For a balanced F5t, you need to use two gain stage boards for each channel, they are connected together by the "link" pads. Then the XLR has pin 1 (ground) to both gain stage ground pad. Pin 2 goes to one gain stage board in +, and pin 3 goes to the other gain stage board in +.
You could build the F5t as single ended, the "link" pad goes to ground. Member XRK971 has a very nice balanced to single ended PCB/kit which will allow you to use the balanced XLR connections to the single ended F5t inputs. Look in the Group Buys forum to find him and send him a message.
That is not correct.
See previous posts and the article re: how to properly wire for a balanced amplifier.
Search for posts specifically by @elwood625. If I recall correctly, he did a balanced build. There is also a post somewhere by @cubicincher, I believe where he takes the simplified schematic and outlines the various boars.
Overall, the positive signal goes to input board 1, the inverted signal goes to input board 2. The link is used to link the two input boards.
If you can't those posts ... it might be my poor memory. Let me know after searching, and I'll try to find them when I get time. The information is definitely in the thread, and I hope I'm giving credit the correct people.
Edited - @elwood625 posted while I was typing. He's not incorrect.
See previous posts and the article re: how to properly wire for a balanced amplifier.
Search for posts specifically by @elwood625. If I recall correctly, he did a balanced build. There is also a post somewhere by @cubicincher, I believe where he takes the simplified schematic and outlines the various boars.
Overall, the positive signal goes to input board 1, the inverted signal goes to input board 2. The link is used to link the two input boards.
If you can't those posts ... it might be my poor memory. Let me know after searching, and I'll try to find them when I get time. The information is definitely in the thread, and I hope I'm giving credit the correct people.
Edited - @elwood625 posted while I was typing. He's not incorrect.
Which capacitors are you guys using with 45VDC rails? Anything like 20k+ uF per cap and 105°C... thanks!
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Looking at cubicinchers pics here, he did single ended mono blocks, I can see only one FE board in there?
https://www.diyaudio.com/community/threads/f5turbo-illustrated-build-guide.254056/post-6809395
You need first to clarify whether you want a 1) balanced amp or 2) only balanced inputs to a single ended amp.
Benefits to 1) audio signal do not reference ground, double voltage swing, faster slew rate, etc. cons: double the cost and space.
Benefits to 2) long cable runs without picking up noise. If you have like 1m of cable length between the source and your amp, you probably don't need this. For a studio with long cable runs and all sort of interferences a must.
Hello F5T-builders,
my F5T V3-Monoblocks are single ended.
How to wire a fully differentially /balanced F5T is described around post #1454 in this thread.
Read also Nelson Pass' article about the F5 TURBO (page 15) where he shows the simplified schematic for a balanced F5T V3.
https://www.firstwatt.com/pdf/art_f5_turbo.pdf
You need 2 frontendboards and minimum 2 N-channel- and 2 P-channel- outputboards for one channel.
There is a difference if you transport a audiosignal over a 'balanced' wire / connection (impedance) or
if you amplify a audiosignal differentially / balanced or single-ended.
Cheers
Dirk 😉
my F5T V3-Monoblocks are single ended.
How to wire a fully differentially /balanced F5T is described around post #1454 in this thread.
Read also Nelson Pass' article about the F5 TURBO (page 15) where he shows the simplified schematic for a balanced F5T V3.
https://www.firstwatt.com/pdf/art_f5_turbo.pdf
You need 2 frontendboards and minimum 2 N-channel- and 2 P-channel- outputboards for one channel.
There is a difference if you transport a audiosignal over a 'balanced' wire / connection (impedance) or
if you amplify a audiosignal differentially / balanced or single-ended.
Cheers
Dirk 😉
elwood625 has balanced mono blocks, pics here
https://www.diyaudio.com/community/threads/f5turbo-illustrated-build-guide.254056/post-6980394
https://www.diyaudio.com/community/threads/f5turbo-illustrated-build-guide.254056/post-6980394
I would like to thank all those who answered my question and helped me understand the singnificance of the silkscreen printing on the FE card.
I am asse,blating a F5T in stereo 50Watt version, I think that to be able to use both RCA and XLR inputs, I have to use passive or active adapters, I still don't understand which one is less invasive and degrades the input signal as little as possible.
I'm thinking of using one of these two kits.
In your experience, which one should I choose?
on the left the passive one
I am asse,blating a F5T in stereo 50Watt version, I think that to be able to use both RCA and XLR inputs, I have to use passive or active adapters, I still don't understand which one is less invasive and degrades the input signal as little as possible.
