Yes

Ahh, great to meet someone else with one of Dennis' amps! Which model do you have? What do you think?

Tonight I will check the temp on the chassis to see how warm it gets and let you know.

Well, after a couple of hours, chassis is warm, but not hot. I can comfortably put my hands on each side. Warmer towards the front of the amp, but still not at all alarming. All three transformers are pretty cool.

[IMG]http://i198.photobucket.com/albums/a...ps96a3f410.jpg[/IMG]

[IMG]http://i198.photobucket.com/albums/a...psa00f386f.jpg[/IMG]

http://i198.photobucket.com/albums/a...ps15850a1f.jpg

Tried it in my bedroom study driving a pair of KEF LS50. As I mentioned, chassis was hot to touch so I took it off. Using a Leben CS1000P as its replacement.

Regards,
Joe Ling

I would contact Dennis about it. That hot doesn't sound right. I'm driving 8 ohm 87db sensitive speakers, not the easiest load either.

I wonder if he offers more models beside this one ? More power would be nice.

I'm only aware of a few. It seems the KT150 is the greatest power. If you go to his ebay pages, or search ebay for "Inspire amplifier" and check the "sold" box on the left panel, you should see 18 auctions that sold in the past. You can see his different models. 12 wpc is the most wattage I see. He has amps called KT150, KT88, KT66, 6V6, EL84, and 807.

I like the KT150 because it has the option of running a wide range of power tubes including most of the above.

My understanding is that it gets exponentially more expensive to build single ended designs with more than ~15watts while keeping up the quality of components. I think his most respected, higher power, single ended amps are the CAD-805's - very expensive to get that 50+ watts.

Been quiet around here!

I had an audio nirvana night last night. I want to use epoxy to freeze all of my settings just like they are now. :scratch2:

I have restored AR2ax speakers. I decided to replace the 40 year old tweeters with the experts' recommended replacements. Wow! Took a few days to tweak mid/hi level settings and find the right tube combos in my SLP05 - back to Sylvania Chrome Domes x4 and RCA Gray Glass x2. Combined with any tweeter break in that might have happened and my perceptual system adapting, last night it all clicked in.

I really love this amp. I'm now talking with Dennis about having him build the matching preamp for it - model LP-2. Will also be in Jag Carnival Red. Unfortunately no remote volume, but I will keep the SLP05.

Report to follow!

Cool. I'll be interested what your take on the pre amp is. I've backed off the SET amp craze for now ... My Treos are too inefficient and I like it loud. Maybe a bedroom system is in order. Keep us posted.

:lurk: interesting to see this, thanks for posting.

I'd like to hear this amp.

Very interesting little amp, thanks for sharing your experiences Peter. I'm assuming when you say 12 watts, we are talking about 12 watts per channel, right? What are the amps dimensions? Has anyone talked with Dennis about making a monoblock pair of these amps? Has anyone gotten contact information for Dennis yet?

I'd like to try one of these amps with my Cary SLP-98P F1 preamp. My speakers are 91 dB sensitivity and a 8 ohm load, my room is 24X14X9. I think that 12 wpc may be enough, though I am currently using a 100 wpc Class A SS amp. Worst case I could bi-amp with the SS amp on the bass.

Right, 12wpc. I am running it at 10wpc with the 274B rectifier. Dimensions are 10" wide, 8" deep. Petite thing! I did ask him about monoblocs and he didn't seem particularly interested, at least for now. Contact info is still through his ebay account, radioman731. He seems to prefer it that way and he responds pretty quickly. I have an email address from sending him money through paypal, but wouldn't give it out without his ok. You can look for one of his listings, or you can contact him and ask for what you want. I had to ask special for the jag red finish. He seems to like either that creamy white or black for the ones he's been posting.

Given my experience, I think you would be fine as your room is smaller and your speakers are more sensitive.

Ever in Anchorage? Just the next state over from you! :cool:

Anyone have any recommendations for favored EL34 tubes? I would only need two for this amp, but don't want to pay the $100 for the rarer NOS. There are several current production brands including JJ, EH, Tung-Sol, SED, Sino, and new production Mullard that are all under $100/pair. I'd go NOS if not too expensive.

I realize it is amp and system dependent to some degree, but I have to start somewhere!

The Inspire will take quite a few different power tubes without modification. I posted this earlier in the thread:

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 might try some of the lower power tubes eventually.

Thanks.......Peter

Sorry I can't help you with the EL34 question Peter, but I do have another question for you. Are these amps self-biasing? I ask because all of the choices for tubes would have more interest for me if the amps were self-biasing. Some tube amps are a pain to bias, and that would limit my tube curiosity.

It is self-biasing or, doesn't need bias adjustment for certain groups of tubes. There are no user bias controls. Dennis has it so different power tubes require certain rectifiers. So that does alter the power going to the tubes, if I understand it correctly. The list of tube combos above are what he provided.

