Magnepans and Amplifier Current

[restorer-john]

When I was first at college (Uni), they had two computers running the entire university, one Decsystem 20 (Teaching was the DEC-20T) and one Decsystem 20 (Research was the DEC-20R). I think there was two printers in the computer lab and a paper punch reader machine. Nothing else.

Somewhere, deep in my storeroom is a copy of the computer guide from my first year. If I ever find it, I'll post the specs for a laugh! I remember there were 2-3 terminals in the residential colleges we could use and spread around the campus. A Gandalf terminal host selector box that communicated with the PACX unit which was about a kilometre away. I remember you only got a very small amount of computer time each semester and the staff in the computer lab were evil bastards. You had to book in to collect whatever you wanted printed and you'd always get a lecture about wasting time/money/paper if it screwed up.

There was some COBOL and FORTRAN stuff I played with until my head exploded.

 

[restorer-john]

I was always glad I upgraded to the 40 MB Hard drive. All that extra storage was so handy.

Yes, 40MB was all you needed in the WinXP days. I had machines that would do anything and everything for years and never fill up 40MB. One of my absolute favourite machines for years was an IBM Netvista P4 machine with a 40MB 7200rpm drive which just wouldn't die. I loved it. Its SMPS finally died (caps) and I swear I'll fix it one day just for fun.

Now in 2020, I look at this on my kitchen bench and wonder what to do with it. I haven't used it for 7+ years or more. Never really used it, as I decided it used too much power and made too much noise. A 5 bay Synology NAS with 5x7200rpm 2TB (10TB total) Seagate Barracudas. Dual gigabit LAN etc.

 

[RayDunzl]

You could always tell who had the fast computers in college based on the speed of the solitaire animation. I was always glad I upgraded to the 40 MB Hard drive. All that extra storage was so handy.

The only personal storage I had in College was punch cards.

It was enough to discourage me from pursuing a Computer Science curriculum.

 

[richard12511]

1. please point out the inaccurate info

2. same for out of date info

Note - I did not ask for things you merely dislike

He already did? I guess you’re saying you don’t think the things he already pointed out are out of date or inaccurate? I mean, I guess that's a position you could take, but most of what he pointed out is so clearly wrong and outdated, I'm personally confused as to how you could take that position.

Big and powerful subs being slow and sloppy?
Class D amps not being as good as class A/B?
Power supply quality?
Somewhat suggesting it might be worth it to spend less on speakers and more on speaker cables?

Maybe you could go through the quotes he posted and explain, in your reasoning, why those statements are correct and up to date? That might be more productive, as I would imagine most of us here probably agree that @CDMC was on point with his assessment of many of those statements. Perhaps my thinking is wrong, but right now, I agree with @CDMC. I can be convinced otherwise, though. I'm no expert here.

It doesn't help that the site itself is terribly out of date. Reminds me of a geocities site.

 

[richard12511]

I sometimes miss the dial up robot noise.

 

[restorer-john]

I sometimes miss the dial up robot noise.

For old times sake.

 

[dougi]

Like amps rated to double its power from 8 to 4 ohms, they have purposely underrated the 8 ohms to achieve that number. it is really 300/500:

https://www.soundandvision.com/content/krell-industries-kav-250a-and-kav-250a3-page-2

Still a wonderful amp and absolutely worth owning.

Yeah, I have a Krell KAV-300i since about 2002. I am in the process of "refreshing" it. Spec is 150/300W 8/4 ohms. I am measuring easily over 200W into 8 ohms (single channel, will have to make another load). After replacing the bulging power supply main caps (with the form factor only local choice was United Chemicon) and biasing optocouplers the left channel SINAD has rocketed up to 80dB from 1-100W! Right channel much worse 3rd harmonic (63dB THD at those levels) so more work to do but that is actually the spec (0.06% at 1kHz no power level specified but seems right up to nominal power)

 

[CDMC]

When I was first at college (Uni), they had two computers running the entire university, one Decsystem 20 (Teaching was the DEC-20T) and one Decsystem 20 (Research was the DEC-20R). I think there was two printers in the computer lab and a paper punch reader machine. Nothing else.

Somewhere, deep in my storeroom is a copy of the computer guide from my first year. If I ever find it, I'll post the specs for a laugh! I remember there were 2-3 terminals in the residential colleges we could use and spread around the campus. A Gandalf terminal host selector box that communicated with the PACX unit which was about a kilometre away. I remember you only got a very small amount of computer time each semester and the staff in the computer lab were evil bastards. You had to book in to collect whatever you wanted printed and you'd always get a lecture about wasting time/money/paper if it screwed up.

There was some COBOL and FORTRAN stuff I played with until my head exploded.

