[Yomaha]

Hello,

Was curious if anyone on the board has any experience or opinions on the Dennis Had Inspire Fire Bottle KT88 Amplifier.  I've read mostly good things about these amps on other forums but haven't seen too much here at AudioCircle.  I would be pushing Salk Songtower RT's.  The main issue I have seen with these amps from other boards is that they don't provide enough power to play well at loud levels depending on speaker efficiency, room size, music style.  The coutner argument to that is that it seems switching out tubes gives more power and seems to remedy the issue.  I have a smaller room and unfortunately can't really crank it anyways due to where I live.   

Any thoughts or feedback is greatly appreciated.

Yomaha

[danabunner]

His standard KT88 SE amp will produce a maximum of 12 watts per channel.  He has a "souped up" edition which will produce 17 watts per channel, again with a single KT88 per channel.  He has recently begun building a parallel single ended version, I believe named a PSE KT88, with two KT88s per channel.  I don't know the output from this one, I believe he can modify it to make 15 to nearly 25 watts.   Switching out the stock KT88s for other KT88s will have almost no impact upon the output power.

I'm presently driving floorstanding 91dB speakers with an 18wpc amp and it works great for me.  But I don't try to achieve concert level volume.   

If one uses a subwoofer, this offloads the power draining low bass, which enables these amps to play a bit louder.

[roscoe65]

His standard KT88 SE amp will produce a maximum of 12 watts per channel.  He has a "souped up" edition which will produce 17 watts per channel, again with a single KT88 per channel.  He has recently begun building a parallel single ended version, I believe named a PSE KT88, with two KT88s per channel.  I don't know the output from this one, I believe he can modify it to make 15 to nearly 25 watts.   Switching out the stock KT88s for other KT88s will have almost no impact upon the output power.

I'm presently driving floorstanding 91dB speakers with an 18wpc amp and it works great for me.  But I don't try to achieve concert level volume.   

If one uses a subwoofer, this offloads the power draining low bass, which enables these amps to play a bit louder.

His KT-88 amps are either 12 wpc (with 5AR4) or 17 wpc (high output version with 5AR4 run at max voltage), or PSE KT-88 at 18watts.  He runs the PSE version at a lower operating point and prefers it with a 5U4 for an easy 15 wpc.  To my knowledge he does not run these at 25 wpc.  He has offered a pair of 6V6 x 4 monoblocks that make 20-25 wpc.

Dennis' opinion is that if you need more than 12-18 wpc you should really be looking at a much bigger (>50 wpc) amp, since going from 12 wpc to 25 wpc is not going to get you you a whole lot.  His use of PSE tubes is not strictly to get more power, but to operate the tubes in their sweet spot at reasonably power and to lower the output impedance to better control the speaker.  An interesting tidbit is that his PSE amps will run different types of tubes at the same time (e.g., KT-88 and 6V6 on one channel and KT-66 and 6L6GC on the other).

[danabunner]

I was told that if you want him to tune one of his new PSE KT88 amps to higher power, that he could do this.  He does build to order. 

Just like his earlier KT88 SE amps were tuned to 12 wpc, but later he introduced the 17 wpc version. 

I do not know this for certain, but he is generally receptive to his customer's requests.