Lafayette LA-84 4 channel amp info?

[radioheadrox]

I may be able to purchase this 4 channel amp. Do you think it is worth it?

The function knob says "SQ Full Logic". Would this be the same full logic circuitry that was in the Lafayette SQ-W?

Any info about this unit would be greatly appreciated.

James

PS - I am currently using a non-logic SQ decoder ( ) but will be acquiring a Sony SQD-2010 in the near future (for use as a decoder and for metering/switching). If the logic in this Lafayette amp is indeed identical to the SQ-W, would it be a worthwhile buy? I would be using the LA-84 amp for the decoder section only.

 

[steve kisner]

james, i,m probably too late for a response, but the sq-w in the lafayette models are about the best i,ve ever heard. i have marantz,pioneer, technics,sansui, well a bunch in my collection. i,ve had a wanted ad for an la-84 on www.classicaudio.com for quite a while now. did you ever get the la-84? i just registered for this site a couple of weeks ago, so a lot of the inquires ore dated. steve

 

[Larry Geller]

It would have to say Full Wavematching Logic to be the same as the SQ-W (or LR-5000 receiver, which is how I have mine). Full Logic was an intermediate step between their regular decoders & their Wavematching ones.

 

[KevinD9052]

I have both the SQ-W and the LR 5000. The SQ-W is the best non Tate decoder ever made. Back in the late '70s I bought an LR 5000 figuring the decoder was the same. It was a good receiver but the decoding was not as good as the SQ-W. It uses a single board unlike the SQ-W which has multiple boards. I heard that the SQ-W was a special project in Japan to create the ultimate SQ decoder without the artifacts, etc. Not sure if it was Sony backed or not, but I can tell you Sony never used it nor marketed it. Their 2020 & 2010 models are not as good. (I have them too). Sony never used the SQ-W boards. How Lafayette got it I don't know but I thank God for small miracles!
As far as the LR 5000, as I remember the decoder was OK- a tad better than mediocre. But this was miles ahead of all the other big brand recievers with logic SQ at that time. In a word, they all sucked. Even some Sonys! (I too had them all in my time.)
Though I can't speak for the LA-84 (which I drooled over back in the '70s-it looked like a large SQ-W-same styling!) I would suspect that it uses the same single decoder board as the 5000. If so, the 2020 would be better if all you want is the decoding.

 

[Warlock]

If you can get a Lafayette LA-84 get it. Anf if you can also get the LT-D10 maching dolby tuner get it also. I have had both for years, Ever since they came out. Also there was an extra board you can get to control CD-4. It did not come with the amp. It had to be purchased seperate. Mine has given me years of trouble free sound.
Lafayette last SQ-L was a SQ-Full logic units. There LR-5000 series reciever as well as there LA-84 amp has SQ-Full with Veriblend logic with wave maching.
Front-Back Logic is designed to keep vocals positioned properly; generally at the front speakers. Wave-Matching Logic (also known as gain-riding) operates similar to front-back but operates individually on each speaker. Variable-Blend Logic senses signals from the front channels that are 'leaking' into the rear and electronically cancels out the leakage. Full-Logic combines two or more of the above to minimize signal leakage from one channel to another.
Early SQ decoders were capable of only around 3db (decibels) of channel separation between the front and rear speakers, creating only a small amount of quad effect. Later research produced "logic" decoders which improved channel separation to as much as 30-40db in some cases. From the start CBS wanted to maintain excellent Left/Right Front stereo effect to the detriment of the quad sound.
SQ-type quad is a 'matrix' quad, as are the QS (RM) and EV-4 types. Any matrix-type decoder will 'decode' a matrix-type encoded record. However, the sound coming out the speakers will usually vary from a little to a lot since each system used a slightly different approach at decoding encoded quad input.

 

[carlane3]

Once you have the decoder in the LR-5000 adjusted properly with the instructions that come with the receiver, you will find the performance pretty much on track with the sq-w. I have had this done by a tech who worked for Lafayette in the 70's and he brought it up to factory spec.

