Hi guys, I have some pics of the build i'm just trying to set the bias now
the right Channel set perfectly
the left channel has an issue
bias set ok to 500 mv but the offset has 17-18v coming through the speaker terminals and the pot does not have an effect something also my led is not on this side either. I checked the jfets and they were ok but I replaced anyway. so
any thoughts before I replace everything
thanks
the right Channel set perfectly
the left channel has an issue
bias set ok to 500 mv but the offset has 17-18v coming through the speaker terminals and the pot does not have an effect something also my led is not on this side either. I checked the jfets and they were ok but I replaced anyway. so
any thoughts before I replace everything
thanks
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swell!
now buy two heatsinkless cases, do some swapping, and you're double good to go
That's the plan! Going to contact HiFi2000 to see if they can do some custom face and back plates but if not, time for some heatsinkless cases and some frankensteining.
Mono-blocks are sweet.
So close, Z! I still need to make another Mouser order to get all the quick connects. Also having to work a separate order with for more of the hardware. I've been hoping the DIYAudio store would get their hardware kit back in stock as I've been having a turrible time tracking down the correct standoffs thru Mouser. Resorting to McMaster Carr but still have to pull the ACAs apart to make some measurements.
If anyone knows the screw lengths, washer dimensions for all the M3 hardware, it'd be greatly appreciated.
Tom,
You are referring to the following?
1. M3 spacers and screws for fixing the amplifier PCB on the heat-sink
2. M3 spacers and screws for fixing the power supply PCB to the floor of the chassis
3. Washer and screw for holding down MOSFET on to the heat-sink
Z!,
Yes. This is what I got so far if you can check my work:
1. Signal PCB/Heatsink:
a. Standoffs: M3, brass, 6mm stand-off height + 5mm thread length
b. PCB screws: M3 x 3mm thread length (maybe 4mm)
2. PSU PCB/floor:
a. Standoffs: M3, brass, 6mm stand-off height + 8mm thread length (have these already)
b. PCB screws: M3 x 3mm thread length (same as 1.b)
3. Transistor/Heatsink (from ACA hardware):
a. Screw: M3 x 10mm, stainless
b. Washer: M3 x 4mm ID x 16mm OD x 0.5mm thick - think this might be a No. 6 fender washer
Is this about right? Close enough?
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Tom,
These look good to go. You should be making sound soon...
Soon!
hardware is expected Monday.
Putting in a final Mouser order tomorrow for the quick connectors and the last bit of resistors, caps and wire.
Thinking of having some fun and getting some fancy rca jacks and speaker binding posts.
Also, approaching HiFi2000 about some custom front and back plates. If not, Frankencase!
Over the weekend, I'll pop in the new zeners and matching resistors and do a trace thru to see if there is anything missing or needing a touch up.
Then it'll be learning about all things in-rush current and other solid-state quirks.
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Hello,
I have concerns about the lower wattage of the F6 and it's ability to drive my 4 ohm Magneplanar speakers. Is it safe to bridge the F6 amplifier. As I understand it, I would need to install an XLR input. Then drive one channel positive phase and the other negative phase. The output would be taken from the positive of one channel to the positive of the other channel. The speaker negatives are tied together. Is that correct?
I looked at the ACA balanced hookup but found the positive terminals tied together to be confusing. Is that because the ACA amp inverts phase?
Thanks for any insight you could provide.
I have concerns about the lower wattage of the F6 and it's ability to drive my 4 ohm Magneplanar speakers. Is it safe to bridge the F6 amplifier. As I understand it, I would need to install an XLR input. Then drive one channel positive phase and the other negative phase. The output would be taken from the positive of one channel to the positive of the other channel. The speaker negatives are tied together. Is that correct?
I looked at the ACA balanced hookup but found the positive terminals tied together to be confusing. Is that because the ACA amp inverts phase?
Thanks for any insight you could provide.
The best bet for building an F6 that can drive 'difficult' or lower impedance loads is to use Mosfets with a higher transconductance. So, not the normal IRFP240.
Try the FQH44N10 instead. And use a power transformer with 20V secondaries. That will help the output devices stay in their higher transconductance region.
Try the FQH44N10 instead. And use a power transformer with 20V secondaries. That will help the output devices stay in their higher transconductance region.
Thank you for your responses. I have built a Cascode, dual-mono F5T which drives the Maggies quite well. It is the best sounding amplifier I've had in my system. Now I've got the Pass Amp building bug and wanted to hear what an F6 sounds like.
I've managed to squeeze in two DIY power supply boards (vertically) into the 4U case, so it is quasi- dual mono, hopefully to drive 4 ohm loads better. If the F6 gain is similar to the F5T, perhaps I could bi-amp the system?
I've managed to squeeze in two DIY power supply boards (vertically) into the 4U case, so it is quasi- dual mono, hopefully to drive 4 ohm loads better. If the F6 gain is similar to the F5T, perhaps I could bi-amp the system?
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My experience earlier this month (June 2021) was: prompt response by telephone to my emailed inquiry; chief engineer helped select the correct model and double-checked my understanding of the leads color patterns, which aren't the same as Antek's; primaries in stock but needed to complete secondaries before shipping, and delivery was sooner than promised. They stated a two-week lead time and the units were here in about a week.
And they had L-brackets, so I ordered four. They prefer that single brackets be ordered with a transformer (because who makes money on a $12 product with $6 shipping costs?)
Price was $125 per transformer, and my Social Security check is generous enough that I could order a second unit for future use.
I live in MD, so it wasn't buy American, it was buy local.
My experience earlier this month (June 2021) was: prompt response by telephone to my emailed inquiry; chief engineer helped select the correct model and double-checked my understanding of the leads color patterns, which aren't the same as Antek's; primaries in stock but needed to complete secondaries before shipping, and delivery was sooner than promised. They stated a two-week lead time and the units were here in about a week.
And they had L-brackets, so I ordered four. They prefer that single brackets be ordered with a transformer (because who makes money on a $12 product with $6 shipping costs?)
Price was $125 per transformer, and my Social Security check is generous enough that I could order a second unit for future use.
I live in MD, so it wasn't buy American, it was buy local.
Hi All,
I am planning to pair this amp with DIY loudspeakers which have 85dB sensitivity (4 Ohm) and wondering if F6 will provide enough power to them. Peak SPL Calculator (Peak SPL Calculator) tells that I'll get about 97dB on the coach considering that F6 provides 50 W at 4 Ohm load. Does anyone have some loudspeakers (or have tested some) with similar sensitivity which work together with F6 to share some experience?
Loudspeakers ScanBySide 2 (they have more detailed description in German, deepl.com translates it well).
Thank you in advance =)
I am planning to pair this amp with DIY loudspeakers which have 85dB sensitivity (4 Ohm) and wondering if F6 will provide enough power to them. Peak SPL Calculator (Peak SPL Calculator) tells that I'll get about 97dB on the coach considering that F6 provides 50 W at 4 Ohm load. Does anyone have some loudspeakers (or have tested some) with similar sensitivity which work together with F6 to share some experience?
Loudspeakers ScanBySide 2 (they have more detailed description in German, deepl.com translates it well).
Thank you in advance =)