You Asked For It, Now Here It Is. Amplifier Clinic

jwes · « **Reply #20 on:** 27 Oct 2009, 04:27 pm »

I would also bring one mono (Spectron M3 mk2). It's rca inputs are bridged for mono operation, but the balanced inputs work as normal. Would that work?

Jim

electricbear · « **Reply #21 on:** 27 Oct 2009, 09:38 pm »

That would be a question for Jeff. I don't know if he can inject a signal in to a balanced input. you can give him a call at 314-277-6393

BPT · « **Reply #22 on:** 27 Oct 2009, 11:14 pm »

Let us know--mine has a balanced input as well.

electricbear · « **Reply #23 on:** 28 Oct 2009, 05:51 pm »

Balanced input will not be a problem. Jeff has adaptors to take care of this.

steve k · « **Reply #24 on:** 29 Oct 2009, 05:01 am »

Tim,
We'll you be able to measure am amp's input impedance?
steve

electricbear · « **Reply #25 on:** 29 Oct 2009, 04:33 pm »

I don't know about the impedance side of things. I think Jeff was just going to do power specs and thd.
We have some door prizes , pens ,mugs, bags etc in limited quantities on a first come first serve basis.

Hebrew Hammer · « **Reply #26 on:** 29 Oct 2009, 05:23 pm »

Classe or Mac door prizes aa

Quote from: electricbear on 29 Oct 2009, 04:33 pm

I don't know about the impedance side of things. I think Jeff was just going to do power specs and thd.
We have some door prizes , pens ,mugs, bags etc in limited quantities on a first come first serve basis.

electricbear · « **Reply #27 on:** 29 Oct 2009, 06:01 pm »

We'll raffle off a pair of Mac 1.2KW power amps. Tickets are $24,000 each. You'll have a 1 in 2 chance of winning.

Bob in St. Louis · « **Reply #28 on:** 30 Oct 2009, 12:31 am »

That's funny!

Alright guys, without being a pig and bringing everything I own, I'd like to know what I should bring. My main channel power amp (Jolida202a), or the pre/DAC which is also the switching unit for the entire HT room (Harman Kardon AVR 645).
Or, I've got the typical "super cheap, high watt" amps.

You guys would probably understand the results better than I would.
Anything I have sound like fun? I'm kinda curious what the modern H/K receiver (pre out) is capable of), but then again, the main amp for the R/L channels is a tubed Jolida......
Any ideas?

Bob

BPT · « **Reply #29 on:** 30 Oct 2009, 12:34 pm »

Bringing a home built amp to check your work is good or if you have a production amp that you suspect is not working up to specification would be another good purpose.
Chris H.

electricbear · « **Reply #30 on:** 30 Oct 2009, 03:18 pm »

Bring something that might blow up. Scott needs a good repair project and I haven't used a fire extinguisher in years.

drummerwill · « **Reply #31 on:** 31 Oct 2009, 01:51 pm »

I plan on coming too!
Trying to decide what to bring. I think i'll just throw the "Train" in the back seat and come out.

Willie

Bob in St. Louis · « **Reply #32 on:** 31 Oct 2009, 03:00 pm »

Quote from: electricbear on 30 Oct 2009, 03:18 pm

Bring something that might blow up. Scott needs a good repair project and I haven't used a fire extinguisher in years.

Well, I've got a 40+ year old bone stock, all original Heathkit A-7 mono block we could let the smoke out of. aa

Bob

Blackmore · « **Reply #33 on:** 31 Oct 2009, 09:03 pm »

Well, as usual, Scott beat me again. I had challenged him to a 2A3 smackdown. I bet him that my AES SE-1 amp would be much worse than his amps and would have lower power also. Turns out that my amp put out 5.8 watts at 1%, 6.7 watts at 2% and 6.9 watts at 3% distortion. Hell, it even beat Scott's 300B DRD amps.
Turns out it was a true powerhouse although I'm concerned that a 2A3 putting out that much juice will have a short life. So, I bow down to you, Scott. You are still the king of low power SET. Thanks to Tim and the Sound Room for a fun time and to Jeff for testing all these amps.