Peter, I just finished a deal with Dennis. He is going to custom make me a KT-88 (his reco) in the black faceplate with the Jaguar blue paint to match my SLP-98P.

He's a lot of fun to talk to. His energy level is contagious! LOL!! I told him that he had me as excited as a kid in a candy store waiting for this amp. I'll keep you posted.

http://usr.audioasylum.com/images/0/...P-98P_0041.JPG

Definitely do! I'm glad to see more custom finishes.

Can you share more about what you told him and the rationale of his recommendation? I've been curious about how he sees things.

Thanks........Peter

Are you going for PP or SET?

As De Niro said, "Are you talkin' to me?" :cheers:

Dennis' current amps are all single ended.

.......Peter

Dennis just sent a shot of the preamp, LP2, bare chassis. It is currently at the powder coater's. All I've got so far!

.


http://img703.imageshack.us/img703/8199/b6cm.jpg

.

Peter, I told him about my preamp and I knew he was also familiar with my speakers (Soliloquy 6.3i's). I also mentioned the size of my listening room, and asked for his opinion on which of his amps would work best for me, KT-88, KT-150, Sweet 807, or some other amp. He replied that he thought the KT-88 would work best. Now was this just because he happens to be making a run of them this week? I can't say for sure, but here is a quote from his e-mail:

"The long and short of it ... utilizing the octal based 6SL7 or 6SN7 as driver tubes. Then add in 6V6, KT66, KT88, KT120 and KT150 plus other beam power tubes, applying fully regulated B+ voltage to the screen grids along with the 6SN7 driver stage resulted in an explosive full range presentation that I have seldom heard before. As I further refined the design I discovered the trusty, mighty KT88 is king of the hill for the full bandwidth. I am sure you are aware of the beautiful midrange 300B, 2A3 and 45's can produce but no slam and or serious control of the loudspeaker. Then one listens to a 6550 or KT90 push pull and you hear base slam but what happened to the glory of the mids and high frequencies. Anyway, I believe my new Inspire "Fire-Bottle" KT88 is one of the best I have done to date. Full bandwidth with some serious bass slam along with splitting dynamics and a glorious midrange. A 12 watt package that on a dealer shelf with a fancy thick front panel would be in the $5K range. Oh, put a blue back lit meter and yes $7K plus."

He also said that the KT-88 and KT-150 tubes clip softly, whereas the KT-120 tubes clip harder. My amp can also use KT-120's, but not KT-150's, he recommends the KT-88 over the KT-120's. I was trying to steer him towards the KT-150 amp, but he kept steering me back to the KT-88. So I trusted his judgment and bought it. Dennis also said he would send some photos along the way. I'll add them when I can.

Thanks for sharing! :yes:

He also told me about the KT120 hard clipping. That's probably important with low power amps as clipping may very well occur in peak passages.

Curious about the KT88 vs. KT150 though. I think the main difference between the two has been the main power supply which is rated higher duty in the KT150. I can run KT88s in my as well. The KT88's listed earlier used a 6H1P (6922) input tube. The KT150 uses 6H30. However, he says he is using 6SL7 or 6SN7 input tube in your model, so it's a bit of a change. Maybe it makes sense given your preamp. Is it also 6SN7 based like my SLP-05? Maybe that consistency of driver tubes is logical. Or maybe you are getting his latest refinement.

Well, I just looked at his closed ebay listings and see the white KT88 that just sold uses the 6SN7. It is also a different chassis configuration than the previous KT88 (same as my KT150), wider. An added benefit is the white KT88 that just sold is $300 less than my KT150 was!

It's probably all too much information - they sound great!

Yes, my SLP-98P uses (4) 6SN7's in the line stage, and (2) 12AX7's and (2) 12AU7's in the phono stage. That white KT88 is the one that Dennis had me bid on, though the one he is building for me will cost an extra $155. Why he had me use the 'Buy It Now' feature for that ad, I do not know.

I was just thinking that maybe the KT-88 would give me more flexibility as far as tube rolling goes. I think Tung Sol is the only manufacturer of the KT-150, or am I wrong? There are a lot more choices for KT-88's.
I'm also wondering why your amp can use KT-88's, but mine can't use KT-150's. Dennis told me this was because the tube sockets are different sizes. Do you need an adapter to use KT88's?

Yes, the one I bought uses a 6SL7 as a driver. I was unaware that earlier versions used a 6H1P.

