Dennis Had Inspire Amps

[Musica Amantem]

One of the very few, genuine soul nourishments ... Life is full of demands and constraints and music is always the oasis, a one-to-one relationship, independent of others ... and still legal!

[jdandy]

Originally Posted by Musica Amantem

One of the very few, genuine soul nourishments ... Life is full of demands and constraints and music is always the oasis, a one-to-one relationship, independent of others ... and still legal!

Musica Amantem.......

[x3workshop]

Originally Posted by Musica Amantem

One of the very few, genuine soul nourishments ... Life is full of demands and constraints and music is always the oasis, a one-to-one relationship, independent of others ... and still legal!

A narcotic for the soul.

[CoGT3]

Originally Posted by CoGT3

I am giving them a try. Ordered a single Psvane CV181 II, grey bottle this week for the incoming PSE. Was going to try H Salience as FloridaBoy had suggested but they only had pairs available in the Premium grade.

Funn_Chen/tube-sale.com seems to have a similar setup to Grant Fidelity, namely taking factory tubes from Psvane and running them through an Amplitrex AT1000 before shipping from China. Theoretically screening out the bad ones and separating the the premium from standard grades. Couldn't find any bad feedback on the auction site, so we will see.

Well tube arrived already. Not bad, 10 days from sale to delivery from China. Tube looks great as others have said, solid construction. In a separate box instead gift but had test sheet included. Gonna through it the 45 set to burn in it while waiting for the PSE.

[straitwire]

Originally Posted by Rosco65

Could you give your impressions of the change from using a cathode follower to using a regulator tube?

Sorry I took so long to reply, I did not want to answer your question until I was certain about how the unit sounded without the cathode follower. I have made too many changes to my setup in the last month. So I listened to it when I could and I thought it sounded fine but still wasn't sure, didn't know why. I took it to the shop today and Dennis ran some tests and sure enough it was rolled off with long output cables (12ft) as expected, but it was still a little rolled off with 3ft cables. I don't have any numbers but roll off was above 20k into a 100k load and above 50k into a 10k load so it may not matter to you. I should have written them down but he ran a lot of tests with different loads and well...sine waves don't lie. so I have removed the VR75 and put the cathode follower back in, I will listen for a week or so then switch back and see if the "sparkle" went away. the VR75 only dropped 75 volts so it replaced only the last diode not all of them so it probably didn't really affect the sound, but it looks cool! if you used two of them you could have true gaseous regulation though

[Analog Addict]

Originally Posted by straitwire

Sorry I took so long to reply, I did not want to answer your question until I was certain about how the unit sounded without the cathode follower. I have made too many changes to my setup in the last month. So I listened to it when I could and I thought it sounded fine but still wasn't sure, didn't know why. I took it to the shop today and Dennis ran some tests and sure enough it was rolled off with long output cables (20ft) as expected, but it was still a little rolled off with 3ft cables. I don't have any numbers, I should have written them down but he ran a lot of tests with different loads and well...sine waves don't lie. so I have removed the VR75 and put the cathode follower back in. the VR75 only dropped 75 volts so it replaced only the last diode not all of them so it probably didn't really affect the sound, but it looks cool! if you used two of them you could have true gaseous regulation though

Actually we tested both Straitwire's pre amp and mine, and found that with a 12' cable, there was a roll off, but it was only 3 db at 50KHz. Dennis said that at least at 12", there was no issue and that 20-20KHz was unaffected. We had a long listening session yesterday, and I'll document that in a separate thread....

[Analog Addict]

Went over to Dennis' yesterday to try and finalize my PSE 45 amp design, and to check out some new developments. Dennis was just finishing up a new Fire Bottle with the IIPS mod.






He said that with KT-88s it was putting out 10 WPC with absolute peak power close to 20 WPC...



Here's the upskirt view.....



Here's the finished product during it's first few hours of life....





And here's the current two completed amps, the Fire Bottle and a Sweet 807 running 5933's.....



We ran a lot of output and driver tubes through the Fire Bottle, and out of everything, the metal based WWII Sylvania 6SN7W and a pair of early 60's vintage Tung Sol solid grey plate 6550's were the fan favorites....

[Analog Addict]

Originally Posted by Comzee

I got this, had to return it because the first one was bad. After 8 weeks of waiting, I finally have one that works.




Melz (6SN7GT/6H8C/6N8S) 5 hole anode
Supposedly this tube comes in grey plate / black plate versions.
I have the grey plate version, I've never even seen a black plate version for sale.

I'm pleasantly surprised by its performance.
I'll add this to my "good" NOS tube list, which now is this:
#1 Melz 5 hole plate
#2 RCA 5962 red base

Out of the 14 NOS 6sn7 I've tried, not a great batting average.

Dennis pulled out a metal based Eastern Bloc tube yesterday that goes for about $100 that looked like this. If it's the same tube, it sounded really nice and went into the "top shelf" list along with the VT-231s and 6SN7Ws. I liked it a lot more than the CV 181s....

[Rosco65]

Thanks for the feedback AA. The salient question is if removing the cathode follower actually improves the sound. If it does, then that is a reason to remove it. The second question is if replacing the zener string with with a gas regulator tube improves the sound. If it does, then that is a reason to replace them. However, if the sound is the same and the gas tube simply makes the preamp look prettier while in operation, then we can say that it may be worth doing just for the aesthetic benefit.

I don't think 3 dB rolloff at 50khz is even detectable by hearing in most systems, unless we are building them for bats and dogs. If we are building the preamp for maximum flexibility and/or intending to use it with very long cable runs and/or solid state amps then I would argue that a cathode follower is desirable. However, my intended system does not meet those criteria. I want to be able to drive to Inspire amps simultaneously with short (<1m) cable runs.

A follow up question would what is the optimum tube and capacitor complement for a KT88HO running only from 6khz up, with peaks never to likely exceed 2 or 3 watts?

[straitwire]

Originally Posted by Rosco65

Thanks for the feedback AA. The salient question is if removing the cathode follower actually improves the sound. If it does, then that is a reason to remove it. The second question is if replacing the zener string with with a gas regulator tube improves the sound. If it does, then that is a reason to replace them. However, if the sound is the same and the gas tube simply makes the preamp look prettier while in operation, then we can say that it may be worth doing just for the aesthetic benefit.

I don't think 3 dB rolloff at 50khz is even detectable by hearing in most systems, unless we are building them for bats and dogs. If we are building the preamp for maximum flexibility and/or intending to use it with very long cable runs and/or solid state amps then I would argue that a cathode follower is desirable. However, my intended system does not meet those criteria. I want to be able to drive to Inspire amps simultaneously with short (<1m) cable runs.

A follow up question would what is the optimum tube and capacitor complement for a KT88HO running only from 6khz up, with peaks never to likely exceed 2 or 3 watts?

I edited my post, and I plan to listen for awhile with the cathode follower then without to see if the "sparkle" changes. I run 3ft cables and only Inspire amps so I figured I would give it a try without a follower just for fun....