Dennis Had Inspire Fire bottle kt88

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Yomaha

Dennis Had Inspire Fire bottle kt88
« on: 21 Jun 2016, 01:42 am »

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 counter 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


weatherman1

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Re: Dennis Had Inspire Fire bottle kt88
« Reply #1 on: 21 Jun 2016, 05:25 am »
Because of the SET design the output wattage will be limited.  If the amp is designed for KT88's and you want-need additional power then you purchased the wrong amp.  If the transformer can handle the KT120 the wattage output will not get you much in listening volume.  Your Salk's are about 88dB and most SET amp's work best with speakers at 90dB of higher.  If your room is on the small size and you have no need crank up the volume then the amp might work depending on the type of music you ask it to reproduce without distortion.

trackball02

Re: Dennis Had Inspire Fire bottle kt88
« Reply #2 on: 21 Jun 2016, 01:57 pm »
I have a Dennis Had Inspire Fire bottle KT88 that is paired with Yamaha NS-1000, which I believe is 90 db.
It has more than enough drive and can play quite loud without any problems. Fantastic sounding by the way. I am rolling different KT88s, rectifiers and driver tubes.

I would ask Dennis directly about your speakers, since he may have customers who have your Salk speakers. He was quite helpful when I asked him about my Yamahas, and is an absolute gentlemen and professional.


roscoe65

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Re: Dennis Had Inspire Fire bottle kt88
« Reply #3 on: 21 Jun 2016, 01:57 pm »
There are a couple of us on AC that own Firebottle amps.  I own a KT-88 HO, but all the amps can be used with just about any beam power tube, from EL84 (with socket adapter) to KT-150.  The maximum output power with KT-88's and a 5AR4 is 13 watts.  With 88dB speakers, we are looking at 99dB output.  To put this in perspective, that is like running a 2wpc amp on 93 dBW speakers.

Personally, I would want speakers that are 92 dB or higher no matter what the amp I use.  There is great value in the improved dynamics and tremendous freedom in being able to choose any amp.

BTW - there is a 178-page thread about Dennis Had Inspire amps over on Audioaficionado.  There is a post there where Dennis sketches the output power with various tubes.

http://s128.photobucket.com/user/simonatsea/media/6V6rollingspecs_zpsc0e67918.jpeg.html

I own a couple of SE tube amps as well as a number of higher power (25-60wpc) solid state amps.  I also have the following speakers:

1.  Altec 414/802d - I can use any amp in my arsenal, from my 4wpc 421a amp to my 60wpc Kenwood KA7100.
2.  Omega SA Monitor - Any amp.
3.  Omega Super 3/RS5 - Any amp.
4.  Yamaha NS-690 - while I can use the Firebottle SE (KT88), it is happier with my Monarchy Audio SM-70, NAD D3020, Marantz NR1606, or Kenwood KA7100.
5.  GR Research XLS Encore (87dB) - It is really only practical to use with solid state amps.


Yomaha

Re: Dennis Had Inspire Fire bottle kt88
« Reply #4 on: 21 Jun 2016, 04:28 pm »
Thanks for the feedback every one! 

I have a friend who had a Cary integrated (not sure the model) way back when, and I remember listening to it nearly a decade ago before I got into hifi.  I was amazed at the imagery, the dynamics, and the soundscape.  That always stuck with me.  For my guitar rigs I've always used early 80's Marshall tube amplification (I know not apples to apples), and tube gear (compressors, mic pre's etc) in the recording studio.  That's what has led me to tubes in home stereo.  I was recently researching Cary, and came across Dennis's info.  I noticed that he had since retired but continued making amps.  To me, that says a lot when you've been doing it for 50 years, retire with probably ample funds to do whatever you want, and then you still keep building amps. 

I emailed Dennis thru eBay.  I sent him the specs on my Salk's and he suggested the KT88 fire bottle saying there should be no issues and that he drives Maggies with that amp.  And yes, he seems like a pleasure to work with. 

I haven't owned any tube gear in my home 2 channel set up before with the exception of a bellari VP130 phono pre, so I've been reading a ton trying to get up to speed.  The audio aficionado thread is epic, and helpful.  From a generic perspective, I like the concept of simplicity of the signal path that is built into the SET amps.  In my previous studio life, for me I preferred to keep the signal path as simple as possible.       

roscoe65

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Re: Dennis Had Inspire Fire bottle kt88
« Reply #5 on: 21 Jun 2016, 07:27 pm »
I think it important to think of Dennis' Firebottle amp as 1/2 of a system; it benefits from a preamp much that the matching LP-27a/LP-3 preamp should be considered mandatory.  Together, they are priced at about $2,500 for 12 wpc, with no phono stage.  While I love the combo, you may want to look at a Leben CS-300 or Rogue integrated on the secondary market.

Yomaha

Re: Dennis Had Inspire Fire bottle kt88
« Reply #6 on: 21 Jun 2016, 07:33 pm »
I have an AVA Insight+ Pre w/ Vision phono....do you think that would mate poorly with the Fire Bottle?

roscoe65

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Re: Dennis Had Inspire Fire bottle kt88
« Reply #7 on: 21 Jun 2016, 07:57 pm »
I think it would be fine.

