Harman Kardon 150+

[krew]

Does anyone know anything about this model? The seller on ebay says its a twin powered receiver like the 30 series. I tried to find some information on it but came up empty. Thanks

[Tomski]

Does anyone know anything about this model? The seller on ebay says its a twin powered receiver like the 30 series. I tried to find some information on it but came up empty. Thanks

Although Im not sure what year or watt rating it is, The twin powers were I believe rated into 4ohms and brief 2ohm ratings,

they were very stable. Is it 2chx2 I assume

Since its older,you will probably need to clean the contacts,bass,treble,ect.This could add to your costs

Does it have a remote? Is it a digital tuner or the spin type,you may have to get up all the time to change a source.

It wont have any digital inputs.

but the specs are still good by todays standards.

[HDBRbuilder]

The H/K 150+ was the "big dog" of the initial H/K quadraphonic receiver series back in the early 1970's. Its replacement in the line-up was the 900+...ACTUALLY, the 150+ was dropped and never really evolved due to over-heating problems...and it was the 100+ that evolved to the 900+. These initial "+" models were called such because of their quad sound field balance "joystick" controls, which made balancing out the four intended speakers much easier. With the sole exception of the early 50+ model, all of these had this "joystick" control.

The 150+ was a bare bones quad unit, and lacked the later evolution units' addition of inboard CD-4 demodulators, and inboard QS and SQ matrixing systems, which the evolved models included...IOW...to properly playback vinyl quad records, one had to add outboard CD-4 demodulators (for CD-4/discrete records), and SQ/QS-matrixed units for those records.

These units were very "busy under the hood", which REQUIRED them to get LOTS of airflow in order to keep from overheating, since the heat-sinks for the four separate amp sections were INSIDE the units, surrounded by numerous circuit boards, which somewhat restricted airflow to those heat-sinks.

WARNING: These units also had a switch on the rear which would "stack" (what we called bi-amping back in those days) the front and rear left channel amp sections together, and the front and rear right channel amp sections together. This was for stereo playback only, and this switch is absolutely NOT to be thrown when the receiver is in operation!!!(ie., do it when the unit is off and COMPLETELY powered down). My advice is just NOT to do it to begin with, unless you NEED the extra power this provides for each stereo channel. Trust me, this is very HARD on the second amp of the pairs when it is running in this manner!

This "amp stacking" takes the 150+ from around 45 wpc in the quad mode, 4 channels driven...to around 150 watts per channel in the "stacked-amp" stereo mode with just two channels driven (L&R front ONLY).

On the 900+ model which replaced the 100+, this is 32 wpc in quad, and 90 wpc in stereo. 150+ models are exceedingly rare in operating condition simply because they were the highest-priced quad units H/K made at the time, AND because so many of them were fried from this "amp-stacking". ALSO, this is the reason that the "evolution" 900+ ,which replaced the 100+, became the second generation "Big-dog" and was rated so much lower in performance than the 150+ had been...in order to somewhat reduce this "amp-frying" tendency.

These receivers ARE twin-powered, meaning they have two power supplies, one committed to the left, and one committed to the right, channel(s), BUT...keep in mind that each of these power supplies is charging TWO channels' amp sections (a front and a rear for each power supply); therefore, those power supplies are a bit more STRAINED than when the twin-powering is only committed to a STEREO-ONLY amplifier section, as in the "X"30 series of stereo receivers. Due to the afore-mentioned nature of these beasts, they also are not as quiet in backround noise as the "X"30 units tend to be...although they ARE relatively quiet in backround noise to the vast majority of other brands of solid-state STEREO receivers which were contemporaries of these units on the market in those days.

Other info: the 75+ evolved into the 800+ (again with inboard demodulator and matrixing units added with around 26 wpc in quad, and around 80 wpc in stacked stereo); while the 50+ was dropped with no evolution.

I currently own two 800+ units and two 75+ units, all awaiting a run-through by a tech; one 150+ unit, awaiting the same "once-over" by a tech; one 50+ unit, awaiting the same "once-over"; and my old buddy, the 900+ that I bought new in late 1975...and which recently had a "once-over" by a tech...and is running like new again! My old 900+ has been put through things most people would NEVER do with a receiver, and has held up magnificently over the years...all things considered!

FAIR WARNING: Keep in mind that the "under-the-hood" complexity of the evolved units (800+ and 900+) makes even COMPLETE tune-ups/check-ups on them exceedingly costly, even when one CAN find a tech who can actually correctly handle the job and who prices his work economically! It becomes much more costly when one has to have the units REPAIRED! BUT, if you can find one that is in great operating condition, and you give it PROPER care, you will be pleasantly surprised at everything it can do...it has capabilities for simultaneously running two separate stereo sources in two separate rooms, with volumes at separate levels for each of those rooms, thanks to its joystick sound-field balance control...and the capability of its FOUR inputs/outputs for tape, auxillary, etc!

One other plus is the built-in "simulated quad", which is called "enhanced stereo" by H/K, and which does cool things to stereo sources that are put through it into four speakers! It makes a great 4.0 surround sound H/T toy, especially when the source is dolby stereo surround encoded...and you correctly wire everything for this!

[heresy2guy]

Love reading posts and replys from you Andy. They're always extremely informative. Thanks. Heresy2guy.

[nicholtl]

Jesus, that's a THUNDEROUS post. HDBRBuilder, I'll bet you were the kind of kid who when the teacher asked for an apple, you came back with a fruit salad, huh?

[Tomski]

Hd I enjoyed learning about some of the earlier H/K twin powered models,I didnt know when the 150+ was made.

I owned two twin powered models,one from 79 and one from 81.

I noticed no one was eager to answer his question,so I tried to give my opinion of my experience with the two twins.

In regards to the 81-680I I will stand by my words above until proven wrong.

Now on a infinitely more important view HD may your journeys to other lands be safe and short!!

Thank You!

Tomski

[krew]

Thanks guys for the replies. I would have thanked you sooner but I have been between computers.

[Daddy Dee]

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On 11/26/2004 1:00:03 AM nicholtl wrote:

Jesus, that's a THUNDEROUS post. HDBRBuilder, I'll bet you were the kind of kid who when the teacher asked for an apple, you came back with a fruit salad, huh?

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Nick, your intuition is actually right on!

HDBRBuilder's college rep is that he would genuinely impress his profs in bringing new research material into his projects. He is one of those Renaissance men.

I am given to understand that in addition to philosophy, he was also known to enjoy an occasional party.

[lipinski]

Talk about some seriously serious trivia!!

[jdavis91]

On 11/25/2004 at 1:47 PM, HDBRbuilder said:

I have a harman kardon 150+ twin power receiver sound not working. Do you know what is the value of it working and the value not working? Trying to see if it's worth fixing or not. I replaced all fuses and sound still doesn't work.