Dennis Had Inspire Amps

[Bombadil]

The Absolute Sound reviews the Dragon Inspire IHA-1 Headphone Amplifier, hand built by Dennis Had.

Dragon Inspire IHA-1 Headphone Amplifier | The Absolute Sound

[CoGT3]

Originally Posted by guitardave

Yes, I have had if for about a week or so. Very nice amp. I am still burning it in, but currently using a 5u4 with 6sn7, a pair of KT 88's, and a pair of Pope 6v6's. Very nice combination! I am driving it with an Audionotekits Mentor preamp.
The amp has a nice "live" sound. Very open, detailed, and nuanced.

Any updates on the amp? I have one of Dennis' 45 SET and am awfully tempted by the PSE.


BTW: it's a small world. My little sis lives in traverse city. Works at Interlochen.

[timeout59]

The Cunningham 27 globe mesh arrived today, put them in the LP27a and they do not sound as good as the RCA ST 27 tubes I have. They don't have as much sparkle in the treble, and just require a lot more volume to get close to the great life like sound, and they never really get there. I guess at $22 a pair no big loss.

[Bombadil]

I now have GuitarDave's old (well, not very old) Inspire SE KT88 High Output amp. So far have run a variety of power tubes through it, including some very old USA 6V6GT, JJ KT77, GL KT88, and, right now, a pair of EI coin-base 6CA7s. Every one of them has very different characteristics. Also 5 different 6SN7s, and each one of them has been subtly different (to my surprise). And several rectifiers, where I didn't always hear a difference.

This amp is very fun to play with. The difference between the 6V6s and the KT88s is quite substantial.

[CoGT3]

Originally Posted by Bombadil

The difference between the 6V6s and the KT88s is quite substantial.

I only have the 45 SET but am considering the new PSE. How would you characterize the difference between the KT88s and 6V6? Was it just the power difference that stuck you or the overall character of the tubes? (From reading the older posts I was thinking toward collecting some 6V6's if I pick up the PSE).

[Bombadil]

There was a substantial overall difference in the sound. The KT88 had better deep bass extension and definition, and a bit more detail on high frequencies. The extra power was very evident too, I could turn it up past where the 6V6s would have clipped. I had a powered subwoofer in my system, I took it out and let the KT88s drive my monitor speakers full range and it did well. Nice full sound, a bit warmer in the mid-bass and midrange than a SS amp.

The 6V6s didn't have the authority in the deep bass and the mid-bass was a little looser. This is a great tube for vocals, which sounded wonderfully natural. I can't really state that my listen was the definitive story, as I tried only one pair of 6V6s, very old USA Delco. And have not listened to either 6L6 or KT66 tubes. The Delcos do test very strong and were quiet. Mind that my amp uses only 1 tube per channel. Dennis' newest PSE 6V6 monoblock amp uses 4 per channel, so there would be a lot more power. His stereo Inspire PSE uses 2 per channel, producing, I believe, around 10-12 wpc. On my amp it is likely producing only around 6-8 wpc with the 6V6 vs 17 with KT88s.

I will add that it is really nice to have an amp where one can tailor the sound to their mood. I'd like to have pairs of KT66 and KT120 to check those out.

[CoGT3]

Bombadil,
Thanks for the input. Kind of sounds like the differences I noticed when I got my Firebottle 45 SET compared to my Thoeress 845 SET that was ultimately sold (put a big chunk of change into the TT upgrade fund). The 845 amp definitely grabbed the speakers better and extended the frequency response on both ends of the spectrums. But there is some true magic with 45 on vocals as you mentioned and more simple arrangements, Lou Reed's Walk on the wide side is spooky good on the 45s.

My speakers are technically quite efficient, 96dB. But they a modified, back horn loaded Lowther design. The Lowther is acoustically rolled off around 200hz into 4 8" drivers, isobaric loaded into the horn. So on more complex music or pieces with deep bass it really does benefit from more juice. The PSE may be that more juice while keeping the 45 for different music. Not to mention the tube rolling options is very intriguing. The 45 has EML mesh plates in it that are really hard to beat in the 45 world.

I wonder if a fresh NOS pair of 6V6GTs that can handle the 5U4 rectifiers would bridge some of the gap between the kt88s and delco 6v6.

Out of curiosity which monitors where you using?

[Bombadil]

So far I have been using Focal Aria 906 speakers. Eventually I hope to use the Inspire with my tower Von Schweikerts, but that may be a while. I am moving and those just got packed away. May not get them out of their boxes until November.

I didn't get the amp to use 6V6s as I was looking for more power than my Inspire EL84 amp and the 6V6s don't go very far on the power scale. But they sounded pretty good and I'm sure I'll revisit them.

I have no 6L6 or KT66 tubes. Am trying to decide what would be the best tube in that family to pick up, at least the best one at a reasonable price.

[robert_kc]

I’m trying some new tubes in my Inspire “Fire Bottle” SE Stereo Tube Amplifier HO. I don’t remember who posted the following:

• 5 watts per channel - 6V6 output tubes and 5Y3 rectifier tube
• 7 watts per channel - 6L6, KT66, 5881 output and 5U4 rectifier
• 10 watts output - KT88, EL34, 6550, KT99, KT120, KT150 output and 5U4/274B rectifier
• 12 watts output - KT88, KT120, KT150 and 5AR4 rectifier

I’ve acquired a pair of vintage Zenith 6V6G. I tried a 5Y3 (Vdrop 60) with the 6V6G and was dissatisfied. (Inadequate dynamics and “life” to the sound.) I briefly tried a 5U4 (Vdrop 44) and the sound quality was better. Nothing seemed to be overheating with the 6V6G and 5U4. Is this a safe combination?

Separately, tomorrow I’ll receive a pair of vintage Sylvania 6L6GA. Dennis told that me that while a 5AR4 (Vdrop 17) could be used with a modern 6L6GC, not with a vintage 6L6. I’ll try a 5U4 (Vdrop 44). Any thoughts if a 5V4 (Vdrop 25) would be OK?

P.S. I’ve been doing quite a bit of tube rolling this summer. I think I’ve found a new favorite tube combination … more to follow …

[Bombadil]

Originally Posted by robert_kc

[*]12 watts output - KT88, KT120, KT150 and 5AR4 rectifier

I wish I knew the output of mine for the different tubes. All I know for sure is that with its larger output transformers and higher voltage, that it produces 17 watts with KT88s. Unconfirmed info is that it may do 19 watts with KT150s and 14 with EL34s.