Hi all. I require 26db gain to match the 4 Hypex modules ive purchased to drive my 4 x 4ohm 10" seas woofers, and I'm wondering if the honey badger would be the right choice to drive the mids. For the tweeters i will probably just modify the gain on my lm3886 gainclones, which is a simple task. I've been searching for days for an answer to the following questions... If anyone knows the answer to these questions, i'd appreciate it.
1) How much voltage Gain does the honey badger provide in the standard build as described in the build guide?
2) Can it be built to provide 26db (+/- 0.5dbs) voltage gain? if so, do you know How? (would it be as simple as changing the gain in a gainclone, for example where gain=Rf/R3)
3) would the 2U heatsinks in a small "2U modushop pessante dissipant" case be adequate for cooling a stereo pair? Thoughts? Im guessing yes with lower biasing, at the expense of lower ab cross over point and distortion.. thoughts?
Application:
almost all channels of amps will drive 4 ohm drivers directly, fed by active crossovers (Linkwitz lab lx521)
1) How much voltage Gain does the honey badger provide in the standard build as described in the build guide?
2) Can it be built to provide 26db (+/- 0.5dbs) voltage gain? if so, do you know How? (would it be as simple as changing the gain in a gainclone, for example where gain=Rf/R3)
3) would the 2U heatsinks in a small "2U modushop pessante dissipant" case be adequate for cooling a stereo pair? Thoughts? Im guessing yes with lower biasing, at the expense of lower ab cross over point and distortion.. thoughts?
Application:
almost all channels of amps will drive 4 ohm drivers directly, fed by active crossovers (Linkwitz lab lx521)
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31.5db gain - standard with 820R/33K feedback ratio
Change R2/5 = 1K ,
R3/6 = 22K,
You will have 26.2db.
2U X 250-300mm heatsinks will do for standard 70ma bias , my bigger 5 pairs
do 35C on 3U x 300mm extrusions.
Dropping to <50ma bias on these amps produces just a minimal THD increase.
OS
Does a change of gain from +31.5dB to +26.2dB require a change in compensation for the increased feedback?
I was wondering if that would be questioned ...
Nope , overcompensated Badger can handle that increased NFB , still
have 70db margin.
This gets compromised at about 20X gain (1K/15K ratio).
PS - badger is 820R/22K with even smaller TMC caps . still >70db PM.
OS
This seems an odd reply.
Changing from gain=+31.5dB to gain=+26.2dB is not a stability problem.
But changing from +31.5dB to gain=+24.1dB (1k:15k) starts to hit the "compromise" region.
The extra 2.1dB of feedback becomes that critical?
With TMC it will show "ringing". Straight miller has a wider range before
"compromise".
I have experimented with my subwoofer blameless , using the single
Cdom (miller) and many ratio's for NFB. The design never oscillates
with the sub's load . But it could - with a capacitive load , like a piezo
tweeter.
Simulation shows even more ringing with TMC .... so I would suggest
more capacitance with <1K:22K ratio's , like 560pF/150pF for the TMC
array. Another "trick" to reduce ringing is to reduce the FB from the
output - increase R24 1.5K-2.2K. Here you trade stability for PPM (THD).
With any blameless , when in the "compromise" region - clipping will
"excite" any misbehavior.
OS
OS
Hello Mr. Ostripper,
I am interest to builld stereo honeybadger. What power is expected(practical with typical loss of voltage/sagging) with 65v rails with 4 ohm speakers? Is it suitable?
Octave1
I am interest to builld stereo honeybadger. What power is expected(practical with typical loss of voltage/sagging) with 65v rails with 4 ohm speakers? Is it suitable?
Octave1
4R speakers .... I would shoot for <55V rails.
Unless you get the better output devices with higher SOA.
OS
Thank you for your kind reply. I am thinking of using MJL21193/94 as o/p. they seem to have better soa compared to 2sc/2sa or 0381/0302.
thanks
octave1
MJL21193/94 = slow .....
Better with MT-200 sanken's (they just barely fit the badger PCB) or
some MGxxxx Semelab output devices. Both these devices are >35mhz Ft.
I've had my 3 pair Sanken amp driving paralleled subs @ 65V rails.
I've also fully shorted it with no damage besides blow fuses.
