Model Stasis I
The Model Stasis I employed a unique circuit topology that was filed for patent as the Stasis Technology.
Model Stasis I
The 400a was soon after
released as a smaller version of similar circuit configuration. With
external heat sinks this unit was capable of handling 100 W/ch into 8 ohms
with distortion less than .1%. This unit was also the first to use
LED RMS and Peak meters.
The NS 10 pre amp was
also released during this time.
Cascode Series
These amps included the CAS 1 and CAS 2.
Model 4000
The 4000 was manufactured from 1978 to
1980. 200 w/ch. The 4000 was a popular amp during
the same time as the 400a. It uses
the peak and RMS LED display placed in a nice machined dress plate.
Also released to production are the CAS 1 and CAS 2 which were smaller internal heat sink chassis at 75 W/ch and 100 W/ch.
Things to be aware of: The most common components to fail are the power switch and the 2W 1K ohm resistors on the Front End Circuit. The output devices are no longer available, but Vintage amp can replace all of them with a newer components. This amp is easily updated with larger main capacitors.
Comments: Good at driving hard loads. This 200 W/ch is pleasant to listen to, but lacks the bandwidth of more modern amplifiers. This amp is best known for its tube like quality.
Stasis Series
Stasis 3
The
Stasis 2 and 3 were manufactured concurrently in the early 1980's.
Both used the same output configuration. The Stasis 3 offers 100
W/ch into 8 ohms. The Stasis 2 was rated at 200W/ch. The Stasis
3 is the same dimension as the 400a. The SL 10 pre amp
was released to production with this line of products.
Many of these units had poor thermal tracking ability. Thus, many were biased too cool to fully take advantage of Class A operation. Vintage Amp can modify the bias circuit and replace the main capacitors for improved performance.
Series I
The series I products
consisted of the early S 500, S 300 and S 150 amplifiers as well as the
Fet 1 and Fet II preamps. The Amplifiers of this era have grey tops
and say "Overall Feedback Free" on the dress panel.
Series II
The line consisted of the SA 3, (50 W/ch class A), the SA 2 mono block (100 W/ch class A mono block, and SA 1, (160 W/ch class A mono. The S500, S300 and S200 rounded out the line in A/B models. At his time the Fet 9, Fet10h, and Fet10p were in production.
Sa 3 Series II Optical Bias
The SA 3 was the 50
W/ch class A model. This amp is one of my favorites.
Very smooth sound, more detail than earlier models and very good thermal
stability.
Many early Series 1 units were upgraded to optical bias in the late 1080s and to E-line status in the early 1990s. E-line upgrades can be improved with some modifications to the gain card, call for details.
E-line
SA 12 E-line
This popular line of amplifiers was the result of years of research and
testing of Stasis circuit improvement. I believe this amp represents
the maximum performance that can be obtained by using bi-polar devices
in this famous patented circuit design of Nelson Pass. Several engineers,
including Eric Lauchli of Coda worked on the amplifier circuit while Rene
Besne designed the particularly sculpted look of these products.
This amp was manufactured at the peak of Thresholds profitability.
The line consisted of many models as well as the introduction of the DAC
1e.
This was a period of
much growth and transision for the company. The Forte line was moved
from simple bi-polar circuits to the IGBT of the model 4 and model 6.
Fet 10 Phono
Although Threshold may have not been best noted for preamps, none can say this is not a sharp looking unit. It offered many cartridge loading options and parallel fets on each gain card. In addition, the gain cards are placed in parallel further lowering the noise floor. Attention to detail is impeccable by any standard of build quaility.
The T
series of products began with the T 2 preamp, the T 50 and
T 100 amplifiers. It was perceived at Threshold that a new approach
was necessary to continue with out Nelson Pass. The products developed
at this time are the work of Mikael Bladilaius, Mike Jaynes and Wayne Coburn.
The T2 was developed as a balanced preamplifier with Remote Control.
The T 3, remote control preamp followed as a scaled down version with similiar
circuits.
The T 200 and T 400
were released shortly after the T 2 and employed the ultimate in IGBT technology
with completely isolated and regulated Front End Circuit power supply circuitry.
T2 Preamp
T 800 D
This amplifier is a testament to the hard
work of engineers who strive to the absolute best that can be achieved.
This is the culmination of the entire T series of products. The design
of the T 800 is based on the technology obtained in production of the T
200. When the T 800 is used with the T2 in a balanced configuration
the signal is completely balanced all the way to the speaker.