AudioCircle
The Commercial Zone => Industry Introductions => Topic started by: straitwire on 22 Sep 2020, 01:34 am
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Hello everyone, I build Inspire audio equipment.
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Welcome do you mean say the Inspire Dennis Had amps ?
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Hello FullRangeMan sorry it took so long to reply.
Yes I work with Dennis Had building Preamps, Headphone amps and occasionally amps.
Started working for him at Cary Audio Design back in the 90's...good times!...
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That's actually really cool, how long does each take just out of curiosity?
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Nice have you here bro, do you could confirm the Inspire OPTs are Trancendar?
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That would be something that I can't talk about.
I can say that our transformers are hand built in small batches.
And that our transformers are built to Dennis's specs.
Dennis evaluated lots of transformers before he decided to go with this manufacturer.
I'll check with Dennis and see if it's ok to talk about this sorta thing.
But having said that, transformers are only part of the recipe.
Circuit design and topology (power supply, input and output circuits) and component choice (resistors, capacitors, wire) are just as important.
Also Dennis never stops experimenting and improving his designs.
I have to run to keep up with him, and my personal Inspire amps and preamps have been rebuilt completely several times and modified more times than I can count in order to stay current
so that we have the same sound and can talk about what we're hearing.
WOW! once you get me started I just can't shut up... :roll:
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Thanks you most kind.
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Hi and welcome to audiocircle, straitwire!
It's great to have you (and Dennis) at audiocircle. You have a lot of fans and customers here. I hope you can stick around!
From a friend of Sol and a former SLI-80 owner :thumb:
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Hey FullRangeMan, I will try to answer as many questions as I can and keep you guys up to date on our plans and offerings.
Hey Richidoo, thanks for the warm welcome, and tell Sol hello for me and that I hope all is well with him.
Of all the memories I have of Cary Audio Design, working with Sol is one of the high points.
He's a really nice guy and smart as a whip.
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Hey MatterG56, depending on the unit it can take 4-6 hours for a one output tube per channel stereo unit and longer for a parallel output tube stereo unit
and of course even longer for a pair of monoblocs.
The headphone amps are the same circuit that they have been since there original design
so building them takes less time because I have built so many that it's practically muscle memory now.
I have built a lot of preamps so they take less time than they used to but we are about to start building a new preamp design with a different circuit and layout.
If I cut a chassis (design the layout, cut holes and get it powder coated) instead of using a chassis that is manufactured for us in quantity, it can take a lot longer.
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Welcome straitwire. :D
In my thinking, it is not so much the individual parts, but the sound that matters.
After buying (all new) a Sweet 807 (and selling it wanting current tube rolling options), an SEP universal (and selling it wanting to try a triode :duh: ), and a SET universal (and selling it :duh: ), I can say Dennis' amps are all very good with a little different flavor for each.
When I received the Sweet 807 I also just purchased a pair of Omega 3i speakers and started to let them run in listening to familiar music. I heard distortion that I never noticed before and communicated with Dennis a few times. He suggested listening with HPs to check if it was the recording, well all I had was an inexpensive pair of Senns. Sure enough I was hearing something in the recording that I never noticed before.
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Hey opnly bafld, you are absolutely right, the sound is really what matters in the end, and the circuit design/topology is the most important part in determining the overall sound.
What I should have said is that it is critical to choose parts that experience has proven to be sonically appropriate for the sound that you are trying to achieve
and that are reliable and durable enough to stand the test of time.
And that using parts that are overbuilt and/or under stressed in the circuit is critical to the amps longevity as well as the overall sound quality too.
But different makes of resistors, capacitors, electrolytics, transformers and other parts do have an impact on the sound also.
It is hard to express that our amp and preamp designs are "evolving" or getting "better" without seeming to disparage older circuit designs.
I should choose different words to express this.
As you indicated different amps have different flavors, and Dennis has produced all kinds of different amps/circuits.
In fact when customers choose to send in units that are several years old to be updated to the latest circuits
Dennis is always excited to take them home and give them a listen before making the updates.
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Nice post.
I think most understand that as products change it doesn't mean the older version was bad and sometimes the older version is still preferred by some.
Some years ago I bought a new version* of a well known speaker brand and never warmed up to the sound. Ended up getting an older pair (2 models down) and absolutely loved them.
*the drivers have been changed again and now they sound superb to me
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Welcome aboard. I have an Inspire [5] tube 4W/ch EL34 output Signed by Dennis on bottom. Does Dennis do that for every amp ?
charles
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Hey rollo, yes he does sign every amp.
