Dennis Had Inspire Amps

[Bombadil]

Originally Posted by Rosco65

The filter you described shows a 9.5dB peak attenuation. It looks like the filter is flattening the response beginning at 700hz or so and bringing it back in over 10khz. That's one hell of a "BBC Dip".

I think a filter like this would be perfect in nearfield use and/or use when listening levels are lower. It is effectively a loudness filter.

I agree with both of these observations.

If this CN is still needed at moderate to loud volume levels, then that implies the speaker in its standard configuration has a real problem. My goodness, a 9.5dB attenuation through the midrange and well up into the lower treble to get it to sound balanced?

[BearCityUSA]

Hello all,

Please understand that the Contour Network that Dennis put together for me was a fun experiment built out of parts he had lying around. I am pretty sure he was shooting from the hip a bit as far as the values of the components. I do not recall him having used a calculator and comments like "this should work" being used. As we listened before and after we enjoyed some of the effects it had on my speakers powered by my amplifier. To all others, YMMV or not at all if you choose not do drive in the same car. I shared this with you all because I thought you might find the story entertaining. Dennis was excited by process and we had fun testing the outcome. Though he told me it was ok to share here I received an email a little while ago where he is having second thoughts. Some here may know why.

[FloridaBoy]

Originally Posted by BearCityUSA

I own both and they are both great but different. MY LP-27a is a Special Edition with all the upgrades. An absolutely wonderful piece. The best I can offer is that it is beautifully transparent. Also the 27 and 56 tubes are relatively inexpensive and according to Dennis should last for 15 years. He does spend quite a bit of time matching pairs in the pre hooked up to the scopes to get the sound and match he is after.

My Lp-3a is an upgrade of a 2013 LP-2 so it uses 9 pin tubes. I little different than the current production using oktals. The biggest difference to the 27 is the amount of Gain. The Lp-3a can be barn burner. Much of the 27's clarity is still there but it can really tear the shingles off. I plan to keep them both.

As for a web site and specs, doubt it. Dennis is retired and doing this for fun. He changes things constantly with his latest ideas and inspirations. Specs and websites could never keep up. I suggest contacting him again if he has not gotten back to you. I get the feeling his inbox is always pretty full and if he did not reply right away it can get lost in the shuffle. With some more info from you he can steer you in the right direction and even tailor one of his current units to your needs. Many here have customized units though the stock items on eBay are outstanding in their own right.

The tubes will last longer than I will.

[pstrisik]

Originally Posted by BearCityUSA

Hello all,

Please understand that the Contour Network that Dennis put together for me was a fun experiment built out of parts he had lying around. I am pretty sure he was shooting from the hip a bit as far as the values of the components. I do not recall him having used a calculator and comments like "this should work" being used. As we listened before and after we enjoyed some of the effects it had on my speakers powered by my amplifier. To all others, YMMV or not at all if you choose not do drive in the same car. I shared this with you all because I thought you might find the story entertaining. Dennis was excited by process and we had fun testing the outcome. Though he told me it was ok to share here I received an email a little while ago where he is having second thoughts. Some here may know why.

I can understand where it could be seen as critical of Omegas. I haven't been taking it that way at all. I have seen the need to supplement lower and higher frequencies but absolutely love my SAMs. I have listened to them alone and they sound wonderful. The bass they provide is pleasing bass, however I like having lower and stronger bottom end. I would say the same about running my SAM/8" woofer combo. When the plate amp is set to extend down to 30Hz, the combo is great. But having a pair of F12s, even for just up to 30Hz improves things even more.

I guess if I were in your shoes, I would probably refrain from this conversation on AC. Even if the CN is benign as electronics in the speaker signal path can be, it is counter to the Omega philosophy and approach.

I like to tinker and this was a good opportunity, not so much from sound quality need, but from need to tinker, explore, and learn. Simple enough (it seemed) to tackle something and learn something. Still true, but the links provided remind me that I will only learn as a rank amateur. Beyond the first level of this stuff I get overwhelmed and shut down. I'll confess that way back in high school when I took Physics this was also true. I was a top student in the the class overall and found most of the areas fascinating and accessible. It was the electrical/electronic area that challenged me the most and I mostly muddled through it.

