Dennis Had Inspire Amps

[pstrisik]

Originally Posted by FloridaBoy

This hobby is a journey and you can go broke chasing the elusive perfect ______________. Fill in the blank.

This weekend my wife and I will go broke chasing the perfect seating for the theater room!

[FloridaBoy]

Hi-Fi Literature

A link to the past. There are some interesting articles by Paul Klipsch and the Mad Magazine does Hi Fi is a hoot. What has really changed?

[x3workshop]

To anyone contemplating the upgrade, I would strongly suggest going for it.

I have mine back and have been listening for only one day and I can tell you there is a significant improvement in performance. Specifically in the upper range, but there is also a slight increase in power output which is confirmed by Dennis.

When pushing the amp at higher volume it is much crisper and tighter than before. Vocals are wonderful(er). Very happy to have done this mod. I highly recommend it as you can still roll to your hearts content.

Direct heated rectifiers are recommended with the 5R4 being the tube Dennis recommends. Seems to like the CV181 now as the pref driver.

More impressions as I listen over the weekend.

[Bombadil]

Was reading about a Von Schweikert audio show demo system, wherein the entire setup carries a combined list price of well over $100K. They are using VAC Signature iQ 200 monoblock tube amps, which employ 6SN7 driver stage tubes. Which brand are they using? New, re-issue Tung-Sol , which cost about $20-$25 each. I find this interesting. For the cost of upgrading to CV181 or NOS tubes would be a pittance considering the total investment and they will be using this system in an attempt to win best sound in show awards at major audio shows. It leads me to believe that they have a high opinion of the Tung-Sols.

[x3workshop]

The Tung Sol reissues are very good. My current preferences are with other varieties.

[Rosco65]

Originally Posted by Bombadil

Was reading about a Von Schweikert audio show demo system, wherein the entire setup carries a combined list price of well over $100K. They are using VAC Signature iQ 200 monoblock tube amps, which employ 6SN7 driver stage tubes. Which brand are they using? New, re-issue Tung-Sol , which cost about $20-$25 each. I find this interesting. For the cost of upgrading to CV181 or NOS tubes would be a pittance considering the total investment and they will be using this system in an attempt to win best sound in show awards at major audio shows. It leads me to believe that they have a high opinion of the Tung-Sols.

I may be useful to think about two sides of high end audio: one side buys expensive components from dealers, accepts the tubesets and other internal components as they are selected by their designers, designers who likely choose tubes or other components based on reliability and widespread availability. It is unlikely a company selling hundred of amps can spec them with NOS tubes without drying out the market. Owners of these systems likely "tweak" them by buying expensive cables, component footers, and other audio jewelry.

The other side of the fence really gets into it. They make their own cables, they tube roll to the point of obsession, they audition and swap out capacitors and other electronic components. They specify the type of volume control that is in their preamp. They don't buy off the rack; they buy or build bespoke audio.

I've been to a few audio club meetings and the number of audiophiles (some of whom are engineers and other technical professionals) who can do anything other than change cables is almost inconsequential. Audio is a pretty small hobby, and the subset of those of us who obsess over the year our Sylvania 6SN7's were made is miniscule.

I've gotten to the point that almost none of my two-channel equipment is factory-stock. Some has been heavily tweaked by myself or others while other equipment is fully custom built.

[FloridaBoy]

Originally Posted by Bombadil

Was reading about a Von Schweikert audio show demo system, wherein the entire setup carries a combined list price of well over $100K. They are using VAC Signature iQ 200 monoblock tube amps, which employ 6SN7 driver stage tubes. Which brand are they using? New, re-issue Tung-Sol , which cost about $20-$25 each. I find this interesting. For the cost of upgrading to CV181 or NOS tubes would be a pittance considering the total investment and they will be using this system in an attempt to win best sound in show awards at major audio shows. It leads me to believe that they have a high opinion of the Tung-Sols.

Simple answer: VAC voiced the amp with the new Tungsols. Not a bad thing at all.

[Rosco65]

Originally Posted by FloridaBoy

Simple answer: VAC voiced the amp with the new Tungsols. Not a bad thing at all.

While the retail price of the VAC is $14k, the company still needs to be price sensitive.

The CV181 tube is $100 more than the Tungsol 6SN7. With 4 6SN7's in the amp, that could add as much as $1,600 to the retail price of the amp. It could be that in this application (high power push-pull, solid state rectification) there is not adequate difference between the two tubes to justify the additional expense. Profit margins on tube amps are already fairly slim. If I were trying to make rent each month, I would be value-engineering every component in my products as well.

[FloridaBoy]

Agreed. No manufacturer can tube roll for you. That VAC may sound mighty fine with the stock tubes and the right speakers. I have not used the new production Tungsol 6SN7.

[x3workshop]

I've spent about 18 hours in total listening to my KT88 SET HO with the upgrade. Tube compliment has been GL KT88's, RCA VT-229, RCA 5R4G

I first mated them to my Desopren Systems 8ohm folded horns @ 93db and the combo sounded just amazing with tight bass and a wonderful vocal midrange. Extremely good spatial presentation and depth. These are not bright speakers, so the highs are naturally subdued, but perfect for most jazz and acoustic recordings.

Next, I had the amp driving a pair of Rega R7's @ 89db efficiency & a nominal 6ohms rating, (known to dip to 2 ohms). These are very difficult speakers to drive with tubegear as the bass driver can be unruly and hard to control. The normal setup is biamped using 4 x McItosh MC30's (on the 4ohm taps) which handle them easily.The Inspire did fairly well, and better than expected, but ultimately was not the best mate at anything above low volume levels.

Lastly, with what I thought would be torture for the Inspire, I ran a pair of Martin Logan EM ESL's @ 91db efficient with a nominal 4ohm impedence.

Granted, I have a high pass filter sending only >100Hz to the ESL's with the rest to an ML sub, but this combo rocked! This is where I heard the biggest improvement in the amp. Effortless at an above average listening level. They sounded the best of any of the three! Tight bass, super soundstage and excellent HF without a note of stress.

As I mentioned in the earlier post, the amp seems to have more reserve and a cleaner high end. The simplest way of quantifying the audible change is that it delivers more of what we like about these amps with less effort, and at slightly higher volume levels.

Very impressive.