The best way to prevent hum is to take a small transformer. Max. 200 watts are beneficial for low hum.
Just an update on further testing I just completed. If you are building Group Buy 2 EF3-3 Boards, Route 2 is the best option. EF3-4 still needs to be tested to confirm.
The debate over TTA/TTC or 2SC/2SA still needs to be measured, I have not had time yet to compare them, but there is a good chance that the differences will be marginal between them, but I would only use the 2SC/2SA if they are E grade, and use whatever is easier to source, which is most likely TTA/TTC.
The debate over TTA/TTC or 2SC/2SA still needs to be measured, I have not had time yet to compare them, but there is a good chance that the differences will be marginal between them, but I would only use the 2SC/2SA if they are E grade, and use whatever is easier to source, which is most likely TTA/TTC.
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Thanks a lot for your tests.
The build guide (V25) is for the first GB I assume? (as it recommends Route 1)
Also: The TTA/TTC vs 2SC/2SA discussion is only about Q105/Q106 or also Q101/Q102 and Q11/Q13?
For Q101/Q102 the BOM mentions to go with the highest hfe; so is that the way to choose these?
Furthermore, for Q7/Q8 the BOM only recommends the 2SC/2SA; is this on purpose or is there a chance that the TTA/TTC also might be better there.
Hello my friend. So you used EF3-3 at 71 volt boards? If so, what drivers did you use and outputs transistors? sorry if I missed something from the discussion. I would like you to confirm this because I have 2 x 50 AC volt transformers already and I will use transistors TOSHIBA 2SC5359 and 2SA1987 from Titan 2000.i have already drivers 5171-1930 i know those the are very fast ,but i have also and Mje15034 and mje15035.
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I am using Sanken 1859A/4883A Drivers and MJL4281/4302 Outputs on these boards.
@fireanimal,
Many thanks for carrying out your tests Andy, much appreciated and thanks for taking the time to do that.
Interesting to see that you now conclude 'Route 2' feedback trace may be the best option for EF3-3 boards? As eluded to, was 'Route 1' only really relevant for the 1st group buy boards in that case? I know there've been a few 'tweaks' made to the 2nd group buy boards, so is that the reason why now different?
Many thanks for carrying out your tests Andy, much appreciated and thanks for taking the time to do that.
Interesting to see that you now conclude 'Route 2' feedback trace may be the best option for EF3-3 boards? As eluded to, was 'Route 1' only really relevant for the 1st group buy boards in that case? I know there've been a few 'tweaks' made to the 2nd group buy boards, so is that the reason why now different?
Hi Guy's.
Just to clarify the information around the negative feedback path.
For the first group buy boards V3.9 we had two negative feedback paths to test. They were never named on the silkscreen. But the one that was tested, measured and shown in the build guide to be the lowest distortion is the the same as route 1 on the second group buy boards v4.0.
When we released the second group buy boards V4.0 I modified the other route from the first group buy boards V3.9 to become route 2 this is a completely new path. So please don't get it confused with the other path on the 1st group buy boards V3.9
Andy's new results are for the second group buy boards V4.0 and only for the EF3-3 at this stage. So like he said if your building a EF3-3 please select route 2.
Route 2 was modified so it heads directly towards the input stage and doesn't pass twice in front of the output terminal.
Theoretically you could tweak the first group buy trace if your prepared to cut the traces and use a jumper but its not probably necessary.
Just to clarify the information around the negative feedback path.
For the first group buy boards V3.9 we had two negative feedback paths to test. They were never named on the silkscreen. But the one that was tested, measured and shown in the build guide to be the lowest distortion is the the same as route 1 on the second group buy boards v4.0.
When we released the second group buy boards V4.0 I modified the other route from the first group buy boards V3.9 to become route 2 this is a completely new path. So please don't get it confused with the other path on the 1st group buy boards V3.9
Andy's new results are for the second group buy boards V4.0 and only for the EF3-3 at this stage. So like he said if your building a EF3-3 please select route 2.
Route 2 was modified so it heads directly towards the input stage and doesn't pass twice in front of the output terminal.
Theoretically you could tweak the first group buy trace if your prepared to cut the traces and use a jumper but its not probably necessary.
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I almost finished the IPS boards.. I managed to buy some NOS 2SA992 locally as this seems to be the one part I missed to order. As you can see I also ended up buying a 12,5mm NPO Cap - it barely fits but there's no space left for the input terminal block. Maybe I still have a chance to finish the Amp before NYE 🙂
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This is a highly sensitive trace and you don't want any extra resistance to the TMC connection
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Hi, what do you think about using Wolverine in low power ( 😊 ~25-30W rms MAX of output) / active speaker situation?
What output power would be expected (if it will work) from +-28V SMPS psu?
