mV Ortofon Kontrapunkt B should bring around 590mV UFSP output at 5cm/sec groove velocity. This isn't exactly weak. Maybe the cart is loaded down?
I wouldn't think there's a mistake in your build when with so good audio results. But to verify gain you can build a 1/1000 divider cable and use 1kHz test signal. Two male RCA with metallic bodies, a length of coax, 10k series 10R shunt small resistors Lpad inside one RCA. So they are shielded from noise.
1V sinewave signal in the straight end coming from a lab gen or some digital device ends up 1mV at the Lpad end, it goes to the phono input. The gen's noise is also divided.
Confirm 1mV entering the phono with DMM in mV AC mode (losses can happen, up the gen's output a little if so).
Now measure the phono output in ACV. Divide this output figure by 0.001V. Translate this ratio to dB.
*Also confirm your correct input load value by measuring Ohms across the phono's input female RCA when free from connection and the power is off.
*62dB gain from a 0.47mV Ortofon Kontrapunkt B should bring around 590mV UFSP output at 5cm/sec groove velocity. This isn't exactly weak. Maybe the cart is loaded down?
Hi Salas,
a 1khz sinewave, 1mv as measured by my DMM is giving 3.721v out. which it think is something like 71dB. My DMM is not great so can happily believe that it is indeed 62db gain. I also tried with my ancient oscilloscope which needs calibration and that gave slightly different voltages that calculated as 64dB. Which actually seems pretty close.
I will look into the cartridge loading and see if that helps.
Thanks
Ian
a 1khz sinewave, 1mv as measured by my DMM is giving 3.721v out. which it think is something like 71dB. My DMM is not great so can happily believe that it is indeed 62db gain. I also tried with my ancient oscilloscope which needs calibration and that gave slightly different voltages that calculated as 64dB. Which actually seems pretty close.
I will look into the cartridge loading and see if that helps.
Thanks
Ian
See about vertical tracking force too. In case it got lighter and you didn't notice. How much voltage gain is there in your F5 version by the way?
My F5 is not the turbo version so I understand the gain to be 15.5dB.
I repeated the FSP gain test again using just the oscilloscope as I think my multimeter is struggling with 1khz AC. On repeat testing I measure a gain of 66dB. Which is within experimental error of your figures. My method was to measure the ac voltage into the potential divider and assume 1 mv out. I did this because my oscilloscope (which is ancient) just sees noise when I try to measure the 1mv output of the divider. I used this online calculator for the dB gain calculation, I hope it was the right thing to use:
dB converter | decibles conversion calculator
I will look into the low gain outside of the FSP as IFIRC I had to increase the gain of my old phonostage. The old one was a phonoclone transimpedance amplifier and when I set the gain as described by RJM it was too low so I doubled it.
I will check the tracking weight would be surprised if its wrong as I checked it about a month ago. Maybe I should check the cable from the arm.
Thanks for your help
Ian
I repeated the FSP gain test again using just the oscilloscope as I think my multimeter is struggling with 1khz AC. On repeat testing I measure a gain of 66dB. Which is within experimental error of your figures. My method was to measure the ac voltage into the potential divider and assume 1 mv out. I did this because my oscilloscope (which is ancient) just sees noise when I try to measure the 1mv output of the divider. I used this online calculator for the dB gain calculation, I hope it was the right thing to use:
dB converter | decibles conversion calculator
I will look into the low gain outside of the FSP as IFIRC I had to increase the gain of my old phonostage. The old one was a phonoclone transimpedance amplifier and when I set the gain as described by RJM it was too low so I doubled it.
I will check the tracking weight would be surprised if its wrong as I checked it about a month ago. Maybe I should check the cable from the arm.
Thanks for your help
Ian
Can your F5 version make 6dB of additional gain without trouble of too little feedback left in it?
It should be easy to implement by changing a couple of resistors value, and that would solve your system gain issue, but you better ask in Pass forums if its allowed and what are the compromises.
Cheapest DMM I can recommend to you for capturing small voltages up to 1kHz with some confidence, is Aneng AN8008 or AN8009.
I have one and noticed its reliable enough on small AC figures. Has its shortcomings vs pricey meters of course. But its accurate. You find it on Banggood, eBay, or similar. Don't expect top construction quality or serious surge protection. A hard plastic case that slides around, but mini size handy, with big enough backlit LCD. Just avoid using it on high energy circuits and it should be alright.
It should be easy to implement by changing a couple of resistors value, and that would solve your system gain issue, but you better ask in Pass forums if its allowed and what are the compromises.