OS
Thank you Mr. Ostripper for your reply. You are very supportive. I will try with sankens.
I learned quite a bit on my first Badger build, and -- despite still knowing next to nothing about the concepts behind the design of amplifiers -- I feel ready to invest some $$$ to make an all-out, no-holds barred, over-the-top Badger... Which is to say, I feel like I can "paint by the numbers" without blowing the thing up this time. Haha! : )
My goals:
I plan to re-use my dual mono supply-- two PSU boards with 40,000uf per rail, and two 40V transformers. The rails are about 59-60v. I'd like to have the largest SOA, but sound quality is my top concern. While none of the speakers I have built are less than 6R, I'd like the option of going as low as 4.
My questions:
1.) I'm willing to drop a lot of dough on parts. I've seen a lot of outputs mentioned. What would be your recommendation for my specs and goal?
2.) What other changes would I need to make (BOM as baseline) to accommodate and tweak the amp for the recommended outputs? Again: the goal is no-holds barred sound quality.
3.) I want to create separate power supplies for the front-end of each board. I see capacitance multipliers mentioned as "sufficient". Are cap multipliers desirable compared to building "Transformer + rectifier + smoothing" type PSUs? What's the ideal supply?
4.) Regarding the use of "boutique" capacitors: I've read several articles/comments/etc. that suggest any potential performance improvements from large "boutique" caps would be compromised, sonically, by their large size and long lead lengths. Is this another capacitor myth, or is there something to it?
5.) Does C4 need to be electrolytic, or (assuming the answer to 4 is favorable) can some sort of non-polar "boutique" cap be used there too, if it can fit?
~~~~
I know these topics have been touched on (I've read the whole thread), but it's all fairly scattered. I'm hoping to get a solid, thorough all-in-one-place answer so I don't miss something.
My goals:
I plan to re-use my dual mono supply-- two PSU boards with 40,000uf per rail, and two 40V transformers. The rails are about 59-60v. I'd like to have the largest SOA, but sound quality is my top concern. While none of the speakers I have built are less than 6R, I'd like the option of going as low as 4.
My questions:
1.) I'm willing to drop a lot of dough on parts. I've seen a lot of outputs mentioned. What would be your recommendation for my specs and goal?
2.) What other changes would I need to make (BOM as baseline) to accommodate and tweak the amp for the recommended outputs? Again: the goal is no-holds barred sound quality.
3.) I want to create separate power supplies for the front-end of each board. I see capacitance multipliers mentioned as "sufficient". Are cap multipliers desirable compared to building "Transformer + rectifier + smoothing" type PSUs? What's the ideal supply?
4.) Regarding the use of "boutique" capacitors: I've read several articles/comments/etc. that suggest any potential performance improvements from large "boutique" caps would be compromised, sonically, by their large size and long lead lengths. Is this another capacitor myth, or is there something to it?
5.) Does C4 need to be electrolytic, or (assuming the answer to 4 is favorable) can some sort of non-polar "boutique" cap be used there too, if it can fit?
~~~~
I know these topics have been touched on (I've read the whole thread), but it's all fairly scattered. I'm hoping to get a solid, thorough all-in-one-place answer so I don't miss something.
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If I remember my test results, I got 170W into 8r0 and 311W into 4r0 from a Leach Lo Tim running on a 230:dual 40Vac, 1kVA, transformer operating on 240Vac. My 3pr output stage is rated for 6ohms, or 8ohms. It does not meet my standards for a 4ohms rating.
If you design for 300W into 4r0, you will need from 300VA to 600VA of transformer per channel.
The output stage will need 5times that 300W, i.e. 1500W, of devices per channel.
Use 3pr of MJ15003/4, or 4pr of 200W devices, or equivalent.
If you design for 300W into 4r0, you will need from 300VA to 600VA of transformer per channel.
The output stage will need 5times that 300W, i.e. 1500W, of devices per channel.
Use 3pr of MJ15003/4, or 4pr of 200W devices, or equivalent.
Smoothing capacitors and local decoupling capacitors.
