13 replies to this topic

[Carlspeak]

Attached is a schematic I recently completed of the AR-5 and offer it up to the AR library archive. After having worked on 2 different pairs of different vintage. I learned one had ceramic magnet woofers and the other set had Alnico woofers. The Alnico set had woofer coil #8. Not sure about the caps and other coils, but believe they should be the same as with the ceramic magnet version.

[RoyC]

Attached is a schematic I recently completed of the AR-5 and offer it up to the AR library archive. After having worked on 2 different pairs of different vintage. I learned one had ceramic magnet woofers and the other set had Alnico woofers. The Alnico set had woofer coil #8. Not sure about the caps and other coils, but believe they should be the same as with the ceramic magnet version.

Carl,

My measurements of (6) AR-5's (all of the very early 70's with alnico woofers) were the same, EXCEPT that the series resistor wire in the midrange circuit did not measure .51 ohms as you have indicated in your drawing. Mine all measured 1.3 to 1.4 ohms. The woofer coil is #10 (3.83mh), the parallel mid coil is #11 (2.3mh), and the series mid coil is #2 (.16mh), just as you have drawn. The .51 ohm resistor wire was used in the AR-3a..which, incidentally, is set up exactly the same way with different component values.

Roy

[Carlspeak]

Carl,

My measurements of (6) AR-5's (all of the very early 70's with alnico woofers) were the same, EXCEPT that the series resistor wire in the midrange circuit did not measure .51 ohms as you have indicated in your drawing. Mine all measured 1.3 to 1.4 ohms. The woofer coil is #10 (3.83mh), the parallel mid coil is #11 (2.3mh), and the series mid coil is #2 (.16mh), just as you have drawn. The .51 ohm resistor wire was used in the AR-3a..which, incidentally, is set up exactly the same way with different component values.

Roy

Roy,
I just assumed that little resistor was the same as for the 3a. I modded a 3a xover schematic I had on file to create the AR5 schematic. Took a couple of measurements with 2 different VOM's of the resistors on the pair of 5's I have (ceramic woofer model) and got about the same values as you noted above. Thus I suspect both the Alnico and ceramic woofer models used the same series resistor. I will correct the schematic and re-post here.

Question: Why a resistor in that location and why with such a low value?

[Carlspeak]

Attached is the updated AR5 schematic.

Attached Files

•  AR5_schematic_corrected.pdf   430.14K   885 downloads

[administrator]

Attached is the updated AR5 schematic.

This will go up in a few minutes.

Mark

[BobM]

Hi! I'm new to these pages--a quick THANK YOU for being here. My Dad had AR-3a's when I was growing up, and he passed the Hi-Fi "bug" to me. These pages are a fantastic resource!

I've recently acquired a pair of AR-5's, and intend to "refurbish" them. (What that means, exactly, I'm in the process of trying to decide.) Currently, I'm wondering about the crossovers. One thing I take as a given is to replace capacitors, and (as needed) the level-adjustment controls. So, a crossover question.

Please forgive my inexperience, but I think I'm mis-reading Carl's AR-5 crossover schematic. It looks to me like the resistor, 24mfd cap, and 2.3 mH coil are in parallel with the tweeter. I understand that the resistor and capacitor are in series with the midrange, but are they also in parallel with the tweeter? Am I getting that wrong? (In case it helps: the larger goal for me is to understand how the schematic for the 3a and that for the 5 is the same, but with different component values for the different driver impedances, so that I know my way around my 5 crossovers like the back of my hand.)

Thanks!

[Carlspeak]

The midrange circuit you describe is analogous to the midrange circuit in the 3a That has the 50 uF cap and resistor wire. The only common connection between it and the tweeter circuit is the yellow ground that is needed for the pots to work correctly and the crossover point remain on target.

[BobM]

Ok--I see--that helps a lot, thank you! Thanks also for all the trouble of making and publishing this schematic--it will save me a HUGE amount of trouble!

So, the midrange is in series with: 24mfd capacitor, 1.35-ohm resistor, and a .16 mH inductor (plus the pot). Great.

Is the midrange in parallel with the 2.3 mH inductor?

And, what is the inductance of AR coil #8?

Thanks again!

[Carlspeak]

According to the AR table I have #8 coil is 3 mH.

[BobM]

Great--thanks for that! I had thought that the midtrange high-pass and the woofer low-pass were 6db filters in the 3a, so I didn't understand how the schematics are analogous. As a result, I couldn't figure out what was going on with that 2.3mH inductor. Maybe I was thinking of AR-3 schemantics? Anyway, cleared that up by going back to the AR-3a restoration guide.

I notice people using the Ohmite RHS15R pot for replacing the pots in both the 3a and the 5. But, it's 15-ohm, and there are 16-ohm pots out there. What are the reasons for using the RHS15R, specifically? Size? Price?

[Carlspeak]

The Ohmite 'pots' are true rheostats as opposed to other controls. The 1 ohm less resistance won't make any difference to the functionality of the Ohmite rheostat.

[DaveQ]

I found an old (but undated) AR-5 schematic/parts list that I got from AR in the mid-1970's.  With it were a "Speaker Component Replacement" sheet and a "Consumer Parts Request Form".  All are attached.  

 

The part request form is a reminder of what a great company AR was to do business with -- they would sell you pretty much any part for their speakers, turntable, or amplifier, or a new carton if you needed one, at prices that were more than fair. 

 

It gives some insight into where their costs were, as well.  The AR-3/3A/5 midranges (and the AR-1/3/3A woofer) are $50, next most expensive are the 10" woofers at $35, and everything else is $22 or less. 

 

 AR-5 schematic (from AR).pdf   413.6K   47 downloads

 AR Speaker Component Replacement.pdf   784.99K   30 downloads

 AR Consumer Parts Request Form mid-70s noaddr.pdf   450.19K   45 downloads

[dynaco_dan]

Hi Dave

 

Thank you very much for posting these here.

 

It is a nice feeling seeing this old information has been cared for by you.

 

I've never owned AR-5's but I still enjoy reading about all of AR classic products.

 

Early on AR even prepaid s&h charges for their parts.