[TomSix]

That tube should be fine.

I've been using the Studio Six with the Audeze LCD-R lately. Even though the headphones themselves are only 2 Ohms, with 103dB sensitivity, they don't require much power at all and work wonderfully with the amp.

This is an interesting report.

The Studio-Six is of course specified for a minimum 6-ohms headphone load at rated distortion levels, but when operated at modest output levels as you mention, *relatively* low distortion operation at lower load impedances should be feasible.

Please elaborate a bit if you can, about the subjective bass performance of the LCD-R when driven by the Studio-Six.

As an aside: a modified Studio-Six with different output transformer ratio to better match the 2-ohm LCD-R, that could be an interesting experiment…

 

[Currawong]

I haven't been listening to much outside jazz lately, so I don't notice weaker bass so much. It's not as impactful as I recall it out of the Master 10, and a quick listen to a track with some tasteful low-bass rumble (When I Get My Hands On you - The New Basement Tapes from the Lost On the River album, or Arlington by The Wailin' Jennys) the low rumble is weaker than ideal and a bit loose. Direct out of the back of the Hugo TT2, the bass is much more full. A 2-Ohm capable version of the Studio Six would certainly be glorious here.

 

[TomSix]

I haven't been listening to much outside jazz lately, so I don't notice weaker bass so much. It's not as impactful as I recall it out of the Master 10, and a quick listen to a track with some tasteful low-bass rumble (When I Get My Hands On you - The New Basement Tapes from the Lost On the River album, or Arlington by The Wailin' Jennys) the low rumble is weaker than ideal and a bit loose. Direct out of the back of the Hugo TT2, the bass is much more full. A 2-Ohm capable version of the Studio Six would certainly be glorious here.

Interesting indeed.

That your Studio-Six is performing enjoyably, if not entirely perfectly, with a 2-Ohm headphone load which is only 1/3 of the amplifier’s rated minimum load impedance — that’s quite noteworthy.

BTW: a “best kept secret” of the Studio-Six is it’s loudspeaker drive capabilities. The amplifier can drive relatively efficient and sensitive loudspeakers to satisfying listening levels.

I used a pair of large Tekton Design ‘Lore’ loudspeakers (10-inch wide-range driver plus tweeter) with the Studio-Six (and the similar specification ‘Studio-Four’ amplifier variant) for a few years, and the match was excellent. Deep, taut, powerful bass. I only sold the Lores because of their rather cumbersome large size, in consideration of a then upcoming long distance household move.

Presently, I use a pair of more modestly-sized Omega Loudspeakers ‘Compact Alnico Monitors’ (6-inch full-range drivers with alnico magnets) which are nearly an ideal match for the Studio-Six, and they sound incredible —within their maximum-SPL and lower-bass extension limitations, of course.

An updated Studio-Six model with integrated loudspeaker binding posts was designed, and discussed at some length, but to date has not been pursed by ALO.

 

[longbowbbs]

Tom, how do you connect a pair of speakers to the S6? I have a pair of DeVore O/93's that are an easy load and they sound great with my Luxman tube gear.

 

[TomSix]

Tom, how do you connect a pair of speakers to the S6? I have a pair of DeVore O/93's that are an easy load and they sound great with my Luxman tube gear

Those DeVore loudspeakers sound like a good possibility to try with the Studio-Six.

It is possible to simply make a dongle which consists of a 1/4-inch stereo phone plug with maybe 1-meter of line connected to a very small cast metal project box with a pair of speaker terminals installed in it. When this dongle is plugged into a Studio-Six headphone jack, the output line can be looped directly underneath the amplifier chassis and exit to the rear of the amplifier.

At one time, ALO actually made a few sets of dongles for the Studio-Six consisting of a pair of full-length (a few meters each L/R leg) speaker lines connected directly into a stereo phone plug. This ‘all-in-one‘ dongle worked, but could be rather awkward and inconvenient in use, and so was never formally offered as an accessory product.

A further possibility would be to make a pair of separate full-length speaker lines, and terminate each line into it’s own individual 1/4-inch stereo phone plug. One speaker line would be soldered to only the R channel contacts of it’s particular stereo phono plug, and conversely the other line would be soldered to only the L channel contacts of it’s stereo phono plug. In this way one gets separate L/R speaker lines which can be plugged into any two of the Studio-Six’s four headphone jacks. As with the short dongle mentioned previously, these lines could be neatly looped to run underneath the Studio-Six chassis and run out from under the back of the amplifier and on out to the loudspeaker.

My own gear has speaker terminals installed into the chassis, which I prefer of course to using dongles. Nonetheless, the dongle approaches can work satisfactorily.

 

[Currawong]

A Studio Six with a few Watts and speaker taps on the back would be fantastic.

 

[TomSix]

A Studio Six with a few Watts and speaker taps on the back would be fantastic.

It‘s actually pretty astonishing how well a good 93dB or more sensitivity loudspeaker can play with the existing Studio-Six.

As long as a loudspeaker doesn’t dip much below 6 Ohms, and doesn’t have a challenging reactive load (complex crossovers are often culprits in this regard) the performance is full and clean.

I proposed a simple modification, whereby when no headphones were plugged into the Studio-Six, the audio output would automatically be routed to a pair of loudspeaker terminals on the rear of the unit.

It’s also possible to increase the output power of the Studio-Six by approximately 50% with fairly simple modifications.

The combination of these two mentioned mods I proposed a few years ago as features of a possible MKII version of the Studio-Six, but the concept did not fully gain traction at the time.

 

[RobertSM]

Well it looks like Classic Tone transformers went out of business at some point late last year. I believe the output transformer in the Studio Six were made by Classic Tone. Maybe also the chokes and mains transformer too?

