Dennis Had Inspire Amps

[timeout59]

That's the same article posted above in #1880. I started reading it, very informative. The first couple pages made my laugh out loud. Lines like:

The real danger here exists to that poor, well-meaning soul who enters into the discussion and tries to play the peacemaker by extolling the virtues of each method and proclaiming them equals, which is the "raw nerve" for both camps. When this happens, you'll usually see Camp SE and Camp PP rise up in unison, beat him like a rented mule and toss his limp,lifeless body aside as fodder for the vultures, and then resume hostilities as usual betwixt themselves.

Or:

The Spudmeisters are a relatively young group that is small and unique, just like their amplifiers. Their common bond is the spud (one tuber) amp. One resistor, one tube, and one output transformer in the signal path per channel, nothing else. Any more than that, and a Spudmeister will fall to the floor convulsing, ears covered, at the thought of putting anything extra in the signal path to contaminate the signal!

[timeout59]

My "17 watt Inspire Fire-Bottle special edition" arrived yesterday. I don't have any higher efficiency speakers yet, so I just swapped it in the system replacing the SS amp, driving the Maggie 3.7's with the help of two Vandy 2Wq subs. Listened for the first time this morning and was amazed at how well it drove these speakers. For early morning listening while my wife was still sleeping, playing acoustic guitar in a jazz trio, I'm pretty sure I was hearing some subtle nuances that I might have missed with the SS amp. My preamp (CJ Premier 17) volume setting was 60. For this volume level with the SS amp it would probably be 30. Before leaving the house had a chance to play a little big band jazz at realistic volume, no problems. I used one of the tube sets it came with: JJ KT-88, JJ 5AR4, and Raytheon 6SN7GT.

I'm sure the Vandy subs help by taking some of the load off the amp for bass. These employ simple high pass filters between the preamp and amp, so the Inspire amp is only handling frequencies above roughly 80 to 100hz.

Needless to say I'm very pleased!

[Musica Amantem]

Originally Posted by pstrisik

Here's an article that get's into the SE/PP difference if anyone is really motivated to read this much!

https://app.box.com/s/3j4joieng7zkgvz3ofuve51z53l5p6cr

Although originally I thought PSE was a variation of PP (my mistake), the difference between PSE and SET is what has been under discussion in my case (not SE vs PP), to understand why Dennis's new toy may be a better proposition than the single-ended Tetrode/Pentode strapped as Triode topology design. Presumably, less distortion and more power at no sound quality cost ... Sounds incredible and pulling this through is further evidence of the Man's ability!

[timeout59]

In a message to Dennis this morning, I asked about output taps, 4 ohm vs. 8 ohm. His answer was interesting and something I've not heard before:

"In regard to the output transformer tap...I use the full winding without a tap selection. This design will play into loads from 3 ohms to 20 ohms with ease. The sonic merits of using the full secondary winding to the loudspeaker is audible in a positive way."

I wonder if he has been wiring all his previous versions of the Inspire amps this way. For me it's great as I'll possibly be using both 4 ohm and 8 ohm speakers.

[Bombadil]

I've seen a few multiple output tube, parallel single ended amps over the years. The one I've seen most often is the Golden Tube SE-40, which used three 5881/6L6GC tubes per channel. It was spec'ed as a 40wpc amp, but really was much closer to a 20 wpc amp. It produced just 26 watts at 1000Hz at 5% THD. But it can sound pretty good in the right setup.

[timeout59]

Question for FloridaBoy. I can't start a thread yet, so thought I'd ask here. Sorry if I'm way off topic. I noticed you have Heresy speakers. That's a high efficiency speaker I've thought of from time to time, and now that I have the Inspire amp, I'm thinking of them again.

I've always been interested in the Klipsch Heritage speakers (maybe because I grew up in that era) but never owned any. I'd keep my main system also and use the Heresy's for a different sound now and then. I've got Magnepan 3.7's with a pair of Vandersteen 2Wq subs, and a Sanders Magtech amp. The Heresy's would fit between the Maggies and be about 7 feet apart center to center. I'd use the subs with them as well.