Hear Clifford Brown

Re: Dennis Had Inspire Fire bottle kt88
« Reply #8 on: 21 Jun 2016, 08:51 pm »
I'm interested in the Inspire amp also and wonder how it will mate with my Conrad Johnson Premier 17 line stage.

roscoe65

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Re: Dennis Had Inspire Fire bottle kt88
« Reply #9 on: 22 Jun 2016, 12:49 am »
I'm interested in the Inspire amp also and wonder how it will mate with my Conrad Johnson Premier 17 line stage.

The amp is two-stage power amp, 1/2 6dj8 - tetrode output tube.  It benefits from the gain of a preamp.  The amp is fairly neutral in character (this ain't a 300B) but can be tweaked by tube rolling the driver tube, the output tubes (6v6's sound much different than KT-88's) and most surprisingly the rectifier tube.  It can sound intimate and inviting or outright rock and roll.  The output transformers are designed to handle almost any speaker impedance (according to Dennis.  IIRC he said they are 10 ohm output impedance but can run from 2 - 16 ohms).

If your speakers are appropriate for the amp, I can't see why any preamp would not work.  It is also hard to beat for the money, and I can't recall a more fun component.  I found myself spending almost as much on tubes as I did on the amp.

Yomaha

Re: Dennis Had Inspire Fire bottle kt88
« Reply #10 on: 22 Jun 2016, 02:27 am »
From what I've read in so many places, it sounds like tube rolling is like a stand-alone hobby in and of itself....which is awesome! 


Wind Chaser

Re: Dennis Had Inspire Fire bottle kt88
« Reply #11 on: 22 Jun 2016, 05:45 am »
I emailed Dennis thru eBay.  I sent him the specs on my Salk's and he suggested the KT88 fire bottle saying there should be no issues and that he drives Maggies with that amp.     

A good SET / SEP wired as a triode is something everyone should hear, regardless if you're open to the idea of a low powered amp or not. I'm running an 8 watt tube amp with speakers rated 90 db, but truthfully, are closer to 86 db according to measurements taken at the NRC. Despite the amps modest power, it enables these speakers to sing unlike any other amp I've heard them with.

Yomaha

Re: Dennis Had Inspire Fire bottle kt88
« Reply #12 on: 1 Oct 2016, 05:32 am »
Curious to see if anyone hasexperienced this and any ideas to remedy:

Noticed music only coming from one channel. Powered down amp. Restarted and now neither channel plays. Switched all tubes except Sophia (BC I don't have a replacement). Still nothing. I can get sound to the headphone section of my preamp but not thru amp.

Going to hook up my van Alstine power amp to see if I can pad signal to speakers tomorrow.

Any insight or suggestions welcome!

Yomaha

Re: Dennis Had Inspire Fire bottle kt88
« Reply #13 on: 1 Oct 2016, 05:46 am »
Checked fuse and fuse looks fine   

Hooked up to van Alstine power amp and immediately got sound thru the mains. That tells me
Something's off the the fire bottle. It had been playing like a dream and then just stopped???  Stumped and any Insight helpful

Thanks in advance

Freo-1

Re: Dennis Had Inspire Fire bottle kt88
« Reply #14 on: 1 Oct 2016, 01:31 pm »
Sounds like you have a power supply issue.  Not sure what the sophia tube is, but I would look at the rectifier tube.  It's likely either that tube or a component in the power supply.   Unless you have experience working on this stuff, best to just try changing the rectifier tube.  If still no joy, see if Dennis will fix it for you.

Tube gear is a lot of fun, but it does break from time to time.

Good Luck!

Yomaha

Re: Dennis Had Inspire Fire bottle kt88
« Reply #15 on: 2 Oct 2016, 07:16 pm »
It was rectifier tube.

Anyone have any opinions of best 5ar4 / gz34 rectifier tubes?  I emailed Dennis and he recommended Gold Lion Genalex reissue GZ34 rectifier tubes as well as the 5U4 rectifier by JJ.

roscoe65

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Re: Dennis Had Inspire Fire bottle kt88
« Reply #16 on: 2 Oct 2016, 08:15 pm »
It was rectifier tube.

Anyone have any opinions of best 5ar4 / gz34 rectifier tubes?  I emailed Dennis and he recommended Gold Lion Genalex reissue GZ34 rectifier tubes as well as the 5U4 rectifier by JJ.

Depending on what you want to spend, you can go broke buying rectifier tubes.  The GL 5AR4 is a good current production tube.  If you want to get the tube with the best reputation, the early Mullard metal base or fat base 5AR4 is the one people want.  You'll pay about $300 for it.  Check out Brent Jessee's site for his recommendations.

Freo-1

Re: Dennis Had Inspire Fire bottle kt88
« Reply #17 on: 2 Oct 2016, 09:04 pm »
If you can take a 5U4G, a top recommendation would be the Sylvania 5931.  It's a MIL-SPEC 5U4G, and one of the best , IMHO.

Any NOS 5U4G is pretty good.  They also cost less than 5AR4 tubes. 

Yomaha

Re: Dennis Had Inspire Fire bottle kt88
« Reply #18 on: 5 Dec 2016, 10:44 pm »



I found this in the back of an old big box all-in-one radio at an antique store.  It was an old RCA unit with built in phono and radio and speakers.  I looked up the model of the radio unit and it dated back to the 1930's.  Of course this could have been a replacement tube and newer than that.  I haven't been able to place the exact date of the tube, but I cleaned it up and it sounds really good in my Dennis Had Firebottle.  Anyone have any insights as to what date range this tube was made?  Or what other identifiers can I use to date the tube?

Thanks!