[opnly bafld]

I've heard that the Line Magnetic amps are way less money in China than in the U.S.,
so what is it's "real" value?

Selling items made domestically for less money is a pretty common thing also done in the UK and Europe.
As always "value" is up to each individual to determine.

[nature boy]

If you're running ANY current Omega the little Zen is a killer match tried and true.  If you need more power to drive less efficient speakers, I would buy a more powerful Decware.

I agree with Canada Rob, as this mirrors my experience with Omega speakers.  Also, if you use a preamp in your system, then additional power should not be a problem.

NB

[smk]

Have not listened to Line Magnetic amp but did live with SE84ZS & 3" Sticks for a number of years & will tell you the pairing sounded seriously good. In my opinion the best I've ever heard as long you keep a tight rein on the level control & live within the 2 wpc power rating. For a better sound use an active preamp (preferably Decware) to make the amp sound a little more powerful.

[Ultralight]

Apologies but how does a preamp make an amp more powerful?   I'm not sure if I understand how the Decware Zen works so am wondering.  Thanks.

Thanks,
UL

[Nailbunny7]

Apologies but how does a preamp make an amp more powerful?   I'm not sure if I understand how the Decware Zen works so am wondering.  Thanks.

Thanks,
UL

It doesn't, though a lot of people think that. It does, however, increase the signal voltage (unless it is a passive preamp). Useful for anything with a low output voltage. It also presents a nice, low output impedance to the power amp, which matters more for solid state power amps, since they often have lower input impedances than tube amps.

[Flyin_V]

I had an interesting conversation with Steve Deckert awhile back. One thing he said was that he found the Zen sounded more powerful and clipped less if the input pot was lowered and an active preamp was used in front of it. "The Zen likes voltage" was his statement.  I've also read that Nelson Pass doesn't like passive preamps as he feels the music sounds less dynamic.

[Nailbunny7]

I had an interesting conversation with Steve Deckert awhile back. One thing he said was that he found the Zen sounded more powerful and clipped less if the input pot was lowered and an active preamp was used in front of it. "The Zen likes voltage" was his statement.  I've also read that Nelson Pass doesn't like passive preamps as he feels the music sounds less dynamic.

Yeah, I'm not super fond of passive preamps either. The have a low input impedance and a high output impedance, neither of which is desirable in an audio circuit.

[G Georgopoulos]

Yeah, I'm not super fond of passive preamps either. The have a low input impedance and a high output impedance, neither of which is desirable in an audio circuit.

Passive preamps can have any input impedance you desire,it is the output impedance that may effect the sound dynamics, in the case of a pot dynamics increase as the pot is turned and shows lower output impedance,anyway,dynamics can be enhanced in the pwr amp,by use of negative feedback and low output impedance...

[Docere]

Have not listened to Line Magnetic amp but did live with SE84ZS & 3" Sticks for a number of years & will tell you the pairing sounded seriously good. In my opinion the best I've ever heard as long you keep a tight rein on the level control & live within the 2 wpc power rating. For a better sound use an active preamp (preferably Decware) to make the amp sound a little more powerful.

I don't understand what this means.

I agree with Canada Rob, as this mirrors my experience with Omega speakers.  Also, if you use a preamp in your system, then additional power should not be a problem.

A pre-amp can make a system sound more powerful. It might go beyond impedance matching, because the phenomenon has been noted by many people using relatively high output pre-amps. Maybe there is something about adding (excessive) gain then reducing it with a volume control that seems to have this effect; or perhaps it is a colouration thing?

A pre-amp does not make a system technically more powerful, unless the additional gain is required to drive the following amplifier closer to maximum output. Gain and power being related, but different and all that.

Cheers,
Ray

[opnly bafld]

A pre-amp does not make a system technically more powerful, unless the additional gain is required to drive the following amplifier closer to maximum output.

This was the case for me with a couple of SE84s that I had.

[smk]

Sorry for hijacking the thread & starting an argument. I was just trying to answer the original question as truthfully as possible. I don't care about the technical explanation but, in my experience, using an active preamp was positive as far as the music goes.

[Nailbunny7]

Passive preamps can have any input impedance you desire,it is the output impedance that may effect the sound dynamics, in the case of a pot dynamics increase as the pot is turned and shows lower output impedance,anyway,dynamics can be enhanced in the pwr amp,by use of negative feedback and low output impedance...

While that is technically true, most amps have an input impedance of 50K or 100K, meaning you have to use a passive pre with an impedance of 5K or 10K, or you may end up with an under damped impedance signal when the pot is turned up.
I don't have a problem with negative feedback in tube amps, it usually increases performance for the reasons you mentioned if you use an appropriate amount. I just have an issue with lots being used because it increases IMD distortion (not THD), which doesn't sound good. To be honest, I think most designers just use no feedback because it makes designing easier and people buy into the "feedback is evil" marketing hype. If it were so bad, I doubt Schiit audio would be so popular, since they use feedback in pretty much every product they have.

[Nailbunny7]

I don't understand what this means.

A pre-amp can make a system sound more powerful. It might go beyond impedance matching, because the phenomenon has been noted by many people using relatively high output pre-amps. Maybe there is something about adding (excessive) gain then reducing it with a volume control that seems to have this effect; or perhaps it is a colouration thing?

