AudioAficionado.org - Dennis Had Inspire Amps

I've been through some tube rolling with my KT88 amp and have generally allowed extended listening periods (weeks) each time to hear the subtle changes as well as the larger, more obvious changes that come with rolling.

Well, as I've been going through my inventory of tubes (way too many) to sort out exactly what I have, in and amongst the caddie of preamp octals I found a beauty of a NOS Sylvania 6SN7GT with perfectly matched sections and ultra low noise test readings.

I thought I'd swap out the RCA I've had in there just to see what difference it would make thinking it wouldn't be huge. Seriously wrong. Massive change in detail, separation and soundstage. Beautiful. It's not coming out of there. I'm looking to see if I have another one.

This is paired with ordinary Sovtek KT88's & a Mullard 5AR4. I'll leave this config in there for a while and then drop in a pair of GL KT88's that I have and give it some time.

These amps respond to driver changes to an even greater degree than any of my other amps do. Really surprising.

I have two Sylvania 6SN7's, a G/B and a GTA. Both sound great, so I know what you mean. The other great 6SN7 is a Super Radiotron Mullard (GTA) which is perfect to tame the resolving exuberance of the 6L6 GC's that I really like. Finally, the Sylvania 6SL7 GT is also very good with the 6V6 GT's. I've tried TungSol 6SL7's, both NOS and current production, to no avail. YMMV

Musica Amantem

02-23-2016 07:30 AM

Quote:

Originally Posted by MWalt (Post 761895)

Thanks for the welcome. I don't have any modern 6L6's, but I do have a pair of the Soviet 6N3C (1971) that aren't the coin base type which is superior. However, I do like them. They are really nice sound sounding Soviet old school tubes. I have tried the following tubes that I have on hand:

RCA Black Plate 6L6GC (NOS)
GE 6L6GC (NOS)
Gold Lion KT88
Tung Sol KT120
6N3C (NOS)

Phillips 5Y3GYS (NOS)
Tube Store 274B (Shuguang?)
Mullard (badged Westinghouse) 5AR4 (NOS)
Brimar 5Z4G (NOS)
GE 5Y3GT (NOS)

6N1P-EB (Rocket-1971) (NOS)
Sylvania JAN 6189
Sylvania 12AU7 (NOS)
CONN 12AU7 (NOS)
The mystery 6CG7 (has to be old school because it has bad yellow labeling)

I am still trying to figure out my favorite combinations, but it is a slow process because I change one type of tube at a time. I know that I really like the 6N1P as a driver, the RCA 6L6GC blackplate is "special" and the Gold Lion KT88 is a really good modern tube IMHO. I am about to go nuts on another tube buying binge and will keep you posted.

Mark W.

You have some great tubes there! I also have the Brimar 5Z4 and it is currently my go-to rectifier in any output tube selection. Try the KT88's with the Westinghouse-labeled Mullard (I have the Westinghouse-labeled Amperex-Holland) 5AR4's or the 5Z4G. In my rig, both pairings are very good. Of course, I would use the 6SN7 input tube that opens up the KT88's to my liking. YMMV. BTW, I have not tried small triode and diode input tubes in this amp yet. I'm not sure it will take them.

x3workshop

02-23-2016 12:33 PM

Quote:

Originally Posted by pstrisik (Post 761934)

Is that the Sylvania "Chrome Dome"? I had one of Dennis' Cary preamps - top of the line SLP-05 - for a while. Those were a favorite of mine for some of the sockets (took a total of 8 tubes - 6 not counting the headphone section).

Not a 'Chrome Dome', but a single bottom getter w/triangular shiny blackplates. It's pretty awesome.

FloridaBoy

02-24-2016 08:37 AM

Quote:

Originally Posted by Musica Amantem (Post 761773)

"I have read nearly every page of this thread and have not seen much reference to those that have used the 6L6GC power tubes."

Well, welcome to the 6L6 GC club! I for one love the Russian 6L6 GC's with about everything, including running them when my preamp carries 56's: Plenty of detail, nice bass, no brightness whatsoever. I reported a few posts back that, to me, in my rig, this is the most resolving tube at hand. Thanks FloridaBoy for making me aware of the 6L6 GC. I'm ordering the Gold Lion KT66 hoping it will combine the traits of the 6L6 GC and the GL KT88.

I've run these beauties with every rectifier without any issues, so I would say the rectifier you're using is no problem. Those RCA's sure look great!

They are actually Russian 6p3s-e with the gold grid. The pre 90's tube are the better ones.

Musica Amantem

02-25-2016 06:46 AM

Correct. Well, these sound very good, so much so I prefer them over my RCA black plate, gray glass 6V6 GT's.

manise

02-26-2016 02:31 AM

Hello,

I own the IFA-1, currently setup with TungSol Reissue EL34, Tungsram ECC85 and RCA 5Z3. I love the sound of the amp, but i am facing an issue... the amp produces a loud hum... you can hear it 8-10 feet from the speakers... I changed the power tubes, rectifier, small tube, all to no effect. Does any of you encounter this issue? What's the remedy to the hum?
I purchased the amp thru the auction site, unfortunately, I live in Singapore and the shipping cost prohibit me from sending the amp to Dennis, for him to check and repair. Any advice is greatly appreciated.

Thanks,
JT

Simonatsea

02-26-2016 05:06 AM

http://i128.photobucket.com/albums/p...psnsbizjty.jpg
http://i128.photobucket.com/albums/p...psj2n8tgnx.jpg
Well, I have finally set up my inspires. And I must say the my eclipse my IFI Retro 50 by a large margin. I was not expecting this as LS50 are notably power hungry. Although you might not reach max db with this setup I listen in the evenings at 9-10 o'clock on my Dact LP-2 and it is perfectly blissful. Now, anyone interested in an IFI Retro 50???? Dennis is truly a master at his craft! Any news on the phono stage? MM/MC? Price?

x3workshop

02-26-2016 01:50 PM

Quote:

Originally Posted by manise (Post 762657)

I would reach out to Dennis. He may know what the best procedure is for troubleshooting it. Also, if you just bought the amp from the auction site you should be able to return it.

BearCityUSA

02-26-2016 02:38 PM

Quote:

Originally Posted by manise (Post 762657)

A ground loop maybe? Does it still have a hum with the preamp/source disconnected?

MWalt

02-26-2016 09:15 PM

Quote:

Originally Posted by manise (Post 762657)

Something has to be wrong here. My amp/preamp are dead quiet. I agree with the advice to contact Dennis.

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