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!

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

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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!!