Tubes for Magnepan’s.

I think the answer to satisfy most is a tube pre, this can give you "tube sound" if your amp can convey that. This satisfies the tube desire and the ability to power them with the Hoover Dam. 😉

@ieales

That's my kind of finagling. I find manufactures attempts to build homages to existing technological presentations often tiring when cross pollination can yield much better results.

Being able to afford 3 amps for a stereo that you can match to the drivers can actually save you a lot of money in the end.

^
It does if you take the closed parentheses off.

http://www.zeroimpedance.com

@russ69

Thank you. I don’t listen to the Maggie’s, 99% of the time, at high volume. And I will also use it to drive the Zu’s on and off.

The instrument and studio supply company Sweetwater has a piece on guitar head amps and how a tube amp of modest wattage will outdrive solid state by a wide margin: Now I can’t find it! Argh! I will look.

Any suggestions on a tube preamp? I like Schiit audio and have considered the Freya, but if I go that route I may want better sound from a pre than what the Freya is reported to provide.

Again, I am lost here.

@russ69 

Well the used market can come into play, and I may be able to pick up a better quality tube unit that way. And I was thinking more for the tube amp price wise at around $4k. 
The Schiit just came to mind as something to fiddle with, but that is not the max I would be willing to spend to go that route.

@jjss49

No, I know about Maggie’s and watts, so this is something to add into the mix for more sophisticated listening sessions, Jazz and Classical.

Thank you for the reference to overdriving, that is what the Sweetwater tech was saying in their video.

@clearthink,

Yes, less efficient, just more musical when overdriven. 

@jc4659 

I have a Benchmark AHB 2. It sounds more dynamic than a Parasound A23; lots of punch.

So tubes are just a "satisfy my fancy" thing. 
Room is 12x24x8.

2 KEF R400 B's for the bottom.

I think I'm just admitting at this late stage in life that no 1 thing will ever satisfy, so the Maggie’s are for Jazz and Classical and the Zu Dirty Weekends will be for head banging rock. 
For a hi current amp I’m thinking of a Parasound or Hegel. And if Russ is right, I may not need a tube amp, just a tube pre. 
It's not just the sound, it's the playing around with all of it.

If the Zu's don’t work out, I may go in the direction of the Klipsh Heritage line for Rock.

The Parasound Halo line seems to be a consensus choice. 

A23+ is fine for the 1.7i's but an A21 if you’re planning on getting the 3.7i's.

Right?

The original tweeter is now part of the midrange, today. 😉


New tweeters are a line array parallel with the panel. Wood has been subtracted and added. I also included bi-ampable binding posts. 


I've been trying to document this rebuild and will sew together a little video that I’ll put together when done.

This is my #1 amp.

Benchmark AHB 2. It comfortably can handle 90- 95db on it’s own with my 1.7i’s, depending on the material. It totally rocks with the KEF’s, and does very well with the bass panels, it’s the tweeters that kill it. 
It’s easy to see how two might sound since it is easy to bridge into one side. 500+ watts into 4ohms bridged.Specs below.

I bought a A23 yesterday online, store demo local, but when I called and asked when I could pick it up they told me they didn’t have one. "!?"

Wtf? 
Thanks House of Stereo! 

I’ve done better ordering online than with my brick and mortar...

I thought I’d give them another try since it looks like the previous owner is out of the picture, but they screwed me again. So far the only thing I’ve bought there that wasn’t a train wreck were my KEF’s.
Arcam? Lemon. They passed on sending back for service, even after Arcam was bought by that Canadian company and promised to resolve past QC issues for customers.


Velodyne sub cause they never did their homework and didn’t know REL existed? Then started carrying them within a year and didn’t want to do a trade?


Magnepan 1.7i? Inductor wired inline to all three elements so there was no treble? See above for customer service after the sale...


I was going to try and run my De’WooferMagnepan panels with the A23 to judge it’s output compared to my AHB 2, but obviously would have tried it in my system. If the Parasound was noticeably more engaging, sort of equal to the AHB2 power wise, then I’d think about an A21.


