[EDS_]

I'd rather go SET or triode PP then OTL, but that is me. 

 
I did the OTL thing for a bit and really hated the experience.

Going a bit further, I prefer PP triode over SET as well. 

[Mariusz]

Hi Ali,
I just bought Melody M300b monos.
Way under your budget ........love it.
just test them with vintage Radio Shack drivers in OB design.
Love it.
I will use these to voice my other single driver designs in the near future.

if you need a good deal on those (new) , let me know.

Mariusz

[kenreau]

I'd rather go SET or triode PP then OTL, but that is me. 

 
I did the OTL thing for a bit and really hated the experience.

Going a bit further, I prefer PP triode over SET as well. 

x 3 vote for PP Triode over SET.     I don't know what it is, but SETs for me run a fine line of working or not and the synergy with the speaker is critical.  In addition, they definitely shine on smaller scale vocals, jazz, folk stuff but not so well on larger scale complex classical and rock.  PP for some reason seems to work more universally with more speakers and types of music.

I had Atmasphere M60 Mk III OTLs for about 1 year then had them upgraded by Jena Labs thinking that would cure my illls.  I still could not enjoy them for extended periods of time.  Just a little to thin and analytical for my tastes. 

For me the EL34 triode amps are rich, resolving, relaxing and provide me hours of musical enjoyment.  aa

Kenreau

[Jon L]

From the published technical specs:

Frequency Response: 30-30kHz +/- 2 dB
Nominal Impedance: 8 ohms.
Sensitivity: 93 dB/2.83V/Meter
Crossover: 450Hz Second Order Acoustic In-Phase Linkwitz-Riley (Woofer to Midrange)
and  2.5kHz Fourth Order Acoustic In-Phase Linkwitz-Riley (Midrange to Tweeter)

That midrange driver appears to be PHL 1120/1130 series, which is 96dB sensitive (at 8 and 16 Ohms respectively).  It's probably being padded down to match the lower sensitivity of the woofer. 
Good ribbon tweeters often hit >96-98dB sensitivity easily, so that's not the problem.  If you were to go the active route, you could have honest-to-goodness 96dB/8ohm (or 16) treble/midrange  module, which will open up great flea-amp potential.  I used to run 1.5 watt 45 SET on 95dB treble/midrange modules with plenty of power. 

I would *not* power the entire speaker passively with most SET's, except maybe certain 6C33C types with high(er) current/damping factor.  Biamping, passively or actively, will be a problem with the 450Hz woofer crossover, which is too high.  I've tried and tried, and I personally cannot accept the degree of coherence loss unless the crossover point is at most ~150Hz or lower. 

Of course, those PHL drivers can be used down to 150-170Hz when loaded into a huge sealed box (6-10L)

Just some ramblings..

[chadh]

I remember hearing those super-cool looking Salk speakers at the Audio Karma fest (with the dome tweeter rather than the ribbon).  At that time, Jim had two forms of amplification available, both from Van Alstine.  One of the amps was the Ultra 70, or whatever Frank calls his upgraded Dynaco ST70.  I never heard it playing though, because Jim said it didn't work with the speakers.  His conjecture seemed to be that the speaker presented a difficult impedance curve for tube amps in general.  I don't know if things have changed in the design, or is this is alleviated by bi-amping, but I'd talk to Jim about the plan before you commit $3000 to SET amp.

If you do choose to go with SET, I'll do the standard thing and recommend the manufacturers that made my gear:  Music Reference and Space-Tech-Labs.  For what it's worth, Albert at Space-Tech-Labs also makes tubed active crossovers, if you're thinking of bi-amping.

Chad

[doug s.]

for amps, i would try almarro and audio mirror.  based upon comments of others, i would also try promitheus, if you can deal with their delivery times.  (these look like a killer deal, even if you cannot conwert them to 120v, and have to use step-up transformers):
http://www.audiocircle.com/index.php?topic=59528.0

i am also a firm believer in active x-overs.  however, short of complete re-design of your speakers' x-over, in your case, i would stick w/bi-wiring an set amp on your mains, and then use an active x-over on a pair of subs, crossed over at ~60-80hz or so.  the set amps will work fine on your mains crossed there, and the mains themselves will sound better w/their woofers not seeing anything below the x-over frequency.

also, re: dsp x-over, i used to use a marchand, (tho not tubed, like rim's), and my winyl still sounds great now that i am using a deqx.  its pluses outweigh it's minuses, imo...

doug s.