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Red CJ5...
This is our new preamp.
Ready for the test bench, then faceplate and knobs.
It uses 6C5 and 6J5 tubes with a 5Y3 or 5u4 rectifier.
(https://www.audiocircle.com/image.php?id=216178)
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I think this one is mine. I ordered it to go with my 6FLV DJH Edition amp.
My 6FLV amp is amazing. It has eliminated my desire for a DHT amp. I am running Bendix 6992 tubes with a Pope 6SN7 and RCA 5U4G. The only word I can use to describe the sound is ethereal. It is better than my KT88 PP amp, especially at the extremes.
Paul Klipsch used to say what the world needs is a good 5 watt amp. This is definitely it.
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Hey datman, I believe you are correct, this probably is your preamp.
I've updated the circuit on my amp to the 6FLV and I'm very happy with it, I'm running metal RCA 6F6's right now.
I do a function test on the preamps and headphone amps I build so Dennis doesn't have any issues on the test bench.
So I listened to it for a little while and...hmmmm...I think I'm gonna to have to build one for myself.
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Finally finished my CJ5, put my own knobs on it.
I'll probably leave it as is without a faceplate, I like the prototype look... :wink:
Gonna dig up one of my old DIY remote volume kits for it.
Sounds great with the amp I updated to the 6FLV circuit.
These metal 6L6's are really nice.
(https://www.audiocircle.com/image.php?id=217274)
(https://www.audiocircle.com/image.php?id=217277)
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(https://www.audiocircle.com/image.php?id=217274)
These knobs look good :thumb:
Congratulations
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Thanks FullRangeMan.
I'm looking at some Russian glass envelope 6C5/6J5's on eBay.
The metal ones sound great but I miss the tube glow.
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Be careful with metal body tubes they have live voltage in metal if the paint is Red.
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Working on a new Inspire KT170 amp.
I'll post more pictures when the chassis gets back from the powder coater.
(https://www.audiocircle.com/image.php?id=219940)
(https://www.audiocircle.com/image.php?id=219941)
(https://www.audiocircle.com/image.php?id=219942)
(https://www.audiocircle.com/image.php?id=219943)
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Hey straitwire,
I'm one of those audio-clowns always tumbling through gear searching for greener pastures....I'm also always in danger of the wife serving me with divorce papers over all the gear.
I have two pieces of kit in permanent use a Spendor S5e speaker pair for background listening while working and a Cary SLI-80 that I bought in '05 IIRC. The SLI-80 has given me thousands of hours of trouble free tube rolling greatness. Per advice from someone I replace the slow blow fuses every odd year Christmas.
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Hello straitwire. Welcome! I feel like I know you. I have just spent the last two and a half weeks reading through the AA Inspire mega thread. What a project that was! I really wanted to join in that conversation but for some reason, try as I might, I can not log into that site. Anyway are you planning to start an Inspire circle here? I for one would like that. I recently picked up a 6/2016 Firebottle SE KT-88 HO with only a few hours on it. By far the best sounding amp I have ever heard!
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Hey Sonicjoy, Welcome to the Inspire family!
I started this thread in Industry Introductions in order to post things about Inspire equipment.
I work with Dennis so I have to post Inspire stuff in this section.
The FireBottle HO is a fantastic amp and one of my favorites.
I am going to post pictures of our newest amp the KT170 on this thread, but I wanted to have all the pictures from start to finish.
Hopefully Dennis should be starting the build this week.
If you have any questions feel free to contact me here.
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Hey thanks for the quick reply! I will likely have some questions. In fact, I sent Dennis a message on ebay about a month ago but have not heard back. I did get a response to some questions when I was first looking to buy the amp. I'm sure he is just very busy. Seems like demand is growing huh? I will try again.
I am mating the HO with a Wyred 4 Sound STP SE pre-amp with stage 2 upgrades and Emerald Physics EP 2.7 OB speakers. This has turned out to be an incredible combo! The EP 2.7's are the big brother to the EP 4.7's that Jerry Seigel (of Ten Audio) used during his glowing review of the Hot Rod HO. The 2.7's have dual 15" woofers where the 4.7's have one. Interestingly he also reviewed the Wyred pre-amp and gave all three components his perfect Ten LP's rating. So these are true reference quality components.
I am enjoying the heck out of this system. Very pleased with this little amp! Amazing what 12 watts can do. Glad to be part of the Inspire family. :thumb:
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Glad you're enjoying your system.
Dennis is usually very busy so sometimes he isn't able to reply, add to this the fact that he receives hundreds of emails a month.
