Upgrading Genesis II's

[garylkoh]

The Genesis II was a magnificent beast. It was one of the first Genesis speakers I fell in love with in the 90's. Six feet tall, nearly 3 feet wide, twelve tweeters, 48-inch midrange, four 12" woofers, the G-II were the best loudspeakers if you could afford the Genesis I. Many owners have had their G-II's since day one, and now over 15 years later, are wondering if they can be upgraded/fixed.

With any loudspeaker, the moving parts wear out - and with the G-II, the only drivers that move enough to wear out are the woofers. The ribbon tweeters (unless blown by an errant tube amp) would last "forever". Same thing with the midrange. The original "brown" woofers were made of an aluminum/kevlar sandwich with the brown coating being a damping varnish. Unfortunately, try as we might, we could not get the cone material made. However, the current 12" woofer used in the Genesis 1.2 can be used. The original holes will have to be enlarged, and this can be easily done by an experience woodworker or a handyman.

Unfortunately, the servo-bass amplifier did not have the same longevity, and might be one of the first things to fade out. The electrolytic capacitors in the power supply would be the first to go, and then, unfortunately, take out the logic circuits. As these used EPROMs and a logic chip from the early 90's, it is not possible to fix the servo-bass amplifier if it dies. The IC's have been obsolete for over 10 years already, and even new-old-stock are no longer available. Also, we are not able to re-program the EPROM even if we could find the chips. Whenever I speak to an owner of a speaker of this vintage, one of the first things I would ask them to do is to go to a good local electronics tech and have all the power supply electrolytic caps replaced. It's good insurance especially since the old Genesis Technologies servo-bass amplifiers run HOT!

The solution would be to upgrade to the new Servo-Controlled Amplifier from the new Genesis 2.2.... unfortunately at modern prices.

The midrange ribbon was manufactured by Carver Corporation, another company that has already gone defunct. A midrange using the crossover and midrange from the new G2.2 is also possible here. A couple of customers have at the same time replaced all 15 tweeters with the new one - just for peace of mind.

 

[MylesBAstor]

View attachment 4121

The Genesis II was a magnificent beast. It was one of the first Genesis speakers I fell in love with in the 90's. Six feet tall, nearly 3 feet wide, twelve tweeters, 48-inch midrange, four 12" woofers, the G-II were the best loudspeakers if you could afford the Genesis I. Many owners have had their G-II's since day one, and now over 15 years later, are wondering if they can be upgraded/fixed.

With any loudspeaker, the moving parts wear out - and with the G-II, the only drivers that move enough to wear out are the woofers. The ribbon tweeters (unless blown by an errant tube amp) would last "forever". Same thing with the midrange. The original "brown" woofers were made of an aluminum/kevlar sandwich with the brown coating being a damping varnish. Unfortunately, try as we might, we could not get the cone material made. However, the current 12" woofer used in the Genesis 1.2 can be used. The original holes will have to be enlarged, and this can be easily done by an experience woodworker or a handyman.

Unfortunately, the servo-bass amplifier did not have the same longevity, and might be one of the first things to fade out. The electrolytic capacitors in the power supply would be the first to go, and then, unfortunately, take out the logic circuits. As these used EPROMs and a logic chip from the early 90's, it is not possible to fix the servo-bass amplifier if it dies. The IC's have been obsolete for over 10 years already, and even new-old-stock are no longer available. Also, we are not able to re-program the EPROM even if we could find the chips. Whenever I speak to an owner of a speaker of this vintage, one of the first things I would ask them to do is to go to a good local electronics tech and have all the power supply electrolytic caps replaced. It's good insurance especially since the old Genesis Technologies servo-bass amplifiers run HOT!

The solution would be to upgrade to the new Servo-Controlled Amplifier from the new Genesis 2.2.... unfortunately at modern prices.

The midrange ribbon was manufactured by Carver Corporation, another company that has already gone defunct. A midrange using the crossover and midrange from the new G2.2 is also possible here. A couple of customers have at the same time replaced all 15 tweeters with the new one - just for peace of mind.

The servos never worked from day one starting with the Infinities My friend had an audiophile and engineer at TI build him a new servo. Much better design, flexibility and sound and has worked perfectly for the better part of 20 years!

 

[carolkoh]

The current servo is improved - Gary's design.

 

[MylesBAstor]

The current servo is improved - Gary's design.

Yes saw that in his writeup

 

[garylkoh]

The servos never worked from day one starting with the Infinities My friend had an audiophile and engineer at TI build him a new servo. Much better design, flexibility and sound and has worked perfectly for the better part of 20 years!

Unfortunately true. I re-designed the servo-feedback circuit in 2006 and it's been far better since then.

This is a case where what was being measured was not sufficient. The original servo-circuit had a ruler-flat frequency response curve down to DC (0Hz). Unfortunately, it was extremely slow and this resulted in the bass sounding slow. You couldn't dance to the old Genesis servo, and with rock music, it sounded like the drummer had a leaden foot at the kick-drum. The old Genesis used a 30-ft long servo-bass cable to slow it down even more so that it wouldn't go into oscillation.

A bit of math cured all of that.

 

[MylesBAstor]

Unfortunately true. I re-designed the servo-feedback circuit in 2006 and it's been far better since then.

This is a case where what was being measured was not sufficient. The original servo-circuit had a ruler-flat frequency response curve down to DC (0Hz). Unfortunately, it was extremely slow and this resulted in the bass sounding slow. You couldn't dance to the old Genesis servo, and with rock music, it sounded like the drummer had a leaden foot at the kick-drum. The old Genesis used a 30-ft long servo-bass cable to slow it down even more so that it wouldn't go into oscillation.

A bit of math cured all of that.

Yes I seem to remember in later years AudioQuest made a cable for Genesis.

