Question for 6L6 and all other our gurus here: I have F5T monoblocks and it set to about 86W with my 6 Ohm speakers. I used it with my tube preamp for awhile and enjoyed SQ. Yesterday, I connected it to B1 (Pass and Salas -hypnotized buffer. Do not remember the exact board name) buffer and I was suppressed how sound become more crisp and detailed. I think I like it more that way. Tubes preamp gave me smooth and relax sound, but with my B1 with opto-couplers volume control brought it to way different sound that I like a lot. With 0 gain it is enough loudness to hear my Acoustic Zen Adagios (6 Ohm nominal impedance). Now is my question: is it make sense to try DCB3, new Salas preamp, with lets say x3 or even x4 gain. What gain can add subjectively to F5T?
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If you've got enough gain, and it seems that you do, I doubt an active gain preamp will make much difference. The source to amp impedances and currents are set properly in your system now (that's what the sound difference is between the DCB1 and the tube preamp) so why would you want to change it?
...except it's always fun to build something new...
Your last sentence is right to the target... .
I would not change a thing, but my DCB1 is belong to my headphone amp located in other room and unfortunately it has only one input. So, I have two chooses:
a. to make new DCB1 (0 gain) with 3-4 inputs.
b. to build DCB3 (flex gain setup + headphone amp) with 3-4 inputs.
Which one would you recommend?
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. I would not change a thing, but my DCB1 is belong to my headphone amp located in other room and unfortunately it has only one input. So, I have two chooses:
a. to make new DCB1 (0 gain) with 3-4 inputs.
b. to build DCB3 (flex gain setup + headphone amp) with 3-4 inputs.
Which one would you recommend?
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You can add on extra outputs from the DCB1.
The 220r output resistor feeds one channel. Just add on more 220r for each extra output channel.
250r to 270r output impedance can drive 3m to 5m interconnect cables if you don't choose high capacitance cable. 75ohm coaxial should be OK for these lengths.
The 220r output resistor feeds one channel. Just add on more 220r for each extra output channel.
250r to 270r output impedance can drive 3m to 5m interconnect cables if you don't choose high capacitance cable. 75ohm coaxial should be OK for these lengths.
The Mesmerize already has 6 inputs.
I thought you were asking about adding a second output.
Post523 right pic shows three outputs each fed through a 220r stabilising resistor.
You only need the three 1Meg if there are DC blocking capacitors on each output.
If no cap coupling then you could work with just one 1Meg, or even none.
I thought you were asking about adding a second output.
Post523 right pic shows three outputs each fed through a 220r stabilising resistor.
You only need the three 1Meg if there are DC blocking capacitors on each output.
If no cap coupling then you could work with just one 1Meg, or even none.
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Thank you Andrew. I am sure I have Hypnotize PCB with one input. It is fine by now since I am using that unit as my headphone amp buffer and I connected it as a test device to see how low impedance input is impacting general F5T presentation.
I'll go for DCB3 and I'll make 3-4 inputs and 3 outputs (just in case that I need to connect active sub and etc.). Not sure about DCB3 gain for my setup. In order to have Sum = 120dB, I need gain x4 (F5T=86W, Speakers 6 Ohm=89dB).
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I'll go for DCB3 and I'll make 3-4 inputs and 3 outputs (just in case that I need to connect active sub and etc.). Not sure about DCB3 gain for my setup. In order to have Sum = 120dB, I need gain x4 (F5T=86W, Speakers 6 Ohm=89dB).
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The F5T gain needs to be used.
What is the input sensitivity to drive the amp to just reach clipping?
Then divide by the gain of your pre-amp to find the sensitivity for clipping at the pre-amp input.
Are any of your sources that low in output?
If a few are, then apply some gain to those sources ONLY and only when you need that high an SPL at the listening location.
The high output sources don't need extra gain if all you end up doing is amplifying the signal and then attenuating it down again to give sensible SPL.
I seriously doubt you need to get near that 120dB figure.
There is no reason for choosing the 120dB number.
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It is my gap since I did not measure input sensitivity till clipping yet. Is any special ways to measure it for my needs? As far as I understand, I need to set like 8 Ohm dummy load, then I need to increase input voltage of 1k sine till I'll see flatness starts on pos and/or neg sine picks on output (on dummy load resistor). That V input will be my input sensitivity of clipping. I'm I correct?
I used my amp with Salas FSP phono which has 1mOhm output resistor. Also, I think that my NAD M5 CD player also has high impedance on output.
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I used my amp with Salas FSP phono which has 1mOhm output resistor. Also, I think that my NAD M5 CD player also has high impedance on output.
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1.To add multiple outputs for DCB1 will be a challenge since main output has relay after 220R. So, the rest (if to add them) will be no time-delayed.
2. Sorry for that misleading. It was my iPhone auto-corrector mess. I meant 1 Mega Ohm on output.
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I assume if I'll have a point when I'll reach clipping on some of intermediate sages (like on fist, second and etc. pair of MOSFETs), then I see clipping at the output any way. So, If I understood the whole procedure correctly, I need to find Vin right prior clipping starts to shown. That would be my MAX input level. Then, I'll measure Vout and Vout/Vin will give me X-times gain.
yes.
Let's assume by way of an example that you have 125mVac at the input as measured on the 199.9mVac scale of your DMM and you have 4.51Vac as measured on the 20.00Vac scale of your DMM.
Then gain = 4.51Vac / 0.125Vac = 36.08times (=+31.1dB)
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