So contact me here and I'll try to answer your questions, and if I can't I'll ask Dennis.
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Thanks Straitwire. Well I guess I should ask while I have you. I was wondering if it would be worthwhile to send the amp in to have it upgraded to the Hot rod version or whatever the latest upgrades are. I am interested in maximum clarity and transparency as well as control of the low end.
The one concern I have with my long term enjoyment of this amp is the slight lack of power in the low frequencies. It is very good most of the time but once in a while I like to turn it up, and sometimes it just can't quite keep up in the bass department. These speakers are capable of incredible dynamic's but do need some power to do that. So I'm thinking that the PSE may be the better choice for the long run. My speakers are rated at 97 db, but that may be a bit optimistic.
Do you have any thoughts on this? Also what is the approximate turn around time or order time if I decide to order a different model?
Thank you!
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Hey Sonicjoy, I am not sure if an upgrade of the circuit would make a difference because it wouldn't increase the power output.
I would have to ask Dennis what he thinks.
From the specs I see on the Emerald Physics site your speakers efficiency was measured at 1khz.
As you mentioned Open Baffle speakers do tend to need more power to deliver low frequencies.
For my OB speakers placement is critical.
Three feet or less from the corners of my living room or they don't put out much bass.
The PSE amps have more power and a lower output impedance so they have better speaker driver control which can improve bass response.
Turn around time for a new unit depends on which unit you are purchasing.
Standard PSE amps are special order so I am not sure how long it would take to build one.
We do have a Gas Voltage Regulated PSE chassis in Red that can be built.
But I don't know what the price would be, I would have to ask.
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I know that updating my current HO would not add more power, but I seem to remember the IIPS upgrade helps a bit with driver control. Is that true? I don't know if my amp has that or not. How does one tell? I could post a photo of the inside.
I suspect that still would not be enough for what I am looking for.
I think the PSE would be the way to go really. Can you tell me about that Gas Voltage Regulated PSE chassis? I may be interested in this, but don't know anything about it. How it compares to the HO. Is it based on KT-88's?
I'm new to tube amps. This is my first, but I have been reading a lot, trying to get up to speed.
Don't get me wrong I absolutely love this Firebottle HO! It drives the EP's very well. (Dennis told me it would) They have excellent bass response. Better than subwoofer bass. Deep, articulate, very satisfying and absolutely no box noise. Love OB for that reason! My speaker position is dialed in very well. About 4 feet from the front wall. I have no issue with the sound for most situations. It's just that when I really want to turn it up like we all sometimes do, it starts running out of steam and the dynamics drop off. These speakers have had their crossovers upgraded and fine tuned by Danny Richie at GR Research. Also better tweeters. He told me that these may be the best sounding pair of Emerald Physics speakers on the planet. (His words) The little HO brings a very engaging and 3D sound stage with these speakers that makes me smile every time I listen.
Keep in mind that I came from class D mono blocks at 270 watts each to the 12 watt Inspire. The bass control at higher volumes is what I am missing. However I am very surprised just how much power this 12 watts really is. Very impressive. I think the PSE would probably be enough.
Thanks again for your help.
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If you could post a picture of the inside of your amp I can tell you if it has an IIPS.
I change the circuit in my amp whenever Dennis comes out with a new mod or with an entirely new design which includes output transformers.
It has been several years since I ran an IIPS so I really can't comment on improved bass.
The Gas Voltage Regulated PSE uses 0A3 voltage regulator tubes instead of zener diodes to regulate the high voltage.
This gives a slightly lower noise floor because VR tubes are quieter than zener diodes.
Otherwise it's the same circuit as a PSE.
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Powder coated KT170 chassis...
(https://www.audiocircle.com/image.php?id=221778)
(https://www.audiocircle.com/image.php?id=221780)
Should be finished soon...
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I think the PSE would be the way to go really. Can you tell me about that Gas Voltage Regulated PSE chassis? I may be interested in this, but don't know anything about it. How it compares to the HO. Is it based on KT-88's?
I own both a HO Hot Rod KT88 and a PSE. The overall power difference is slight, but deep bass is more powerful and better defined with the PSE. I have run it with KT77, KT88, KT120 and KT150. Driving 91dB speakers in a small to moderate sized room (240sf).
Room size and desired volume level really decides how much power you need. When I had the same speakers in a large room (600sf) back in the days when I played the music loader, a 100 wpc amp was insufficient. Now I get by comfortably with 20-23 wpc.