If anyone knows a way to get a hold of one for demoing, let me know.


AHB2 specs:

CONTINUOUS AVERAGE OUTPUT POWER

< 0.0003 % THD+N at full rated power, 20 Hz to 20 kHz

• 100 Watts per channel into 8 Ohms, both channels driven
• 130 Watts per channel into 6 Ohms, both channels driven
• 190 Watts per channel into 4 Ohms, both channels driven
• 240 Watts per channel into 3 Ohms, both channels driven
• 200 Watts into 16 Ohms, bridged mono
• 380 Watts into 8 Ohms, bridged mono
• 480 Watts into 6 Ohms, bridged mono

All speakers have variations in input impedance. Select loads based on nominal impedances not minimum impedances. The AHB2 is stable into all loads. The AHB2 is conservatively rated at an output level where THD+N is < 0.0003 % instead of the more typical 1% THD+N. Power at 1% THD will be higher.

OUTPUT VOLTAGE INTO VARIOUS LOAD IMPEDANCES

< 0.0003 % THD+N at the following output voltages and load impedances, 20 Hz to 20 kHz

• 29.03 dBV, 31.25 dBu, 28.28 Vrms into 8 Ohms, both channels driven
• 28.92 dBV, 31.14 dBu, 27.93 Vrms into 6 Ohms, both channels driven
• 28.81 dBV, 31.03 dBu, 27.57 Vrms into 4 Ohms, both channels driven
• 28.57 dBV, 30.79 dBu, 26.83 Vrms into 3 Ohms, both channels driven
• 27.14 dBV, 29.36 dBu, 22.76 Vrms into 2 Ohms, both channels driven
• 35.05 dBV, 37.27 dBu, 56.57 Vrms into 16 Ohms, bridged mono
• 34.83 dBV, 37.05 dBu, 55.14 Vrms into 8 Ohms, bridged mono
• 34.59 dBV, 36.81 dBu, 53.67 Vrms into 6 Ohms, bridged mono
• 33.16 dBV, 35.38 dBu, 45.52 Vrms into 4 Ohms, bridged mono

Use dBV to calculate the peak SPL from your speaker/amplifier combination. Use the following formula: Amplifier output voltage in dBV + speaker sensitivity at 2.83V - 9 dB. Example: (29.03 dBV at 8 Ohms) + (90 dB SPL @ 2.83V 1m) - 9 dB = 110 dB SPL at 1 meter

SNR & DYNAMIC RANGE

Rated output relative to output noise, inputs shorted

• 132 dB A-weighted, Stereo Mode
• 135 dB A-weighted, Mono Mode
• 130 dB Unweighted, 20 Hz to 20 kHz, Stereo Mode
• 133 dB Unweighted, 20 Hz to 20 kHz, Mono Mode

NOISE VOLTAGE

Output noise voltage, A-weighted, inputs shorted

• -103 dBV, -101 dBu, 7.1 uVrms, Stereo Mode
• -100 dBV, -98 dBu, 9.8 uVrms, Mono Mode

Use dBV to calculate the SPL of the noise produced by your speaker/amplifier combination. Use the following formula: Amplifier output noise voltage in dBV + speaker sensitivity at 2.83V - 9 dB. Example: Mono mode driving very high efficiency speakers: (-100 dBV) + (104 dB SPL @ 2.83V 1m) - 9 dB = -5 dB SPL at 1 meter. This means that the system noise will be 5 dB below the threshold of hearing when driving speakers with a very high 104 dB efficiency.

NOISE RELATIVE TO 2.83 VRMS

Output noise relative to 2.83 Vrms, A-weighted, inputs shorted

• -112 dB, Stereo Mode
• -109 dB, Mono Mode

THD+N

1 kHz, 80 kHz LPF, at full rated output into any rated load

• < -118 dB (< 0.00013%), Stereo Mode
• < -118 dB (< 0.00013%), Mono Mode

THD

1 kHz, 20 kHz LPF, at full rated output into any rated load

• < -119 dB (< 0.00011%), Stereo Mode
• < -120 dB (< 0.00010%), Mono Mode

CROSSTALK

• Better than -115 dB at 1 kHz
• Better than -92 dB at 20 kHz

FREQUENCY RESPONSE

• Better than 0.1 Hz to 200 kHz, +0/-3 dB
• -0.01 dB at 20 Hz, -0.17 dB at 20 kHz, 8-Ohm Load
• -0.23 dB at 20 Hz, -0.32 dB at 20 kHz, 4-Ohm Load