What output power would be expected (if it will work) from +-28V SMPS psu?
A tip for anyone thinking what enclosure, etc. to get - I went for the HiFi 2000 Dissipante 3/400 enclosure with their Wolverine modded heatsinks and got the inner baseplate as well, intending to run all mains/power beneath this plate for additional screening (every little helps!).
Mounting the pcb's parallel to this heatsink (with O/P trans' legs bent at 90 degrees) as I decided to do, positions the edge of the pcb very low down (or very high up - depending on your orientation!) if using use the pre-drilled & tapped hole locations as provided for both trans' and pcb. I'd also intended to assemble things with one heatsink 'trans up' and the other as 'trans down', if you see what I mean - in order to keep the I/P at the same relative ends to each other.
However, the edge of the pcb ends up so close to the securing 'rail' attached along the edge of the heatsink that there's no way the inner baseplate can be fitted! The only way, therefore, to fit this baseplate will be to position both heatsinks with the pcb towards the top, which will leave the inputs at different ends (not that this is so critical - as discussed here in some depth, the cable routing is more important in order to prevent loops).
Not the end of the world, but not as I'd hoped or intended - unless anyone has any other ideas about this? If intending to use the baseplate not sure if the 4/ enclosure would be better, if the heatsink holes are placed more central height wise (don't know if they are or not)?
Having now mounted everything on the heatsinks and fully tested (all working great by the way, exactly as per build guide - good stuff!), didn't fancy needing to dismantle everything, drill & tap new holes in the heatsinks, with all the hassle, mess and potential problems that would create!
Mounting the pcb's parallel to this heatsink (with O/P trans' legs bent at 90 degrees) as I decided to do, positions the edge of the pcb very low down (or very high up - depending on your orientation!) if using use the pre-drilled & tapped hole locations as provided for both trans' and pcb. I'd also intended to assemble things with one heatsink 'trans up' and the other as 'trans down', if you see what I mean - in order to keep the I/P at the same relative ends to each other.
However, the edge of the pcb ends up so close to the securing 'rail' attached along the edge of the heatsink that there's no way the inner baseplate can be fitted! The only way, therefore, to fit this baseplate will be to position both heatsinks with the pcb towards the top, which will leave the inputs at different ends (not that this is so critical - as discussed here in some depth, the cable routing is more important in order to prevent loops).
Not the end of the world, but not as I'd hoped or intended - unless anyone has any other ideas about this? If intending to use the baseplate not sure if the 4/ enclosure would be better, if the heatsink holes are placed more central height wise (don't know if they are or not)?
Having now mounted everything on the heatsinks and fully tested (all working great by the way, exactly as per build guide - good stuff!), didn't fancy needing to dismantle everything, drill & tap new holes in the heatsinks, with all the hassle, mess and potential problems that would create!
I hear what you are saying. I have the EF3-3 boards and the 3u/400 enclosure also, including the base plate. When assembling the heatsinks I inadvertently mated the two heatsinks with one of them end for ended. This resulted in two holes being in the wrong positions and one of the output device holes missing.
Something I did not notice was that these latter holes had been drilled but were being hidden behind the steel angle section that the heatsinks are mounted on. It was not untill I had drilled and tapped the "missing" holes and separated the two heatsinks that I realised they were not needed. Fortunately, there were no broken drills or taps involved in the exercise. The lesson learned from this exercise is to pay attention to the orientation of the heatsink pairs such that If tapped holes are not where they should be one of them needs reversing.
Keith
Something I did not notice was that these latter holes had been drilled but were being hidden behind the steel angle section that the heatsinks are mounted on. It was not untill I had drilled and tapped the "missing" holes and separated the two heatsinks that I realised they were not needed. Fortunately, there were no broken drills or taps involved in the exercise. The lesson learned from this exercise is to pay attention to the orientation of the heatsink pairs such that If tapped holes are not where they should be one of them needs reversing.
Keith
Ok all, results are in on the TTA004 TTC004 vs 2SC3503E 2SA1381E discussion. These measurements were taken from the same EF3-4 board, only swapping the predrivers out. I do multiple sweeps at 25 volts into 8 ohms every 5 minutes to check for temperature deviation on the distortion results. 
In my opinion use whichever you have on hand, or easier to source as there is only a very minor difference between them. The Sanyos seem to hold tighter during time, and the toshibas measure a touch better at 1k, but to be honest @ -125 db there are both AWESOME 😀, actually its just the whole amp that is!!
Cheers and Merry Christmas !!!
In my opinion use whichever you have on hand, or easier to source as there is only a very minor difference between them. The Sanyos seem to hold tighter during time, and the toshibas measure a touch better at 1k, but to be honest @ -125 db there are both AWESOME 😀, actually its just the whole amp that is!!
Cheers and Merry Christmas !!!