I would rather have new Genalex Gold Lion KT77 tubes in that amp than JJ KT77s. The new Genalex are very good. It would add about $100 to the total cost, but I think that is worth it.

Do you have any pictures of you amp? I am interested how larger power and output transformers would handle my Kef ls-50's

Great! Post a pic. The pic of the one here appears to have a quad of power tubes and a 6SN7...no tube rectifier.

I can post a pic when I receive it. I think it is shipping today. I have seen multiple pics as build progressed. It looks great!!

Listening session....
 

Dennis wanted me to come over to listen to his new amp yesterday, so I headed over after work.
http://i443.photobucket.com/albums/q...psofekcb73.jpg

He didn't give me a lot of notice, so I only had a few minutes to grab a couple of 6SN7s before leaving the house in the morning. I thought this was a mono block setup, so I brought pairs. Silly me...


http://i443.photobucket.com/albums/q...psruslayzx.jpg

We tried 1955 CBS balckplates, 1953 JAN CHS Sylvi WGTs, 1940's vintage metal base Sylvi Navy marked 6SN7Ws, and some RCA red base 5692s.


http://i443.photobucket.com/albums/q...pslrsfl4st.jpg


We also did 4 KT-88s and mixed 6V6/KT-88s....

http://i443.photobucket.com/albums/q...ps2fhj4yud.jpg

http://i443.photobucket.com/albums/q...psaswrn3te.jpg

Dennis also had a new Chinese CV181 we tried.

http://i443.photobucket.com/albums/q...psjh7iy1rg.jpg

The verdict. The 40's vintage 6SN7W sounded the best with a huge soundstage and deep articulate bass. . Next was either the CBS 6SN7 or the CV 181.
Neither Dennis or I have been big fans of 5692 in the past,
but we both thought that this was the best we've heard this tube sound. We also liked the 5U4GB rectifier over the 5AR4.

I liked this amp so much that I made Dennis a deal and pinched it out from underneath Guitar Dave.....:D






Here's Dennis fiddling with a LP-27 variant that he just finished today. Said it sounded a bit sterile since the caps hadn't burned it yet.

http://i443.photobucket.com/albums/q...psvshnlzvh.jpg

http://i443.photobucket.com/albums/q...psttvspb9i.jpg


BTW, just kiddin Guitar Dave. Dennis said I should give you a hard time. He plans on shipping this amp out today.

SOme upskirt shots
 

http://i443.photobucket.com/albums/q...ps42xubf8d.jpg

http://i443.photobucket.com/albums/q...pspp6ipgkt.jpg

Dennis is very proud of this build, saying it's a true work of art...

Hey Analog, you had me going there! I am looking forward to seeing this amp in MY listening room!
Thanks for the update info. I appreciate the recommendations!
What was the best sounding power output tube combination?

Personally, if you can live with 9-10 watts, I would definitely try a quad of 6V6s. You'll have to run a 5U4 type rectifier or maybe even a 5Y3. I might even round up a quad of 6V6G ST shaped tubes with a 5Y3G ST shaped rectifier. The beauty of this amp is it's complete flexibility. You could run 4 different power tubes if that's all you had and as long as you had the proper rectifier in it, not worry in the least...

Hmmm....OK. So be it. I suppose if anyone wants more info on the Inspire OB speakers at this point, contact Dennis via his e-bay seller ID or look me up/send me a PM on Audiokarma. Hopefully that's OK to say w.r.t. forum rules...

I was wondering if you could post a pick of your 17 watt SE amp that might be up for sale..... Cheers

That would be a fun day! How did the mixed power tube combo sound?

I really liked it. The 6V6s IMO definitely sweetened the midrange

Dennis gave me the short notice to stop by and listen to this amp on Monday as well. To short since I live 4 hours away. I am sorry I missed he fun. It would have been nice to meet you Analog and of course have a listen and to this beauty. Dennis has been teasing me with pictures and his excitement a great deal of late. So much so that I have a PSE on order myself. I could not resist. Dennis is a good salesman weather he knows it or not. How many times have I heard 'Dennis said I had to have one" here on AA. Anyway his persistence got me. Really excited. Its hard to sleep sometimes. I look forward to Guitar's impressions.

Scott

*I* like 6V6's in my Inspire. I ran it with Pope 6V6's and a 5Z3/5U4 into my friends Volti modified La Scalas and it held its own against excellent 2A3 and 45 amps. My LP27a was used with all of the amps. We were both pretty amazed.