My SLP-05 is all 6SN7's, but he was all excited about the new KT-150 tube when I corresponded with him. Now that I think about it though, he was offering a choice between Northern Electric KT-88's and the Tung-Sol KT-150's at first with the KT-150 amp. He had been listening to the new 150's and recommended them at the time. I haven't tried other output tubes yet, but here is his list of what can be run in the KT-150, directly from the ebay listing:

• 12 watts output with the KT-150, KT-88 or KT-120 output tubes and 5AR4 rectifier tube
• 10 watts output into 2 ohm loads with KT150 output tube with 5AR4/GZ34 rectifier

Though I was under the impression that I could run anything the "old" KT-88 could run plus the 150's. Here is that list:

• 5 watts per channel output with 6V6 output tubes and 5Y3 rectifier tube
• 7 watts per channel with 6L6, KT66, 5881 output tubes and 5U4 rectifier tube
• 10 watts output with KT88, EL34, 6550, KT99, KT120, KT150 output tubes with 5U4, 274B rectifier tube
• 12 watts output with KT-88, KT-120 or KT150 output tubes and 5AR4 rectifier tube

I'm going to double check with him to make sure. I want to at least try EL34's.

Here is what he described in the KT-150 listing about the change from the "old" KT-88:

Ostensibly, the increase in power and output transformer capacities allow for the KT-150.

And I'm pretty sure that all of the above power tubes are octal (same 8 pin configuration) so would at least fit physically in the socket. Whether they are appropriate to run, even though they fit, in any particular amp is another question.

Justlisten2,

Just re-read your post. A couple of loose ends...

Tung-Sol is the only KT-150 manufacturer. It just came out about eight months ago I think. And I'm realizing it is only the 6SL7. I don't think it's interchangeable with the 6SN7, but I included that in my inquiry to Dennis.

He seems to like ebay. We'll see if he has me purchase the preamp through ebay or not. At least some of the premium you are paying is for the custom color. The red and blue are one off orders that he has to pay extra for. The white and black he can do in batches.

Yes Peter, the 6SL7 is NOT a 6SN7. Also, the breakdown on the $155 extra cost was $125 for the Jaguar blue painted chassis and $30 for the custom faceplate.

Who knows? Maybe Dennis is just pushing whatever amp he is batching that week. That may explain why he was so high on the KT-150 when you were buying, but seemed to push the KT-88 over the KT-150 for me. I pushed for the KT-150, I wanted one, but Dennis seemed to steer me towards the KT-88. After having more time to think about it, I think I will be better off, due to more tube rolling options. He also seemed to imply that the KT-150 wouldn't fit on my amp because the diameter of the base was bigger than the KT-88/KT-120. I don't know if this is true or not, but that is how I read it.

The specs for the KT-88 amp look exactly like the specs for your KT-150 amp, both are 12 wpc.

What are the details of your LP2 preamp? Are you looking for it to replace your SLP-05? Does it have a phono stage?

I've basically heard that the SLP-05 is basically just a fully balanced version of the SLP-98, which is why it uses (8) 6SN7 tubes instead of the (4) 6SN&'s in the SLP-98. My SLP-98P is dead quiet, even the phono stage, and I have owned 3 BAT preamps running fully balanced. So for me, the onboard phono stage is more important than a balanced design.

Alright, I just got a e-mail of clarification from Dennis. LOL! Peter, he must have gotten your e-mail, here is what he wrote:

"I have received a few emails over the last hour or so about your Jag Blue Inspire. I guess there is a organized web site these folks monitor that you are participating. There was a question about the KT150 vs KT88 in your amplifier. The KT150 will work great in your new upcoming amp. The reason I mentioned not to use the KT150's in your machine is because they almost touch each other physically. Which is just fine ... looks a bit strange. LOL It is perfectly AOK to fire up with a pair of the KT150's in your amp. The cost is soooooooo much higher for the same performance as the KT88's in my opinion. My cost on a pair of the KT150's is more than double my price of the Gold Lion KT88's.


Hey keep the words going on the web ... love it!!!! Have a great evening and I'll talk to you soon .........."

So I guess I was wrong, the size of the KT-150 base is the same as the KT-88, and I could use the KT-150 tube in this amp. It won't be the first tube that I'll play with on this amp though. I'm in no rush to try the KT-150, but I may give it a go down the road, just for kicks.

Cool! So you can check out the Buck Rogers tubes! They are expensive though. $100 each I think. A lot for modern production tubes. I haven't compared them with anything yet else. As I mentioned earlier, I'll be trying out EL34's at some point. I have some 6550s I could run. Just something else to get a contrast. It will either be, "Hmm, some good possibilities in tube rolling here". Or it will be, "Wow! That KT150 is clearly better. I may play around a bit, but this is the tube to beat!" Either direction would be positive for me.

Dennis replied to me as well. Gave me the thumbs up for all of the tubes that will run in the KT-88 as well as several possibilities for driver tubes, along with his preference:

I'll have to double check what I have in there at the moment. I can swap with that with 6922s I have. I would also have to check, but I think my other amp has a 6CG7 I could "borrow" as well. Roll'em, Roll'em, Roll'em.... tubified!

