I'd be happy to check your tube for you. I have a calibrated Hickok 533 mutual conductance tester, and plenty of Inspire designs to do a real world test. I'lll send you my snail mail addy in a PM and we'll get you squared away...:thumbsup:

Awesome, thanks!

Great activity in the last week.
Tube rolling in Pre.
New finding: the CJ5 reacts much more strongly to different tubes than the 2030.
With the CJ5 it is possible to change the sound in different ways in all directions and to find a perfect result for the respective set up.
The 2030 hardly rules on the different tubes. Only subtle changes can be heard.
Phillips' 509 and a one pair Cunningham 301s seem to have a problem. They sound softer, with beautiful voices, but lack control and contour in the bass range.
I think they are at almost the end of their lifespan.
71 and 171 should actually be the same tubes in different designs, but the stage with the Ken Rad 71a is a little smaller and she plays with less volume. Neither of them are my favorites.
The other pair of Cunningham 301 and the 01A of Sylvania and Silvertone play at the same level, here is almost no difference to be heard. For me the best tubes in the Pre.
Cunningham's 112 plays very similar in size of the room and resolution, but timbres are slightly golden. slightly warmer, but not exaggerated. Very nice with voices and acoustic instruments.
The best alternative for me.
With the 0A3 I could not see any difference between Sylvania, the mil. version and the Orion GT.
In the case of rectification, the size of the room changed slightly. GE and Mullard very close to each other in terms of timbre and size of the image.
The EML makes the room slightly larger and airier, but without changing the size of instruments and voices. The instruments are all in the right place. Women's voices have the right volume that suits the body, and do not appear artificially enlarged. The control in the bass range is the same as with the other two rectifier tubes.

https://live.staticflickr.com/65535/...9e36761b_k.jpgIMG_20220924_122246 by cgn- dt-n, auf Flickr

https://live.staticflickr.com/65535/...c917a972_k.jpgIMG_20220924_122252 by cgn- dt-n, auf Flickr

I’ve got another great budget combo featuring the GE 6bg6ga. The brown base Sylvania 6sl7wgt gives back the top end that the much more expensive round plate tungsol 6/12sn7 lacked. The Tungsol does give a satisfyingly thick sound, this particular 6sl7 has a more balanced sound overall. The Sylvania tube is pretty easy to get for around $30. It is a pretty smooth sounding 6sl7 IMO. Some of them can get overly bright and glare but this particular combo is great.

I may have found my ideal tube combo
 

I have been cycling tons of tubes through my KT88 Firebottle, had a whole thread about some of my adventures. One output tube that I kept coming back to is the Cossor 807.

https://www.isaharr.com/wp-content/u.../IMG_0451.jpeg

https://www.isaharr.com/wp-content/u.../IMG_0453.jpeg

I have seen them labeled as GEC and Cossor, as 807, ATS25, and VT60. I have also seen them with a brown base instead of the ceramic.

In my system they are consistently the most open, spacious, and enjoyable of all the tubes I have tried. I have 807 tubes from Sylvania, Fivre, Mullard, Mazda, and Firenti. All of them sound good with the right combination off tubes but the Cossor always shine through for me. The accuracy of timbres and revealing quality is addictive. I use a 5u4gt rectifier either an RCA or Electro Harmonix, I can't tell any difference between them.

The input tube has a dramatic impact of course. My go to inout tube is the 14n7 clear glass. It has a very similar character to the Cossor tubes. The combo doesn't have any weaknesses tonally. Highs, mids, lows, are all where I want them. I believe the 14n7 isn't just the 12v version of their similar looking 7n7 or regular 6sn7. It sounds deeper and clearer than the other Sylvanias. I'm pretty sure it is the 12v version of the sought after metal base 6sn7w. I don't have one to compare sonically but they look the same to me, down to the copper support rod.

If I want to warm things up I can use the grey glass 14n7 or the MOV CV1102.

I never thought I'd say this but I think I'm done tube rolling with this amp! It sounds so so good! Ironically, I actually have another amp coming next month. This one isn't made by Dennis, had Thomas at Ultrasonic Studios make an amp to my demented specs. It is a push pull amp designed specifically around tube rolling. I'm going to keep my KT88 Firebottle as my single ended amp. have a feeling that the push pull simply won't sound the same. I have talked to Dennis about the possibility of another amp in the future but we will see...

Anyway, I'll keep checking in here to talk about these wonderful amps but don't be surprised if I become scarce next month when my new toy comes in lol.

FYI, if anyone is interested in trying the Cossor 807, the best prices I have found have been from Vintage Electronics https://www.vintage-electronics.co.u...alve-tube-nos/

Not affiliated of course but the prices on ebay were making me scratch my head. Know they were available at a more reasonable price. Still pretty good deal IMO, especially considering what new tubes and popular NOS go for.