OK, I've followed this example with the Inspire OB speakers....

Ok, my PSE arrived and is playing nicely. Now too many amps!!

What tubes were included with it?

Included with which one? The PSE or my Set?

The new PSE. Just wondering what Dennis is shipping with that amp.

Mine came with a quad of Genalex kt88's and and a nos rca 6sn7, and two rectifiers, both jj's, a gz34 and 5u4. But that does not mean that is the standard tube set. I think it probably varies. It would be something to discuss with Dennis if you order one.

Have heard a lot of good things about the Genalex KT88s. I'd read that the PSE produced about 20 wpc with KT77 / EL34 tubes. Does Dennis claim a bit more power with the KT88s?

No. He told me 18-20 WPC. These amps are limited by being set to the lowest common denominator. If you were going to try and squeeze every last drop out of KT-88s, you'd smoke up a set of 6V6s in a hurry....

A comment from Dennis on the power rating of this amp....

I found that in actual listening I prefer the PSE operating at the 15 watt per channel level with the 5U4 rectifier. This is a nice equivalent to a mild 7 1/2 watt per KT88 output tube. The tubes will last forever so to speak and this seems to be the sweet spot for this design. With the 5AR4 the peak power output is on the order of 18 watts.

I would imagine that a KT88 tube would last several thousand hours at 7.5 watts.

As opposed to running the same tube at 17 watts in the Firebottle SE amp. He's got to be really pushing it in that amp. The "standard" KT88 Firebottles sold on eBay usually drive the KT88 at 12 watts.

I've been giving my Inspire SE EL84 a lot of hours over this past week, in my new setup with the low frequencies going over to a subwoofer. I must say that vocals, piano, and strings are fabulous. On good recordings the sound is so lifelike. Not the epitome of high frequency detail or the best on complex symphonic music or hard driving rock, but on folk, jazz trios, female vocals, etc, it can be magical.

I noticed this still on Audiogon just now and got to wondering, since DH sells his creations on ebay (and Moon Audio) might those looking for one be more likely to be looking there in the first place. That is a nice unit and at a fair price. I would have thought it would have sold on the bay by now, especially since DH has nothing listed and has not for a week or two. A thought, though you may have issues with ebay. Many seem to.

Good Luck,

It is possible that the amps sell better on eBay than Audiogon. I purchased my Inspire SE EL84 off of Audiogon after it listed there for over 6 weeks and the price was below 50% of list.

I a difference may be that you are selling the higher output SE version of the amp. Not everyone either need or appreciates the extra 5wpc. Dennis' new 12wpc HO version typically goes for about your asking price. May be a factor.

Perhaps this has been asked before, but does Dennis have a favorite output tube? When he sits down to listen to music, does he favor a particular tube in his SE amp? I know designers who favor KT88/KT120 types for their tighter bass and flatter frequency response. But others prefer the rich midrange of a KT77 or EL34, and still others go back to the 6L6CG as the most visceral experience.

When I go to my tube amps (I have 3 SS amps too), I tend towards tubes with a warm presentation. I have two EL84 amps and a 6CA7 amp in triode mode.

As he said in the interview he posted a while back Dennis has a "soft spot for 6v6s". I seem to remember someone here posting images of Dennis' personal 6v6 amp a while ago as well. He sold me on the JJ kt77s with JJ 5ar4 as I visited with him a month or so ago. They are still in my amp now. He must have a fondness for GL KT88s since he just did a run of 25 KT88 amps prior to this PSE turn of events which, if I am not mistaken he sent GuitarDave's with a quad of those. I also know he is fond of many of the current production tubes and is not fond of the cost of NOS though he does like the Bendix Red Bank tubes because of their construction. I guess he is a bit all over the map.

I've spoken to multiple amp designers and tube dealers who are very high on some of the current production tubes. I've been told that this is sort of a second Golden Age of tubes. Gold Lion KT77s and KT88s, Tung-Sol KT120, EH 6CA7s (at a bargain price), the recently discontinued SED Winged C 6L6GC, some of the PSVANE tubes, and more, have been positively compared to classic NOS tubes. Even some of the lower priced tubes, like Sovtek EL84s and Tung-Sol EL34B have fans. And the JJ KT77s are said to be quite good for the money. I've had two amp builders tell me that they prefer the new GL KT77 over the uber expensive vintage GL KT77.

