Dennis Had Inspire Amps

[Musica Amantem]

Originally Posted by goldhorse

Dennis did suggest the 6SL7's if I wanted more sparkle on the high end. But judging from what I'm hearing, I may find them fatiguing too. After tweaking around with cables and phono loads, I seem to have found an equilibrium with the stock 6SN7 and KT66 combination. These do have sufficient details without being too clinical. I'm thinking of trying KT77's next, as they seem to be a nice compromise for the EL34.

I've never liked the pushy sound of the 6SL7, and as a rule of thumb, I tend to keep away from those ... Nothing like a great 6SN7 (i.e., Chinese CV-181's, RCA Super Radiotron GTA, Sylvania 6SN7 GTB, and others). I have had stridency in the past using the wrong input tubes in the AMP, one needs to find the input tube that allows detail without stridency. The Sylvania 6SN7 GT is an example of stridency-prone sound in my gear, OTBE.

Remember, it is an easy way out to use a forgiving (i.e., warm) input tube, but you would be missing a piece of the fun offered by the transparency in these amps, especially in Triode configuration.

IME, the GL KT-77 needs a PRE to be able to offer that ideal balance between midrange transparency and instrument timbres with enough body of sound weight. Not so with larger tubes, i.e., 6550 and KT-88, which I find too bold when pushed by the PRE. The PRE is ideal for all mid-size to small tubes (i.e., 6V6, 6L6, 350B ...).

All my caveats relative to 6550 / KT-88 in terms of bold sound masking the nuances is solved when running the amp directly from the source. In my case, I use the balanced signal through the ZBit, and the results are excellent: All the body of sound and dynamics plus a level of transparency which had so far been elusive when coupled with the PRE. BTW, my PRE is using a setup oriented to transparency: 56's and CV-181 T.

Curiously, the KT-66 in my setup is indifferent to using the PRE or going straight to the AMP ... It always sounds dull relative to the GL KT-77, VA 6550 or GL KT-88, so I'm not much of a fan of that tube anymore. YMMV.

[goldhorse]

Originally Posted by Musica Amantem

I've never liked the pushy sound of the 6SL7, and as a rule of thumb, I tend to keep away from those ... Nothing like a great 6SN7 (i.e., Chinese CV-181's, RCA Super Radiotron GTA, Sylvania 6SN7 GTB, and others). I have had stridency in the past using the wrong input tubes in the AMP, one needs to find the input tube that allows detail without stridency. The Sylvania 6SN7 GT is an example of stridency-prone sound in my gear, OTBE.

Remember, it is an easy way out to use a forgiving (i.e., warm) input tube, but you would be missing a piece of the fun offered by the transparency in these amps, especially in Triode configuration.

IME, the GL KT-77 needs a PRE to be able to offer that ideal balance between midrange transparency and instrument timbres with enough body of sound weight. Not so with larger tubes, i.e., 6550 and KT-88, which I find too bold when pushed by the PRE. The PRE is ideal for all mid-size to small tubes (i.e., 6V6, 6L6, 350B ...).

All my caveats relative to 6550 / KT-88 in terms of bold sound masking the nuances is solved when running the amp directly from the source. In my case, I use the balanced signal through the ZBit, and the results are excellent: All the body of sound and dynamics plus a level of transparency which had so far been elusive when coupled with the PRE. BTW, my PRE is using a setup oriented to transparency: 56's and CV-181 T.

Curiously, the KT-66 in my setup is indifferent to using the PRE or going straight to the AMP ... It always sounds dull relative to the GL KT-77, VA 6550 or GL KT-88, so I'm not much of a fan of that tube anymore. YMMV.

Thanks for the tip!
This will certainly help me in finding the right sound for me.

I have two sources connected to the LP-3a, one analogue coming from a TT via a phono stage (no volume controls), and the other digital streaming from a NAS via a LINN DSM's line out.