I still have a 125 wpc Class D amp, and occasionally use it. Deep bass output and definition is better with it, even as compared to the PSE. And it sounds very good throughout, but I prefer the PSE.
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Thanks Tom. That's helpful info. My room is larger with vaulted ceiling but not huge. And ya the bass power dropped off a bit with the HO as compared to the class D's, but it is still very nice and once I adjusted to it I find it just fine. Sounds very balanced. Anyway I agree with your assessment and prefer the HO.
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New 300B Inspire prototype...
(https://www.audiocircle.com/image.php?id=221842)
(https://www.audiocircle.com/image.php?id=221843)
(https://www.audiocircle.com/image.php?id=221844)
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Are those original WE 300B's ?!?!?!?
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New 300B Inspire prototype...
(https://www.audiocircle.com/image.php?id=221842)
(https://www.audiocircle.com/image.php?id=221843)
(https://www.audiocircle.com/image.php?id=221844)
Very Nice..
Would like to here what makes up this amp (parts-Tubes)..
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Are those original WE 300B's ?!?!?!?
Hey genjamon, they are new production 300B's
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Nice!! What are your impressions of their sound relative to other new production 300B's available?
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Nice!! What are your impressions of their sound relative to other new production 300B's available?
Dennis say's they sound better than all the other new offerings.
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Wow, great to hear that assessment. Even the Takatsuki’s? That’s saying a lot.
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Let me rephrase that :duh:...The new WE 300B's sound better than all the tubes he has compared them to...Which probably does not include the Takatsuki's...
I have not listened to the amp yet, we have a listening session scheduled for next Thursday.
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That 300B looks great! Would love to hear it. Heck I wish I could hear all the Inspire amps, so I could pick my favorite.
Straitwire here is my 6/28/2016 amp. Can you tell if it has the power supply upgrade?
Also I never did get a reply from Dennis about a tube chart. I would really like that info if possible.
(https://www.audiocircle.com/image.php?id=222055)
This is the sellers photo from the ad. It's much cleaner now.
(https://www.audiocircle.com/image.php?id=222056)
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Hey Sonicjoy, sorry it took so long to reply.
Your unit does not have the IIPS (Infinite Impedance Power Supply).
I will ask Dennis about the tube chart that applies to your amp.
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Hey thanks a lot Straitwire! That would be great! I still have the stock tubes in it, and it sounds great, so have not been worried about rolling yet.
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Here you go Sonicjoy.
(https://www.audiocircle.com/image.php?id=222097)
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Awesome! Thank you.
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You're welcome Sonicjoy, I spoke with Dennis about your amp and there are some things that can be done to update your unit.
I brought home some KT170 tubes (thanks Dennis) and I'm very impressed with them.
Lately I've been using a 6BX7 input tube.
It has less gain than a 6SN7 but my phono preamp has enough output to compensate.
(https://www.audiocircle.com/image.php?id=222220)
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Wow! Those KT-170's are huge! They are a new tube to the market correct? Can I use them in the HO? They seem to be related to the KT-88, 120's and 150's which all work in the HO. I have been thinking of trying the KT-120's next.
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Hey Sonicjoy, Yes they're a new tube and they'll work in your amp.
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Cool! Just looked up the specs, and they look like they would be a very tight fit. They would almost touch each other and also the driver tube. 68mm dia.
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I have not put them in that chassis so I need to see if they fit or not.
Dennis has his in a 6V6'er chassis which is similar to mine.
It looks like there is about 9mm difference between a KT150 and a KT170.
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Please post when you get a chance to try them. Be nice to know if they fit. I do want to try tube rolling soon and why not start with these.
Should I try and contact Dennis about upgrading the amp, or is that something you can arrange?
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I have not put them in that chassis so I need to see if they fit or not.
Dennis has his in a 6V6'er chassis which is similar to mine.
It looks like there is about 9mm difference between a KT150 and a KT170.
6v6’er chassis is the same as my 6flv-v amp, correct?
Does that mean I can give them a try? :hyper:
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Hey Sonicjoy and david45, OMG I just spent a half hour typing a reply only to have it disappear. :duh:
I will post a reply in an hour or so.
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Okay, all of the layouts I have done on all the different amps we have built I made sure that the KT150 tube would fit.
The KT170 is a new tube and I had not looked up the size of it.
The KT150 is 59mm at it's largest point.
My KT170 tubes are 67mm at their largest point.
I have done some measuring using the template for the 8"x10" chassis that you have Sonicjoy.