Edit: Forgot the price, 45 Pounds.

Update:

Many thanks to Analog Addict for confirming my 5AR4 was DOA. The eBay seller has agreed to refund, so basically no harm done.

I finally got the next tube type on my list to test—the Gold Lion KT77 (New production). It does look pretty and at first blush, I seem to get both power/dynamics as well as transparency. Does anyone know the break-in time for this new production tube?

[IMG]https://live.staticflickr.com/65535/...689aaaf0d3.jpgGold Lion KT77, Sophia 274b, Sylvania GTB by Tube Dad, on Flickr[/IMG]

[IMG]https://live.staticflickr.com/65535/...a2515d1a16.jpgKT77 in the Dark by Tube Dad, on Flickr[/IMG]

I have heard plenty of good things about those tubes. Haven't tried them myself. I do really like their KT66. I'm not a big believer in long burn in times. My audio memory simply isn't good enough to reliably remember "the sound" from weeks ago. I do seem to recall that after a few days I thought they stopped changing. No idea how many hours that was.

Yea, that’s why I pulled the trigger—ton’s of good reviews as one of the best new production Gold Lion tubes out there. Upscale Audio (where I got it from) is recommending a 100 hr burn in based on feedback they have received from their customers. I have also heard at least 50 on one site. Seems like par for the course.

One idiotic thing I did is when I removed the RCA 807’s from their adapter, I forgot to first detach the top plate cover and with the force I applied, the top cap snapped the top plate cover right off. I can plop it back on but not sure if it’s safe to put it back on in the amp.

Oh man that sucks. I have 3 807 tubes with problem caps. 2 are loose and one came off completely. I'll glue the loose ones back on, that should be fine. The problem is that the wire coming out of the top of the tube is actually soldered. If the cap comes off that tells me that the solder joint was broken as well. I'm not sure if the remaining wire is long enough to resolder. My Cossor tubes are about $50 a piece so maybe worth trying to save but I'm not motivated enough to try right now. Not sure I would bother for less expensive tubes.

It just struck me last night that I’ll be at Decware next week where there are going to be plenty of ppl skilled to perform surgery on the tube. So I sent a picture and at least one member is going to bring his solder, iron, and epoxy to seal the deal.

Woo! that's awesome! I think I could probably handle doing it myself if I had a soldering iron or even a place to do it lol.

You might have already answered this, if so sorry. Are you taking your amp there?

Unfortunately not. I’m flying and due to weight and space restrictions, that just wasn’t practical. It might have been different if I was driving.

Update: Another attendee of the fest has agreed to bring his solder, iron, and epoxy to fix the 807.

I switched over to the Mullard 807 just because it has been so long since I last heard it and had never used it with the 14n7. Compared to the Cossor these sound "smoother" and a little more reserved. Very pleasing sound, possibly more laid back. The Cossor still has more detail and therefore more space. The Mullard tubes are about 1/3 less expensive so fantastic bargains.

Hello folks. I’m new to the forum and have spent several hours reading through this long and informative thread, primarily looking for tube recommendations for an Inspire KT88 SEP that I purchased over the weekend.
I’m using a pair of Decware Zen Master clones, an open baffle / fullrange driver design rated 100dB / 8 ohm.

I’ve a number of tube options on hand that I’ll begin experimenting with soon, but I wondered if someone might be willing to suggest a combination of output, input/driver and rectifier tubes that would deliver a warm, lush sound in the way of classic designs like the old Leak Stereo 20 that I remember so fondly, or even some of the older CJs?

With the stock GL KT88 the sound is detailed, dynamic, open/transparent, but lacks a little tube warmth and bloom.

Having only acquired the Inspire a couple days ago I haven’t played around much with cables and ancillaries, but I like what I hear so far and I’m just looking for a ‘quick-start’ to get me going in the right direction.

Many thanks!

Rooze… Welcome to AA! :wave:

Hmm, think it’s going to be tough to get that kind of sound out of the Firebottle. It’s just such a different design. Off the the top of my head the “warmest” combo I’ve had in mine is probably Tungsol 6k6gt with a Raytheon gf8g input tube. Oh and a Tungsol 5w4gt rectifier. I also think the GE 6bg6ga is a pretty warm tube in the Firebottle using a 5u4gt rectifier.

In the end I think the KT88 Firebottle will always sound more open and “transparent” than classic push pull amps. Personally I think those old amps ended up masking the music and the Firebottle lets it come through. I once loved a system built around a McIntosh mc240 and big Spendor BBC monitors. So warm, so lush! But after a while I realized that everything sounded like that on that system. I like chocolate cake but it turns out I can’t eat it for breakfast lunch and dinner.