DAMPING FACTOR

• 350 at 20 Hz, 8-Ohms
• 254 at 1 kHz, 8-Ohms
• 34 at 20 kHz, 8-Ohms
• 7 at 200 kHz, 8-Ohms

MAXIMUM AUDIO OUTPUT CURRENT

• 29 A peak, per channel, both channels driven

INPUT SENSITIVITY

• Low-Gain = 22 dBu (9.8 Vrms), Gain = 9.2 dB
• Mid-Gain = 14.2 dBu (4 Vrms), Gain = 17.0 dB
• High-Gain = 8.2 dBu (2 Vrms), Gain = 23 dB
• Use Mid-Gain or High-Gain settings for unbalanced inputs
• Unbalanced inputs require RCA to XLRM adapter cables

INPUT IMPEDANCE

• 50 k Ohms, normal mode
• 1 M Ohm, common mode

INPUT CMRR

• 80 dB at 20 Hz, typical
• 80 dB at 1 kHz, typical
• 65 dB at 20 kHz, typical

TRIGGER I/O

• 12 VDC 200 mA current-limited output to trigger turn-on of remote devices
• DC input for slaving to remote devices
• Input responds to 3.3 V logic and higher, VIL = 1.26 V, VIH = 2.7 V
• Absolute maximum input voltage = 30 VDC
• Absolute minimum input voltage = -0.3 VDC
• Input Impedance = 20 k Ohms

PROTECTION CIRCUITS

• Fully Electronic, No Relays
• Mute Sequencing
• Distortion Detection
• Short Circuit Detection
• Over Current Detection
• Over Temperature Detection
• SOA Detection (Output device safe operating area)

DIMENSIONS

NON-RACK-MOUNT VERSION:

• 11.04" W x 3.88" H x 9.34 " D - Including feet and binding posts
• 11.04" W x 3.47" H x 8.33 " D - Excluding feet and connectors
• Faceplate height is 2RU

RACK-MOUNT VERSION:

• 19.00" W x 3.88" H x 10.62 " D - Including binding posts, handles and removable feet
• 19.00" W x 3.47" H x 8.33 " D - Excluding feet and connectors
• 9.09" rack depth, including binding posts, excluding cables
• 11" rack depth, including cables
• Faceplate height is 2RU

WEIGHT

• 12.5 lbs., 16 lbs. shipping - Non-rack-mount version
• 13.5 lbs., 17 lbs. shipping - Rack-mount version

AC INPUT

• Auto-ranging AC Input
• 100 to 120 VAC +/- 10%, 8 Amps, 50 - 60 Hz
• 220 to 240 VAC +/- 10%, 8 Amps, 50 - 60 Hz
• Idle Power Consumption = 20 W
• Standby Power Consumption < 0.5 W

@russ69

Thanks.

@secretguy 

Why the tweeter array? 

The tweeter on the 1.7i is serviceable at best. Since they don’t make the 2. series anymore with the ribbon tweeter, and I have good subs, so don’t need the additional bass of the 3.7i panel, why spend $4k more?

When it comes right down to it, the 1.7i might be the best midrange driver on the planet. 😉

These tweeters take it to a whole nother level, and don’t break the bank like Rhaal ribbons or Mundorf AMT's would.

https://www.parts-express.com/GRS-PT5010-8-10-Planar-Mid-Tweeter-8-Ohm-272-130

My world famous factory X-overs from Magnepan. Notice how the inductor is inline to ground, and so most of the mid and none of the treble came through in the beginning.


I posted the image on my FB page so you can see it for yourself. 

Wonder if this forum will ever support pics?

https://www.facebook.com/william.pietrzak.56

@sgreg1


Yes, I have been intrigued by Vincent, but don't like the fact that they are built in Shina. The PS Audio BHK concept at a better price point.