The 6FLV-V chassis should also be on an 8"x10" chassis david45 unless Dennis used a 6.5"x13" like my chassis.
Sometimes Dennis uses a different chassis at the beginning of production of a unit before he settles on the chassis he wants to use on an ongoing basis.
I assumed that the KT170 tube would work on the 8"x10" chassis.
I think it will from my initial measurements but I don't have an 8"10" chassis at my house.
I will go to the shop tomorrow and mount tube sockets and plug in my KT 170 tubes and a straight glass input tube to make sure they fit.
Sonicjoy, I will tell Dennis you are interested in an update and I will let you know what to do.
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Hey Sonicjoy and david45, OMG I just spent a half hour typing a reply only to have it disappear. :duh:
I will post a reply in an hour or so.
When in the middle of typing a long post, every once in a while "paint and copy" it. This way if you somehow lose the post, just start a new post and "paste" it. What you lose is limited to what you typed since your last "copy".
Like you, I learned this the hard way. :?
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LOL! I think we all have had that happen.
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Sonicjoy, I will tell Dennis you are interested in an update and I will let you know what to do.
Great, thanks! I will wait to hear from you.
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Thanks sunnydaze I'll do that.
Hey Sonicjoy, I couldn't wait till tomorrow (I have no patience) I went to the shop and like I initially thought, KT170's will fit with regular 6SN7/6SL7/6BX7 tubes.
The input tube I used is the tallest and biggest around 6SN7 I have.
(https://www.audiocircle.com/image.php?id=222224)
(https://www.audiocircle.com/image.php?id=222225)
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HaHa! I get like that when I'm excited about audio stuff too. There is more room than I thought. Cool! I found some KT-170' being sold by "wpc1896" on ebay. Ever purchased from that seller? Also VIVAtubes has them. That's all I have seen so far.
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I'll have to ask Dennis where he got them.
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HaHa! I get like that when I'm excited about audio stuff too. There is more room than I thought. Cool! I found some KT-170' being sold by "wpc1896" on ebay. Every bought from that seller? Also VIVAtubes has them. That's all I have seen so far.
You can trust Warren (wpc1896). He's friends with my brother in Lakewood OH. I've been to his house and listened to his system when visiting the bro. Good guy. And yes, I've bought tubes from him. Completely reliable. :thumb:
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Thanks sunnydaze! Good enough for me.
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Alright order placed. Here I go down this rabbit hole. :lol:
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KT-170's are in the house! :thumb: They fit just fine with the 6SN7 input. Only had them in a couple of hours, but they sound great right out of the box. Very similar to the KT-88's. Looking forward to comparing them after some run in time.
(https://www.audiocircle.com/image.php?id=222431)
(https://www.audiocircle.com/image.php?id=222432)
(https://www.audiocircle.com/image.php?id=222433)
(https://www.audiocircle.com/image.php?id=222435)
(https://www.audiocircle.com/image.php?id=222436)
I think they look really cool too! Thanks for the help guys.
And by the way this is an 8X10 chassis.
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Nice photos looks like a pro.
Do you can inform us the KT150/170 glass bottle are thin as the 88 or are thicker ?
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Thanks FullRangeMan. I just used my phone and good light. The second photo was with the flash. Thought it would show some details better. The rest are without flash.
How does one tell how thick the glass is?
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How does one tell how thick the glass is?
Break one and measure. :thumb:
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That's kinda what I was thinking. :lol:
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Mucho macho looking toob. Very cool!! :thumb:
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looking good Sonicjoy!!
I hope you like them as much as I do!!
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So far so good. They sound Great! If they get better with break in that will just be a nice bonus. Been running them all day so far about 8 hours. They almost seem to have a bit wider sound stage than the GL KT-88's maybe just a touch more 3 dimensional. Very nice!
Straitwire have you had a chance to ask Dennis about upgrading my amp?
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Hey Sonicjoy, yes I spoke to Dennis about upgrading your unit and he says we can.
I will ask him about a shipping address.
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Cool! Any idea on wait time? I would hate to be without for very long. I would like to ship it right before he would be ready for it.
Aside from the IIPS what else could I expect to be changed? If you have an idea. Ballpark cost? I was guessing around $350 -400. Am I close?
Ship with or without tubes?
Thanks again for all your help.
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Hey Sonicjoy, Dennis is really busy right now filling orders for amps.
I will ask him when and where he wants you to send it.
Once he starts on the amp it should only take a day to update, then burn in overnight, then test and box up for shipping
The update will involve installing an IIPS and some other updates to the unit.
I will ask what the estimate for the updates will be.