So, I think I will break out REW when I get the chance (hard as our kitchen remodel starts Wednesday!). I would be interesting to see how my frequency response is on paper - ie, how flat or how "contoured"!

[Rosco65]

Originally Posted by BearCityUSA

Hello all,

Please understand that the Contour Network that Dennis put together for me was a fun experiment built out of parts he had lying around. I am pretty sure he was shooting from the hip a bit as far as the values of the components. I do not recall him having used a calculator and comments like "this should work" being used. As we listened before and after we enjoyed some of the effects it had on my speakers powered by my amplifier. To all others, YMMV or not at all if you choose not do drive in the same car. I shared this with you all because I thought you might find the story entertaining. Dennis was excited by process and we had fun testing the outcome. Though he told me it was ok to share here I received an email a little while ago where he is having second thoughts. Some here may know why.

Thanks for posting the CN details. I think most of us just like analyzing the tweaks we can do to our systems. I fail to see anything that would cause drama: Dennis listened to a pair of well-regarded single driver speakers, applied an on-the-fly tweak that you both liked, and you told us about it. Those of us with Omega speakers tend to try out tweaks on our own (adding supertweeters, subwoofers, helper drivers, etc.).

TWIW, Seas also publishes a contour network in the application notes for their Alnico FR driver. It is supposed to shelve the upper frequencies in rooms that are too live. Seas also recommends trial-and-error experimentation with parts values.

[Rosco65]

Originally Posted by BearCityUSA

I own both and they are both great but different. MY LP-27a is a Special Edition with all the upgrades. An absolutely wonderful piece. The best I can offer is that it is beautifully transparent. Also the 27 and 56 tubes are relatively inexpensive and according to Dennis should last for 15 years. He does spend quite a bit of time matching pairs in the pre hooked up to the scopes to get the sound and match he is after.

My Lp-3a is an upgrade of a 2013 LP-2 so it uses 9 pin tubes. I little different than the current production using oktals. The biggest difference to the 27 is the amount of Gain. The Lp-3a can be barn burner. Much of the 27's clarity is still there but it can really tear the shingles off. I plan to keep them both.

As for a web site and specs, doubt it. Dennis is retired and doing this for fun. He changes things constantly with his latest ideas and inspirations. Specs and websites could never keep up. I suggest contacting him again if he has not gotten back to you. I get the feeling his inbox is always pretty full and if he did not reply right away it can get lost in the shuffle. With some more info from you he can steer you in the right direction and even tailor one of his current units to your needs. Many here have customized units though the stock items on eBay are outstanding in their own right.

What were the upgrades that made your LP-27a a Special Edition? Mine has a DACT attenuator but is otherwise "stock". I can see maybe a bit more PS filtration and a difference component choice.

[BearCityUSA]

Originally Posted by Rosco65

What were the upgrades that made your LP-27a a Special Edition? Mine has a DACT attenuator but is otherwise "stock". I can see maybe a bit more PS filtration and a difference component choice.

IMG_0930.JPG
IMG_0933.JPG

Take a look. I do not remember the particulars. My wife told him to give me "the works". It was a gift.

[BearCityUSA]

Sorry that photo is pretty worthless. I'll try and get a better shot.

[Wgarcia]

Thanks for the replies regarding the heat of my fiery Fire Bottle. I assumed it was normal but I rarely touch the transformers of tube amps (my previous home audio one was an utterly different push-pull type A/B anyway), and with guitar amps I simply haven't noticed…I will check out the transformer in my single ended guitar amp if I ever remember to plunge my hand in there...

[Bombadil]

My Inspire KT88 amp typically has lukewarm transformers. However if I drive it hard, they do heat up. This is driving speakers which I believe to be approximately 91dB efficiency. Mine has the larger 20w output transformers. I suspect yours has 15w.