Smoothing capacitors will always be remote from the output stage. They cannot be expected to respond to fast transient demands. Any good quality commercial/industrial electrolytics will meet the duty required for smoothing capacitors. I use Epcos for my lower voltage amplifiers and use Nichicon, or Pacom for 50Vdc/60Vdc
Local decoupling supplies all the fast and not quite so fast current demand. These need to be the correct type to suit the duty and need to be in the correct location to suit the duty and need to be connected with low impedance traces to suit the duty.
It has become my view that getting the local decoupling right has the most effect on amplifier performance and sound quality.
Smoothing capacitors will always be remote from the output stage. They cannot be expected to respond to fast transient demands. Any good quality commercial/industrial electrolytics will meet the duty required for smoothing capacitors. I use Epcos for my lower voltage amplifiers and use Nichicon, or Pacom for 50Vdc/60Vdc
Local decoupling supplies all the fast and not quite so fast current demand. These need to be the correct type to suit the duty and need to be in the correct location to suit the duty and need to be connected with low impedance traces to suit the duty.
It has become my view that getting the local decoupling right has the most effect on amplifier performance and sound quality.
So Andrew if your building for the most power on the HB, would it be a better choice to use an MJ15023/24 set of outputs than the 21193/194? Can I use the T03 package with the DIY boards and just use short connections from board to the outputs?
I guess the HB would work with TO-3's.
But , it would be so easy to use these ....
2SA1295 Sanken | Discrete Semiconductor Products | DigiKey
http://www.digikey.com/product-detail/en/2SC3264/2SC3264-ND/3929388
Why? , even as the badger is not a fast CFA .... the TO's are slow.
Possibly close to X conduction slow.
The sanken ring emitter MT's are quite a bit more friendly to the
HB driver stage. MT's have much higher beta vs current (and frequency).
I Have a 3 pair Sanken setup - it can easily do a real 2R load at >300W.
PS - I have actually seen GLOWING 10A rail fuses.
The Sankens fit with the to-220 drivers all the way down into the holes
and the outputs soldered out to the ends of the package leads.
You would have quite a formidable amp run at <60V , 2-4R NO issue.
OS
My post shows an example of how to arrive at the output stage device dissipation to allow reliable operation into a reactive load.
It is not a recommendation to use mj15003/4.
The Sankens are probably 200W devices. 3 pair gives a total dissipation of 1200W.
My recommendation for a 3pair of 200W devices is to aim for a maximum output of 240W
That could be 240W into 4ohms or 240W into 6ohms or 240W into 8ohms.
If I were designing for the 240W into 6ohms I would select a transformer that is roughly 40-0-40Vac 350VA to 500VA with +-30mF smoothing capacitance.
I would expect the supply rails to run at ~ ±58Vdc. That should get pretty close to the 240W target when a 230Vac transformer is running from a 240Vac mains supply. It might only get 220W to 230W when on a 230Vac mains supply.
I would expect that 3pair output stage to drive a 3r0 test load for 10 to 20seconds at >400W into 3r0, but it will start to warm up quite quicky. It needs to be done from a cool heatsink and not allowed to overheat.
It will also drive a 2r0 test to ~500W, but only do this for 1 to 2 seconds. It will heat up very quickly.
Just long enough to take a very quick voltage measurement on the scope to show no clipping, then off and then a second on for the DMM measurement.
Each of these one/third load resistance tests are quite stressful in that you can quickly exceed the temperature de-rated SOAR as the heatsink and the Tc and the Tj go beyond maximum operating temperatures.
R.Cordell tells us that a Power Amplifier should be able to drive 180% of it's maximum rated power into a test load of half it's recommended speaker impedance.
i.e. an amplifier rated @ 240W into 4ohms speaker, should be able to drive 430W into 2r0 for a second or two, without clipping and without oscillating and without ringing due to an earlier stage starting to overheat a junction due to current overstress.
For sure, that is right.
And, it may be inconvenient that it will depend on the amplifier design as to what is the ideal decoupling for it. Even though we could probably average a bit, it is still true that there isn't a one size fits all convenience for all cases. The decoupling does need to be large enough to support bari harmonics and small enough to avoid supporting midbass fundamentals; and, so, it is a mercy that there won't be a huge variance, so long as we had intended an audio amp with a speaker.
I have tried this several times. 😀
That is linearity, except for a higher word-count.
Also, linearity sounds fantastic.