You should ship the amp without tubes.
I suggest using FedEx or UPS.
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Thanks Straitwire. I'm not in any hurry so whenever he can work it in is fine. You can PM me with the details if you want.
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Ok, I'll talk to him this week and let you know what he says.
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Great, thanks!
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Hello everyone, I build Inspire audio equipment.
Hello Straitwire, I am hoping you can assist me with a tube rolling guide for Fire Bottle SE Stereo Tube Amplifier HO with the IPS upgrade. I recently bought the amp used, and well love it. My only complaint is no tube rolling guide. Thank you in advance, and for building such great gear.
My Best, Alan
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Hello Straitwire, I am hoping you can assist me with a tube rolling guide for Fire Bottle SE Stereo Tube Amplifier HO with the IPS upgrade. I recently bought the amp used, and well love it. My only complaint is no tube rolling guide. Thank you in advance, and for building such great gear.
My Best, Alan
See post 46 or Dennis ad at Ebay.
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Hey Alan, because your amp has an IIPS (Infinite Impedance Power Supply) you can run a 5Y3 a 5U4 or a 5AR4 rectifier or their equivalents because the high voltage (B+) on the output tube plates doesn't change regardless of which rectifier you use.
The B+ on the input tube plates is regulated so it doesn't change either.
The output tubes you can use are.
6F6
6V6
6L6
V350B
EL34
5881
6CA7
KT66
KT77
KT88
6550
KT90
KT120
KT150
KT170
The input tubes you can use are.
6SN7
6SL7
6BX7
CV181
Let me know if you have any other questions.
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I believe Straitwire meant 6CA7 not 6CA4 above.
You can also use 7581a output tubes, these are upgraded 6L6GC.
I've even used EL84 in my Inspire amps, but it requires an EL84 to 6V6 adapter.
You could also use Russian 6H8C/6N8S (equivalent to 6SN7) or 6H9C/6N9S (6SL7).
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Hey Tubefly, I'm running some KT170's and they're really nice.
(https://www.audiocircle.com/image.php?id=222814)
Here's some pics of the new 300B amp.
(https://www.audiocircle.com/image.php?id=222815)
(https://www.audiocircle.com/image.php?id=222816)
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I must say I agree Straitwire. The KT-170's are sounding wonderful in the SE HO. Very nice deep bass, and clean, detailed and smooth.
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You gents have convinced me to buy a pair of KT-170's. I'm currently using the KT-120's in my SET Universal, which I like a lot. Hopefully, these tubes will not be as unreliable as some of the early production KT 150s were.
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Well so far so good, I'm around 400 hours. Very happy thus far! Just enjoying the music! :thumb:
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That's good to hear. I can't wait to fire them up.
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(https://www.audiocircle.com/image.php?id=223398)
The KT 170's have arrived! Everything about this tube is big...big size, big clean bass, big deep soundstage, and big on detail/imaging. Loving it so far and the tube isn't broken in yet. This is my favorite output tube in my Inspire so far.
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Again I concur. They seem to do everything well. Glad you like them!
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Working on a phono preamp.
Built a prototype on an LP-3 chassis and put in some voltage regulator tubes for the heck of it.
The production prototype chassis is smaller and configured differently without using VR tubes.
(https://www.audiocircle.com/image.php?id=224080)
(https://www.audiocircle.com/image.php?id=224081)
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Very cool! I have been looking at the Decware ZP3 phono amp but would really like a matching Inspire phono stage.
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A post I may published elsewhere:
I made a trip East from Asheville, NC this past week and of course stopped by Cary for a visit with Dennis and Tony (Straitwire). Allen (Analog Addict) could not make it.☹️ As usual we caught up over lunch and then off for some critical listening, sharing of ideas, and also what has become a real treat, story time. I brought my latest speaker project, a single driver rear loaded horn. Pictures to follow. System components included the shop Rega P3 turntable> Assorted phono-preamps> Inspire CJ5 preamp (prototype)> The new Inspire 300b amp and a new Inspire KT88 SETamp (to be shipped on Monday to a customer). Speakers were various prototypes of the the speakers I brought which we have all been playing with.
My interests going in were to give the KT170s a listen. I knew Dennis had a pair. I also wanted to hear the new 300b amp with those new production Western Electric 300b tubes. I also wanted Dennis and Tony to hear my latest speakers. IMO, at present, these are the best yet from my shop. We hooked up the speakers before we went to lunch so they would be all warmed up when we got back. We had to wheel the shop 4 ways out and the pair with the Lii f15 drivers I made for Dennis a while back so as to make room to move around. There is a lot of equipment there at the toy factory, often just out of view of the pictures shown here.