(but my distortion characteristics on the scope were damn sexy. aa You had to be there)

lonewolfny42 · « **Reply #34 on:** 31 Oct 2009, 09:43 pm »

Quote from: electricbear on 30 Oct 2009, 03:18 pm

Bring something that might blow up. Scott needs a good repair project and I haven't used a fire extinguisher in years.

Did you get to use the fire extinguisher ?

Blackmore · « **Reply #35 on:** 31 Oct 2009, 09:47 pm »

No, Chris. That was a bit of a disappointment too!

They made us sign a release form if our amps blew while testing, but nothing was said about burning down the store. I doubt that was covered. I believe the biggest amp tested was around 225 watts and the smallest may have been Scott's Lafayette at 1.5 watts.
Cool to see the distortion curves and have Jeff school us on what was happening with each amp.

lonewolfny42 · « **Reply #36 on:** 31 Oct 2009, 09:52 pm »

Quote from: Blackmore on 31 Oct 2009, 09:47 pm

No, Chris. That was a bit of a disappointment too! They made us sign a release form if our amps blew while testing, but nothing was said about burning down the store. I doubt that was covered. I believe the biggest amp tested was around 225 watts and the smallest may have been Scott's Lafayette at 1.5 watts.
Cool to see the distortion curves and have Jeff school us on what was happening with each amp.

Very cool.....

Bob in St. Louis · « **Reply #37 on:** 31 Oct 2009, 10:15 pm »

First of all, a HUGE thanks to Jeff, Tim, and The Sound Room for the time, effort, and space taken up. I learned quite a bit listening to Jeff. The guy's got a noggin full of truth regarding amps.

Regarding the fire extinguisher, I set it on the table just before Willie put his "locomotive", and Al put his monster VTL[?]s on the table.
I think Ken took a picture.

I love my new B&W swag. aa Neat stuff. Thanks for that (to whomever).
I can't wait to hear (and see?) the DVD DTS-ES disk.

Turns our my little Jolida has a slight issue on the right channel. Without sending it to "the shop", it could be anything from a simple bias adjustment, a tube going south, or a full blown frame off restoration. Thanks again to Jeff for looking at it.

Bob

wedweb · « **Reply #38 on:** 1 Nov 2009, 12:12 am »

Cool about all the fun you guys had. I was wanting to go but the kids got sick and had to stay home with them. The B&W swag sounded cool too. I had been looking at getting one of those as a test DVD.

Any pics?

Bo

Scott F. · « **Reply #39 on:** 1 Nov 2009, 02:22 pm »

Quote from: Blackmore on 31 Oct 2009, 09:03 pm

Well, as usual, Scott beat me again. I had challenged him to a 2A3 smackdown. I bet him that my AES SE-1 amp would be much worse than his amps and would have lower power also. Turns out that my amp put out 5.8 watts at 1%, 6.7 watts at 2% and 6.9 watts at 3% distortion. Hell, it even beat Scott's 300B DRD amps.
Turns out it was a true powerhouse although I'm concerned that a 2A3 putting out that much juice will have a short life. So, I bow down to you, Scott. You are still the king of low power SET. Thanks to Tim and the Sound Room for a fun time and to Jeff for testing all these amps.

I was amazed about how all our amps tested. For me, it was on a few levels. First was just how clean the Welborne 300b DRD was. It tested at .64% THD at 5 watts. The amp is rated at 7.5wpc but the best we could get it to produce was just over 5.5 watts.

The next was my little Handmade 2a3. Anthony Cirella rates at 2.5wpc but the numbers said different. We got just over 5 watts at 3% THD out of it. If I remember correctly, that was both channels running which put much more of a demand on the power supply.

That explains a lot when I swap back and forth between my 300b and 2a3. I've always wondered why my 2a3 had almost as much headroom before audible distortion sets in. Now I know. They both put out 5 watts.

Like Paul Klipsch said....What the world needs is a good 5 watt amp!

Quote from: Blackmore on 31 Oct 2009, 09:03 pm

(but my distortion characteristics on the scope were damn sexy. aa You had to be there)

...oooh but wait! We have evidence. Nipples and a navel

A HUGE thanks goes out to Tim and The Sound Room for hosting the MAC amp clinic. Another big thanks to B&W and Audio Quest for all the free stuff. and last but not least a BIG thanks to Jeff at Computronics for sharing his knowledge, time and all his test gear. The event was a blast!