Yeah, I may give the KT-150's a try down the road, but I'm in no hurry. I'd probably want to try a pair of Psvane, Shuguang Treasure, or Northern Electric KT-88's before I would try the KT-150's. Though it looks like the amp comes with a pair of Genelax Gold Lions, which I had been impressed with earlier in a VAC amp.

In other cool news, Dennis also just told me that I could also use a 6SN7 as a driver tube in place of the 6SL7. This is nice because I have plenty of 6SN7's laying around to play with, but I have no 6SL7's on hand. He did not mention using any other tube in the driver position though, so I don't know if I have as many options overall as you do Peter. I do like the 6SN7 tube though, so I'm happy.

He did mention that he is constantly playing around with different combinations, not just of tubes, but of other parts as well. Even using some RF parts from his other hobby, radio. Just playing around with the sound. These amps could well turn out to be like snowflakes, where no two amps are the same. LOL!!

I do get that impression (snowflakes). This started out as a hobby for him in retirement but he now seems to have his hands full!

I've tried a few 6SN7's as well (SLP05), but won't be able to use them in my amp. I've settled on four Sylvania "Chrome Domes" and two RCA "Grey Glass", both NOS tubes. The Sylvanias have nice clear extension and the RCAs add some warmth. I also got a NOS Mullard 5AR4 rectifier. I love that preamp! It will be interesting to compare with his simpler LP-2 when I get it. Here's how he described it to me:

I am not familiar with the 6FM7. It's very interesting though, as a combo of 6SL7 and 6SN7.

I like Gold Lion as well. I've had a CJ preamp that used 6922's (Premier 17LS). I tried a few makes and like the Gold Lion 6922's the best among current production. I will be trying one as the input in the KT150. I would probably look at those if I was to try KT88's. Northern Electric 88's are $100 each.

KT150 vs KT88
 

I just built a SEUL amp originally built for KT88. I'm assembling parts for a KT150 mono block build based around the same circuit as the KT88 just more voltage/current. For giggles I dropped in my KT150 tubes I have on hand for the next build into the KT88 amp I've been running in my listening room. Well all I can really say is they were dropped in to test drive and I've not taken them out yet. They sound better than the KT88 GL new issues I had in there, wider bigger sound stage, deeper more controlled bass, just a bigger sound and that's with the voltages set for a KT88. The KT150 can take a bunch more voltage than the KT88. The KT150 wants more current on the heaters so if you sub them in be sure your PT is up to snuff in that regard. It sounds as if Dennis is OK with swapping them into his KT88 amp, you'll get the same power as the KT88 but in my experience with a similar amp to his that those KT150s sound a little better to my ears. I run horn loaded 105dB efficient speakers with 15" woofers so I can hear subtle changes. Usually when rolling power tubes I don't really notice much, very very subtle but in this case I really like the KT150 noticeable in a good way for sure. They cost me $75/tube which I've paid close to that for GL KT88s maybe only $10 cheaper. I'd post a pic of my amp but I'm new here so I don't think I have privileges yet.

IMHO the KT150 for a few more bucks is worth it. I'll be getting some more of them.

Justlisten2 I'm around the corner from you in Mt Airy - you want to take a listen to my amp we could arrange that... best to hear your speakers so I could stop by some time and can bring a set of KT88s and KT150s sub them in so you can hear the differences. I've got my amp set up with a volume pot so you can plug whatever direct sans a TT but I've got a portable battery powered phono preamp I could tote along easily as well ifn's you like vinyl.

Cheers,
Bob Brown

Hi Bob,

Thanks for posting. Where are you finding the KT150 for $75? I see them at tubedepot for $94.95. I suppose they may start coming down in price somewhat when they are not so new.

What you say about the KT150 mirrors what Dennis has said when he first tried them in his modified KT88 based amp.

I got them from a feller on Ebay he actually lives in my mom's home town not far from me and I kinda know him (small town everyone knows everyone kinda thing). Ebay seller name is "gobble75" I'd post a link but not sure if that breaks any rules here! $149.99 for a matched pair, cheapest I've found anywhere and I looked around. I was going to go tubedepot route but remembered gobble75 had em a few weeks ago, he ran out and recently got some more and currently selling them now.
Cheers,
Bob

bobrown14... Welcome! :wave:

Thanks MasterLu - that's some crazy gear there! I'll show my wife and that (hopefully) will nip any complaining about excessive gear in the bud. :thumbsup:

Cheers,
Bob

Appreciate that! ;)

Peter - have you discussed a phono-preamp with Dennis? Any chance he will be building a 6SL7 based model?

No to both. I use an external phono preamp and just trusted his design expertise, in particular with matching pre to the amp.

An external phono preamp is what I was asking about. The Cary PH 302, which I assume is a Dennis Had design, based on its age, uses 6SL7 tubes.