Well, sounds like a plan may be hatching. If you prefer feel free to PM / email me, that may make the transfer of files easier. I'm more than happy to assist with the creation of files for posting if that helps you at all.
And yes, I like the VSSA very much. It has its limitations but sounds lovely, I have built a few of them.
HP's is 320F by default. when I read first about toner transfer , HP's were
recommended - less iron heat, better-quicker adhesion to the copper.
Brother sucks ... they say.I bought an HP just for transfers. (It prints well
for the house hold , as well). 🙂
OS
This is what the "plan" will be.
Being "practical" , the OPS .. if perfected , will eliminate any waste of FR-4 if
"fickle" audiophiles want to "play" with topological changes.
At 25-30K current gain and a good .05% OPS distortion , any IPS
"sings" wonderfully on it.
BTW- I have ....
a few in me.But .. this will go well.
OS
i like the plan, finally a chance to make two amps, one CFA and one VFA with identical output stage, i will build both types, and then do a controlled listening test to find out user prefference...
OS, are you running a group buy for FR4 boards?
i suggest you get quotes for 2oz output stage as well...
OS, are you running a group buy for FR4 boards?
i suggest you get quotes for 2oz output stage as well...
i use the Samsung ML-2165 laser printer, same print quality as the HP ones we used at work before...anybody else using this printer?
i bought this printer new and very cheap at about U$50....the toner will cost 3x as much...
i bought this printer new and very cheap at about U$50....the toner will cost 3x as much...
I tried with a Samsung CLP-320N to do toner transfer using both magazine paper and Pulsar's PCB Fab-In-A-Box to no avail. I pondered getting a printer specific to the task but just couldn't justify it.
When I do a one-off, or a small batch I use the photographic technique. More cost and effort to get quality artwork from a print shop, but splendid end results and once you have the artwork you can easily produce additional boards with consistency and of very high quality.
When I do a one-off, or a small batch I use the photographic technique. More cost and effort to get quality artwork from a print shop, but splendid end results and once you have the artwork you can easily produce additional boards with consistency and of very high quality.
I use a glossy magazine with a lot of clay content. I find a page with little
content (no dark images). I attach (tape) this page to a standard 8.5X11
and print.
Some magazines are better than others (southern living magazine) , real good
(southern) clay !!!!
OS
It's all in the acid !!
I've done 1 oz. FR-4 in 90 seconds , no undercut.
Just the right temperature/ ratio of peroxide/HCL - instant PCB...
OS
I've done 1 oz. FR-4 in 90 seconds , no undercut.
Just the right temperature/ ratio of peroxide/HCL - instant PCB...
OS
yes, but the amp is now out of my hands, some guy purchased boards and all components and asked me to build it for him..that is why my continuing interest...
is there a possibility that you can offer the front end of the badger as an option? or any VFA for that matter, i believe you had a diamond type a while back...
is there a possibility that you can offer the front end of the badger as an option? or any VFA for that matter, i believe you had a diamond type a while back...
I'll just do BOTH ... about 2 Hours a board . Each will be easier than
that "infernal CFA" and I have actually either built or repaired both.
"Wolverine' and the "symasui" will be "born". !! 😀
PS- I'm a "VFA MAN" 😀 .... The NAD-H should be a "show stopper"
,I spent a whole day on it !!
Edit - If you like the "badger" sound .. the "wolverine" is the "next generation" for this
topology.
OS
Is this the HK680 that you've mentioned here:
http://manuals.harman.com/HK/service Manual/HK680 sm.pdf
Do you measure gain and phase margin in your real hardware prototype?
And just to be certain, the schematic below is for the NAD372 that you've also mentioned?
Interesting that it has a CFP output stage.
http://manuals.harman.com/HK/service Manual/HK680 sm.pdf
Do you measure gain and phase margin in your real hardware prototype?
And just to be certain, the schematic below is for the NAD372 that you've also mentioned?
Interesting that it has a CFP output stage.
Attachments
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Hey OS, i am also a VFA man, i have very good memories of the Leach Super amps....but that does not mean i can not enjoy CFA.....
my early builds were CFA's....😀
my early builds were CFA's....😀
Better yet , that is the actual integrated amp that is in my living room.
Easy to reverse engineer the real mcCoy , aye...
I showed my wife (with a hair dryer) on the both the OPS and drivers ,
that the current (mV-Re) would only deviate less than 1mV.
It is 18 years old (according to it's sticker)..
I will not drop "duds" on my beloved community !
here is PM/bode .. below... (with the EF 3)
OS
Attachments
OS,
Your LTSpice simulation commands do not have a long enough delay for the power supply voltages to settle. For those keeping score, this affects THD data.
==========
Your LTSpice simulation commands do not have a long enough delay for the power supply voltages to settle. For those keeping score, this affects THD data.
==========
I've liked HK products since I was very young and took a look at the Citation 12
and 11.
I have an HK870 power amp but I think it is much older than the 680 and it is
a bit odd with a CFP driver.
That is quite impressive about the thermal comp on the HK680 - I like it.
Interesting that the NAD and HK870 use inductors across the stoppers to
provide maximum current drive at audio frequencies but maintain the
stability advantage where it matters. They can probably be wound right on
top of the stopper resistors.
and 11.
I have an HK870 power amp but I think it is much older than the 680 and it is
a bit odd with a CFP driver.
That is quite impressive about the thermal comp on the HK680 - I like it.
Interesting that the NAD and HK870 use inductors across the stoppers to
provide maximum current drive at audio frequencies but maintain the
stability advantage where it matters. They can probably be wound right on
top of the stopper resistors.
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hugh dean commented on the H/K Vbe when I first posted it ..."advanced"
With my different drivers ,I know the C-B to C-E vbe ratio will have to
go 1.2K/ 1k (already calculated this) .. but It is much more accurate than my
sansui EF3 single Vbe thermal comp. (+/- 10mv).
OS
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