Cheapest DMM I can recommend to you for capturing small voltages up to 1kHz with some confidence, is Aneng AN8008 or AN8009.
I have one and noticed its reliable enough on small AC figures. Has its shortcomings vs pricey meters of course. But its accurate. You find it on Banggood, eBay, or similar. Don't expect top construction quality or serious surge protection. A hard plastic case that slides around, but mini size handy, with big enough backlit LCD. Just avoid using it on high energy circuits and it should be alright.
I also used F5T with 24V transformer on its PSU and gain was 22dB. 17dB is seems quite low.
My measurements:
Max input V = 1.42Vac RMS
Max output V = 18.5Vac RMS
The GAIN = 18.5/1.42 = 13 times = 22.3dB
Wattage = 18.5²/ 8R (speakers) = 42.7W
The common practice to increase gain on F5Ts is to increase PSU Voltage which is limited by your PSU smoothing capacitors MAX spec and cascoded setup in your amp input board. I upgraded my amp with 45VDC PSU and have 135W on my 6 Ohm speakers.
I have my both FSPs (56dB with 1mV cart and 62dB with 0.5mV cart) sound similar in same or very close volume level as I have with my CD player or DAC for loudness perspective. With my current setup with UFSPs, DCG3 (x3), F5T and my 6R nom impedance speakers, I enjoy very load music with 1/2 on volume pot and my neighbors really enjoy it with 3/4. And I live in house, not in apartment...
My measurements:
Max input V = 1.42Vac RMS
Max output V = 18.5Vac RMS
The GAIN = 18.5/1.42 = 13 times = 22.3dB
Wattage = 18.5²/ 8R (speakers) = 42.7W
The common practice to increase gain on F5Ts is to increase PSU Voltage which is limited by your PSU smoothing capacitors MAX spec and cascoded setup in your amp input board. I upgraded my amp with 45VDC PSU and have 135W on my 6 Ohm speakers.
I have my both FSPs (56dB with 1mV cart and 62dB with 0.5mV cart) sound similar in same or very close volume level as I have with my CD player or DAC for loudness perspective. With my current setup with UFSPs, DCG3 (x3), F5T and my 6R nom impedance speakers, I enjoy very load music with 1/2 on volume pot and my neighbors really enjoy it with 3/4. And I live in house, not in apartment...
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Hi Salas,
I took your advice and bought an Aneng AN8008. It seems somewhat better than the meter I was using before. Latest calculated gain is 60.3db. So slightly short of 62db but once again it sounds about right.
I was wondering about adding gain into the DCG3 and have asked the question on its thread.
Thanks,
Ian
I took your advice and bought an Aneng AN8008. It seems somewhat better than the meter I was using before. Latest calculated gain is 60.3db. So slightly short of 62db but once again it sounds about right.
I was wondering about adding gain into the DCG3 and have asked the question on its thread.
Thanks,
Ian
50VA is humongous for the job.
What would be the minimum for this job: could two 20VA transformers with 32 V secondaries work in a 230 V environment? Or better one more powerful transformer with 32 + 32 V secondaries?
Thanks!
What would be the minimum for this job: could two 20VA transformers with 32 V secondaries work in a 230 V environment? Or better one more powerful transformer with 32 + 32 V secondaries?
Thanks!
Typically both solutions would work. Its about CCS consumption loading, no time break, and full bridge rectification steals 40% of a transformer's AC current rating.
I have seen 30VA frame transformer becoming substantially warm under such conditions.
I have seen 30VA frame transformer becoming substantially warm under such conditions.
Thanks Salas!
In other words better borderline humongous using one or two 50VA transformers with 32 V secondaries than letting the transformers sweat🙂
In other words better borderline humongous using one or two 50VA transformers with 32 V secondaries than letting the transformers sweat🙂
One more UFSP finished.
As I had already the previous blue boards, this one is better.
More detail, less noise, more depth.
Of course these comments are not very objectives, as I used different and little bit better components, I feel that this new design is a worthwhile upgrade.
As I had already the previous blue boards, this one is better.
More detail, less noise, more depth.
Of course these comments are not very objectives, as I used different and little bit better components, I feel that this new design is a worthwhile upgrade.
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50VA Antek which is very much used by American builders has magnetic shield that their lesser VA models don't have is another reason why usually recommending 50VA
Congratulations for your build. It looks by now well established from enough reports, including yours, that the black UFSP redesign also offers little more subjective performance beyond gain set up flexibility with DIP switches which was the main update goal.