Altec Lansing 1594A - 1967 [100W Solid State Mono Power Amplifier] BOM + Manual

[TelRay]

Hi all,

I have recently bought a couple of these monsters just because I though they would sound good for Hi-Fi (mostly vinyl records playing). The main thing that attracted me to buying them was their reputation and the big output transformer.



So, I have been working on a BOM to refurbish / upgrade the units and thought I should share here as I have found almost no information of people having worked on them in case it's useful for anyone in the future.

#	VALUE	RATING	MOUSER	PRICE	LINK	NOTES
C1	1 µF	25 V	505-MKS2C041001FKI00	$ 0.63	https://www.mouser.com/WIMA/Passive-Components/Capacitors/Film-Capacitors/_/N-9x371Z1yzvvqx?P=1z0wrj5Z1z0z7l5Z1yx4avvZ1yx4avuZ1yx4atuZ 1z0zldh&FS=True&Ns=Pricing|0	new WIMA
C2	500 pF	100 V	505-FKP2D004701D00HA	$ 0.40	https://www.mouser.com/ProductDetail...tIjO9YnQ%3D%3D	now ceramic 500 pF 100V 10%, new WIMA 470 pF 2.5%
C3	500 pF	100 V	505-FKP2D004701D00HA	$ 0.40	https://www.mouser.com/ProductDetail...tIjO9YnQ%3D%3D	now ceramic 500 pF 100V 10%, new WIMA 470 pF 2.5%
C4	1 µF	25 V	505-MKS2C041001FKI00	$ 0.63	https://www.mouser.com/WIMA/Passive-Components/Capacitors/Film-Capacitors/_/N-9x371Z1yzvvqx?P=1z0wrj5Z1z0z7l5Z1yx4avvZ1yx4avuZ1yx4atuZ 1z0zldh&FS=True&Ns=Pricing|0	new WIMA
C5	50 uF	25 V	647-UKZ1H470MPM	$ 0.60	https://www.mouser.com/ProductDetail...Fi0TLMbQ%3D%3D	new NICHICON 47 uF 50 V
C6	50 uF	25 V	647-UKZ1H470MPM	$ 0.60	https://www.mouser.com/ProductDetail...Fi0TLMbQ%3D%3D	new NICHICON 47 uF 50 V
C7	0.005 uF	100 V	598-WMF1D5K-F	$ 1.78	https://www.mouser.com/ProductDetail...RJCYfD5A%3D%3D	now ceramic 100V 10%, new PP or PET film
C8	0.005 uF	100 V	598-WMF1D5K-F	$ 1.78	https://www.mouser.com/ProductDetail...RJCYfD5A%3D%3D	now ceramic 100V 10%, new PP or PET film
C9	50 uF	50 V	647-UPW2A470MPD	$ 0.45	https://www.mouser.com/ProductDetail...q5OXcsjg%3D%3D	new NICHICON 47 uF 100 V
C10	50 uF	50 V	647-UPW2A470MPD	$ 0.45	https://www.mouser.com/ProductDetail...q5OXcsjg%3D%3D	new NICHICON 47 uF 100 V
C14	0.02 uF	100 V	505-MKS4D022202A00JI	$ 0.51	https://www.mouser.com/ProductDetail...Gh7PrxQw%3D%3D	new 0.022 uF WIMA
C15	0.01 uF	100 V	505-MKS4.01/100/10	$ 0.41	https://www.mouser.com/ProductDetail...7xbRXGAg%3D%3D	new 0.01 uF WIMA
C16	0.1 uF	100 V	598-715P10452LD3	$ 4.10	https://www.mouser.com/ProductDetail/Cornell-Dubilier-CDE/715P10452LD3?qs=SfuicISz1S%252BBjTgI%252BI9ikg%3D%3D	new Orange drop 0.1 uF 250 V
C17	7,000 uF	35 V	80-ALS70A822DA063	$ 16.70	https://www.mouser.com/ProductDetail...LTC40Z0Q%3D%3D	new 10,000 uF 100 V low impedance UPW or UHE
C18	1,000 uF	50 V	647-UPW1J222MHD	$ 2.51	https://www.mouser.com/ProductDetail/Nichicon/UPW1J222MHD?qs=Z9twEOuL%252B%2FL4qjLnhETbww%3D%3D	new 2,200 uF 63 V low impedance UPW or UHE
C19	1,000 uF	50 V	647-UPW1J222MHD	$ 2.51	https://www.mouser.com/ProductDetail/Nichicon/UPW1J222MHD?qs=Z9twEOuL%252B%2FL4qjLnhETbww%3D%3D	new 2,200 uF 63 V low impedance UPW or UHE
C20	0.01 uF	100 V	810-FA28C0G2A103JRU6	$ 0.43	https://www.mouser.com/ProductDetail...2Fp1vUCA%3D%3D	now ceramic 20%
CR3	1N456A		512-1N456A	$ 0.19	https://www.mouser.com/ProductDetail...FnRGEMKQ%3D%3D	Diodes to UF, Protection circuit?
CR4	1N456A		512-1N456A	$ 0.19	https://www.mouser.com/ProductDetail...FnRGEMKQ%3D%3D	Diodes to UF, Protection circuit?