What I have not tried yet is use the LINN Majik DSM as a PRE, by connecting it directly to the AMP, as checking that everything is ok with the Inspire PRE and AMP after a harrowing journey half across the globe was the first order of business

That said, I will be experimenting with the Majik/Hot-Rod just to get a feel, of what the LP-3a does for the total sound, and take it from there. I have a GL KT77 on the way, and will repeat the same exercise with it, then the KT88. Then tweak the inputs. I will be looking for the right balance between clarity and warmth, as I think neither extreme is the answer, and neither do I believe there is one combination to rule them all as different genre would require different balance. Even the day's mood may affect what I want to hear for that matter

Just as a side note. You may or may not have heard of a Japanese who goes to the extreme of designing an amp just for one, and only one, piece of music. I sort of feel where he's coming form, and would like to visit the restaurant he owns one time, but I don't have the will, skill, and time to do what he's doing. I think tube rolling with the Inspire is a good enough compromise for me

[Analog Addict]

Originally Posted by BearCityUSA

AA,

Thanks for the advice BTW. I re read my previous post and it reads a bit less than gracious. Anyway, where do you suggest getting the reference tube? I see Brent Jesse has a 6l6 but he seems to want a good amount for one. Likely the going rate retail.

No worries. I didn't even notice.

Seems like $65 is the going rate on line. I asked the fellow who restored and calibrated my Hickok if he would consider a calibration tube for you. If you're interested, I can hook you up with him...

[Musica Amantem]

Originally Posted by goldhorse

What I have not tried yet is use the LINN Majik DSM as a PRE, by connecting it directly to the AMP, as checking that everything is ok with the Inspire PRE and AMP after a harrowing journey half across the globe was the first order of business

I would bet the Source > LP-3a > AMP is the optimal signal path as that PRE is extremely transparent and complements the Hot-Rod through design. If you have volume control on the amp (I have a DACT stepped attenuator), I would suggest you try Source > AMP, directly when using larger, more powerful tubes in the Hot-Rod, as these do not require boost from the PRE to have body of sound, and the signal path is simpler, shorter. It is a tradeoff worth checking.

I have a GL KT77 on the way, and will repeat the same exercise with it, then the KT88. Then tweak the inputs. I will be looking for the right balance between clarity and warmth, as I think neither extreme is the answer, and neither do I believe there is one combination to rule them all as different genre would require different balance. Even the day's mood may affect what I want to hear for that matter

True. Yet, the less input manipulation, the better, more natural sound ... IME the GL KT-77 benefits from the PRE, while the KT-88 not so much, as it becomes bolder. The latter and larger tubes would sound better without signal manipulation (source of distortions, etc.) going straight to the AMP. This is just my opinion and based on my setup, YMMV.

Just as a side note. You may or may not have heard of a Japanese who goes to the extreme of designing an amp just for one, and only one, piece of music. I sort of feel where he's coming from, and would like to visit the restaurant he owns one time, but I don't have the will, skill, and time to do what he's doing. I think tube rolling with the Inspire is a good enough compromise for me

I had not heard of this individual, and it seems what he does is art, but you will have plenty of fun dialing-in your gear for a while. I know I'm still at it

[goldhorse]

Originally Posted by Musica Amantem

I would suggest you try Source > AMP, directly when using larger, more powerful tubes in the Hot-Rod, as these do not require boost from the PRE to have body of sound, and the signal path is simpler, shorter. It is a tradeoff worth checking.

True. Yet, the less input manipulation, the better, more natural sound ... IME the GL KT-77 benefits from the PRE, while the KT-88 not so much, as it becomes bolder. The latter and larger tubes would sound better without signal manipulation (source of distortions, etc.) going straight to the AMP. This is just my opinion and based on my setup, YMMV.

Unfortunately, I just have the stock Hot-Rod AMP from eBay, so it does not have the DACT. I didn't think Dennis still offered customization these days. I had actually taken a similar route before, where I had a passive pre-amp linked to a pair of mono block power amps, but then these were solid state and had 100W each, not the 12Wpc I have now, so I thought ahead and ordered the LP-3a for the extra boost. If I still had that passive PRE, I would have tried it, but I'll keep this option in mind in case a run across one in some second hand shop.

Originally Posted by Musica Amantem

I had not heard of this individual, and it seems what he does is art, but you will have plenty of fun dialing-in your gear for a while. I know I'm still at it

He's called Sakuma (san). Here's one link to a documentary about him. Sorry, couldn't find English subs, but I think it will still be an interesting video regardless.

