If I was embarrassed with each wrong spelling...I often turn to my nine year old for grammar advice.
And I've been also adding a letter, thought it was a Super input section, therefor a Kryptonite derivative. We all know that Pete's alter ego is Superman! Up Up and Away.
That is what I would love to nothing else.🙂
I can not build all the IPS TO TEST IT FOR MYSELF, please forgive me for that
Kapton-ND sign up. Price is TBD depending on how many we order.
1 - evanc - 1pair KND
2 - kindhornman - 1pair Kapton-ND
3 - jim hamley - 1 pair KND
4 - gwrskien - 2 pair KND
5 -kool lites -1 pair KND
6 - mrsavage - 4 pair KND
7 - tjencks - 3 x KND
8 - presbel - 1 pair KND
9- Arthur -4 pairs KND
10- marsupialx -1 pair KND
1 - evanc - 1pair KND
2 - kindhornman - 1pair Kapton-ND
3 - jim hamley - 1 pair KND
4 - gwrskien - 2 pair KND
5 -kool lites -1 pair KND
6 - mrsavage - 4 pair KND
7 - tjencks - 3 x KND
8 - presbel - 1 pair KND
9- Arthur -4 pairs KND
10- marsupialx -1 pair KND
Of all these posts I picks yours !
To really discern between these IPS's requires time and every genre , movies ... and yes - some imagination.
By that I mean your mind must be able to "capture" long term and short
term data.
I had the wolverine , "C" , and spook for months. Always returned to
the spook , even as all three work perfect.
I might get strung up for this , but I chose the IPS that I emotionally preferred.
I actually heard the spook before I even designed it - the HK990. If
I was able to keep that , I might never of bothered with the slewmaster.
OS
you won't get strung up by me. I "compare" the same way....Listening for a week or two before making a change.
Since we are talking about the same output section and we aren't being influenced by the look of the equipment it would seem a simple A/B test would make any real differences apparent. If you can switch back and forth and not detect a difference you have a null result which would lead you to think the differences are at the level of undetectable.
I think this has been what Terry has been saying for some time. Perhaps there are some slight differences at the extreme upper or lower frequencies but you should be able to hear this in an A/B test once you listen for those exact things.
I think this has been what Terry has been saying for some time. Perhaps there are some slight differences at the extreme upper or lower frequencies but you should be able to hear this in an A/B test once you listen for those exact things.
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If you are switching that quickly between two IPS's - too quick .
Not "burn-in" (I don't believe strongly in this). An IPS will take
a good 5 minutes to settle 100% thermally (which also affects I/V).
Switch IPS , put the cover on ... let everything stabilize to 30C+.
Then check VAS for 5.3ma , output stage for 70ma bias.
Only at this point , can you eliminate the OPS from the equation.
So my quickest "switch" can only be 10 minutes ... to be "fair".
OS
Not "burn-in" (I don't believe strongly in this). An IPS will take
a good 5 minutes to settle 100% thermally (which also affects I/V).
Switch IPS , put the cover on ... let everything stabilize to 30C+.
Then check VAS for 5.3ma , output stage for 70ma bias.
Only at this point , can you eliminate the OPS from the equation.
So my quickest "switch" can only be 10 minutes ... to be "fair".
OS
I had the luck of being a member of the Michigan Audio Club where the ABX test box was invented so many years ago. I took part in some of the early studies where I quickly learned that I didn't really hear as many differences in gear as I had previously believed. Terry's method is closest to my practice since those eye opening (ear opening??) days.
Of course I also often get bored and start swapping hardware for no particular reason too! Go figure ...
Of course I also often get bored and start swapping hardware for no particular reason too! Go figure ...
I did not think of that , does terry have 2 complete slews already set up
with the IPS's already attached ? Then just switch a pair of speakers
between them.
I don't have two (not enough room) , have to switch IPS's.
Another factor , even as I have tried to keep global closed loop gain
similar on these IPS's ... there is a possible 1db variation between them.
My use of standard JEDEC values and the many differences in topology
meant I had to do the best I could to meet the design goals.
OS
with the IPS's already attached ? Then just switch a pair of speakers
between them.
I don't have two (not enough room) , have to switch IPS's.
Another factor , even as I have tried to keep global closed loop gain
similar on these IPS's ... there is a possible 1db variation between them.
My use of standard JEDEC values and the many differences in topology
meant I had to do the best I could to meet the design goals.