CR5	1N456A		512-1N456A	$ 0.19	https://www.mouser.com/ProductDetail...FnRGEMKQ%3D%3D	Diodes to UF, Protection circuit?
CR6	1N456A		512-1N456A	$ 0.19	https://www.mouser.com/ProductDetail...FnRGEMKQ%3D%3D	Diodes to UF, Protection circuit?
CR7	1N456A		512-1N456A	$ 0.19	https://www.mouser.com/ProductDetail...FnRGEMKQ%3D%3D	Diodes to UF, Protection circuit?
CR8	1N456A		512-1N456A	$ 0.19	https://www.mouser.com/ProductDetail...FnRGEMKQ%3D%3D	Diodes to UF, Protection circuit?
CR12	Zener 10 V 5%		512-1N4740A	$ 0.24	https://www.mouser.com/ProductDetail...PvH22DMA%3D%3D	Zener 10V 1W 5%
R4	3.3 KΩ	0.25 W	603-MFR-25FTE52-3R3	$ 0.18	https://www.mouser.com/ProductDetail...2BXJPsrg%3D%3D	Signal path 1% film 50 PPM/C
R10	680 Ω	0.25 W	603-MFR-25FTE52-680R	$ 0.12	https://www.mouser.com/ProductDetail/Yageo/MFR-25FTE52-680R?qs=UFD7vfw3J8pqz%2F5S%2FQHkFQ%3D%3D	Signal path 1% film 50 PPM/C
R24	330 Ω	1 W	71-CMF60330R00FKEA	$ 0.53	https://www.mouser.com/ProductDetail...GNuejwmz4Vo%3D	1% film 50 PPM/C
R25	47 Ω	0.50 W	71-CMF55-39471%T1TR	$ 0.85	https://www.mouser.com/ProductDetail...1KuxQ41g%3D%3D	1% film 100 PPM/C
R26	47 Ω	0.50 W	71-CMF55-39471%T1TR	$ 0.85	https://www.mouser.com/ProductDetail...1KuxQ41g%3D%3D	1% film 100 PPM/C
R27	330 Ω	1 W	71-CMF60330R00FKEA	$ 0.53	https://www.mouser.com/ProductDetail/Vishay-Dale/CMF60330R00FKEA?qs=sGAEpiMZZMtlubZbdhIBIN0gBBrNeZH6GNuej wmz4Vo%3D	1% film 50 PPM/C
R37	22 Ω	1 W	71-CW00122R00JE70	$ 0.85	https://www.mouser.com/ProductDetail...XiGju4XhQLI%3D	new wirewound 5% before carbon 10%
R38	22 Ω	1 W	71-CW00122R00JE70	$ 0.85	https://www.mouser.com/ProductDetail/Vishay-Dale/CW00122R00JE70?qs=sGAEpiMZZMtlubZbdhIBIMpVPzcZDNApXiGju4 XhQLI%3D	new wirewound 5% before carbon 10%
R39	0.50 Ω	10 W	71-CP10-K-0.5	$ 1.36	https://www.mouser.com/ProductDetail...bNKJKeMA%3D%3D	Emitter R 0.5 Ohm 10W 10% Dale
R40	0.50 Ω	10 W	71-CP10-K-0.5	$ 1.36	https://www.mouser.com/ProductDetail...bNKJKeMA%3D%3D	Emitter R 0.5 Ohm 10W 10% Dale
R42	0.50 Ω	10 W	71-CP10-K-0.5	$ 1.36	https://www.mouser.com/ProductDetail...bNKJKeMA%3D%3D	Emitter R 0.5 Ohm 10W 10% Dale
R50	0.50 Ω	10 W	71-CP10-K-0.5	$ 1.36	https://www.mouser.com/ProductDetail...bNKJKeMA%3D%3D	Emitter R 0.5 Ohm 10W 10% Dale
R41	4.7 KΩ	1 W	71-CMF604K7000FKEK	$ 0.50	https://www.mouser.com/ProductDetail/Vishay-Dale/CMF604K7000FKEK?qs=sGAEpiMZZMtlubZbdhIBIBrleWQMc4Kf8Ei%2 52B7wNPQsw%3D	Signal path 1% film 50 PPM/C
Q1	AL41440	2N3906	512-2N3906TAR	$ 0.21	https://www.mouser.com/ProductDetail...vU5pgBbw%3D%3D
Q2	AL41441	2N3906	512-2N3906TAR	$ 0.21	https://www.mouser.com/ProductDetail...vU5pgBbw%3D%3D
Q3	AL41442	2N3906	512-2N3906TAR	$ 0.21	https://www.mouser.com/ProductDetail...vU5pgBbw%3D%3D
Q4	AL41443	2N3906	512-2N3906TAR	$ 0.21	https://www.mouser.com/ProductDetail...vU5pgBbw%3D%3D
Q7						AL40934 NPN new 2N3055
Q8						AL40934 NPN new 2N3055
Q9						AL40934 NPN new 2N3055
Q10						AL40934 NPN new 2N3055
Q11						AL40934 NPN new 2N3055
Q12						AL40934 NPN new 2N3055
Q13						V regulator AL2712 NPN new 2N2715 min 25 Vceo
Q14						V regulator AL2712 NPN new 2N2715 min 25 Vceo
SR4	Diode Rect	1N4002	512-UF4007	$ 0.34	https://www.mouser.com/ProductDetail/ON-Semiconductor-Fairchild/UF4007?qs=NwIfwa72FlplAHiXupLMBA%3D%3D	now 1N4002, now UF4007 Vr 1KV If 1A Vf 1.7V
SR5	Diode Rect	1N4002	512-UF4007	$ 0.34	https://www.mouser.com/ProductDetail/ON-Semiconductor-Fairchild/UF4007?qs=NwIfwa72FlplAHiXupLMBA%3D%3D	now 1N4002, now UF4007 Vr 1KV If 1A Vf 1.7V

