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Threshold - SA/4e stereo amplifier
THRESHOLD SA/4e AMPLIFIER
You are reading the review of one of our 5 prefered amplifiers in the world, the THRESHOLD SA/4e.
My co-administrator Nounours18200, says that it is one of the very best transistors amplifier ever built on the planet... Whatever the forum you read a feedback on it, it always gets an excellent ranking, and more precisely, it is always ranked as the cream of the amplifiers.
The THRESHOLD SA-4e was built from 1990 to 1994. It has been a great commercial success in the States but not in Europe simply because the importer put the price at the celling, nearly 75,000 French Francs at this time ... If you give a look at this article where we have estimated what the current Threshold prices would be if they were still manufactured, you would see that 75,000 FF represent more than 16,000€ in 2008: more or less 24,000$ ! It is therefore easy to understand 2 things:
The manufacturers should also investigate to understand why the current $/€ exchange rate is purely and superbly ignored by the Europeans importers... There is a safe way for the manufacturers to largely increase their sales, simply by adjusting the importers margins, oblige their importer to take the current €/$ exchange rate in their calculation of the retail price, in order to keep the street price at a more reasonable level (in comparison with the States)....
THRESHOLD SA-4e front view.
Consequently in 2008, this amplifier is very rare on the French market, mine is comming from the USA.
It is a 100W pure class A designed by Nelson PASS, who left this company to create his own PASS LABORATORIES as you surely already know if you use to visit our site.
The THRESHOLD SA/4e is built like a tank: thanks Mr PASS. And when we say like a tank, it means than it is impossible to destroy ! Like all the SA serie amplifiers, the cabinet is unblievable thick and robust: have a look at the SA/6e monoblocks in this article: the mechanical build quality is the same. Outstanding.
Do not try to find the same mechanical buid quality nowdays: since the electronics are designed to match the Finance Directors objectives, and since the internal parts are chosen to match the Purchasing Director cost reduction objectives, there is no way to find this quality anymore.
Maybe the PASS LABS cabinets are still as robust as the SA/4e one, but we know no brand actually manufacturing so impressive cabinets (maybe MBL on their monoblocks amps ?, and PASS on their X.5 serie).
The THRESHOLD SA-4e back view.
Regarding the maintenance, there is no problem at all, as for any Threshold SA amp, there is only few things to do, which are fully normal after 15 years of service:
These points have a huge impact on the final musical result.
Threshold SA/4e, inside view
There are only a few amplifiers able to correctly drive the Apogee DIVA and all of them are "monsters", with huge possibilities regarding the current delivery: the SA/4e can deliver more than 35 amps continuously !.
The SA/4e has 26 transistors for each side (i.e 26 transistors per channel), the well known bipolar MOTOROLA MJ15011 et MJ15012 , each of them being able to deliver 10 A (250V) and 200W ... Consequently, the stability of the SA/4e is outstanding, regardless the impedance caracteristics of the loudspeakers.
System used for review is the Reference system #2:
CD player : WADIA 850, Preamp JADIS JP80MC, Loudspeakers APOGEE DIVA (the ribbons have been changed for new ones), interconnect cable silver SILTECH 4-80S , speaker cable silver SILTECH LS2-090.
How to be in the right way with the sound of SA/4e :
First of all, all the tips given in this article remain true, but there a few other things to know to get the best from the SA/4e.
As usual with a new amplifier, I have changed / upgraded some internal components.
First of all, the power supply main capacitors which were too old and had to be replaced (it is fully normal after 15 years of service). The original ones were 27,000µF x 6, but I did not find the same value (more precisely, there is not enough space inside the SA/4e cabinet for housing 6 x 27,000µF new high quality capacitors) so I took 6 x 22,000µF.
Regarding the driver stage, I have changed also some transistors and zener diodes for new ones, with better caracteristics.
I have not forgotten to put 4 small capacitors from Vishay (0.47µF) in // on the main 22,000µFpower supply ones, as it has already been explained in the SA/3.9e and T2 upgrades articles.
As an example, find herebelow 2 pictures of a SA/4e recently upgraded by FIDETECH:
The SA/4e when it arrived at the facility:
and the same one after it has been upgraded by FIDETECH:
With the SA/3.9e, I had changed the tubes of my preamp to the Telefunken 12AX7. With the SA/4e, the best reult is achieved with the GT Groove 12AX7 tubes which perfectly match with the SA/4e.
During the transition period from the upgraded SA/3.9e to the SA/4e, I have also discovered a simple trick that I have described in the Apogee side (left bar). It was to validate HP cable (red and black) in a new dispatch. And the sound is better !
Amongst all the Solid State amplifiers I have eard to date, and I have lessoned to a lot of them (...), I have to say that the SA/4e is IMHO, the best one.
Why ? simply because it is very difficult to find any area in which it is not excellent.
Eveything is very linear, you do not have any excess of medium or bass. With this straight line, you will discover a lot of informations in many CD's that are not present with other poor amplifiers.
You will also discover that a lot of CD are not well recorded. You will be very surprised that there is some portion of your favorite CD that have a 3D aspect totaly new now.
For the cons, I would say that the bass are so well maintained in a velvet glove that it seems they are not enough present under 40Hz.
I am still searching for a bad area but ... there is not !
If I compare it with the upgraded SA/3.9e, I must said that SA/4e has a more extended bandwidth, whereas the SA/3.9e is more medium focused.
The power measured on my SA/4e is not 100W in class A, but 120W. And the energy is uniformly delivered everywhere on the bandwdith, so it seems that the power is inferior of the SA/3.9e. In fact, with more power, you have more ability to drive panels effortless.
My search never ends, but the THRESHOLD SA/4e is a really an exceptional amplifier and you will have also no maintenance and no tubes to changed every 5000 hours.
Article writen by Florent .
Creation date : 19/05/2008 @ 17:43
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