This is in the "fiddling" price range though if I ever get a wild hair, or when this series comes up used somewhere. Of course they make better ones, and there is always the tube premium for the Automatic Tube Upgrade necessity.

I bought a Schiit Lyr with the phono pre onboard for my studio and when I upgraded to the old RCA Red, about ‘58? it added definition to the mid's.


https://upscaleaudio.com/products/vincent-audio-sa-32-tube-hybrid-preamplifier

@jjss49 

We have already settled on a tube pre into a SS amp, I think. 

But thanks so much for you detailed response. I want to buy a used A23 just to gauge the difference between the Parasound Halo line and my Benchmark AHB2. I can always use that in my studio, since my Adcom 555 is dying.

I was thinking a Parasound A21 or a Hegel 20 or 390 used for a high current amp.

Let there be Peace in this valley.... 😉

Steve Guttenberg thinks the Rhumba 3.1 is the choice in my price range.


https://backertlabs.com/rhumba-1-3-preamp/

@fiesta25

It is necessary because:

1. Some people feel the need to reiterate the fact that Maggie’s need a "LOT OF POWER". Which we already know. Many of us are happy with 100w's a channel into 8 ohms with our speakers though and we are not crazy, lazy or stupid. 

2. Not many people are familiar with this amp, but some automatically dismiss it as inadequate. And the most important spec is that if one is not powerful enough for a given person, two in bridged mode will make your ears bleed.

3. I would rather defend people who know what they want "en masse", and I want to hear what others have to say regarding their positive experiences with tubes and Maggie’s, and some people are closed minded and don’t understand that, so feel that we are somehow not listening to the Mantra of Maggie’s.

4. I'd rather hear the positive of someone else’s experience with a Maggie and a Zen Triode than someone that has 2000watts per side AB because that is already established doctrine, and we heard them the first time.

✌️

The Cary pre looks interesting, and the price is certainly right. Thanks @russ69.


Conventional wisdom never is. 

It would be easier if Magnepan just incorporated copper resistive ribbon into their design. A resistor can be any material that resists flow of electricity by definition, so why not just build it in to give the speaker a higher ohm rating, and so better bass control?


Just sayin...

Or they could use less pure foil tape... Length x diameter x resistance is total resistance. You don’t have to use a resistor to increase resistance.

Sorry, school isn’t in session. 

I’m discussing tube amps and Magnepan’s here. Sometimes I get too close to sharing things that should not be.

Knowledge isn’t necessarily power, but knowledge and money can be.

@pkatsuleas


Thank you. 

A wealth of information pertinent to the topic.

The one thing that is already done is changing the speakers over to bi-amp connections, so I can indeed drive the woofers with a ss amp and the mid-hi's with a tube amp. Experimenting with adding depth to the baffles today to improve bass. I think this has been disguised as frame bracing by other moders. It is after all, and open baffle design.

The first time I heard Maggie’s they were hooked up to Audio Research equipment, 1978. That's when I first fell in love with them.

@drbarney1

Thank you for the info and offer. Not going to be building any new amps for the foreseeable future as I have some rebuilds in the works and am also building some Fostex folded horns this year. But I will put the link and your note in my project file.

As of today I am waiting for some new crossover parts for some ideas I have for my 1.7i’s, everything should be here by Wed. of this week, so it’s back to my wife’s garden for me until they get here.

@kellyp

Yes, Magnepan’s are another compromise in the speaker world. Good enough? What is "good enough"?

@Decathlon1991

Please don’t make me talk to Wendell. 😉

@atmasphere 

Thank you for the information. There are so many tube amps I have never heard of. Fortunately many posters here have been providing new ones for exploration.

 It seems the only way to start to be informed is to attend the major audio shows. There are two stereo stores here in Jax, and I am sort of between Atlanta and Miami, and while there are a number of stores available to visit within a days one way drive, they do not come close to representing the products available to the consumer.

Is there a national show that highlights valve amps?

I hope the big shows return this year so I can attend one.