[nickb]

That was a lot of work and very kind of you. Can I suggest a pdf of the BOM would be a more useful format?

[vintagekiki]

https://vdocuments.site/altec-lansing-1594-b-owners-manual.html

https://www.hifiengine.com/manual_library/altec-lansing/1594a.shtml

https://www.hifiengine.com/manual_library/altec-lansing/1594c.shtml

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[J M Fahey]

Thanks for all the effort.

A WEIRD amplifier, but, hey, they were opening an new path where previously there was none.

I know Argentine Musicians playing in small villages high in the Andes, in Peru and Ecuador, travelling on mule packs, no kidding (safer than decrepit buses with drunk drivers travelling 6 ft wide roads along the abyss) , being promised "high quality PA equipment" on arrival, and finding "green Altec amps" all over the place, driving farmer market approved tin horns.
They WERE heard no doubt, for miles away ... if you are happy with 250 to 4000 Hz speaker response.

[Jazz P Bass]

Welcome back Juan!!!!

[J M Fahey]

Thanks JPB

[TelRay]

Thanks for all the effort.

A WEIRD amplifier, but, hey, they were opening an new path where previously there was none.

I know Argentine Musicians playing in small villages high in the Andes, in Peru and Ecuador, travelling on mule packs, no kidding (safer than decrepit buses with drunk drivers travelling 6 ft wide roads along the abyss) , being promised "high quality PA equipment" on arrival, and finding "green Altec amps" all over the place, driving farmer market approved tin horns.
They WERE heard no doubt, for miles away ... if you are happy with 250 to 4000 Hz speaker response.

ahhh... I bet you could find jewels like this even deep in the amazon forest too. hahahah...
btw... i remember waiting in line with my dad at your shop in "La Boca" back in 1989 (?) while you finished soldering the last components of a bass head amp for me

[The Dude]

I'll second JPB........ Welcome back Juan!

[J M Fahey]

ahhh... I bet you could find jewels like this even deep in the amazon forest too. hahahah...
btw... i remember waiting in line with my dad at your shop in "La Boca" back in 1989 (?) while you finished soldering the last components of a bass head amp for me

WOW!!! Small world indeed!!!
Thanks for the good memories

dude

I'll second JPB........ Welcome back Juan!

Thanks dude

[J M Fahey]

ahhh... I bet you could find jewels like this even deep in the amazon forest too. hahahah...