OS
OS just said it. He has had a romance with the HK990 since the day he fixed and listened to one who knows how many years ago. Enter Spooky. My feeling is that there are just too many choices now. Look how many boards that have been sold through the group buy that Jason. How many have been built? Too many choices? A lot of folks waiting for someone to tell them which one is the best. Maybe afraid they will waste money building one of them only to find they should have built another. It is my opinion that if OS had only brought one, anyone of these IPS/OPS combinations to the forum, everyone would have built it and been singing its praises.
And you Terry have every single one of them and more it seems! Could you pick one out of all of them or do you still think they are all close enough that it really doesn't matter, they are all great sounding I have a feeling.
You are undoubtedly right Terry. But I for one am very glad that OS has put so much effort into variations. I have learned a bunch and will continue to do so. Pete has succeeded in crafting legitimate amplifier test and development platform. I don't think that has been done before in the DIY world. I say Kudos to Pete! Thank you for sharing.
My A/B setup included two identical pair of Slew 5P OPS. MJL3281/1302 outputs. +-72V rail. There is a dual volume control set up to feed the two separate IPS so the volume can be equalized in case there is a difference in gain. Both OPS feed into a speaker switch which switches each amp to a single pair of speakers, usually a pair of JBL4412 speakers, but I have several different speakers that I can attach. I usually let the amps play for hours, many times for a few days if I can spare the space to keep them set up. The switching is seamless and transparent. If you are not watching you would not know a switch was made. That is of course, when the amps sound identical. Obviously when they don't you would hear the switch. I haven't had the slewmaster "twins" hooked up for a while since my findings were ignored or worse, rejected. the last few slew IPS were only A/B'd against other models that I consider good base models, i.e. Honey Badger, Symasym, Peeceebee DX-Blame. I intended to set it up again yesterday but soon realized it would only lead to more rejection so I spent the day working on the new Leach Superamp I'm building. I can't wait to put it on the A/B setup even if only for my own enjoyment.
Blessings, Terry
But I'm still open for a change. With an standardized OPS .. they don't spend much for a "leap of faith".
Some love the symasym , blameless ... If they are "emotionally" attached
to a particular design , we have the wares to let them realize their
preference at a much higher power.
Some just like to build , or design .... or test for PPM.
Whatever the "fetish" , we have what they need - and none of it
is poorly engineered BS , either.
We also have soft clipping VAS's , amps that can go open loop with no smoke.
I slipped the probes and shorted out everything ... I'm NOT
the builder you are !!! These designs are quite hardy for tinkering
and especially heavy use/abuse. WAY better than OEM.
That's what we have really done by all this designing/testing , made
better amps.
Edit - I would not of learned much just designing one.
OS
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I wholeheartedly agree. This has been a wonderful ride and I have learned a lot. I rarely have to seek help when things go awry unless I am the first to build and discover issues with the circuit that didn't show up in the simulations. The Slewmaster has been life changing for me.
If the group buy of Kypton-ND is still open, I am interested in getting 4 boards (2 pair).
I still haven't had any time to build my Slews yet, but I am collecting the PCBs and other parts while they are available. Hopefully my new work area will be put to good use this winter. OS has made an interesting platform for trying out multiple designs, without making extensive chassis modifications.
I still haven't had any time to build my Slews yet, but I am collecting the PCBs and other parts while they are available. Hopefully my new work area will be put to good use this winter. OS has made an interesting platform for trying out multiple designs, without making extensive chassis modifications.
Kapton-ND sign up. Price is TBD depending on how many we order.
1 - evanc - 1pair KND
2 - kindhornman - 1pair Kapton-ND
3 - jim hamley - 1 pair KND
4 - gwrskien - 2 pair KND
5 -kool lites -1 pair KND
6 - mrsavage - 4 pair KND
7 - tjencks - 3 x KND
8 - presbel - 1 pair KND
9- Arthur -4 pairs KND
10- marsupialx -1 pair KND
11 - akimmet - 2 pair KND
1 - evanc - 1pair KND
2 - kindhornman - 1pair Kapton-ND
3 - jim hamley - 1 pair KND
4 - gwrskien - 2 pair KND
5 -kool lites -1 pair KND
6 - mrsavage - 4 pair KND
7 - tjencks - 3 x KND
8 - presbel - 1 pair KND
9- Arthur -4 pairs KND
10- marsupialx -1 pair KND
11 - akimmet - 2 pair KND
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