I believe variables are so inter-dependent with each other there is no specific unique combination that could be generalized. System components, room conditions, specific tastes in music and sound preferences, all bear vote in the final count. It is an unavoidable trial-and-error process to gradually find the two or three best combinations for each system assuming main components are not changed in the process. Otherwise one would have to start over.

In my current setup, 6V6's are anemic and lifeless compared to 6L6 GC (Russian) and GL KT88's. Depending on the type of music, I would choose one over the other between those two. Same with the 56 vs 27 in my preamp and whether I use the preamp or do balanced with the ZBit straight into the amp. Of course, I have not tested a whole bunch of possibilities, but I'm happy.

Musica_Amantem expressed my sentiments before I could finish typing. :)

IME the Inspire single-ended-pentode amp can be finicky about speaker synergy. My short answer is that the best sound quality depends on your speakers, your room, the type of music that you listen to, and your preference regarding which inevitable colorations suit you.

I listen to classical music and opera. I employ my Oppo player’s built-in crossover for 2.1 in order to off-load bass from my Inspire “Fire Bottle” SE Stereo Tube Amplifier HO and Klipsch RF-7II speakers to a 15” powered sub. I’ve tried almost every possible output tube in my Inspire amp (which was originally equipped with GL KT88). With my RF-7II speakers, my favorite remains the 6L6GC variants. Thus far the best combination for me is GT6L6 GE (performance rating 5), 5AR4, and Amperex (Holland) 6DJ8 – which sounds fabulous. With that said, I’ve been able to achieve good sound quality with almost every output tube I’ve tried - KT150, KT88 (which tend to sound bright with my Klipsch), EL34, KT66, 7581A, various new and vintage 6L6GC, and 7408 (6V6 variant that I received today) - when paired with the right input tube and rectifier, and when paired with a particular type of music (e.g., chamber music vs. large scale orchestra).

IMO, other important factors include pairing with the best bourbon or rye … phase of the moon … etc …

Has anyone tried a lower rated rectifier? Like substituting a 5V4GA for a 5U4G? Dennis told me via email that one can do this. Or even go all the way down to a 5Y3GT, which he also said was okay. I've got a handful of the 5V4GAs. They can't handle as much voltage or current, but the voltage drop is just 25. The 5Y3GT is really low with a big voltage drop - not sure there would be much reason to try it. Except that I've got some very pretty vintage ones just laying in my tube box.

Definitely try them. I have not found a better pairing with 6v6gts than a 6106 bendix red bank (5y3). Forget the numbers and roll. You may be surprised.

I have used 5AR4/GZ34, 5U4GB, 5Y3GT, 274B, 5R4GYA, 5Z4GY/CV1863 and 5U4G rectifiers in various configurations with 6V6, 6V6GT, KT77, KT88 and 6L6 in my amp.

Any favorite combinations? Or any that you felt didn't work out so well?

I overall prefer 6V6GT output tubes.

Overall top combos for me to date are:

Pope 6V6GT, RCA 5U4G, Raytheon VT231
Visseaux 6V6GT, Zalytron (Holland) 5Y3GT, Zalytron 6SL7
Bendix 5992, RCA 5U4G, Raytheon VT231
Genelex KT77, RCA 5U4G, Tung-Sol 6SU7GTY
Tung-Sol 6L6G or SED Winged "C" 6L6GC, Sophia 274B, Sylvania 6SN7

both the KT77 and KT88 output tubes are interesting when driven hard with a 5AR4/GZ34 rectifier

In my system the Sophia 274B has a mid bass hump and is not a good match with many output tube/driver combos that I have tried

The best thing to do is experiment with the tubes you have. There are just too many variables between systems to recommend specific combinations. Me? I like the 6V6/6L6 family of tubes in my rig. If you want to use ST 6L6G or 6V6G's use a 5Y3 rectifier. You can get Zenith ST 6V6G's for little money. They are rebadged RCA or Sylvanias.

The new production power tubes, IMHO, are excellent. My favorite power tube is the Shuguang Treasure KT66z. The GL KT66 and KT77 are also very good. The general consensus on the GL's is that they outperform the original old production. YMMV.

On my Inspire EL84, it is my perception that when using a 5V4GA the sound is a bit edgier. As in a bit too edgy. Smoother with the stock 274B or a vintage 5U4G.