Dennis Had Inspire Amps

[Rosco65]

Originally Posted by CoGT3

Can sign me up as another Guinea pig. Jumping in line for a PSE this week too. Would love to see Dennis throw the kitchen sink at it. (Already suggested trying some Jupiter caps, he thought current silver caps voice better for his amps).

He is probably right. The Jupiters tend toward a more romantic sound, what Dennis would call an "old man's amp". He specifically calls the PSE a "young man's amplifier". His cap choices for the the Inspire amps have three things in common: they are detailed German caps (Audyn and Jantzen), they hit a great price/performance point, and they are available from Parts Express.

The Cary Audio stuff has had a reputation of being a bit romantic and soft on top: more like traditional Conrad Johnson than Audio Research. I suppose this is what he would refer to as the old man's sound. The cap upgrades available for Cary include Jensen PIO caps. These are very good (I have them in a custom triode amp) but are something you would expect to find in a more traditional SET amp.

I would follow Florida Boy's approach and begin rolling caps in the LP-27a. It has more room and you can use the romantic sound to balance the drier PSE. You might even find room to squeeze in a pair of Duelands, but no guarantees. You could also put in a pair of silver foil Jensens, but they would increase the cost of the preamp by 50%.

[Musica Amantem]

Originally Posted by x3workshop

I don't disagree with anything that you've said, but since I am not running incredibly efficient speakers, the modification to minimize any distortion when pushing the amp to higher levels is a benefit for me.

Chasing the latest mod would be time consuming, unsatisfying, and expensive. Since I've requested a couple of modest tweaks to be done at the same time as the power supply change, I don't feel it's a waste of time, or money, but an investment in better performance for my use.

To be truthful, the Inspire gear is the newest kit that I own outside of my ML ESL's and DAC's. Everything else is of a vintage that dates from the mid fifties to early 2000's. Proven designs and outstanding performers.

On another note, how great is it that we all have the benefit of watching these Inspire designs evolve as Dennis tries new solutions to certain problems and deficiencies that he's identified?

If we wish, we can even choose to try a completely new design, the PSE. I chose not to buy another amp right now since I feel there can be some improvements made to the original amp that I own that will satisfy my needs.

I hear you about needing a good second hand market to make this hobby work. I'm lucky to live in a place that has that market for pre owned, higher end gear. That, and a good supply of friends that wait for my gear to become available make this feasible for me!

Good for you! Keep us posted on the sound quality improvements from the mods.

[Simonatsea]

Originally Posted by Analog Addict

Scott/Bearcity came by to pick up his PSE when I happened to have a day off. (Greetings! Nice to meet you!) I got there earlier to have lunch and play with my new build. Ran both amps with my new 27 preamp all afternoon. These are both awesome sounding amps, but my impression is that the Hot Rod is a little warmer and a bit more intimate in sound. The PSE throws a huge sound stage but Al Hirt's horn or Diana Krall's alto move back into the sound stage, kinda like the difference between a club and an arena. Personally, I'd rather have Diana sitting in my lap if that was possible. Anyway, I'm sure Scott will post his opinions eventually, but after a 4 hour drive home, I'm betting it will be tomorrow or later....

What is the 3rd picture of? Looks like a preamp of sorts....

[FloridaBoy]

Originally Posted by Rosco65

He is probably right. The Jupiters tend toward a more romantic sound, what Dennis would call an "old man's amp". He specifically calls the PSE a "young man's amplifier". His cap choices for the the Inspire amps have three things in common: they are detailed German caps (Audyn and Jantzen), they hit a great price/performance point, and they are available from Parts Express.

The Cary Audio stuff has had a reputation of being a bit romantic and soft on top: more like traditional Conrad Johnson than Audio Research. I suppose this is what he would refer to as the old man's sound. The cap upgrades available for Cary include Jensen PIO caps. These are very good (I have them in a custom triode amp) but are something you would expect to find in a more traditional SET amp.

I would follow Florida Boy's approach and begin rolling caps in the LP-27a. It has more room and you can use the romantic sound to balance the drier PSE. You might even find room to squeeze in a pair of Duelands, but no guarantees. You could also put in a pair of silver foil Jensens, but they would increase the cost of the preamp by 50%.

The LP 27a coupling caps are 1.5uf, quite large and more expensive than the couplers in the amp(s). It was tough fitting the Jupiters, $118 each, in it. The couplers in my amp are .022uf and Jupiter's are $60 each. I'm not using Jupiter's there though. Caps are like spice and we all like different things. My present speakers are Klipsch and PIO type caps work best for me. With another speaker I may prefer something else. It's all about synergy and rolling caps can be less expensive than rare old production power tubes. Also, the most expensive ones may not work best for you.