I'm thinking of using one of these two kits.
In your experience, which one should I choose?
on the left the passive one
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Hi @tricksters -
I'm now on a computer with a keyboard and a monitor I can see, and I can do some simple sketches 🙂 Sorry for the brevity, clearly bad typing, lag, and maybe some confusion earlier.
I think it is now clear that you want to build a standard stereo F5TV2. Previously, I thought you were building balanced amplifier(s), using a differential signal as an input though the XLR cable.
Could you explain why you want to use both RCA and XLR inputs, please? Are you thinking that the XLR cable will do something special re: noise? You may have a very good reason for this, but I cannot think why. If you can help to tell us why, we can help choose a good solution.
For SOME of my projects when I get a bit lazy, I wire it like this... there is really no need except for my laziness of not wanting to reach behind the pre-amp... but maybe you have a similar reason... Others feel free to discuss pros and cons, or if I completely ooked.
I'm now on a computer with a keyboard and a monitor I can see, and I can do some simple sketches 🙂 Sorry for the brevity, clearly bad typing, lag, and maybe some confusion earlier.
I think it is now clear that you want to build a standard stereo F5TV2. Previously, I thought you were building balanced amplifier(s), using a differential signal as an input though the XLR cable.
Could you explain why you want to use both RCA and XLR inputs, please? Are you thinking that the XLR cable will do something special re: noise? You may have a very good reason for this, but I cannot think why. If you can help to tell us why, we can help choose a good solution.
For SOME of my projects when I get a bit lazy, I wire it like this... there is really no need except for my laziness of not wanting to reach behind the pre-amp... but maybe you have a similar reason... Others feel free to discuss pros and cons, or if I completely ooked.
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Yes, indeed the solution you proposed is the easiest and quickest to implement.
But don't you create problems of increasing DB of the input signal ?
But don't you create problems of increasing DB of the input signal ?
Please note that connecting Pin 3 to any sort of ground may severely degrade most kinds of actively balanced outputs (where the hot and cold are actively driven, for example by a differential design or by a dual opamp).
While doing so will not damage said chips and only degrade distortion performance, there are very few (to my knowledge) drive chips that will remain unaffected by this connection.
This does not apply to transformer balanced outputs or the quite common 'pseudo-balanced' outputs.
One advantage of using a balancer is the cancellation of all H2 up to the amplifier entry, if such an effect is desired. Another is the ability to use a transformer like the Jensen JT-14 to allow the full 4Vrms of a balanced source and eliminate any need of a signal preamplifier, again, if deemed desirable.
While doing so will not damage said chips and only degrade distortion performance, there are very few (to my knowledge) drive chips that will remain unaffected by this connection.
This does not apply to transformer balanced outputs or the quite common 'pseudo-balanced' outputs.
One advantage of using a balancer is the cancellation of all H2 up to the amplifier entry, if such an effect is desired. Another is the ability to use a transformer like the Jensen JT-14 to allow the full 4Vrms of a balanced source and eliminate any need of a signal preamplifier, again, if deemed desirable.
Someone more articulate, concise, and knowledgeable might be able to help more.
Sangram points out some exceptional reasons why it's not the best practice to do it the way I outlined. They also point out some precautions. There have been some great suggestions re: balanced / differential to SE "converters", but if your pre-amp already has RCA outputs, I am not sure why you would use one.
So, you still have not said WHY you must use the XLR outputs from your pre-amp. Why won't you just use RCA outputs from your pre-amp and install RCA inputs on the amplifier?
Others may understand completely, but I have not seen a good reason to do this yet. I may be missing the entire point. If so, I apologize.
No. dB is reduced by taking the inverted signal and "throwing it away".
Sangram points out some exceptional reasons why it's not the best practice to do it the way I outlined. They also point out some precautions. There have been some great suggestions re: balanced / differential to SE "converters", but if your pre-amp already has RCA outputs, I am not sure why you would use one.
So, you still have not said WHY you must use the XLR outputs from your pre-amp. Why won't you just use RCA outputs from your pre-amp and install RCA inputs on the amplifier?
Others may understand completely, but I have not seen a good reason to do this yet. I may be missing the entire point. If so, I apologize.
Actually, there is no real need to use the balanced outputs of the preamp, I can also use the RCA outputs.
I simply wanted to make the power amp much more versatile and then from a listening comparison with SE cables and XLR cables, using other power amps (aleph-J, PASS X150.5) it seemed to me that by using the XLR outputs and inputs, the music had more naturalness and transparency.