FWIW one such Artist was Valeria Lynch, playing *everywhere* (including high in he Andes and yes, on Amazon forests too) after one of her songs became a BIG hit after becoming a popular "Telenovela" theme.
Her sessionist Bass player, who was already a Pro customer, came desperate asking for "a loud shoebox sized 200W Bass amplifier" or as close to that as possible, because voice, guitar, even drums could be played through those fruit market tin horns, sounding nasal, tinny, muffled, you name it, but still heard ... except the Bass, he had to fill those valleys on his own, unaided.
To boot, he came desperate on Tursday morning ... he had to fly on Friday night

[TelRay]

there's one thing that took me a bit to figure out about these 2 units

there was a difference in R41, was 22 Ohm in one unit and 4.7 Ohm on the other.
Turns out the oldest Amp corresponds to Rev 4 (manuf date 1969 WK46) and the newer to Rev 5 (manuf 1970 WK48) and there were 2 changes between those two versions:

- R41 changed from 22 Ohm to 4.7 Ohm
- C21 0.01 uF was added to ground (from the + terminal of the big cap C17)

I will change R41 in the older unit to the new value. Can anyone help me understand what would be the benefit of this change?
I will also add C21 on the older unit. Again, what would be the added value?

Addionally, there is a later change on Rev 6 that changed R20 from 150 Ohm to 390 Ohm (5% 0.5 W). I have not replaced this resistor when refurbishing the unit, should I?

thanks!

PS: schematic attached to post #1 (in the users manual)

[Enzo]

Just in general, should we not determine first what benefits might accrue before we decide the changes are to be made?

Probably won't hurt, but sometimes changes are made for reasons not apparent. I will make one up. What if they made the amps with Texas Instrument transistors, and it all worked fine. Then for supplier reasons they switched to Motorola and found a little tendency toward instability at high levels. SO they changed the value in that stability circuit. The change works for the Moto and has no effect on the TI.

C21 might have been added to solve occasional RF issues in some locations. My shop was a half mile from an AM radio transmitter, and that signal was all over my shop. Across town, no such issue.

R20 looks to me like it and the other two resistors near it are a voltage divider providing a bias voltage for the drivers. I wouldn't mess with it unless you amp is running hot or cold or something,

[TelRay]

thx Enzo!

[TelRay]

after finishing the two units I was wondering how to check the bias
the manual describes the procedure as hooking a scope across the 4 Ohm speakers output and feeding the unit with a 1,000 Hz signal
i am wondering:
- should i have a load connected to the speakers output as well while doing that?
- how loud should the 1,000 Hz signal be? i’ve read that the amp’s input sensitivity is 0.8 V
- what should i see on the scope while moving the bias pot? a distorted or pure sine wave?
thx!

[Leo_Gnardo]

- should i have a load connected to the speakers output as well while doing that?
- how loud should the 1,000 Hz signal be? i’ve read that the amp’s input sensitivity is 0.8 V
- what should i see on the scope while moving the bias pot? a distorted or pure sine wave?
thx!

My general method for testing solid state amps for power & bias.

NOTE: since this is the first power-up after a rebuild, it would be a very good idea to start by having no load attached to the amp's output, and either bring the amp slowly up to full power voltage with a variac, or at the very least use a light-bulb current limiter setup on your AC power line. If the light-bulb limiter doesn't glow brightly and/or you variac up to 120V without popping a fuse or having smoke come out then continue testing with a load resistor.

Definitely, have the amp driving its rated load, resistor for this, not speaker. First and foremost, because in case the amp fails and puts DC rail voltage on the output, you'll see that with your scope and/or meter. And with a resistor, you'll just heat it up a bit instead of wrecking a speaker.

Power up the amp but don't run the signal level up - let it sit there for a while then check the heat sink temp after say 15 minutes or so. If it's a little warm, then you're not overbiased (in terms of bias current). If it's hot then let's see about adjusting your bias pot.

Apply 0.8V sine wave to the input, and slowly advance the volume while you observe the output on your 'scope. Dial up the volume until you see obvious clipping of the output sine wave. Ideally it will clip evenly top & bottom.

Typically you will see crossover distortion as a discontinuity halfway between the upper & lower limits of the sine wave, iow a "glitch" at the zero-crossing of each wave. If you see no such thing, there's adequate bias.

FWIW I test amps using lower frequencies like 100 or 200 Hz. Of course after initial testing use any frequency you like. Two reasons: 1: most of the energy in music signals is in the bass and B) my ears can't stand listening to 1000 Hz when we go to the speaker test. It's much easier to hear a crossover distortion artifact when using a low frequency rather than a higher one. But that's me and my old ears.



If your amp passes the test, attach a speaker & find out if you like the sound. Good luck!

I'm sure others will sound off - I'll be happy to see it because I might learn something new - ya never know...