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Old 3rd January 2014, 07:38 AM   #1141
AJT is offline AJT  Philippines
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Default Born on New Year's Eve....

my finished Badger...
bias setting is still class B.....
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Old 6th January 2014, 11:16 AM   #1142
rohot01 is offline rohot01  Taiwan
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Hi gut,I have some question.
T finish other PCB .
DC offset about 30~50mV,and R14 is 8.25V.
After I try to bias of R30.
I turn on about 270 ohm(measure) .
Bias is 0 mV.Is it normal???
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Old 6th January 2014, 04:16 PM   #1143
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Quote:
Originally Posted by rohot01 View Post
Hi gut,I have some question.
T finish other PCB .
DC offset about 30~50mV,and R14 is 8.25V.
After I try to bias of R30.
I turn on about 270 ohm(measure) .
Bias is 0 mV.Is it normal???

R14 = 8.25V excellent (to spec)

DC offset = can be adjusted with trimmer afterwards.

270R R30 = output stage will start conducting at about 250R , 175-180R
will produce optimum output stage bias.

Also, biasing R14(CCS adj.) to 9V or a lower Value for R27 (56/68R) will bring that
"optimum" range of R30 to the 220-270 ohm range. This is the reason for
a 500R trimmer for R30 - to allow for these choices.

OS
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Old 8th January 2014, 12:55 AM   #1144
janusz is offline janusz  Australia
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I need some advice. I do not have some of the recommended transistors for HB but I have plenty of other types.
Which would be best for:
1. cascode (Q3-4) - 2n5551 (hfe about 140) or 2sc2240bl (hfe >400)?
2. Q7 - 2n5551 or 2sa970bl or bc550c or ksc1815?
3. for Q10, 11, 12 - 2sa1209s/c2911s or 2sa1249s/c3117s or ksa1220Ay/c2690Ay or ksa1142y/c2682y?

For Q5-6 I'm using bc560c, Q8 is KSC1815, Q9 is 2sa970bl (hfe>500) and for Q13 I'll use 2sc3117s/t. All the other transistors are as recommended.
Thanks,

PS Spice models for 2sa1209/c2911:
------------------------------------------------
* Spice netlister for gnetlist
* Device models

.MODEL 2SC2911 NPN(IS=1.91E-13 ISE=4.9E-11 NF=1.073 NE=2.8 BF=274
+IKF=0.0836 VAF=320 CJC=6.4E-12 TF=8.84E-10 MJC=0.31 VJC=0.98
+CJE=6.4E-12 MJE=0.3 VJE=0.4 LEVEL=1)

.MODEL 2SA1209 PNP(IS=1.6E-13 ISE=5.2E-11 NF=1.073 NE=2.57 BF=257
+IKF=0.081 VAF=125 CJC=8.7E-12 TF=9.95E-10 MJC=0.313 VJC=0.975
+CJE=8.7E-12 MJE=0.3 VJE=0.4 LEVEL=1)
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Old 8th January 2014, 01:48 AM   #1145
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I did some testing with your models. Q1/2 and 5/6 were the "touchy"
ones. Try to aim for < 500Hfe for both.

Cascode just needs to be a high Vce device, no gain here.

For the VAS and CCS's nothing critical. 2911/1209 pair
worked good for the VAS. Don't use too high of a rail voltage with
this pair (60-65V max).

Using a high gain Q5/6 was where I could get instability.

OS
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Old 8th January 2014, 08:46 AM   #1146
janusz is offline janusz  Australia
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Thanks ostripper,
for Q1-2 I'm using ss9014d with hfe of 560 perfectly matched but I increased R15-16 to 121ohm and R17 is 2k. Will that do?
I'll replace Q5-6 with low Hfe transistors, bc327 or ksa1015y (max hfe about 240).

For cascode I'll use 2n5551 as it's common base so Hfe as you said does not matter.

I'll be using 2x45V or 2x40V toroids so I should not get more than +/-65V no load.
I also have 2sa1406/c3600 which have better SOA than 2sa1209/c2911.

cheers,
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Old 8th January 2014, 09:37 AM   #1147
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The early badgers were designed with a PILE of F grade KSA992/KSC1845 ...
(300-600Hfe) Anything in this range should work well.
Only one person used 1200-1400Hfe devices , got a little "squirrelly".

Thanks for tipping me on ..http://www.sm0vpo.com/_pdf/2SA/2SA1406.pdf

I am looking for a 3503/1831 replacement (soon to be discontinued). they
even look better than the KSA/C's. SOA does not matter much for the VAS,
6-10mA is not much - using a larger heatsink is helpful - 40 X 80mm of
plain ol' aluminum roof flashing is what I used.

OS
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Old 8th January 2014, 10:00 AM   #1148
AJT is offline AJT  Philippines
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OS, will you consider TO-220's instead of to-126's?

some choices here...http://users.tpg.com.au/gerskine/gre...ransistors.htm
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Old 8th January 2014, 10:32 AM   #1149
janusz is offline janusz  Australia
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There are also 2sa1541/c3956 with Ic=200mA (pulse 300mA) but I do not know if these are still in production. I bought mine years ago for Stochino amp.

BD Enterprises sell these transistors but these are not cheap. 2sc3600 costs now $3.80 and $2.90 for 200 plus. 2sa1541 is even more expensive: $3.99, 2sc3956 is cheaper @1.20 and $0.70 for 200 plus.

cheers,
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Old 23rd January 2014, 03:09 AM   #1150
idooley is offline idooley  United States
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Question Can I use Honey Badgers for surround sound?

After reading 115 pages of this thread, I've decided that I'm very interested in putting 8 channels of Honey Badger into a single 5 U enclosure (i.e. the one in the DIYA store with heat sinks for sides). I'm thinking about mounting 4 channels on each side. I'd keep some decoupling caps in the center of the enclosure along with some output relays. But, I'd put a big Toroid >= 1500VA and power smoothing caps in a separate enclosure along with a microcontroller (or tiny computer) to handle startup/shutdown/over-temp. I'd probably put some one-wire thermometers various places in there too. Of course this would result in me running the ~60VDC rails over some thick cabling between the two chassis.

My use would be mostly for home entertainment (movies and some music), so most of the time I wouldn't be driving it that hard.

Would I be able to fit at least 7 channels in a 5-U enclosure? Are there better enclosure options? Is this a bad idea for other reasons?

I read Self's discussion on separating out the power supply, and he seems to think the concept is sound.
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