I simply wanted to make the power amp much more versatile and then from a listening comparison with SE cables and XLR cables, using other power amps (aleph-J, PASS X150.5) it seemed to me that by using the XLR outputs and inputs, the music had more naturalness and transparency.
AH! I see.
But both of those amplifiers (in differing ways, I think) have the intention for differential signaling as part of their topology. Aleph J at the input and X150 throughout. The F5T does neither. This is where I am the most fuzzy, but I believe I have the overall situation correct. That is why even stock, factory units (Aleph J and X150) come with XLR inputs.
Even if you use one of the "converters", you are are only amplifying a SE signal within the F5T. You must either "throw away" the negative/inverted signal or use a converter to combine the negative and positive signals before the amplifier. Personally, I'd stick with the SE output from your pre-amp.
However...
The "converter" may have two advantages... or it could be a detriment. It will simply do what it does. Sangram said it very well, and I will attempt to paraphrase.
OR you can get rid of the pre-amp, and use some kind of passive (or digital) attenuation...
I understand your WHY now... but I'm not sure I agree that it would provide the benefits that you think it will. Again... others more knowledgeable and/or that have differing opinions will surely chime in.
But both of those amplifiers (in differing ways, I think) have the intention for differential signaling as part of their topology. Aleph J at the input and X150 throughout. The F5T does neither. This is where I am the most fuzzy, but I believe I have the overall situation correct. That is why even stock, factory units (Aleph J and X150) come with XLR inputs.
Even if you use one of the "converters", you are are only amplifying a SE signal within the F5T. You must either "throw away" the negative/inverted signal or use a converter to combine the negative and positive signals before the amplifier. Personally, I'd stick with the SE output from your pre-amp.
However...
The "converter" may have two advantages... or it could be a detriment. It will simply do what it does. Sangram said it very well, and I will attempt to paraphrase.
Some people REALLY like the H2. Some don't. Depending on your pre-amp, it could be a complete non-issue / irrelevant. If you have a factory pre-amp, it's likely that the distortion is so low as no not matter much... but... maybe you can hear the difference. Maybe your pre-amp does sound better when run fully differential (if it does).
Edited a bit - It will be louder at a given volume setting.... if you keep your pre-amplifier...
OR you can get rid of the pre-amp, and use some kind of passive (or digital) attenuation...
I understand your WHY now... but I'm not sure I agree that it would provide the benefits that you think it will. Again... others more knowledgeable and/or that have differing opinions will surely chime in.
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@tricksters have you understood this?
Is your pre-amp or source balanced by nature? If yes, then build your power amp balanced as well and use only XLR cabling.
If your preamp or source is single ended, then skip the whole XLR input/output thing if you are in a single room home environment and build the F5Tv2 single ended as well and use chinch cables.
"Is your pre-amp or source balanced by nature? If yes, then build your power amp balanced as well and use only XLR cabling."
That's your opinion, it is not necessary. I might not have stated that quite so definitively.
I don't happen to agree with that opinion for this amplifier...
I like (and agree with) your previous list of pros and cons w/o stating that one should do it one way or the other. However, I would have added one or possibly two more cons to your list (for this amp).
Ultimately, in my shoes, in my circumstances, I don't see the need for balanced... even if the pre-amp is balanced... for this particular amplifier. But, it's DIY, and we all have our own needs and like different build challenges to fill out our army of amplifiers.
Cheers! 🙂
That's your opinion, it is not necessary. I might not have stated that quite so definitively.
I don't happen to agree with that opinion for this amplifier...
I like (and agree with) your previous list of pros and cons w/o stating that one should do it one way or the other. However, I would have added one or possibly two more cons to your list (for this amp).
It's a more complicated build and biasing / offset nulling procedure.
One of the 'features' of this amp is to potentially 'tune P3' for the distortion profile of choice. Balanced operation makes that much more complex. This may be irrelevant for some builders, but I feel it should be noted.
Ultimately, in my shoes, in my circumstances, I don't see the need for balanced... even if the pre-amp is balanced... for this particular amplifier. But, it's DIY, and we all have our own needs and like different build challenges to fill out our army of amplifiers.
Cheers! 🙂
Considering that there are no balanced inputs for the F5T, only SE inputs, I might do some tests with XLR to SE adapters, if the performance is satisfactory I might consider making the upgrade permanent, otherwise I'll just leave the SE inputs.