Here is the "lowdown". Since I designed it , (below) is the exact MT-200 - TO-220
arrangement as it would mate with the Badger PCB .
It's just "do-able" - to the mm. Worse case, the to-220's could be out on wires
above the MT-200's. The TO-126 vbe fits perfect with plenty of room
PS- electrically , the sanken's have higher beta / less EF2 current "droop" than
the ON's - higher Ft , as well (faster).
OS
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For a dual mono-configuration Honey Badger driving 4 Ohm loads, what transformer power would you recommend? Would 500VA per channel be enough? I ask because I'm a little unsure about required Amperage. I'd like to use 8x8200uF caps per channel, 8x10000uF if I can find/get them.
I've looked through the Multicomp offerings at Farnell.com. There I see that a 500VA 40-0-40V transformer can supply 6,25A per secondary. The 800VA does 10A per secondary and the 1kVA does some 12A per secondary. I think that, concidering the physical dimensions of the things, I'm more or less limited to a maximum of 625VA. That would be a tight fit under a riser panel in the 5u case. I'm guessing this will be plenty to provide good bass-grunt for more than just a few short transients. But is that guess correct..?
What kind of transformers have you guys used?
Thanks!
James.
I've looked through the Multicomp offerings at Farnell.com. There I see that a 500VA 40-0-40V transformer can supply 6,25A per secondary. The 800VA does 10A per secondary and the 1kVA does some 12A per secondary. I think that, concidering the physical dimensions of the things, I'm more or less limited to a maximum of 625VA. That would be a tight fit under a riser panel in the 5u case. I'm guessing this will be plenty to provide good bass-grunt for more than just a few short transients. But is that guess correct..?
What kind of transformers have you guys used?
Thanks!
James.
I got over 300W into 4r0 from an amplifier on +-58.5Vdc, using a 3EF with a 3pair (230W) output stage, that was rated for 6ohms and above.
I would expect your 4ohms proposal to achieve similar using 40-0-40Vac.
That would require 5times 300W of output device Pmax. i.e. 3pair of 250W devices in plastic packages. They are rare.
The metal packaged To3 250W devices are in a different (higher) league.
If you intend using 4ohms speakers, then I suggest you think through the power capabilities before you order a 40-0-40Vac transformer.
I remember your previous proposal was with a 35-0-35Vac transformer !
I would expect your 4ohms proposal to achieve similar using 40-0-40Vac.
That would require 5times 300W of output device Pmax. i.e. 3pair of 250W devices in plastic packages. They are rare.
The metal packaged To3 250W devices are in a different (higher) league.
If you intend using 4ohms speakers, then I suggest you think through the power capabilities before you order a 40-0-40Vac transformer.
I remember your previous proposal was with a 35-0-35Vac transformer !
Hi Andrew.
I think it's safe to say that the theory of a complete system is way beyond my capabilities. I know that I won't need sustained output at max power. I do like transients and dynamics, though. And having some power helps with that.
What do you propose I do next? I'd like to build it, but not if my lack of understanding will ruin it.
Built properly with due attention to current capability a 35-0-35Vac transformer will achieve a target of 200W into 4r0 and will with the badger's output stage have a 4ohms rating.
Surely that is enough?
Two channels of 200W will work from a 400VA to 800VA transformer.
The 625VA would meet that. You don't need two 625VA for 200W+200W. Two 400VA is plenty if you adopt dual mono.
If you do go dual mono, then ensure maximum isolation between channels.
Surely that is enough?
Two channels of 200W will work from a 400VA to 800VA transformer.
The 625VA would meet that. You don't need two 625VA for 200W+200W. Two 400VA is plenty if you adopt dual mono.
If you do go dual mono, then ensure maximum isolation between channels.
Thank you all for you replies and help. Each answer I think I find here, raises at least two more questions. Quite bad for motivation. Nevertheless, I think it's very fascinating material and I enjoy the learning.
The 2x400VA sounds good, from a pratical point of view. These can be built into a 4u case, with some distance between them for isolation. I'll see if I can find a way to build them into some sort of Faraday's cage.
I'll read that link on power supplies Janusz sent me. See if I can dertermine the right amount of capacity. What other tips can you give me?
And with that, I hope to be done asking questions and just get on with it
Thanks very much!
James.
The 2x400VA sounds good, from a pratical point of view. These can be built into a 4u case, with some distance between them for isolation. I'll see if I can find a way to build them into some sort of Faraday's cage.
