Dennis Had Inspire Amps

[pstrisik]

Originally Posted by Analog Addict

Spent some time listening to Peter's upgraded amp yesterday.

I think he is going to be very happy with the results. I didn't hear it before the upgrades, but Dennis says the change is not subtle. I just wish he could keep a tube pre amp in stock so we wouldn't have to use this Audio Research piece.

Thanks for posting AA. Dennis said he will ship Monday so I should have it for next weekend.

Upgrades:

** New Infinite Impedance Power Supply circuit
** Dual auto bias supply
** New Jantzen silver coupling caps
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Here are photos of the inside before and after:
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[x3workshop]

Originally Posted by pstrisik

Thanks for posting AA. Dennis said he will ship Monday so I should have it for next weekend.

Upgrades:

** New Infinite Impedance Power Supply circuit
** Dual auto bias supply
** New Jantzen silver coupling caps

You will notice a significant improvement in the sound. More clarity and detail. I would describe it as MORE of what makes these pieces so good. Also a slight bump in usable power. Enjoy it. I've been loving mine since I got it back.

[pstrisik]

Originally Posted by x3workshop

You will notice a significant improvement in the sound. More clarity and detail. I would describe it as MORE of what makes these pieces so good. Also a slight bump in usable power. Enjoy it. I've been loving mine since I got it back.

Thanks for the positive anticipation! I'm hearing nothing but good things about this upgrade. Sounds like Dennis put at least a few hours on. Did you find need for break in time? Some say breaking in equipment is really letting one's perception adapt to the difference. Maybe some of both. I guess with new caps, it fits in the typical break in approach for new amps.

I would expect some differences in choosing the rectifier. Did you find any difference in your driver or power tube preferences?

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Edit: just got this from Dennis:

The dual auto bias is an identical, individual bias circuit for each output tube. This way you would be able to even have way off balance tubes and still have a proper bias on each tube. This will also add to the stereo center fill imaging …. For best results use any rectifier that is directly heated cathode like the 5Y3, 5U4, 274B ….. you may use a 5AR4 type as well but I like the good ole directly heated job-a-dos.

[x3workshop]

Originally Posted by pstrisik

Thanks for the positive anticipation! I'm hearing nothing but good things about this upgrade. Sounds like Dennis put at least a few hours on. Did you find need for break in time? Some say breaking in equipment is really letting one's perception adapt to the difference. Maybe some of both. I guess with new caps, it fits in the typical break in approach for new amps.

I would expect some differences in choosing the rectifier. Did you find any difference in your driver or power tube preferences?

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Edit: just got this from Dennis:

I'm not sure how much I buy into the concept of cap burn in beyond a couple three of hours of use and since I'm not a materials physicist I can't prove that it doesn't make a difference. I just don't hear it.

I've been running TS KT120's and GL KT88's w/5R4GY. Was using an RCA VT 229 Blackplate driver but am liking the Sylvie 6SN7GT Blackplate bottom getter more now. I like the KT120's for classical piano, acoustic/folk and some chill/lounge. The KT88's for Jazz, vocals and all other. I haven't tried my KT77, EL34, 807's or 6L6's yet. I take my time with rolling.

Quick revision: I think we have slightly different amps. Pics are old with different tubes

[pstrisik]

Originally Posted by x3workshop

I'm not sure how much I buy into the concept of cap burn in beyond a couple three of hours of use and since I'm not a materials physicist I can't prove that it doesn't make a difference. I just don't hear it.

I've been running TS KT120's and GL KT88's w/5R4GY. Was using an RCA VT 229 Blackplate driver but am liking the Sylvie 6SN7GT Blackplate bottom getter more now. I like the KT120's for classical piano, acoustic/folk and some chill/lounge. The KT88's for Jazz, vocals and all other. I haven't tried my KT77, EL34, 807's or 6L6's yet. I take my time with rolling.

Quick revision: I think we have slightly different amps. Pics are old with different tubes

Yes, our amps are different. Mine uses a 9 pin 6DJ8 family driver. More curious if you found different preferences after the upgrade or if the same driver/power tubes remained your preference.

[x3workshop]

Originally Posted by pstrisik

Yes, our amps are different. Mine uses a 9 pin 6DJ8 family driver. More curious if you found different preferences after the upgrade or if the same driver/power tubes remained your preference.

I went from a 6SL7 variant to a 6SN7. I felt it sounded smoother. Power tube choice pretty much stayed the same. That said, I haven't begun to roll yet. I honestly feel the driver has the biggest impact.

[pstrisik]

Originally Posted by x3workshop

I went from a 6SL7 variant to a 6SN7. I felt it sounded smoother. Power tube choice pretty much stayed the same. That said, I haven't begun to roll yet. I honestly feel the driver has the biggest impact.

Thanks. I'll obviously see for myself, but curious about others' experiences.

[Bombadil]

To my ears the power tubes have made more of a difference than the driver, in most cases. I should say that the only drivers I've used are 6SN7 tubes, I've compared more than a dozen of these. I believe this is the optimal driver tube (including the direct equivalents for a 6SN7, like the 5692, VT-231, 6n8s) for this amp.

In the same vein, if something is spec'ed as a 6DJ8, you can use 6922, 7308, 6H23P and roll away, trying to find the one you like best. Some people will stick a 6BQ7 into a 6DJ8 socket as it is pin compatible. But it is not an equivalent and it will change the sound.

[Bombadil]

Per Dennis: "For best results use any rectifier that is directly heated cathode like the 5Y3, 5U4, 274B ….. you may use a 5AR4 type as well but I like the good ole directly heated job-a-dos. "

Interesting. So far I think I've slightly liked the indirectly heated rectifiers better. Like the 5V4GA and 5AR4/GZ34. But I could reverse that opinion as I get more hours with the amp in its new system. The differences between rectifiers is less to my ears than between drivers or power tubes. There have been several instances of where I could not detect any difference between rectifiers, even those of different types.

[FloridaBoy]

Originally Posted by x3workshop

I'm not sure how much I buy into the concept of cap burn in beyond a couple three of hours of use and since I'm not a materials physicist I can't prove that it doesn't make a difference. I just don't hear it.

I've been running TS KT120's and GL KT88's w/5R4GY. Was using an RCA VT 229 Blackplate driver but am liking the Sylvie 6SN7GT Blackplate bottom getter more now. I like the KT120's for classical piano, acoustic/folk and some chill/lounge. The KT88's for Jazz, vocals and all other. I haven't tried my KT77, EL34, 807's or 6L6's yet. I take my time with rolling.

Quick revision: I think we have slightly different amps. Pics are old with different tubes

MA and I have the same triode wired amp as you. It appears that the upgrade is a good move. Hmmm...

Burn in is a controversial topic.