 

[Larry Geller]

Once you have the decoder in the LR-5000 adjusted properly with the instructions that come with the receiver, you will find the performance pretty much on track with the sq-w. I have had this done by a tech who worked for Lafayette in the 70's and he brought it up to factory spec.

I have an LR-5000. The only adjustment on the receiver is for the CD-4 decoder, in the back. There are NO SQ settings to change.

 

[carlane3]

I beg to differ....The service manual has a section where the SQ decoder can be adjusted on the circuit board itself. There are around 8 steps listed to properly adjust the decoder. I have the manual and the tech used it to calibrate it . I would be happy to scan it and mail you a copy if you'd like.

 

[emaidel]

I worked for Lafayette for 14 years, and have posted that before. Both the LR-5000 and the outboard SQ-W were full-logic, wavematching SQ decoders with Variblend, but that in the outboard unit vastly outperformed that in the receiver. I was never aware of any internal adjustments for the LR-5000's decoder, but used the SQ-W along with the LR-5000 for far superior SQ performance. The receiver, like most of the day, had a "Regular Matrix" decoder, which was for the Sansui system, and was also supposed to provide a simulated quad effect from normal stereo sources. It did a horrible job in that respect.

Lafayette really blew it on this, as the "Composer A" circuit in the older LR-4000 receiver, as well as the SQ-W unit, was not only perfect for decoding the Sansui "QS" records, but did a far better job of simulating a quad effect from 2-channel sources. Thus, the outboard unit, along with the receiver, provided that "Composer A" circuit, as well as superior SQ performance, providing the best of both worlds in a pretty decent receiver.

 

[markbark]

I'm looking at Lafayette 1975 catalog as I type " SQ wavematching full logic with Variblend" " Has latest ic solid state circuits" I have both this unit and the LR-300 receiver as well as an Sony 2010 and I feel they are equal. Have a great day!

 

[Zerochief]

I just purchased a excellent condition, fully funtional LA-84 on eBay. $200 shipped.
(Sansui QS-1 was $117 Shipped)

Spade to Banana connectors:
https://www.amazon.com/gp/product/B07XGC6GHX/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

 

[surround.sound.enthusiast]

Nice score for an even nicer price! Is it equipped with the CD-4 demodulator card?

 

[Akaiquadster2]

I worked for Lafayette for 14 years, and have posted that before. Both the LR-5000 and the outboard SQ-W were full-logic, wavematching SQ decoders with Variblend, but that in the outboard unit vastly outperformed that in the receiver. I was never aware of any internal adjustments for the LR-5000's decoder, but used the SQ-W along with the LR-5000 for far superior SQ performance. The receiver, like most of the day, had a "Regular Matrix" decoder, which was for the Sansui system, and was also supposed to provide a simulated quad effect from normal stereo sources. It did a horrible job in that respect.

Lafayette really blew it on this, as the "Composer A" circuit in the older LR-4000 receiver, as well as the SQ-W unit, was not only perfect for decoding the Sansui "QS" records, but did a far better job of simulating a quad effect from 2-channel sources. Thus, the outboard unit, along with the receiver, provided that "Composer A" circuit, as well as superior SQ performance, providing the best of both worlds in a pretty decent receiver.

I have several Lafayette decoders- L and W, but was once told that the SQ-W model that has the brand name in CAPITALS had a superior processing capability? Any thoughts? Here’s a few and I have another in storage with the Capital letters.

 

[Paul Pettegrove]

I think this is visited in an earlier part of the thread. LAFAYETTE labeled SQ-W’s are said to be Full Logic but absent VariBlend. Yours are both “Lafayette” SQ-W‘s. In theory, yours both appear to the later model with VariBlend.

 

[Zerochief]

Nice score for an even nicer price! Is it equipped with the CD-4 demodulator card?

No CD-4 card unfortunately.