Richard,
Not sure about the BOM but the NAD V1.2 design back a couple of pages is his best CFA design. All of the different input section work with the same output section. I'll let OS give you the recommended parts list but I think he is leaning to some of the Sanken output transistors. I think with the 5 pairs and 70V rails you are up in the 300 to 400 watt range.
Not sure about the BOM but the NAD V1.2 design back a couple of pages is his best CFA design. All of the different input section work with the same output section. I'll let OS give you the recommended parts list but I think he is leaning to some of the Sanken output transistors. I think with the 5 pairs and 70V rails you are up in the 300 to 400 watt range.
Member meanman64 is getting the group-buy together.
Below is the closest I can render to the real output.
The 3-pair OPS can be used with ....
1.OP's ...the MG6330r/9410r - 10A-80V 100ms SOA
http://products.semelab-tt.com/pdf/bipolar/MG6330%20MG6330-R.pdf
2. TO-3p drivers .... Sanken 2SA1294/2SC3263
http://www.sanken-ele.co.jp/en/prod/semicon/pdf/2sc3263e.pdf
They are outputs that think they are drivers - 1.25A 80V 100ms SOA
More than enough for the rather low Cob of 3 pair MGxxxx (250p each) ,
and expected base currents (.6A Ie at 2R full power).
Hell , use another pair of MGxxxx's as drivers .... lowish Cob (250p) higher
gain . We are using TO-126 predrivers , BTW ... why not.
200W ??? ha ha... , try like 400+ with a setup like this. Elector's single
pair MGxxxx amp kit is rated at 125/200W 8/4R !!
We chose the Hawksford +CCS NX (bonsai) for IPS.
His is a good amp , smallish with a little offset.
NOT MINE ! 82+V rails - 145V p-p with <1mv offset (below 2)
Servo works good. Clips nice too.
Member NAF's 3-pair OPS/NAD CFA worked first time as predicted
- no issues.
Coming soon...
PS - If 40-80ppm right up to that huge clipped wave is not enough..
I don't know ?? (typical 20-30ppm any model/any freq.)
OS
Attachments
With the MGxxxx's the 5-pair is a 600W amp and the 3-pair a
350-400 watter.
OMG ! the SOA on them MG's is 2+ times a MJL21193/4 !!
OS
OS,
Along with the boms for each different implementation of the ips and the ops will you also give a feedback design for the different combinations? I know they can be done in different types but will you give a couple of or one best feedback circuit for each combo?
I guess I was thinking of the three pairs output power when I tried to answer Richard. So you are saying an average of 150 watts per output pair as a SOA at 70V. That is at 8ohms I imagine.
Along with the boms for each different implementation of the ips and the ops will you also give a feedback design for the different combinations? I know they can be done in different types but will you give a couple of or one best feedback circuit for each combo?
I guess I was thinking of the three pairs output power when I tried to answer Richard. So you are saying an average of 150 watts per output pair as a SOA at 70V. That is at 8ohms I imagine.
Last edited:
Feedback design ?
Feedback is a full level output signal going right to the IPS.
From there , either the CFB low Z divider or the Higher Z VFA divider ... plus
the servo tap is derived.
The one drawback to this is that the layout has to leave "space"
around the "NFB" pad. Such a huge signal might not go well
with any hi-Z circuitry.
OS
OS,
Perhaps I am getting this totally out of context but I thought that with a VFA you used a capacitor in the feedback loop and a CFA used a resistor and any shunt component that may be used with different types of feedback topology? Am I way off on that?
Perhaps I am getting this totally out of context but I thought that with a VFA you used a capacitor in the feedback loop and a CFA used a resistor and any shunt component that may be used with different types of feedback topology? Am I way off on that?
To hit the SOA of 10A like on semelab datasheet ... I had to run 4R .
At 30A (all 3) , those trannies might melt the rail trace (4mm 2 oz.) you might
have to drill a couple holes in that trace to add a rail buss !!
A single pair of Semelab Op's have like 14A 60V SOA ... might make
a good 200W+ /4R sub amp with only 1 pair.
VERY impressive devices at 6$ apiece.
OS
wolverine/ badger uses a DC blocking cap (220u) and TMC (400/82pF) with
that pair "pole split" by a secondary 1.5k Op feedback path.
This is in addition to the standard 22K/820R feedback network (27X gain).
The NX just gets its HF compensation from the VAS. The global
NFB from OP is in the form of a 1k/39R low-Z network.
Different amps / different feedback.
ps - THE "LEACH" has dual HF compensation caps on the VAS and
a standard resistor feedback network. Also , there is a "lead comp"
of 3-5pF in parallel with those resistors .... also different.
OS
Thanks OS,
I don't think you address the NAD, that wasn't the leach, which was one of the VFA's I think. I can wait for those details, I just wanted to ask to see if we would have had to figure out the global feedback ourselves. You'll have to later explain the rail buss addition. I think I know what you mean but how you implement that and attach the output devices to it I am not sure? Keep the details for later, thanks for all of this.
I don't think you address the NAD, that wasn't the leach, which was one of the VFA's I think. I can wait for those details, I just wanted to ask to see if we would have had to figure out the global feedback ourselves. You'll have to later explain the rail buss addition. I think I know what you mean but how you implement that and attach the output devices to it I am not sure? Keep the details for later, thanks for all of this.
Skewbaby
Hello OS,
I would like to get verification for the components I intended to use.
For the big stones I have Toshiba O grade 2sa1943/2sc5200 or onsemi mjl0302/mjl0281.
For drivers I have 2sa1837/2SC4793 or mje15034/35.
For T=-126 devices I have a lot of different options.
I guess toshiba all the way would be perfect?
J
Hello OS,
I would like to get verification for the components I intended to use.
For the big stones I have Toshiba O grade 2sa1943/2sc5200 or onsemi mjl0302/mjl0281.
For drivers I have 2sa1837/2SC4793 or mje15034/35.
For T=-126 devices I have a lot of different options.
I guess toshiba all the way would be perfect?
J
"For drivers I have 2sa1837/2SC4793" - you will have the exact
HK680R , go for the MJL's ..
OS
Is it possible to use Q6,Q7 2N5401
Q5,Q8 2N5551
With changes pins e.c.b of cource and just for first test?
Q9,1381E & Q10,3503E ?
Q5,Q8 2N5551
With changes pins e.c.b of cource and just for first test?
Q9,1381E & Q10,3503E ?
S=H , maybe i should call it SH 😀
PS -S - servo
H - hawksford
You have the final version.
OS
Q5/6 need the higher voltage.
Q7/8 can be 1015/1815 or any low voltage- high gain pair.
Q9/10 -cascode pair,,, need to be very high voltage (bigger I , as well)
... that is the reason for TO-126 mje340/350 or equiv.
OS