I have a pair of .022uf Jensen copper foil ceramic tube in the parts box and will try them in the amp eventually. Roscoe, be bold and daring. Try the Jupiter copper foil in your triode amp. ;-)

[Simonatsea]

I purchased the wrong spec cap for my 6V6 amp. Currently I have .01uf Auricap in place. Does anyone know the implications of putting .022uf RelCap TFT in their place?

I am however looking at ordering .01uf Vcap cutft, smaller sizes are actually not that expensive.

This will leave the RelCap TFT .022uf, RelCap TFT .1uf and .22uf Jupitor Copper foil to play around with bypassing the 1.5uf Audyn Copper Max in my LP-2. Like you said, some speakers might prefer a different cap compliment than others.

That is dependant on wether they let me return the 0.1uf RelCap TFT pair....

[FloridaBoy]

Originally Posted by Simonatsea

I purchased the wrong spec cap for my 6V6 amp. Currently I have .01uf Auricap in place. Does anyone know the implications of putting .022uf RelCap TFT in their place?
I am however looking at ordering .01uf Vcap cutft, smaller sizes are actually not that expensive.

This will leave the RelCap TFT .022uf, RelCap TFT .1uf and .22uf Jupitor Copper foil to play around with bypassing the 1.5uf Audyn Copper Max in my LP-2. Like you said, some speakers might prefer a different cap compliment than others.
That is dependant on wether they let me return the 0.1uf RelCap TFT pair....

I would not double the value of the cap. It will alter the frequency response.

I have used the Vcap cutft and liked it. They do take forever to settle in.

True, no ones system is identical so there is no perfect tube or cap.

[Rosco65]

Originally Posted by FloridaBoy

The LP 27a coupling caps are 1.5uf, quite large and more expensive than the couplers in the amp(s). It was tough fitting the Jupiters, $118 each, in it. The couplers in my amp are .022uf and Jupiter's are $60 each. I'm not using Jupiter's there though. Caps are like spice and we all like different things. My present speakers are Klipsch and PIO type caps work best for me. With another speaker I may prefer something else. It's all about synergy and rolling caps can be less expensive than rare old production power tubes. Also, the most expensive ones may not work best for you.

I have a pair of .022uf Jensen copper foil ceramic tube in the parts box and will try them in the amp eventually. Roscoe, be bold and daring. Try the Jupiter copper foil in your triode amp. ;-)

At that size Dueland 400V RS are only $84 each. Stock up!

The coupling caps in the PSE are Jantzen Silver Z 1200V 0.33uF. That is actually not a bad value from a cost or size perspective. Alternatives include the Jupiter 600V Copper Foil and the Dueland 400V RS.

Jantzen Silver Z Cap 1200V 26 x 45 mm $16

Jupiter Copper Foil 600V 20 x 52 mm $60

Dueland RS Copper RS 400V 32 x 37 mm $88

I'm not sure the Jupiter or Dueland caps are 4-6 times as good as the Jantzens, but they certainly will be different. The change will cost no more than some NOS tubes, so that offers some perspective. If one wanted to change the coupling caps to something less clinical and/or more romantic, it would appear that the Jupiter is the better physical fit. It is slightly longer than the Jantzen but also slightly smaller in diameter. They Dueland is shorter but slightly fatter. It would appear that chassis depth is the limiting factor with the Inspire amps.

My custom triode amp uses the traditional wood base and metal top plate for construction. It is also sized between the KT88 and PSE, so it has a bit more room for larger coupling capacitors. If need be, I can build a deeper base to accomodate larger caps, but I don't think it would be necessary.

[Musica Amantem]

Funny, when I asked Dennis what he thought about replacing caps in his amp he was not too enthusiastic and mentioned his stock Russian caps were good enough and reliable. That was last year. All in all, I believe he had not bother with caps for fine-tunning (also to keep costs in line, I suppose), which is surprising given his normally perfectionist attitude in his designs.

I wish I knew how to solder ... FloridaBoy, you definitely need to come down and visit, and bring your soldering iron and some hot caps along

[Rosco65]

Originally Posted by Musica Amantem

Funny, when I asked Dennis what he thought about replacing caps in his amp he was not too enthusiastic and mentioned his stock Russian caps were good enough and reliable. That was last year. All in all, I believe he had not bother with caps for fine-tunning (also to keep costs in line, I suppose), which is surprising given his normally perfectionist attitude in his designs.

I wish I knew how to solder ... FloridaBoy, you definitely need to come down and visit, and bring your soldering iron and some hot caps along

A decent soldering station can be had for $50. Its an easy skill to learn and cheap to practice.

[Musica Amantem]

Originally Posted by Rosco65

A decent soldering station can be had for $50. Its an easy skill to learn and cheap to practice.

You mean something like this?

https://www.amazon.com/X-Tronic-3020...5114638&sr=1-3

With that and some instructions, I think I'd be set to practice and learn what is required for me to do some Cap-rolling, eventually. For what I read from others' experiences, this alternative is as impacting as tube-rolling (or even more) to the amp/preamp sound. Thanks!