LOL…no such excitement yet.
Just slow progress…as usual…life, duties blah blah blah.
I did eventually have both channels running on the bench from late afternoon into the evening yesterday.
I was tweaking Iq and offset as the chassis saturated with heat.
I will repeat the process again today just to observe and make sure things are as they should be.
I noticed the bias continued to drift down later in the evening and had to keep chasing it. I was continuing to adjust offset as a result.
I think it might have to do with line voltage fluctuations in my house at night that I’ve noticed before.
Just want to make sure before hand.
Just slow progress…as usual…life, duties blah blah blah.
I did eventually have both channels running on the bench from late afternoon into the evening yesterday.
I was tweaking Iq and offset as the chassis saturated with heat.
I will repeat the process again today just to observe and make sure things are as they should be.
I noticed the bias continued to drift down later in the evening and had to keep chasing it. I was continuing to adjust offset as a result.
I think it might have to do with line voltage fluctuations in my house at night that I’ve noticed before.
Just want to make sure before hand.
Yes those are my long term OB tinkering speakers.
Currently have the Babelfish J2 driving the Sonido field coils up top.
I’m thinking I will have to put together some babysitters…running a bit hot like this…at least 53C.
When I was last using the all IRFP version I was driving my Tannoys and they ran a bit cooler.
Currently have the Babelfish J2 driving the Sonido field coils up top.
I’m thinking I will have to put together some babysitters…running a bit hot like this…at least 53C.
When I was last using the all IRFP version I was driving my Tannoys and they ran a bit cooler.
^ Cool. I’m currently working with a new pair of Nelson’s SLOB from the Speaker Camp in July. I have my M2x driving the Moth Cicada fullranges and a Naim NAP 250 for the 15” Eminence drivers. It has taken a while to dial in a good balance between the two amps. Adding 30 Ohms in parallel with each bass driver has helped.
I’m enjoying this Semisouth down version immensely.
It really seems to work beautifully in this system…and not just on certain material.
The system seems to now have more cojones.
There is clarity without harshness.
That is something I also felt about my F2J monoblocks.
However, there were certain recordings that I felt the F2J struggled with regarding scale and impact.
I love the F2J enough to have gone back to them after building a round 1 VFET amp.
I’m not sure I would go back so quickly from the BJ2…but more comparisons will be made.
As is the case with now having the Semisouth down version to compare to the all IRFP version. I’m honeymooning with the SS down for now.
I can’t help but think about the heat buildup and the fact that it is holding me back from upping the bias to experience what that has to offer.
Trying to mimic the 4U/300 for these was a mistake. I chalk it up to inexperience…but that doesn’t solve anything.
I’m debating over whether I can really cool these things with fans enough to even approach 1A7 Iq without creating a lot of fan noise.
Only other option is to Frankenstein bigger heatsinks onto the case or a transplant to something bigger.
I have some 4U/400 cases, but was saving them for SissySIT, LuDef or F3.
It really seems to work beautifully in this system…and not just on certain material.
The system seems to now have more cojones.
There is clarity without harshness.
That is something I also felt about my F2J monoblocks.
However, there were certain recordings that I felt the F2J struggled with regarding scale and impact.
I love the F2J enough to have gone back to them after building a round 1 VFET amp.
I’m not sure I would go back so quickly from the BJ2…but more comparisons will be made.
As is the case with now having the Semisouth down version to compare to the all IRFP version. I’m honeymooning with the SS down for now.
I can’t help but think about the heat buildup and the fact that it is holding me back from upping the bias to experience what that has to offer.
Trying to mimic the 4U/300 for these was a mistake. I chalk it up to inexperience…but that doesn’t solve anything.
I’m debating over whether I can really cool these things with fans enough to even approach 1A7 Iq without creating a lot of fan noise.
Only other option is to Frankenstein bigger heatsinks onto the case or a transplant to something bigger.
I have some 4U/400 cases, but was saving them for SissySIT, LuDef or F3.
I’ve tried several experiments at different voltages with some 12CM 12V fans I bought when Radio Shack closed down. Can’t live with the noise. I guess they’re just drek.
The smaller 40mm ones aren’t horrible at 7-9 volts. I have to set something up to see if using 4 of them might be able to move enough air up through the chassis.
Things are made more difficult by the fact that not only is there a base plate inside the chassis preventing free flow of air up through the ventilation slots…but the amp PCBs are also mounted horizontally above the vents in the bottom of the case.
I may have no choice but to install them in the back panel and then have to figure out how to integrate a power supply for them.
No doubt I want to build the SissySIT…it was the first set if board’s I ordered. I wish I had a matching second V1 kit in case I want a pair to bi-amp with.
I felt I should build the BJ2 first because I loved the F2J so much…and moreover Mighty ZM donated the BJ2 boards at BAF 2019 where I attended and won them in the raffle.
The smaller 40mm ones aren’t horrible at 7-9 volts. I have to set something up to see if using 4 of them might be able to move enough air up through the chassis.
Things are made more difficult by the fact that not only is there a base plate inside the chassis preventing free flow of air up through the ventilation slots…but the amp PCBs are also mounted horizontally above the vents in the bottom of the case.
I may have no choice but to install them in the back panel and then have to figure out how to integrate a power supply for them.
No doubt I want to build the SissySIT…it was the first set if board’s I ordered. I wish I had a matching second V1 kit in case I want a pair to bi-amp with.
I felt I should build the BJ2 first because I loved the F2J so much…and moreover Mighty ZM donated the BJ2 boards at BAF 2019 where I attended and won them in the raffle.
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Am I right in thinking at 115-120 volts this bias setting should have a power consumption of about 155-160 watts?
Just trying to put things in perspective and come to terms with limitations of the chassis I built as well as decide if I need to try different transformers if I want to run higher current.
Rails on amp that is running in system are about 23.5V…so estimate puts it around 70 watts per channel or 140 total.
You recommended 1A7… or just short of 90 watts per channel 175-180 total.
Even if I can dissipate the heat, I have to assume buzzing coming from donuts may get worse.
They are inaudible with the cover on now… no idea what will happen with more current.
Oh well, I guess one step at a time.
You recommended 1A7… or just short of 90 watts per channel 175-180 total.
Even if I can dissipate the heat, I have to assume buzzing coming from donuts may get worse.
They are inaudible with the cover on now… no idea what will happen with more current.
Oh well, I guess one step at a time.
