I would love to hear suggestions and opinions about mounting two more heat sinks for my balanced stereo F5T build. I can mount the heat sinks on the top panel of the enclosure. This would make wiring and maintenance more tricky, but seems optimal for heat removal. I could also mount the heat sinks internally as indicated in the photo. I will have a separate power supply box, so internal space is not an issue.
Might need to Open images in a new tab:
Might need to Open images in a new tab:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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I was thinking along these lines:
Pictures of your diy Pass amplifier
Heatsinks on all four sides. Connectors on the bottom of the chassis. Use tall feets to make room for the cables.
Pictures of your diy Pass amplifier
Heatsinks on all four sides. Connectors on the bottom of the chassis. Use tall feets to make room for the cables.
volume difference left/right
I have build me an F5 turbo v2 and all is good except for one little detail.
playing with Troels Gravesen DTQWT MKII I did experience a slight difference in volume between left and right channel. The sound was slightly drawn to the left speaker.
It did not bother me much. But recently I swapped the DQWT for a pair of Ekta Grande (also designed by Troels). Very nice speakers, little less sensitive but now the music is in the living room and the speakers really disappear.
The music still draws a little to the left.
How can the volume (gain) of the two sides be set and leveled?
Is there a simple solution for this?
Best,
Nils
The Netherlands
I have build me an F5 turbo v2 and all is good except for one little detail.
playing with Troels Gravesen DTQWT MKII I did experience a slight difference in volume between left and right channel. The sound was slightly drawn to the left speaker.
It did not bother me much. But recently I swapped the DQWT for a pair of Ekta Grande (also designed by Troels). Very nice speakers, little less sensitive but now the music is in the living room and the speakers really disappear.
The music still draws a little to the left.
How can the volume (gain) of the two sides be set and leveled?
Is there a simple solution for this?
Best,
Nils
The Netherlands
How can the volume (gain) of the two sides be set and leveled?
Is there a simple solution for this?
I would think the gain of the F5 amplifier is set by the feedback loop, which should be the same in both channels. I've had a similar problem in the past, and in the end I realised the problem was not the amplifier (or any other electronic unit). Is the level difference really due to different gain between the two channels of you amp?
Some things to check:
- What happens if you swap the inputs (L <--> R) to the amplifier? If the level difference changes to the other side, the problem is not in your amp, but somehwere in the source (preamp, DAC, whatever).
- What happens if you swap the speaker outputs? This might seem like a silly test, but in my situation this was an eye opener. The level difference did not change even after swapping the speaker connections. The room acoustics were such that one side seemed louder than the other, although all the electronics and the speakers were fine.
good point about the acoustics. Will try swapping the speakers and again the inputs and return with the result.
Nils
Keep in mind that some recordings, particularly those from the early stereo era have some issues with balance, often featuring instruments skewed totally to one side. Depending on the song this can lead to the entire perspective of the performance shifting off centre.
I have experienced this slight imbalance in channels over the years. There have been good suggestions made about room acoustics and front end equipment issues. Sometimes, in my case, the problem is with my ears. I sometimes have problems with allergies and this leads to my hearing being impacted more in one ear than the other. It has been happening lately due to the very high levels of tree pollen in the air at this time of year.
With regards to room acoustics, if you have asymmetrical room reflections in the high frequencies this can cause the treble to pull to one side. You could experiment with speaker toe in and maybe some room treatment, perhaps as simple as a wall hanging to break up a large expanse of reflective wall area.
You could simply try to compensate with a balance adjustment.
I have experienced this slight imbalance in channels over the years. There have been good suggestions made about room acoustics and front end equipment issues. Sometimes, in my case, the problem is with my ears. I sometimes have problems with allergies and this leads to my hearing being impacted more in one ear than the other. It has been happening lately due to the very high levels of tree pollen in the air at this time of year.
With regards to room acoustics, if you have asymmetrical room reflections in the high frequencies this can cause the treble to pull to one side. You could experiment with speaker toe in and maybe some room treatment, perhaps as simple as a wall hanging to break up a large expanse of reflective wall area.
You could simply try to compensate with a balance adjustment.
some tracks are from the early era indeed. there is more than just my F5!
I'm using the Camridge Audio Azure 851N as Digital pre-amp and streamer. So yes I can play with balance as you mentioned.
But I will try to figure out if the amp is OK.
I bought a pair of F5 Turbo V2 boards and silicon about 6 years ago on a sleep deprived new father hood, uneducated whim. I slowly bought components and heat sinks and have designed what will be (one day) a pair of mono blocks. I've subsequently had some sleep, read what a wonderful chap Nelson is and built the B1 Korg with much success. Thank you very much to all for the wonderful documentation this site gives.
But I have made a mistaken purchase. The transformers are 500VA 230 primary to dual 25V secondary. Mains is measured at 240+V round our way so I think I should expect to see ~36V at the rails. The V2 aims for 32V rails and I'm worried that the extra 4V will be to much for the input JFETs.
What do you think. Risk it with heat sinks on the JFETs or cascade as suggested for V3.
If cascading, can anyone help me understand what value R25/R27 and R26/R28 voltage dividers should be to get the correct (32V?) at the JFETs please?
And is 32V the 'optimal' voltage for the JFETs, or should I target something else, and why?
No hurry, I haven't built up the PSU yet and the boxes are only just drilled and ready for paint and oil. Still very much in the shed and not ready for the kitchen table yet.
Best regards
Steve
But I have made a mistaken purchase. The transformers are 500VA 230 primary to dual 25V secondary. Mains is measured at 240+V round our way so I think I should expect to see ~36V at the rails. The V2 aims for 32V rails and I'm worried that the extra 4V will be to much for the input JFETs.
What do you think. Risk it with heat sinks on the JFETs or cascade as suggested for V3.
If cascading, can anyone help me understand what value R25/R27 and R26/R28 voltage dividers should be to get the correct (32V?) at the JFETs please?
And is 32V the 'optimal' voltage for the JFETs, or should I target something else, and why?
No hurry, I haven't built up the PSU yet and the boxes are only just drilled and ready for paint and oil. Still very much in the shed and not ready for the kitchen table yet.
Best regards
Steve
![IMG_20200622_210144[1].jpg](/community/data/attachments/787/787300-40db562317506a31bf250212ce2e31e6.jpg)