Listening began with the 300b. WOW what a presentation. The best way I can convey the experience: remember the first time you heard a good SE setup? That feeling of realization regrading all you have been missing previously in your audio system listening life. Well damn if Dennis did not do it again with this one. There is no doubt that this amp bests his other offerings of which I own several. His SEP Firebottle amps are currently running about $2k (maybe the best bargain in hi-fi) and this 300b is $4k so it should, and it does in spades! As I sit here now listening to it in my listening room (yes, I took it home with me) I am just floored by the detail, fluidity, and timbre. The instrument separation is unmatched. Absolutely amazing presentation.
We switched to the KT88 SET (triode) amp next with the KT170s. BTW, same OPTs in both amps I was told. I will preface this with this statement. I have yet to meet a pair of KT 88/120/150s I cared for. I know there are many out there who love this class of tube but I always seem to prefer the 6f/l/v6 Pentodes. The KT 170s are the same for me. I switched them out for a pair of 6f6g from the mishmash of tubes there on the coffee table. There was the sound I know so well and absolutely love from my other Inspire amps (custom Universal, PSE, and 6V6er). Wonderful! If the fellow who is having this amp shipped on Monday is here reading this. You are in for a real treat. This is a wonderful amplifier. But IMO, get yourself some 6f6s to try.
Listening was through the various cabinets and with various drivers (Fostex 4”). Dennis has been in love with the FE126NV for a while and we have each been playing with the FF125WK. No firm conclusions were made but I was coerced into leaving my latest cabinets. You’ll have that there at the toy factory. I am missing them a lot as I sit here.
After a lot of listening, laughing and sharing, we seem to find ourselves engrossed in Dennis’s stories of times past. We went strolling down memory lane with him and his before and after Dentron Radio days. Mid to late 70’s. He pulled up some youtube videos on his phone which brought up more stories. Maybe we can get a podcast together someday. The man has really seen and done a lot in his lifetime.
Anyway, I had to get on the road and they each had to get home to their families. Another great visit was over. As always I look forward to the next.
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BearCity,
Thanks for the update on your recent visit to the "Toy Factory", sounds like an awesome experience. I am glad I stumbled across the Inspire amps a few years back. I love the fact that I can roll in a variety of tubes, the craftsmanship, and the engineering that goes into his labor of love. I Look forward to future updates.
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I have a pair of Inspire MB12 monoblocks from 2014 and I absolutely love them. They drive the top part of my GR Research Super 7 speakers better than any other amp I've heard. The Super 7's are a perfect match for them, with the planars covering 150hz to 20khz, 97db efficient and ruler flat 8 ohm impedance, and all bass is offloaded to a separate, self powered bass section.
In my setup the MB12's are simply exceptional.
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I'm almost done with the new phono preamp.
I ordered some caps for it, they should be here Thursday.
Once I complete it I'll give it to Dennis so he can finalize it.
(https://www.audiocircle.com/image.php?id=225862)
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Fired it up, sounds great!
(https://www.audiocircle.com/image.php?id=225973)
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:thumb:
What I like in Dennis amps are he use the big tone 6SN7 octal :weights:
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If you could post a picture of the inside of your amp I can tell you if it has an IIPS.
I change the circuit in my amp whenever Dennis comes out with a new mod or with an entirely new design which includes output transformers.
It has been several years since I ran an IIPS so I really can't comment on improved bass.
The Gas Voltage Regulated PSE uses 0A3 voltage regulator tubes instead of zener diodes to regulate the high voltage.
This gives a slightly lower noise floor because VR tubes are quieter than zener diodes.
Otherwise it's the same circuit as a PSE.
Hi Straightwire,
Can you elaborate on why you don’t run the IIPS?
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Hey roscoe65, I modify/upgrade my amp to the latest circuit that we're building so Dennis and I can discuss it's performance and characteristics.
I like the IIPS and I've switched back and forth several times.
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Would you characterize the IIPS as a worthwhile upgrade?
Could you relay your experiences with the different circuits?
Thanks,
R
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My experience with all of these circuits is that they all sound different but saying one is "better" than another or is an "upgrade" really isn't the way to look at it.
I like to use the ice cream analogy.
The flavors I like may not be the ones you like but as a new flavor is introduced one could say it's "better" to them than another.
This is subjective so I have to choose my words carefully.
