Hello,
Can someone knowledable with this amp config check the following please?
I'm aiming to build a 2 channel EF3-3 Build please?
I have in my spreadsheet:
Kind regards,
Adrian
Can someone knowledable with this amp config check the following please?
I'm aiming to build a 2 channel EF3-3 Build please?
I have in my spreadsheet:
- 2x EF3-3
- 2x IPS
- 2x Heatsink Set (IPS, Pre driver, Driver) ??
- 6x Pairs transistors ??
- 1x Dual bridge rectifier board
- 2x Speaker protector
- 1x T Ground board
- 1x Ground lift
Kind regards,
Adrian
Assuming you meant EF3-4, this will depend on which output transistors package you use.
MT200
TO264
TO3P
This will depend on which DC rail voltage you target, which will depend on your target output power and whether your target speakers are "typical" or fall under the rarer "difficult to drive" umbrella. (where Re (DC Resistance) of the speaker is half of the rated impedance)
Rail voltage will determine what size heatsink / chassis you need.
Please clarify your question. EF3-3 or EF3-4?
Speaker protection is sold as a pair so you would have enough for a stereo amplifier. 1 per channel.
If you get the deluxe chassis only, and do not request custom drilling (they have templates for all EF3-4 output arrangements), the only wolverine option that you can "plug-n-play" is the EF3-3 with TO3P package output transistors. Limiting you to 64V rails max. (see table above)
You need to order one set of EF3-3 heatsinks. For 6 heatsinks total.
I think for V5 you need 8 pairs minimum to complete a stereo set.
1 speaker protect set as they sold in a pair, 1 per channel.
1x dual bridge rectifier and 1x ground lift board will work for a standard dual AC secondary winding transformer. (If you are doing a dual mono type of supply with 4x ac secondaries, you will need 2x dual bridge and 2x ground lift boards.)
Thank you. I need some time to figure out what's what here so I can decide which way to go. When are you closing this group buy cycle?
Ah sorry, I see you say you already have heatsinks from modushop, and may have been referring to the auxiliary heatsinks. You would need a set of EF3-4 heatsinks (4x heatsinks total). The drivers mount underneath the EF3-4 boards on the main modushop heatsink in this case.
Also if any mods available, that table I had posted above had some typos in it, here's the correct table.
Is it safe to assume that two independent transformers each 500VA would be good for the 2 x 200W@8 ohms in dual mono config? If yes, then I can continue figuring out what I need to order on the amp side...
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Yep 👍 1x 500VA will do 1x channel 200W 8ohms with 64 or 71V dc rails
Awesome, that's what I'm aiming for.
I guess this covers the PSU side of the build:
2 x 500VA - 64 or 71 DC rail
Dual Mono class A W12 PSU kit + 4 rectifiers (from TatcherDIYAudio)
Now the big question, what do I need to order from you guys to get that dual mono 2x200@8ohm for the amp end from you guys? And how to make a payment?
Much appreciated!
Need to decide how big the chassis you're going to get is. If you don't want to drill/tap any holes; 4U Deluxe (300mm deep) from modushop, as I said earlier you want the EF3-3 boards limiting you to 64VDC rails max. Due to TO-3P output transistors fitting the UMS heatsink holes. This will still get your 200W out, with your oversized 500VA traffo.
If you purchase 5U Deluxe, you can go the EF3-4 boards and 71VDC rails, because 400mm deep heatsinks and more outputs sharing the load. But you need to drill and tap a few holes, due to drivers being mounted under the PCB on the main heatsink. Or you can get modushop to tap holes for you, based on your choice of chassis and output transistors. (For example, a 4U 400mm deep chassis is not a "deluxe" package option, but it can be arranged if you email modushop.)
*All above assumes mounting the amps mounted parallel with the main heatsinks. EF3-4 boards will not fit the 300mm deep chassis.
I'll leave Stuart to comment on payments. I believe this stage is only EOI, payment would be a while away. I have used paypal in the past, but fees.
If you purchase 5U Deluxe, you can go the EF3-4 boards and 71VDC rails, because 400mm deep heatsinks and more outputs sharing the load. But you need to drill and tap a few holes, due to drivers being mounted under the PCB on the main heatsink. Or you can get modushop to tap holes for you, based on your choice of chassis and output transistors. (For example, a 4U 400mm deep chassis is not a "deluxe" package option, but it can be arranged if you email modushop.)
*All above assumes mounting the amps mounted parallel with the main heatsinks. EF3-4 boards will not fit the 300mm deep chassis.
I'll leave Stuart to comment on payments. I believe this stage is only EOI, payment would be a while away. I have used paypal in the past, but fees.
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Ok this clears a lot of questions I had. Thank you so much!
Is there any drawbacks going with the 64V rails instead of 71V?
I guess 64V config will heat up more but not sure what else.... Asking because I found an AnTek 500VA 2 x 64V trans and it's reasonably priced, but in 70ish V realm, only 70V or 75V (toroidy, they go incrementally up in secondaries voltage +5V), didn't had any luck finding the exact 71V.
I'm potentially heading to Japan - Akihabara in the middle of the year and thinking about this amp I thought I might be able to buy the output transistors and maybe a transformer there to save some cash.
I found a store with 2SA1494, their website lists 1000 in stock. Are these likely to be fake/after markets at this stage?
If these aren't wise to base the build on due to obsolesence, what are other people planning to base their build on?
I found a store with 2SA1494, their website lists 1000 in stock. Are these likely to be fake/after markets at this stage?
If these aren't wise to base the build on due to obsolesence, what are other people planning to base their build on?
Be careful -
Secondaries on transformers are in V AC. I have been referring to V DC amp rails. See the table for the AC secondaries the transformer needs to get the target DC rails.
For a 64V DC PSU you need a transformer with 45VAC secondaries. The DC output is higher than the AC input thought the rectifiers and bulk smoothing caps typically at a ratio of approximately 1.4x. For ~71VDC you need ~50VAC
64V DC rails the amp will run cooler than 71V. 71DC needs larger heatsinks.
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