One of my absolute favorite things about the Firebottle KT88 is how many shades of sound you can get with different tubes. I’ve had a blast trying out many different tubes. I started a thread in this forum just about tube rolling.

Hi Rooze,

I don't think it's because of the GL KT 88. They solve well but have no bright sound and a slight emphasis in the upper bass range.

This should actually match your sound description.

KT 170 and RCA 6L6 are similar. slight overemphasis in the upper bass range.

Play more with the driver tubes.

6SL7 more heights
6SN7 balanced
6BX7 more bass

I finally managed to listen to the Marconi 6V6GT.
operated for about 80 hours. Very balanced, great with any kind of music.

If I hadn't heard the Fivre 6V6 GT and my Kron KT88 as a comparison, you could listen to music very well in combination with the Melz and Sylvania 6SN7, long-term suitable, nothing annoys.

Thanks for the feedback and suggestions. I’ll start rolling through some of the tubes I have here for starters, and see where that takes me. I’ll also throw in a tubed preamp to replace the fairly clinical sounding W4S preamp that I started out with for convenience.

I have to say that this is a fantastic little amp! I wasn’t expecting the level of resolution and dynamic ability from such an inexpensive component. I’ve a pair of 300b monoblocks that use a quad per side and it’s great to have a worthy alternative that isn’t costing a few bucks in tube life whenever I power it up.

I’ll post a picture of the system when I figure out how.

Cheers

While not in a an Inspire amp, I've always found the 6550s and other derivative tubes (EL34s, 7591s, KT77s, etc.) to provide a more 'liquid' mid-range. Of course, the bias has to be set properly for each different tube.

Terrific speakers. I've kept my pair longer (almost 4yr & counting) than any other set of speakers I've owned in the past 30+ years.

I almost always prefer old stock US and Euro tubes. I tend to find many new manufacture Eastern bloc tubes harsher and less warm then the older tubes. If you’re stash is lacking in these tubes, I’d start with some 6F6s or 6V6s and see how you like them before moving on to the more expensive models…

But as suggested, don’t neglect rolling the driver tubes as well.

I know I said I had found my combination but I was able to get a tube I never thought I'd be able to! Got in some Marconi b63 tubes. If you're not familiar, Marconi, Osram, and GEC are all the same company. The b63 is equivalent to a 12sn7. The b65 is the 6sn7 equivalent. I wouldn't recommend looking up the price of b65 tubes if you have any heart conditions. The b63 is much more reasonably priced (as all 12v tubes are) and I got some deals on them on top of that.

I got a pair of old school Marconi b63 (very different years and glass types unfortunately) made by MOV and a pair of tubes branded Marconi b63 but actually made by Fivre. The originals are a little smoother, there is a little bit of a glare/brightness in the lower treble with the Fivre. Having said that they are more similar than different. On the warm side, very detailed, more restrained highs, outstanding bass extension and definition, and there is a great depth to the image as well. The standout feature off these tubes has to be the timbre reproduction though.

Mind you, I wouldn't pay the going price of the b65 for the sound. I get most of the way there with the grey glass 14n7. Still, if you have deep pockets, the b65's reputation is well deserved. If you want the sound without breaking the bank get some b63 and an external heater supply. Still not cheap but the cheapest way to get hear the best versions of the *sn7 tubes.

Not sure if anyone noticed but Steve Huff Photo and HIFI has the Inspire 300b amp for review. This should be interesting. First to my knowledge, that an Inspire amp has gone to a well known reviewer. He released a sneak peak to members only at this point, but I expect it to be public later this week.

While nice to get a review, for me, Steve Huff is one of the most "Uninspired" of reviewers. Hope he does a better job than usual with the Inspire 300b.

Update: Over 120 hours on the new production Gold Lion KT77’s and I’m really digging this power tube. Really really good. After falling in love with 6V6, I was a bit unmoved with the 807, but the KT77 is stopping me dead in my tracks just like the 6V6. It will be interesting to go back to them soon to compare, but I’m no rush.

It's always fun to find new tubes to enjoy. I think I mentioned it earlier but I really didn't like those 807 tubes when I first heard them, to the point that I was going to throw them out. Later on I was able to use them with a different input tube and really enjoyed them. It's all about the combinations!

I finally got some adapters for the 5b/254m, a shrunken down 807 from STC with a loctal base. Didn't really like them with my usual suspects of input tubes. The Raytheon 6f8g t plate came close but I still wasn't satisfied. On a whim I tried a clear glass RCA 6sn7. I haven't any luck with RCA tubes in this amp, input or output. Much to my surprise this combo is great! A satisfyingly thick sound. Sometimes it pays to be insane and have scads of input tubes to try:)

The review dropped this morning:

https://youtu.be/l-lRvZVyZ0o

Seems like he put in a lot of work and effort to make a video that amounts to a few posts here lol.