BTW, I just go the KT77 and listened to them just briefly, but my first impression is that compared to the KT66, it was as if you took a few steps back from the stage, and instead of hearing each sound separately, all the parts are still there but now you are hearing them as one coherent sound. Liking this already for listening to orchestral music. You could say KT66 offers better dynamics, but the KT77 is easier on the ear, and you could push the volume higher and still sound sweet. If it were chamber music, the KT66 are a treat to listen to as individual players stand out. I wonder what KT88 have to offer.

[Musica Amantem]

Originally Posted by goldhorse

Unfortunately, I just have the stock Hot-Rod AMP from eBay, so it does not have the DACT. I didn't think Dennis still offered customization these days. I had actually taken a similar route before, where I had a passive pre-amp linked to a pair of mono block power amps, but then these were solid state and had 100W each, not the 12Wpc I have now, so I thought ahead and ordered the LP-3a for the extra boost. If I still had that passive PRE, I would have tried it, but I'll keep this option in mind in case a run across one in some second hand shop.

The LP-3a is a wonderful PRE. For a given genre and configuration of the recording, you may enjoy it more or less, depending on the output tubes' size and profile, in the amp.

He's called Sakuma (san). Here's one link to a documentary about him. Sorry, couldn't find English subs, but I think it will still be an interesting video regardless.

I saw the clip. Quite interesting. This guy seems to know much about this art form of his, amazing!

BTW, I just go the KT77 and listened to them just briefly, but my first impression is that compared to the KT66, it was as if you took a few steps back from the stage, and instead of hearing each sound separately, all the parts are still there but now you are hearing them as one coherent sound. Liking this already for listening to orchestral music. You could say KT66 offers better dynamics, but the KT77 is easier on the ear, and you could push the volume higher and still sound sweet. If it were chamber music, the KT66 are a treat to listen to as individual players stand out. I wonder what KT88 have to offer.

KT-77 ... Give them time! You'll be surprised. These are the most revealing, balanced and sweet output tubes I've heard, and they work best with my LP-27a. Regarding the KT-88, I prefer 6550's from Valve Art, but that is just me. The KT-88 from Gold Lion are nice and very rhythmic, but unless played direct to the Amp, it tends to mask nuances through boldness. It also has great bass (along with the 6550), which is the only limitation with the KT-77

[goldhorse]

Originally Posted by Musica Amantem

[I]The LP-3a is a wonderful PRE. For a given genre and configuration of the recording, you may enjoy it more or less, depending on the output tubes' size and profile, in the amp.

I did the experiment I mentioned earlier with the LINN today; bypassing the LP-3a, and connecting the LINN's PRE OUT directly to the Hot-Rod. The difference was quite obvious after just a few bars of music. With the KT66, the sound was hard-edged, and lackluster. The KT77 was more forgivable, and I could just bear enjoying a few tunes, but did not take long for me to long for the LP-3a again. I liked the LINN as one complete system, as the source, PRE, and AMP. But it's PRE just did not have the chemistry with the Hot-Rod. So I definitely made the correct decision in getting the LP-3a, at least as far as the KT77 and KT88 are concerned.

Originally Posted by Musica Amantem

I saw the clip. Quite interesting. This guy seems to know much about this art form of his, amazing!

I'm thinking of sending the link to Dennis, see what he thinks

Originally Posted by Musica Amantem

KT-77 ... Give them time! You'll be surprised. These are the most revealing, balanced and sweet output tubes I've heard, and they work best with my LP-27a. Regarding the KT-88, I prefer 6550's from Valve Art, but that is just me. The KT-88 from Gold Lion are nice and very rhythmic, but unless played direct to the Amp, it tends to mask nuances through boldness. It also has great bass (along with the 6550), which is the only limitation with the KT-77

Valve Arts don't seem to be in wide circulation over here. I found one reseller but he doesn't seem to keep them in stock, thus has a very long lead time. Tung-Sol 6550 seem interesting as well. Have you had a chance to hear Psvane and Shuguang variants? I see a lot of good reviews, though as a matter of personal taste I don't like smoked valves. Where's the fun in that

BTW, I don't find the KT77 lacking in bass, not as big as the KT66 for sure, but still has very good presence. Must be my system.

