@CoGT3: The Q4/R15/R16 combination is a current limiter. These parts, together with the 0.47R source resistors for the output mosfets, give a hard current limit of about 2.2A per output device. This protects against driving into low impedances (even a short). But the limiter does have a slight effect even before the current approaches this hard limit and the effect is more pronounced the closer you get. So if your load/current combination stays safely within a reasonable range, removing the limiter should eliminate any potential distortion coming from it.
I haven't tried this one yet. But it's easy enough to simply leave that ZTX450 and associated resistors out of your build. Or build with them in, listen a while, then snip then out. If you do the ZTXectomy, please report on the results.
I may be the group's Huckleberry on the ZTXectomy. After Dennis' excellent explanation of potential distortion it makes a comment by Papa in the Reloaded thread make more sense:
"It's hard to blow up the circuit without the protection, and nobody likes
to look at it (spoils the cow's milk), so I deleted it. "
Sounds like Papa was never worried about the safety of the circuit but more worried about what customers might do. So if we build the amplifier correctly and don't subject the amp to an improper load we should be good.
Reasonable plan to me seems to build the amp as Randy specced and run it for 1-2 months to insure that has been an error on the builders side and give oneself a chance to learn the sound of the amp. Then pull the the ZTX, crank up the Zeppelin and see what happens (my speaker load is 10 ohm, 8 ohm nominal).
"It's hard to blow up the circuit without the protection, and nobody likes
to look at it (spoils the cow's milk), so I deleted it. "
Sounds like Papa was never worried about the safety of the circuit but more worried about what customers might do. So if we build the amplifier correctly and don't subject the amp to an improper load we should be good.
Reasonable plan to me seems to build the amp as Randy specced and run it for 1-2 months to insure that has been an error on the builders side and give oneself a chance to learn the sound of the amp. Then pull the the ZTX, crank up the Zeppelin and see what happens (my speaker load is 10 ohm, 8 ohm nominal).
Getting started on my build.
Last week I finished the F4, so being an apparently Foolish Amp Builder, I'm turning my attention to the serious project, the Aleph 60. What's that? It's Fearless Amp Builder? Oh, my bad.
This will be done in monoblocks with the new modushop chassis, front end board on one side of sinks, and the extension board on the other. I'm also intending to put in a balanced or single-ended input selector switch, and have the outputs to two pair of binding posts for bi-wiring.
I spent some time yesterday and today stuffing the PSU board, the extension board, and am starting in on the amp boards.
Mrs Toadroller observed that I have many more amplifiers than listening environments. And...? I'm not sure what point she was trying to make. Seems like a win to me. 🙂
Last week I finished the F4, so being an apparently Foolish Amp Builder, I'm turning my attention to the serious project, the Aleph 60. What's that? It's Fearless Amp Builder? Oh, my bad.
This will be done in monoblocks with the new modushop chassis, front end board on one side of sinks, and the extension board on the other. I'm also intending to put in a balanced or single-ended input selector switch, and have the outputs to two pair of binding posts for bi-wiring.
I spent some time yesterday and today stuffing the PSU board, the extension board, and am starting in on the amp boards.
Mrs Toadroller observed that I have many more amplifiers than listening environments. And...? I'm not sure what point she was trying to make. Seems like a win to me. 🙂
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how does it go? How many amps is enough? N+1 where N is the current number of amps.
A word of caution on that power supply. I think you have a green LED. We all know on the Pass forum that blue sounds better. 😉
Looking forward to pix of more build progress!
LOL. Both the F6 and the F5 had LEDs on the amp boards as well as the PSU boards, so I thought I'd have a place for my Pass-approved blue LEDs. Alas, I shall have to replace. Is it cosmic coincidence that in guitar forums, it is an established fact that blue guitars sound better as well?
we all know that Blue LEDs are used by those going conservative - Papaways
real proper Fearless Chickens are using ZMways - 3mm diffuse LEDs, in plentiful quantity
real proper Fearless Chickens are using ZMways - 3mm diffuse LEDs, in plentiful quantity
Can confirm, I built my F3 with red LEDs on the PS, green LEDs on the amp boards, and the Aleph 30 with blue PS LEDs. No prizes for guessing which is my current favorite.
Just want to close out my trouble ticket. To refresh, I had installed the wrong pot in P2. Anyway, I decided to order the correct one, rather than adjust with a different resistor value to keep it the same as the other Aleph 30 boards I ordered for a mono-block config. Got all adjustments to spec, and have been enjoying the beautiful sound.
Being my first build, this has really been an enjoyable experience. Gotta give much thanks for the assistance, and outstanding build instructions and ordering from Randy, and the helpful nature of the community! I've already ordered a pair of Th51's for a to be determined build for this Fall/Winter! Thank you!
Being my first build, this has really been an enjoyable experience. Gotta give much thanks for the assistance, and outstanding build instructions and ordering from Randy, and the helpful nature of the community! I've already ordered a pair of Th51's for a to be determined build for this Fall/Winter! Thank you!
Fearless Chickens…of the Seawe all know that Blue LEDs are used by those going conservative - Papaways
real proper Fearless Chickens are using ZMways - 3mm diffuse LEDs, in plentiful quantity
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I have one Aleph 2 mono built and I fired it up tonight.
3.0A bias
<10mV DC Offset
44.6V rails using antek 35+35 600VA Donut.
It’s in a 5U deluxe chassis which was running at ~52c after about 30 mins of playing music on the bench and testing / making adjustments. I need to do a final bit of wire dressing and do the final donut spin and tightening. Then I’ll put the covers on and let it cook a while to get a temp measurement at equilibrium. It will be a hot one.
I’ll publish the build doc tomorrow and post pix.
I also plan to post pix of doing P2 AC gain setup, too.
3.0A bias
<10mV DC Offset
44.6V rails using antek 35+35 600VA Donut.
It’s in a 5U deluxe chassis which was running at ~52c after about 30 mins of playing music on the bench and testing / making adjustments. I need to do a final bit of wire dressing and do the final donut spin and tightening. Then I’ll put the covers on and let it cook a while to get a temp measurement at equilibrium. It will be a hot one.
I’ll publish the build doc tomorrow and post pix.
I also plan to post pix of doing P2 AC gain setup, too.
For all fearless Aleph 2 builders... 💪
The Aleph 2 Build Notes document is now in Post #1 of this thread.
The Aleph 2 Build Notes document is now in Post #1 of this thread.
The twin cities of Alephopolis are populated and ready for moving in.
I put in C20, C21, and went to cross them off my schematic. Not there. Huh? Looked at the BOM, not there. Well then, they're on the PCB and you bought them for a reason, go look it up. Sure enough, a search of the thread for C20 and Randy had documented it. I really need to change my reference schematic and BOM to the latest revision, eh?
I put in C20, C21, and went to cross them off my schematic. Not there. Huh? Looked at the BOM, not there. Well then, they're on the PCB and you bought them for a reason, go look it up. Sure enough, a search of the thread for C20 and Randy had documented it. I really need to change my reference schematic and BOM to the latest revision, eh?
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Randy,
Your excellent table that you posted on #417 should be on your 1st post I think to let folks know the heatsink requirements. It may be useful to include them in the appropriate build documents as well.
Best,
Anand.
Your excellent table that you posted on #417 should be on your 1st post I think to let folks know the heatsink requirements. It may be useful to include them in the appropriate build documents as well.
Best,
Anand.