 

[garylkoh]

Yes I seem to remember in later years AudioQuest made a cable for Genesis.

Yes, they did. It was better than the original Genesis Technologies cables, but still not good enough. The cable is inside the feedback loop, so design was quite critical.... I'll start another thread on the cable design.

 

[MylesBAstor]

Yes, they did. It was better than the original Genesis Technologies cables, but still not good enough. The cable is inside the feedback loop, so design was quite critical.... I'll start another thread on the cable design.

Look forward to it!

 

[Thf99]

Gary, can the G1.1 be upgraded to the G1.2? If possible, what would the cost be?

 

[garylkoh]

Gary, can the G1.1 be upgraded to the G1.2? If possible, what would the cost be?

Please see PM. I'll post a thread on the Genesis One soon......

 

[Thf99]

Please see PM. I'll post a thread on the Genesis One soon......

It'll be great to have a G1 thread.

 

[garylkoh]

A happy customer with a completely upgraded Genesis II - woofers, servo-bass amps, cables, internal wiring, crossover, midrange, tweeters. The speakers are so old that the veneer is bleached by direct exposure to the sun, but the cabinets are still in superb condition.

We had to make the woofer holes bigger, drill new holes for re-wiring, but the 17 year old loudspeakers are now better than new!!

 

[Steve williams]

Not only do the speakers look good but what a wonderful room for them

 

[garylkoh]

It is a magnificent room. Both husband and wife are real music lovers. Except for the power amps which are hidden behind the speakers, all the electronics (plus 10,000 LPs and about as many CDs) are in a room behind the green wall.

Source is the Goldmund Studietto with T3 arm and the Jadis CD player + Jadis DAC.

Totally un-audiophile, but the system was extremely musical. I tuned it for NO sweetspot. They weren't interested in soundstage and imaging, and wanted it to sound the same anywhere in the huge living room.

 

[mep]

I tuned it for NO sweetspot. They weren't interested in soundstage and imaging, and wanted it to sound the same anywhere in the huge living room.

Does that mean you "detuned" the system?

 

[garylkoh]

Does that mean you "detuned" the system?

Absolutely not. It was more difficult than to tune for one sweetspot, or even a love-seat. I had to make sure that there were no hot spots in the room and there wasn't a "hole" in the middle. The trick was to use the rock wall behind the speakers as a focus - it took moving the speakers almost millimeter by millimeter to find that sweet spot when the two speakers coupled together and with the reflection of the rear-radiation of the dipole. It did mess with the imaging, but we didn't lose clarity.

 

[A.wayne]

Garry ,

aren't the mids planar magnetic , not ribbon , the gen1/2 were never ribbons if memory serves me right ...

View attachment 4121



The Genesis II was a magnificent beast. It was one of the first Genesis speakers I fell in love with in the 90's. Six feet tall, nearly 3 feet wide, twelve tweeters, 48-inch midrange, four 12" woofers, the G-II were the best loudspeakers if you could afford the Genesis I. Many owners have had their G-II's since day one, and now over 15 years later, are wondering if they can be upgraded/fixed.

With any loudspeaker, the moving parts wear out - and with the G-II, the only drivers that move enough to wear out are the woofers. The ribbon tweeters (unless blown by an errant tube amp) would last "forever". Same thing with the midrange. The original "brown" woofers were made of an aluminum/kevlar sandwich with the brown coating being a damping varnish. Unfortunately, try as we might, we could not get the cone material made. However, the current 12" woofer used in the Genesis 1.2 can be used. The original holes will have to be enlarged, and this can be easily done by an experience woodworker or a handyman.

Unfortunately, the servo-bass amplifier did not have the same longevity, and might be one of the first things to fade out. The electrolytic capacitors in the power supply would be the first to go, and then, unfortunately, take out the logic circuits. As these used EPROMs and a logic chip from the early 90's, it is not possible to fix the servo-bass amplifier if it dies. The IC's have been obsolete for over 10 years already, and even new-old-stock are no longer available. Also, we are not able to re-program the EPROM even if we could find the chips. Whenever I speak to an owner of a speaker of this vintage, one of the first things I would ask them to do is to go to a good local electronics tech and have all the power supply electrolytic caps replaced. It's good insurance especially since the old Genesis Technologies servo-bass amplifiers run HOT!

The solution would be to upgrade to the new Servo-Controlled Amplifier from the new Genesis 2.2.... unfortunately at modern prices.

The midrange ribbon was manufactured by Carver Corporation, another company that has already gone defunct. A midrange using the crossover and midrange from the new G2.2 is also possible here. A couple of customers have at the same time replaced all 15 tweeters with the new one - just for peace of mind.

 

[garylkoh]

aren't the mids planar magnetic , not ribbon , the gen1/2 were never ribbons if memory serves me right ...

Correct. Actually, they are all planar magnetic as there is a substrate under the foil. However, the industry and most audiophiles call all this type of drivers "ribbons". True ribbons are quite rare.

 

[A.wayne]

Correct. Actually, they are all planar magnetic as there is a substrate under the foil. However, the industry and most audiophiles call all this type of drivers "ribbons". True ribbons are quite rare.

I know ..

I found your comments on the old servo system interesting and correct , had the weirdest bass tone , steady steady and then a big rumble ....

I have admired what you have done with the current line , congrats ...!

 

[MylesBAstor]

Correct. Actually, they are all planar magnetic as there is a substrate under the foil. However, the industry and most audiophiles call all this type of drivers "ribbons". True ribbons are quite rare.

Strathearn. Maggie tweeter. Gold drivers? Carver? Kelley? Townshend Super Tweeter?

I remember Larry Smith and Sal Demicco building a speaker that was based upon an Infinity RS1b except they used Strathearns for the mid/tweeter.