There's going to be an analogue audio fair in a couple of weeks in Tokyo. A number tube distributor, will be bringing his wares and I'm hoping to dig up some interesting valves.

[Musica Amantem]

Originally Posted by goldhorse

I did the experiment I mentioned earlier with the LINN today; bypassing the LP-3a, and connecting the LINN's PRE OUT directly to the Hot-Rod. The difference was quite obvious after just a few bars of music. With the KT66, the sound was hard-edged, and lackluster. The KT77 was more forgivable, and I could just bear enjoying a few tunes, but did not take long for me to long for the LP-3a again. I liked the LINN as one complete system, as the source, PRE, and AMP. But it's PRE just did not have the chemistry with the Hot-Rod. So I definitely made the correct decision in getting the LP-3a, at least as far as the KT77 and KT88 are concerned.

You will enjoy the LP-3a even more with smaller 6L6 / 6V6 tubes

I'm thinking of sending the link to Dennis, see what he thinks

Valve Arts don't seem to be in wide circulation over here. I found one reseller but he doesn't seem to keep them in stock, thus has a very long lead time. Tung-Sol 6550 seem interesting as well. Have you had a chance to hear Psvane and Shuguang variants? I see a lot of good reviews, though as a matter of personal taste I don't like smoked valves. Where's the fun in that

It does not have to be Valve Art. Any good 6550 may do the trick, but this is in my system, not yours. Trial-and-error is unavoidable.

BTW, I don't find the KT77 lacking in bass, not as big as the KT66 for sure, but still has very good presence. Must be my system.

It lacks in bass relative to the 6550 and KT-88 in my system

There's going to be an analogue audio fair in a couple of weeks in Tokyo. A number tube distributor, will be bringing his wares and I'm hoping to dig up some interesting valves.

That must be a very interesting experience. Japan is famous for having revived the SET amps many years ago.

[FloridaBoy]

Originally Posted by goldhorse

I did the experiment I mentioned earlier with the LINN today; bypassing the LP-3a, and connecting the LINN's PRE OUT directly to the Hot-Rod. The difference was quite obvious after just a few bars of music. With the KT66, the sound was hard-edged, and lackluster. The KT77 was more forgivable, and I could just bear enjoying a few tunes, but did not take long for me to long for the LP-3a again. I liked the LINN as one complete system, as the source, PRE, and AMP. But it's PRE just did not have the chemistry with the Hot-Rod. So I definitely made the correct decision in getting the LP-3a, at least as far as the KT77 and KT88 are concerned.

I think an Inspire pre and amp is an unbeatable combination.

I'm thinking of sending the link to Dennis, see what he thinks

Valve Arts don't seem to be in wide circulation over here. I found one reseller but he doesn't seem to keep them in stock, thus has a very long lead time. Tung-Sol 6550 seem interesting as well. Have you had a chance to hear Psvane and Shuguang variants? I see a lot of good reviews, though as a matter of personal taste I don't like smoked valves. Where's the fun in that

Amplified Parts has some Valve Art tubes. Valve Art is Shuguangs export label. Ruby Tubes, I believe are very similar. Ditto for tubes labeled Electron Valve. There some excellent Chinese tubes that are no longer in production.

BTW, I don't find the KT77 lacking in bass, not as big as the KT66 for sure, but still has very good presence. Must be my system.

Give the KT77's some time to settle in.

There's going to be an analogue audio fair in a couple of weeks in Tokyo. A number tube distributor, will be bringing his wares and I'm hoping to dig up some interesting valves.

That should be

I have the TS6550 new production but prefer the pair of Electron Valve 6550's for $35 on the auction site. The TS is quite good though.

IMHO, the Shuguang and Psvane CV-181/6SN7's surpass the old production tube I have for long term enjoyment. YMMV.

[FloridaBoy]

Originally Posted by Musica Amantem

That must be a very interesting experience. Japan is famous for having revived the SET amps many years ago.

Check this out: https://www.stereophile.com/interviews/399/index.html