So this begs the question. If the Studio Six does use these critical parts for the amp and with these parts no longer being made will ALO have to revise the SS?

It's definitely possible to find other high quality transformers from other manufacturers but with other transformers also comes different sonic characteristics. I mean the SS has been tuned to have a specific desired sound. I can only believe that this might be a great time for the nearly 10 year old SS to be refreshed.

On that note, I'd personally be interested in a new SS with the same tubes used throughout but with ultra premium internals. TOTL resistors and true TOTL filtering capacitors as well as TOTL output capacitors. No need to change the chassis, it's beautiful and classy. But a refresh of all the internals is something that I'd buy in a second.

ALO Studio Six MK II

Has a nice ring to it, don't you think?!

 

[xtr4]

Well it looks like Classic Tone transformers went out of business at some point late last year. I believe the output transformer in the Studio Six were made by Classic Tone. Maybe also the chokes and mains transformer too?

So this begs the question. If the Studio Six does use these critical parts for the amp and with these parts no longer being made will ALO have to revise the SS?

It's definitely possible to find other high quality transformers from other manufacturers but with other transformers also comes different sonic characteristics. I mean the SS has been tuned to have a specific desired sound. I can only believe that this might be a great time for the nearly 10 year old SS to be refreshed.

On that note, if personally be interested in a new SS with the same tubes used throughout but with ultra premium internals. TOTL resistors and true TOTL filtering capacitors as well as TOTL output capacitors. No need to change the chassis, it's beautiful and classy. But a refresh of all the internals is something that I'd buy in a second.

ALO Studio Six MK II

Has a nice ring to it, don't you think?!

Speaker taps, don't forget the speaker taps lol

 

[TomSix]

Well it looks like Classic Tone transformers went out of business at some point late last year. I believe the output transformer in the Studio Six were made by Classic Tone. Maybe also the chokes and mains transformer too?

So this begs the question. If the Studio Six does use these critical parts for the amp and with these parts no longer being made will ALO have to revise the SS?

It's definitely possible to find other high quality transformers from other manufacturers but with other transformers also comes different sonic characteristics. I mean the SS has been tuned to have a specific desired sound. I can only believe that this might be a great time for the nearly 10 year old SS to be refreshed.

On that note, I'd personally be interested in a new SS with the same tubes used throughout but with ultra premium internals. TOTL resistors and true TOTL filtering capacitors as well as TOTL output capacitors. No need to change the chassis, it's beautiful and classy. But a refresh of all the internals is something that I'd buy in a second.

ALO Studio Six MK II

Has a nice ring to it, don't you think?!

Very astute observations Robert.

Yes, indeed, Classic Tone has sadly gone out of business. In fact, the power transformer is the *only* Classic Tone device utilized in the Studio-Six. The power supply chokes and output transformers are from other, very established companies that are doing robust business today.

Good news: The Classic Tone power transformer used, is in fact a near-clone of a very popular Hammond power transformer which has excellent availability. Just a couple primary wiring connection changes, and the Hammond units would fit and operate identically to the original Classic Tone transformers.

Even better news: The high quality power transformer in the Studio-Six is very under-stressed, as it is being run quite conservatively by design. The failure potential of this part, even very long term, is quite low.

Serviceability, reliability, conservative operation—these were all design imperatives of the Studio-Six. The avionics and mil-spec construction ideals informed the design of the Studio-Six quite significantly.

In 8 years of production, the reliability of the amplifiers has been demonstrated to be excellent. The vast majority of the small amount of factory maintenance and warranty work required by units over these years has been limited to simple vacuum tube replacement.

 

[RobertSM]

@TomSix

It's nice to hear that the core sound that we all love won't be impacted by a lack of parts availablelity.

As always thank you for sharing your insights. Your participation in this thread is greatly appreciated.

 

[longbowbbs]

Very astute observations Robert.

Yes, indeed, Classic Tone has sadly gone out of business. In fact, the power transformer is the *only* Classic Tone device utilized in the Studio-Six. The power supply chokes and output transformers are from other, very established companies that are doing robust business today.

Good news: The Classic Tone power transformer used, is in fact a near-clone of a very popular Hammond power transformer which has excellent availability. Just a couple primary wiring connection changes, and the Hammond units would fit and operate identically to the original Classic Tone transformers.

Even better news: The high quality power transformer in the Studio-Six is very under-stressed, as it is being run quite conservatively by design. The failure potential of this part, even very long term, is quite low.

Serviceability, reliability, conservative operation—these were all design imperatives of the Studio-Six. The avionics and mil-spec construction ideals informed the design of the Studio-Six quite significantly.

In 8 years of production, the reliability of the amplifiers has been demonstrated to be excellent. The vast majority of the small amount of factory maintenance and warranty work required by units over these years has been limited to simple vacuum tube replacement.

I have enjoyed mine for seven years. It is never leaving my system.

 

[TomSix]

Excellent new review of the Audeze LCD-5 by Currawong:



My question for Currawong: Have you yet had a chance to try the LCD-5 with the Studio-Six?

From the review, it is evident the performance of the LCD-5 is quite amplifier dependent.

I am curious —how does the LCD-5 plus Studio-Six combination play?

Your frank commentary/impressions would be appreciated

 

[longbowbbs]

I will say that the LCD-X's are a great pairing with the Studio SIx. I would assume the new ones should be a good match as well.

 

[Currawong]

I will say that the LCD-X's are a great pairing with the Studio SIx. I would assume the new ones should be a good match as well.

They are. Due to popular demand, I shot a followup with the Susvaras, using the LCD-5s out of the Studio Six.