COMTEK M72 Option 7 and PR-72b

[Alejandro Reyes]

Hi Everyone,

 

I'm happy to say I now have some COMTEK 72 series IFB units. I recently purchased some headphones off of Amazon. The ones I got were the Hamiliton SchoolMate Personal Mono/Stereo Headphones. Unfortunately I was only able to hear off my left ear bud, thinking it was just one receiver I checked all three and I got the same thing. I decided to check with B&H to see what my options are as far as headphones go. For the time being I can't afford the recommended COMTEK LS-3 headphones, so I'm looking at the Williams Sound HED 027 Heavy-Duty Folding Mono Headphones as a viable option. So besides asking you all about these options in headphones here are my following questions for you all:

 

1. Is there anyone here that has used the Williams Sound HED 027 Heavy-Duty Folding Mono Headphones, if so, what did you think of them?

 

2. How many Crystals are there to the 72 PR-b receivers and where can I buy them after the current ones die out?

 

3. Also when I was checking for the Audio Root headphones as an option they only came out as one bud rather than 2, not sure if I researched the wrong ones or if they only available that way?

 

Finally I appreciate everyones help and guidance. As some of you are probably wondering, I'm not to familiar with the 72 series COMTEK, I've only ever used the 216's. After playing around with them earlier today I noticed they aren't much different as far as sound quality goes.

Edited May 19, 2019 by Alejandro Reyes
Spelling error

[afewmoreyears]

2. How many Crystals are there to the 72 PR-b receivers and where can I buy them after the current ones die out?

 

 

 

1- xtal per unit..  There are a bunch...A,B,C,D E, F, G, H, I etc...and 5-6, and other numbered frequencies.. you must match the transmitter to the Xtal style..meaning 5-6 won't work on the Letter channels..A,B ,c etc..    They do not make them anymore... You will need to beg borrow or steal them...  keep an eye out on ebay, this site etc.

 

Question:

and yes, they sound about the same...

But why would you need other crystals unless you need to change frequencies? I've never heard of a crystal wearing out although I suppose it could happen. I have some that must be substantially more than twenty years old and still functional.

 

Because if you do need to change frequency, you can swap out 12- A's with 12 -I's...  It rarely happens, but it does..

 

They don't wear out, but they do break...I have replaced many over the years...they are literally crystals..

 

[David Waelder]

I haven't been using Comteks in awhile so I tender advice with a caveat to check with a known source. (e.g. knowledgeable people in a pro audio shop - Trew Audio, Location Sound, The Audio Dept., Pro-Sound, etc.)

 

1. Comtek receivers output a mono signal. Any headphones with a stereo plug that you connect will give you audio in one side only. You simply need to replace the plug with a mono connector. (Some soldering is necessary.) An alternative workaround is to cut a notch in the plug at the point of the two hot leads with a file and melt some solder into the groove to short the left-right leads. With those little 1/8-inch plugs, that is probably more trouble than it is worth.

 

2. I don't know how many crystals are available in the PR-72 series (many I would guess) but you could always go on the Comtek website to research this.

 http://comtek.com

But why would you need other crystals unless you need to change frequencies? I've never heard of a crystal wearing out although I suppose it could happen. I have some that must be substantially more than twenty years old and still functional.

 

3. I don't know about Audio Root headphones but many headphones work well with Comtek receivers. Location Sound sells rebranded Sennheisers for less than $20 each and can supply them with suitable plugs to use with Comteks. I don't think you can get much cheaper. Headphones for this application are considered expendables - Video Village residents sit on them, drop them and generally abuse them. You might want to have a medium good pair for the director but otherwise cheap and serviceable is better.

 

David

 

 

[Philip Perkins]

There are no M72 compato xtals available from Comtek and there haven't been any for a long time.  I bought what they said was the last of a few of the "letter band" types from them about 10 years ago.   I did what was suggested, which was patrolled Ebay and equipment auctions and bought up what I could, often having to take more than I wanted.  I'd advise particularly watching for sales by sound people retiring or quitting the business, who might still have been using the M72/PR72 units.  But they haven't been made in quite awhile now, and I had to find other techs to fix mine since Comtek didn't want to service them either.  If you can keep them going they still work just fine (no tuning issues ever with crystals), but I was always very paranoid about clients losing or breaking them since replacement was a major issue.

[Steve Foy]

I have been using the Williams Sound HED 021's with my R1a's and have found them to be excellent and ticked all the boxes. My brief was: small over ear style, lightweight, single lead on one side, mono, right angle plug, reasonable price.

[afewmoreyears]

When they break on set, or are lost, bill for them at a PR-75 cost and replace it with one of those... Newer style, and you can choose any lettered frequency..you will update your package in the process .

[Derek H]

You mean PR-75a I think. 

[afewmoreyears]

29 minutes ago, Derek H said:

You mean PR-75a I think. 

Yes..

[Johnny Karlsson]

Maybe give this one a shot:

 

https://www.haltertechnical.com/scene-monitor.html

 

[Alejandro Reyes]

On 5/20/2019 at 7:44 AM, Johnny Karlsson said:

Maybe give this one a shot:

 

https://www.haltertechnical.com/scene-monitor.html

 

Hi Johnny,

 

Also thanks to everyone that shared their knowledge and responded to me. I did manage to get a pair of Halter Technical Scene Monitor Headphones, I also got help from Doc Justice himself and my local shop, Second City Sound here in Chicago. We also made the the proper adjustments as scene in the photos down below. Though the wires are very small, you can pretty much get a general idea of what I was doing. Basically it was pretty much what David had suggested. Also this was done moments before I found out that 3.5 mm stereo to mono connectors existed. Still though this was a great experiment and learning experience, plus as some of you said these headphones are considered expendables, but for the meantime I'll be using both these headphones and my COMTEK until I can upgrade to the 216's. Once again, thanks everyone!