well, subjective opinions don't count as much to me as long as i have not experienced it myself, while i do not discount the possibility that an H/K can beat the Parasound, i want to know the circumstance surrounding it...
myself made a tube preamp that was like by those who heard it, as better than another costing 5 times more...😉
Wish I had the Parasound .. I'd "gut" it and use the heatsinks
and PS's to power my CFA's 😀 .
OS
and PS's to power my CFA's 😀 .
OS
i have seen a Parasound,😀 the owner brought it me to be converted to 220 volts, we did not listen to it as he was in a hurry, did not want't to leave his unit with me....
but by the build quality of unit i have seen, it is really tops...😎
but by the build quality of unit i have seen, it is really tops...😎
I would go for the 3-pair OPS/NAD ... as discussed. Naf says "it sings"
(with killer bass - that kicks the VSSA's butt).
What do you think .. vote , or go ??
OS[/QUOTE]
So be it
(with killer bass - that kicks the VSSA's butt).
What do you think .. vote , or go ??
OS[/QUOTE]
So be it
Are you are thinking of the Semelab MAG6332/MAG9412 output devices?
Which Sanken drivers?? And do you see any problem using those in your 'Spooky Leach'? Could be fun!
OS, Final question on making PCB's what is the Wattage of your Iron?
For everyone, how do you correct for the BMP size to make the correct size Toner image for the boards?
For everyone, how do you correct for the BMP size to make the correct size Toner image for the boards?
A better V1.2 NAD-H
So be it[/QUOTE]
This was my first IPS , no errors .... but my layout skills have
increased considerably after the wolverine/leach.
Super "purdy" Nad-H V1.2 below ...
OS
So be it[/QUOTE]
This was my first IPS , no errors .... but my layout skills have
increased considerably after the wolverine/leach.
Super "purdy" Nad-H V1.2 below ...
OS
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DPI of the bitmap ... my paint shop pro says all are 300DPI , and tells me
the board size (3" X 3"-3.5")
OPS's are 76.2mm or 3" wide and 6-8" long , IPS's are also 3"(76.2mm).
Bitmaps are pretty standard .... what viewer are you using ?
clothes iron ?? , or soldering iron ?
OS
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Sanken makes many new MT-100 (to-3p) output devices.
2SA1186/2SC2837 are 110pF Cob 60mhz Ft , but only 150V
devices ( 60-70V rail amp)
For your super high powered mega amp ....
The Sanken 2SA1294/2SC3263 is the 230V equivalent with 230p Cob .
Same as the typical MJE15032/33 , but 130W devices. - The "mega driver".
http://www.semicon.sanken-ele.co.jp/sk_content/2sc3263_ds_en.pdf
All these , all the ON semi's -will work with my OPS/IPS combo ...
some devices will be more optimal.
PS - compared to the typical DIYA "leach clone" , this one is a cut above.
OS
Small progress in NAD-S ver.1.2.
Ostripper can i use 2sa1015 and 2sc1815 in this input stage?
Best regards.
Thimios.
Ostripper can i use 2sa1015 and 2sc1815 in this input stage?
Best regards.
Thimios.
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Ostripper,
Bob Cordell makes a pretty good case for using a dual op amp rather than a single op amp for power servo applications. Have you considered that? The details start on page 155 (Chapter 8) of his "Designing Audio Power Amplifiers" book.
Bob Cordell makes a pretty good case for using a dual op amp rather than a single op amp for power servo applications. Have you considered that? The details start on page 155 (Chapter 8) of his "Designing Audio Power Amplifiers" book.
Just cleaned up the NAD for professional use ....
2sa1015 + 2sc1815 is the best IP stage device since we are all +/- 12V
here.
For the second stage, we are 1/2 full rail to rail voltage ...
2Sc/a 1845/992 pairs or a heftier TO-92L equivalant is best here.
This stage does the "evil" current feedback work , so even a fast Ft/
low Cob to-126 pair would work here (even a 2sa1220/2sc2690).
Larger to-126 devices would fit perfect here,as well (E-C-B).
OS
Thanks sir , all my boards cleaned in the last step ,after all parts have been installed 🙂
I haven't any 2sa992 so i must wait for a long🙁
Regards.
Thimios.
I haven't any 2sa992 so i must wait for a long🙁
Regards.
Thimios.
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Nad H uses both op-amps , one is the buffer ... one is the integrator.
A extra .47u cap can be added to existing NAD-H's or... the new
1.2b has a extra set of pads.
This will both give the .2hz LP and attenuate HF to a
greater degree . The NAD uses neg. Servo feedback to offset
the Hi-Z input pair - different than Cordell's book examples.
The HK990 servo uses one op-amp only , but has a 2 stage LP
filter set at .2HZ. Why would a room full of engineers at HK
just use 1 op-amp on a 2500$ unit ...
.... and ground the unused channel 😕.
This does not even seem to be a matter of economics.
PS - My HK (21 years) and Sansui (33 years) both use a dual (single op-amp) servo's
split between channels. Lasted for decades. 🙂
OS
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Ostripper,
What caused me to make a comment was when I found myself studying your SpookyAmp schematic. In the version that I am looking at you show a single channel LT LT1001A or 1/2 of a TI TL072 op amp as servo.
Hmm ... those are two different packages. Your PCB layout looks to be for the single. That would the described LT LT1001A or TI TL071.
EDIT: So per your comment below, a TI TL072 is what it is ..
What caused me to make a comment was when I found myself studying your SpookyAmp schematic. In the version that I am looking at you show a single channel LT LT1001A or 1/2 of a TI TL072 op amp as servo.
Hmm ... those are two different packages. Your PCB layout looks to be for the single. That would the described LT LT1001A or TI TL071.
EDIT: So per your comment below, a TI TL072 is what it is ..
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No problem with thinking out loud and asking questions.
But the "spooky servo" IS the HK990 servo ... 0 issues , 2500$ flagship
receiver , no design flaws or reliability issues known.
PS - one side of the TL072 is shorted (- to out) and the + is grounded.
(same as the HK !)
edit - The spooky / 5-pair OPS would essentially be a HK990 /HK680R hybrid.
Proven , well reviewed audio products ....
OS
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Thimios ...
Don't want a needed builder to be left wanting for parts.
To show the flexibility of the NAD-S IPS ,I simulated it with mje 340/350
for Q5/ Q6 (they will fit) , a better pair would just be another
1381/3503 pair , as they have low Cob /higher Ft-Hfe.
You would have a real heavy duty current feedback stage , as well. 🙂
Both swaps worked very well , THD was the worst with the MJE340/350,
1381/3503 were dead even with the KSA/C 992/1845.
Anything at the input can be (anything) as long as it fits. At 12V ,
use the 1015/1815 pair for both the IP pair and the CCS's (Q1-4).
Making these changes in some amps would be harder ... not here - the
servo cleans things up nicely.
You might change the standing current of the VAS with these device
"swaps" ... No problem , as I told NAF .... use either 820R or 1K for R13/16
to bias the VAS for 7-8ma total.
Subtract the VAS LED current , and you should get 4-5ma at the
collectors of Q9/10.
R17/21 (150R) should read about 1.2V at the correct current.
PS - you don't need any 992/1845's to get a working amp , I highly
doubt the larger device's will degrade sound Q.
Below is the schema with changes.
Also , green leds (different If) might also need VAS I adjustment.
You will know when you get it running (NAF ran his VAS "hot" at first - no smoke). 😀
Edit- if you anything other than all plastic devices for Q5/6 , make sure they don't
touch (metal to metal -to-126) ... insulator in between ... then the shrink tubing...
OS
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