I'll read that link on power supplies Janusz sent me. See if I can dertermine the right amount of capacity. What other tips can you give me?
And with that, I hope to be done asking questions and just get on with it
Thanks very much!
James.
Questions, Questions........
Stuffing boards I have come up short on some values of Resistors. R27 is specified as 68R 1/2 W, can I use 56R or should I use 75R 1/2W?
Also, just to be sure, Hole C to Z is just a jumper wire? or do I need a diode there? yes, I've searched and am confused by what I've found.
So excited about this amp, I dropped off the front plate at the engraver today.
"Honey Badger" engraved on the front, because the HB just don't give a $ hit!
Ron
Stuffing boards I have come up short on some values of Resistors. R27 is specified as 68R 1/2 W, can I use 56R or should I use 75R 1/2W?
Also, just to be sure, Hole C to Z is just a jumper wire? or do I need a diode there? yes, I've searched and am confused by what I've found.
So excited about this amp, I dropped off the front plate at the engraver today.
"Honey Badger" engraved on the front, because the HB just don't give a $ hit!
Ron
Stuffing boards I have come up short on some values of Resistors. R27 is specified as 68R 1/2 W, can I use 56R or should I use 75R 1/2W?
Also, just to be sure, Hole C to Z is just a jumper wire? or do I need a diode there? yes, I've searched and am confused by what I've found.
So excited about this amp, I dropped off the front plate at the engraver today.
"Honey Badger" engraved on the front, because the HB just don't give a $ hit!
Ron
C-Z is the cascode/zener ground reference - solid wire jumper.
Edit - you could even put an LED (cathode toward ground -Z)there - red would raise cascode 2v/blue 4v ...
17-20V cascode - would make no difference
75R is better for R27 , it will give a rock solid 8ma VAS current.
56R would be good for real low Z speaker loads , and you might have to
adjust r29 (bias limiting R) ... for that 10ma+ current.
OS
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this is my upcoming honey badger build, chassis design on going...
An externally hosted image should be here but it was not working when we last tested it.
will connect them in parallel to the 68k's...
i am using a 36-0-36 volt traffo good for about 500va...
i will deploy a soft start/speaker protector board,
and a SOA protection board harvested from a Luxman lv-103 amp...
the psu will be modularised and can be lifted off the chassis if needed...
Most builders "over-cap".
HK 990 - 5 pair = 2 X 32Kuf
Hk 680 - 2pair = 2 X 16Kuf
Mine = 5 pair = 2 X 42Kuf
Mine - sub (single amp) with 3-pair mt-200=32Kuf..
Not only no "droop" ... but less than 1V ripple on all these.
Only benefits to more than one pair caps is ESR.
Same caps = same ESR
Different caps in parallel ... one
pair might work harder under load than the other (pair).
Sort of like similar output pairs in a multi-pair OPS.
PS - just your 68K's would be literally "overkill" for a 2
channel badger.
Think the Pass X250 w/ 6 pair uses 125Kuf !!
OS
HK 990 - 5 pair = 2 X 32Kuf
Hk 680 - 2pair = 2 X 16Kuf
Mine = 5 pair = 2 X 42Kuf
Mine - sub (single amp) with 3-pair mt-200=32Kuf..
Not only no "droop" ... but less than 1V ripple on all these.
Only benefits to more than one pair caps is ESR.
Same caps = same ESR
Different caps in parallel ... one
pair might work harder under load than the other (pair).
Sort of like similar output pairs in a multi-pair OPS.
PS - just your 68K's would be literally "overkill" for a 2
channel badger.
Think the Pass X250 w/ 6 pair uses 125Kuf !!
OS
What about 8x8200 per channel at 500VA per channel? Probably still overkill, but I'm aiming at a ripple smaller than 5% of the power rail voltage at sustained high output. That way I'm sure to have little to no ripple at normal use.
I am a bit concerned with inrush- and charging current for the capacitors. Probably install a softstart circuit to be safe?
I am a bit concerned with inrush- and charging current for the capacitors. Probably install a softstart circuit to be safe?
8 X 8200uf is ideal (65Kuf) for a badgers. You will reach your 5% goal.
I'm only using 42Kuf X 2 for a larger amp !
Your 130Kuf will take about >5 seconds to charge to 90% with a 20R
soft-start power resistor. My 82K takes 3.5 seconds (for 90%) , so I scripted
my microbased - http://www.diyaudio.com/forums/solid-state/264313-how-build-21-st-century-protection-board.html
controller to switch from inrush > full AC in 3500ms.
OS