A pre-amp does not make a system technically more powerful, unless the additional gain is required to drive the following amplifier closer to maximum output. Gain and power being related, but different and all that.

Cheers,
Ray

Voltage and power headroom is always a good thing, as long as the output is clean (no hum, etc.). Many active preamps add color, which is something many people like (me included, since I really enjoy my Aikido 6SN7 preamp I built).

[DaveC113]

Voltage and power headroom is always a good thing, as long as the output is clean (no hum, etc.). Many active preamps add color, which is something many people like (me included, since I really enjoy my Aikido 6SN7 preamp I built).

I have a 6SN7 Aikido too, it's excellent. Currently building a zero gain pre with Tortuga's LDR and Broski's ACF-2 kit, which is the cathode follower portion of the Aikido with a bipolar power supply. The Aikido makes for an excellent SET driver stage too, far better than a single triode or CCS loaded triode. Once the zero gain pre is done I'll bypass the Aikido's VC and source selector and just use it as the driver for my driverless EL34 SET amp. The combination is excellent, in fact Broski posted this combination with PS ripple sent to the EL34s cathode using 2 caps as voltage dividers/DC blockers in one of his blogs. I compared it to a friend's Air Tight pre and Fi 2a3 monoblocks... we both thought the EL34 amp was better.   

[Nailbunny7]

I have a 6SN7 Aikido too, it's excellent. Currently building a zero gain pre with Tortuga's LDR and Broski's ACF-2 kit, which is the cathode follower portion of the Aikido with a bipolar power supply. The Aikido makes for an excellent SET driver stage too, far better than a single triode or CCS loaded triode. Once the zero gain pre is done I'll bypass the Aikido's VC and source selector and just use it as the driver for my driverless EL34 SET amp. The combination is excellent, in fact Broski posted this combination with PS ripple sent to the EL34s cathode using 2 caps as voltage dividers/DC blockers in one of his blogs. I compared it to a friend's Air Tight pre and Fi 2a3 monoblocks... we both thought the EL34 amp was better.   

Depends what you mean by better
A CCS loaded triode will have more gain and be more linear than an Aikido, but worse PSRR (plus, I think the CCS sounds worse, but if you need the gain...)
Yep, design is really everything. I actually prefer most pentode/tetrode power tubes like the KT88 over the big triode ones like 300B.

[DaveC113]

I've tested out various drivers for my EL34 and the Aikido is in a whole 'nother league compared to a single triode or CCS loaded triode. I didn't expect that much of a difference but it's a huge night and day type difference. Gain is also close to the same, at least with the ECC99 and 12BH7A I was using for a driver. I was surprised but the CCS doesn't really make that much of a difference with those tubes, but it probably would make a much larger difference with a less linear/higher gain tube like an AT7. There's also probably something to Broski's theory that voltage amplifier tubes should be buffered so they are not both amplifying voltage and supplying much current at the same time.

I did not measure my triode drivers separately but I did measure the Aikido after I built it, it's very low distortion and ruler-flat FR, able to output over 30 V RMS no problem before it starts getting ugly... I seriously doubt the CCS loaded triode is any better, in the Aikido the amplifying triode is loaded by the other triode in an attempt to cancel out nonlinearities, so it may be that the Aikdio measures much better... according to my ears it does, and it's much closer to the sound of a good solid state amp vs using the CCS loaded triode which sounded slow and bloated in comparison, much more how you'd expect an EL34 SET to sound. In it's current configuration my SET does not sound all that SET-like in some ways, it's way better imo.

[Nailbunny7]

I've tested out various drivers for my EL34 and the Aikido is in a whole 'nother league compared to a single triode or CCS loaded triode. I didn't expect that much of a difference but it's a huge night and day type difference. Gain is also close to the same, at least with the ECC99 and 12BH7A I was using for a driver. I was surprised but the CCS doesn't really make that much of a difference with those tubes, but it probably would make a much larger difference with a less linear/higher gain tube like an AT7. There's also probably something to Broski's theory that voltage amplifier tubes should be buffered so they are not both amplifying voltage and supplying much current at the same time.

I did not measure my triode drivers separately but I did measure the Aikido after I built it, it's very low distortion and ruler-flat FR, able to output over 30 V RMS no problem before it starts getting ugly... I seriously doubt the CCS loaded triode is any better, in the Aikido the amplifying triode is loaded by the other triode in an attempt to cancel out nonlinearities, so it may be that the Aikdio measures much better... according to my ears it does, and it's much closer to the sound of a good solid state amp vs using the CCS loaded triode which sounded slow and bloated in comparison, much more how you'd expect an EL34 SET to sound. In it's current configuration my SET does not sound all that SET-like in some ways, it's way better imo.

Yep, the Aikido is pretty great, as long as you don't mind buying 4 times as many tubes as a CCS loaded triode (I don't mind it, since driver tubes are relatively cheap and last a long time).
The CCS is something I only every use on driver tubes like the 12AT7, 12AX7, etc. when I need the gain, such as in a phono preamp (CCS would need only 2 tubes, vs the 8 required for the Aikido).

[dodger4]

the line magnetic 518ia is superb piece of gear ,,auditioned this against   integrateds costing up to 3x as much  the 518ia sounded the best 3 people who listened agreed  the 845 rules the SE world and it is heaven for a tube roller point to point wiring ,,built like a tank ,,