He also has a pretty detailed write-up that I also appreciated: https://www.stevehuffphoto.com/2022/...by-dennis-had/

Quick questions:

Does anyone know the weight of the Firebottle KT-88? I can’t recall. I am thinking of buying the isoacoustics ZaZen isolation platform and the entry level platform has a weight capacity of 25 lbs.

Fielding a question for someone who is interested in the 300b amp. Will Dennis consider selling it without the 300b tubes and hence bring the price down? This gentlemen either already has 300b tubes or looking to purchase a cheaper variety but is interested in pairing it with the amp. He has no need for Western Electric tubes and hence the question.

I finally got some adapters for the 5b/245m tubes. They are a mini 807 with a local base. Super cheap, the adapters cost more than the tubes! Not something a sensible person would do. Luckily no one has ever accused me of being that lol.

Had trouble finding an input tube that worked well with them and had started to wonder if they just weren't very good. Like every other tube I've tried the magic is in finding the right combo. This one required a tube that I had never had any luck with. The RCA 6sn7gtb with silver lettering never sounded right with any output tubes I tried. Until now.

The combo is rich as opposed to my regular combo's (Cossor 807 and Sylvania clear 14n7) open and deep sound. Great for electric guitars and any music you want to emphasize the "texture" of the sounds. Being a nut when it comes to accumulating tubes pays off again!

FYI there is an Inspire triode Hotrod on eBay right now. I’m curious what the sound difference is between the SET and SEP sound apart from whatever a little more power can do.

Exciting times at the Toy Shop. Look what just came in...

https://live.staticflickr.com/65535/...8d212489_b.jpgUntitled by analog addict, on Flickr

https://live.staticflickr.com/65535/...e2573e12_b.jpgUntitled by analog addict, on Flickr


You may have read or seen the Steve Huff review on the 300b. Well, I'm here to tell you that not only is that amp the bee's knees, but there is something potentially even more spectacular on the horizon....The PSE 300B.

It will feature a 5U4G rectifier, 3 VR-75 regulators, a 396a predriver, a 6SN7 driver and two 300Bs per channel.

You heard it first here. Pix soon......:music:

Whoa! That sounds like an amazing amp. Don’t think I’ve ever heard a PSE 300b amp before. One of the best systems I have ever heard used a push pull 300b and I’ve had several PSE amps but not the combo lol. Dennis is heading back to the super high end!

Also that is the largest pile of WE stuff I have ever seen!

Whow,

a WE300b PSE in times of inflation and recession?

Highest respect for such a decision. This can only be afforded by someone who is one of the best of the best!!! Phenomenal.

Quality, albeit expensive, prevails over cheap and bad from the discounter.

As with a car engine, a little more displacement and power can never hurt.

If I didn't already have the big WE300b DHJ and was very happy with it, I could get weak.

He plays with the LP2030 the Burmester combination 088 PRE and 956 MK2 Power as well as Soulution 325/311 and my Symphonic Line "Power Source 2" with update in 2019 with the new double shaft rectifier module apart from the maximum volume in the ground!

Since I don't need too much power with my 93db horn speakers, I would be more interested in a PSE 46 or 45/2a3.

But who knows what the future will bring.

So I have to dream a little and wait for the ordered phono station.

I borrowed some rectifiers and 6SN7 from a friend to play with the KT170 in the KT88SEP amplifier.

One combination was good, this inner nervousness in the music had disappeared. But it was a 5R4 and not a 5U4.

Does anyone have experience with this rectifier?
In terms of parameters, it should be between 5AR4 and 5U4.

can I operate the 5R4 in the amplifier or do I get problems with it in the long run.

5R4 and 5U4 are not all that different. You can use it without any difficulty.

Dennis has made PSE 45s before, although I don't remember seeing a PSE 2A3.
From my own experience with the first PSE 45, it's everything a regular 45 amp is, with twice the power.

Speaking of the 300b amp...

https://live.staticflickr.com/65535/...2e7479ea_b.jpgUntitled by analog addict, on Flickr

https://live.staticflickr.com/65535/...9966aacc_b.jpgUntitled by analog addict, on Flickr

https://live.staticflickr.com/65535/...14103d85_b.jpgUntitled by analog addict, on Flickr

Or how a 300b is born...

Speaking of born, here's the first look at a brand new bouncing baby PSE 300b...

https://live.staticflickr.com/65535/...415d13e2_b.jpgUntitled by analog addict, on Flickr