I am a bit younger than you, but when I started grad school there was still no world wide web. I remember being pissed off because our e-mail was hosted on a VAX server and I had to learn new commands (I was familiar with Unix). One of my fellow students commented: "I liked Vax when it came out, 20 years ago."

 

[CDMC]

The only personal storage I had in College was punch cards.

It was enough to discourage me from pursuing a Computer Science curriculum.


View attachment 89903

My first boss told me the same thing. He said he couldn’t see it amounting to anything.

 

[restorer-john]

My first boss told me the same thing. He said he couldn’t see it amounting to anything.

Imagine taking your iPhone back in time and showing that first boss of yours. Or a modern laptop.

 

[RayDunzl]

Imagine taking your iPhone back in time and showing that first boss of yours. Or a modern laptop.

Or, I could take a Bic Lighter back with me and tell him nothing had changed.

 

[Johannesen]

Speaking of sensitivity... Here's the speaker I'm looking to drive with an 1ET400

 

[TheGhostOfEugeneDebs]

I use NC400 DIY amps with my MP1.7i. Sounds excellent. I do have a bit of a volume concern though. I can max out the volume knob on my pre-amp and still only be getting good but not *loud* volume when playing certain low tracks or basically anything from HBO Max (I don't know why that shit is so low volume). I plan to swap up to an Appollon NC1200 unit at some point in the near future with the hopes of being able to get the volume up a smidge more, or use slightly less of the volume knob.

 

[ethanhallbeyer]

I use NC400 DIY amps with my MP1.7i. Sounds excellent. I do have a bit of a volume concern though. I can max out the volume knob on my pre-amp and still only be getting good but not *loud* volume when playing certain low tracks or basically anything from HBO Max (I don't know why that shit is so low volume). I plan to swap up to an Appollon NC1200 unit at some point in the near future with the hopes of being able to get the volume up a smidge more, or use slightly less of the volume knob.

do you think nc1200 will only enable a smidge more volume? also did you consider vtv vs apollon?

 

[CDMC]

I use NC400 DIY amps with my MP1.7i. Sounds excellent. I do have a bit of a volume concern though. I can max out the volume knob on my pre-amp and still only be getting good but not *loud* volume when playing certain low tracks or basically anything from HBO Max (I don't know why that shit is so low volume). I plan to swap up to an Appollon NC1200 unit at some point in the near future with the hopes of being able to get the volume up a smidge more, or use slightly less of the volume knob.

You have a gain issue somewhere upstream, not an amp issue. Changing amps won’t fix your problem.

 

[TheGhostOfEugeneDebs]

do you think nc1200 will only enable a smidge more volume? also did you consider vtv vs apollon?

I'm also wondering about how the frequency response might be altered by the extra juice from a purely curious perspective.

Never heard of VTV, they have good Ncore implementations and clean builds? Their website doesn't show interior shots of the mono 1200. I love the Apollon boxes and the builds look very nice inside.

 

[TheGhostOfEugeneDebs]

You have a gain issue somewhere upstream, not an amp issue. Changing amps won’t fix your problem.

You can see my upstream from the signature. It's probably the Matrix Audio DAC. The turntable can get decently loud (though I have almost maximum gain set on the Schiit Mani too) but when I remove the Freya from the chain, I'm getting blah volume. It's not clipping, so there is probably amp headroom at max volume with the DAC alone. I do get distortion at max volume with the Freya though.

I also just want another amp so I can put these NC400s in my secondary setup because I want to use them to run my Stax headphones through an Energizer and I can't really do that in the living room. I could just build a couple more of the same but I figure why not upgrade to the NC1200 since that is what is in those fancy Mola Mola amps and I want to know what the hullabaloo is about, haha.

 

[Johannesen]

I picked up a VTV Purifi 1et400a stereo amplifier to power a set of Tympani IDs in all their 83db efficient glory.

 

[Sukram]

I'm using my 3.7i's with a Purifi amp, the best amplifier I ever owned.

 

[Head_Unit]

I have only seen one amplifier that actually doubles it output when the impedance is halved, the Sunfire Load Invariant. When Audio Critic tested the Stereo it clipped at 310 watts into 8 ohms and 620 into 4 ohms (rated at 300/600).

Oh interesting! I've only seen 2 amps, which I can't remember. Some crazy expensive thing Stereophile tested and one other. I've seen lots of great amps that don't truly double their power; the 8 ohm is underrated. In car audio where I worked for a long time that was endemic; I spearheaded doing the same thing-if you can't lick 'em join em-got applause from the sales reps, engineers proud as new parents, sold ton$$$ of amps.

As for the Magnepan, they are not *perfect* 4 ohm loads (per looking at a bunch of Stereophile measurements). Fairly easy loads, that I'd concur. Do they sound better with "high current" amps? Probably, but more because those amps just sound better anyway - or not, depending on your beliefs.