I have listened to just about all of Dennis's designs, and some of them work well with my system and some not so much, but only in presentation not sound quality.
As for me, I tend to prefer Pentode operation over strapped Triode.
But having said that, I appreciate strapped Triode's midrange presentation.
The midrange "hump" from strapped Triode can bring voices and solo instruments to the front, producing more intimacy with singers or instruments.
Pentode operation tends to produce more articulate lower midrange and bass, and puts things in there "place".
But once again this is subjective and depends on a lot of different factors.
Your choice of music, your system, your room, your preferences, and too many other factors to list here.
To answer your question about updates (I really shouldn't call them upgrades), Dennis is really busy building amps and many of these updates require tearing down the unit and that just isn't practical.
Sorry to be so long winded.
If you have any more questions or if I haven't fully answered your questions let me know.
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Trying to get in touch with you @straitwire.
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Hey ilikerecords, whatsup?
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Hey ilikerecords, whatsup?
I've messaged you. Was just giving you a heads up.
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I give up.
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I give up.
Straitwire went and got himself a day job.🤪 not sure how often he checks these threads. I’ll nudge him and see if I can get you a response.
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A post I may published elsewhere:
We switched to the KT88 SET (triode) amp next with the KT170s. BTW, same OPTs in both amps I was told. I will preface this with this statement. I have yet to meet a pair of KT 88/120/150s I cared for. I know there are many out there who love this class of tube but I always seem to prefer the 6f/l/v6 Pentodes. The KT 170s are the same for me. I switched them out for a pair of 6f6g from the mishmash of tubes there on the coffee table. There was the sound I know so well and absolutely love from my other Inspire amps (custom Universal, PSE, and 6V6er). d they each had to get home to their families.
To clarify, you found the KT170 to sound very similar to the KT88 / KT120 / KT150 family of tubes?
That's what others have told me. I own GL KT88, TS KT120 and TS KT150. There are some subtle differences, but I find all three of these to sound more alike than different in my Inspire KT88 HO and in my Inspire PSE. I never popped for KT170 and now a quad of them costs a small fortune. I just didn't have faith that they would sound all that different and they would produce no extra power in either amp.
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I think you're spot on about the KT 170. If you like KT 88 strapped in triode or single-ended, then the KT 170 gives you a wee more bloom, imaging, and space (insert your favorite adjective) IMHO. It was an excellent option but not at these current prices. I got mine pre-sanctions at $170 for a matched pair. Even at the presanction price, I would argue they are overkill for my Universal Amp. Prior to the KT 170's, I rolled in a pair of KT 120's which were similar as I would imagine the KT 150's would be. The upside is that these tubes will last a long time in an Inspire amp. They are not run all that hard in comparison to their rated output.
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I was fortunate to pick up some slightly used (roughly 150-200 hours claimed) KT120 and KT150 after they had been used at an audio show. This was last year. $30 each for the KT120, $40 each for the KT150. They tested & looked new.
I like both types. Not as warm or midrange sweet as some other tubes but big open soundstage, neutral and well-defined with the strongest, clear bass I've heard from any tube in my gear.
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You got an excellent deal, especially on the KT150's. I would agree with your experience with the KT 120 tube; I'm a big fan of the 88 series tubes -big tube = big sound.
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Another tube I really like in both of my Inspire amps is the Gold Lion KT66. It produces a punchier, more dynamic sound. I've liked all of the 6L6-type tubes I've used, this one is my favorite of that group. While some always favor vintage, and for good reason, the Russian factories do a good job on 6L6 tubes. The Tung-sol 7581a & KT66 are both very good and the GL KT66 (which is significantly different from the T-S) is better yet, IMO.
I've read posts from three or four long-term and well-regarded tube amp builders who all sang the praises of the new production Russian 6L6-types. Saying that on their test gear and to their ears, they are right there with the vintage GE and other old production.
Several Inspire owners prefer the smaller 6V6, and even 6F6. I have several of each and I find them to be fine tubes which produce a pleasant sound, but they don't sound as "magical" to me as they seem to do for others.
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I rolled in some NOS RCA metal can 6L6's and they were very good. I have also tried some metal can 6F6, also a sweet-sounding tube. I preferred the 6L6 over the 6F6; especially when driving my speakers full range (GR Research NX Studio Monitors).
Since I listen mostly nearfield I prefer the larger pentodes when listening in full range. Crossed over to subs; I find it doesn't matter much which tubes I roll in. I also have a pair of the original Soundfield Monitors, with KEF COAX's built-in sealed subs. Any tubes I roll in with these speakers sound great.