[boead]

This is very hard to beat. From Peters website at http://mcalisteraudio.com/

Peter McAListers SE44 : Single Ended Class A Stereo Amplifier

The SE44 stereo single ended power amplifier utilizes four horizontal output tubes paralleled in triode mode to produce 22watts per channel in class A.
The input stage for each channel utilizes an improved Mu follower design that utilizes a 6LU6 as the voltage amplifier (triode section) and ( pentode) section as the constant current source. This is a true constant current source that has more than enough gain to properly respond to the small signal / voltage changes without a resistor dropping large amounts of voltage typically in standard Mu follower designs.
Additionally a driver stage has been included which is a critical factor to ensure excellent low end response and a quick rise time. The driver stage uses a 6/12SN7 of which one triode provides regulation with the other triode directly driving the output tubes in a cathode follower configuration without the need for capacitors.
The only capacitors in the signal path are between the input and driver stage which are high quality polypropylene. The output stage for each channel consists of four 12GE5 or horizontal sweep tubes paralleled in triode mode with class A operation. This output configuration can pass a large amount of current with harmonic distortion in dB relative fundamental of 2nd -26, 3rd -44, and 4th - 60.
A separate and well regulated bias supply with external top mounted chassis adjustment is used. The negative voltage is adjustable and fed to the control grid of the output tube that determines the current flow and class of operation.
All of my power amplifier designs use a fixed bias voltage that eliminates the cathode resistor and electrolytic by-pass cap producing an amplifier with fast rise times, superior dynamics and transparency. The output transformers are custom designed and hand wound with four primary and three secondary interleaved sections with each layer varnished prior to insulation.
The power supply has over 2,000uf of capacitance by-passed with film capacitors- electrolytic capacitors are only used in the power supply and never directly in the signal path. Plate voltage is delayed 30 seconds to prevent cathode stripping. This automatic system uses a damper diode providing D.C. relay voltage through a controlled warm up. Quality Ceramic tube sockets, point to point wiring, IEC input, 5 way binding posts and NOS tubes complete the package. All tubes are NOS with 13 tube compliment of 2X6LU6, 2X6/12SN7, 8X12GE5 and 1X6AX4 thermal delay tube.

Build Features:
• Only film capacitors in the signal path- no electrolytic capacitors (only in power supply circuits).
Regulated fixed bias
• Thermal delay to prevent cathode stripping.
• Hardwired point to point.
• 12GE5 horizontal output tubes that have lower harmonic distortion than 811, 300B ,6550, EL34 etc and are more efficient than 300B’s. A minor modification will allow the use of a variety of different types such as the EL509/PL519 or 6KG6 currently produced in Russia.
• Aluminum one piece powder coated chassis design
• Amplifier dimensions: 21”W x 14”D Power supply 8”H x 14”W X 8”D

Build Options:
• Front panel lettering in white or gold
• LED color choice for power on and operation status
• Umbilical cord length between the power supply and amplifier to suit your needs.
• Solid side panels in Maple, Cherry, Oak or Paduke ( similar to mahogany )
• 240 volt configuration available on request
Pricing: SE-44 $2299
All prices are in USD and do not include shipping or customs duty and brokerage fees if applicable.

[toobluvr]

Some of my suggestions, based on what is on A'gon right now....

$900 offers good value, could be modded later

........

I owned these ASL 845 monos for several years and loved them.  You still get the sweet tone, harmonics and inner-lit quality that we chase SET for, but the 845 tube provides more grunt and power output (22 wpc) than the typical SET amp.  On the right speaker, it is great!

And I can only imagine how good the DeHavilland 845 is!
I would own it in a heartbeat!

 

[opnly bafld]

This is very hard to beat.

Peter McAListers SE44 : Single Ended Class A Stereo Amplifier

From Peters website at http://mcalisteraudio.com/
The SE44 stereo single ended power amplifier utilizes four horizontal output tubes paralleled in triode mode to produce 22watts per channel in class A.

I agree. 

Lin