What other speakers have you owned, and how do the Heresy's compare? I'm looking for something with great dynamics, but still have plenty of detail and image well. It seems I heard or read somewhere that this type of speaker may not image all that well.

[Rosco65]

Originally Posted by timeout59

In a message to Dennis this morning, I asked about output taps, 4 ohm vs. 8 ohm. His answer was interesting and something I've not heard before:

"In regard to the output transformer tap...I use the full winding without a tap selection. This design will play into loads from 3 ohms to 20 ohms with ease. The sonic merits of using the full secondary winding to the loudspeaker is audible in a positive way."

I wonder if he has been wiring all his previous versions of the Inspire amps this way. For me it's great as I'll possibly be using both 4 ohm and 8 ohm speakers.

I can't find the email from Dennis but I recall that he told me that the output transformer was something like 10 ohms, but could handle anything from 3 ohms to 20 ohms as well (I had both 8 ohm and 16 ohm speakers).

[guitardave]

I have a new PSE coming next week and Dennis told me the output transformers are optimized for an 8 ohm load, but yes, they are fine with anything from 3 to 20 ohms.
Since I am getting the PSE, I will likely be selling my SET 17 watt Special Edition Fire Botttle amp built in May. Probably no need to keep both. Beautiful amp!

[Analog Addict]

Originally Posted by timeout59

Question for FloridaBoy. I can't start a thread yet, so thought I'd ask here. Sorry if I'm way off topic. I noticed you have Heresy speakers. That's a high efficiency speaker I've thought of from time to time, and now that I have the Inspire amp, I'm thinking of them again.

I've always been interested in the Klipsch Heritage speakers (maybe because I grew up in that era) but never owned any. I'd keep my main system also and use the Heresy's for a different sound now and then. I've got Magnepan 3.7's with a pair of Vandersteen 2Wq subs, and a Sanders Magtech amp. The Heresy's would fit between the Maggies and be about 7 feet apart center to center. I'd use the subs with them as well.

What other speakers have you owned, and how do the Heresy's compare? I'm looking for something with great dynamics, but still have plenty of detail and image well. It seems I heard or read somewhere that this type of speaker may not image all that well.

I may have some thoughts for you. I have a series of single ended amps, all designed and built with Dennis' help and mentoring. They range from a 45 SET amp at 2 wpc to a 6550 SEP amp pushing 8-10 wpc that is essentially a one off built by Dennis originally as a sweep tube amp, then modified by him to run 6550s.

The 45 amp currently powers a set of Klipschorns in my workshop. My main system is a set of Altec VOTTs/Model 19's set up in a tower configuration along with a set of Altec 604-8Gs all powered by a 3.5 wpc 2A3 SET amp, also built with Dennis' oversight. I'm running well over a half a ton of speakers with one flea powered amp.









Dennis' amps will give you all the dynamics you'll want or need with speakers in the 94db or higher sensitivity.

[FloridaBoy]

Originally Posted by timeout59

Question for FloridaBoy. I can't start a thread yet, so thought I'd ask here. Sorry if I'm way off topic. I noticed you have Heresy speakers. That's a high efficiency speaker I've thought of from time to time, and now that I have the Inspire amp, I'm thinking of them again. I've always been interested in the Klipsch Heritage speakers (maybe because I grew up in that era) but never owned any. I'd keep my main system also and use the Heresy's for a different sound now and then. I've got Magnepan 3.7's with a pair of Vandersteen 2Wq subs, and a Sanders Magtech amp. The Heresy's would fit between the Maggies and be about 7 feet apart center to center. I'd use the subs with them as well. What other speakers have you owned, and how do the Heresy's compare? I'm looking for something with great dynamics, but still have plenty of detail and image well. It seems I heard or read somewhere that this type of speaker may not image all that well.

I've had some excellent speakers over the years. The original Heresy was the first good speaker in the mix. I downsized and went with B stock Heresy III's. They are not perfect but they are quite good. Perhaps you could take your Inspire to dealer and have a listen. They are still in production for a reason.

The reviews on line are pretty accurate.