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Difference between the 77b and 77IB is ??
Posted by: Tom_in_CA
Date: August 28, 2016 08:10AM
Can anyone tell me what the difference was between the Compass 77b, and the Compass 77IB ?

I know that the "i" in IB stood for "induction balance". And I always assumed that all the "77s" were the same. Is there a difference in the ones where it had the "i" in the name/title ?

Followup question:
Posted by: Tom_in_CA
Date: August 28, 2016 03:33PM
On one of the 77b's I have, that simply has the decal "77b" [no "i" in there], it has battery pods for 3 sets of double A 4-pack batteries. Ie.: the 4-packs each (4 x 1.5 volts = 6 volts total). For a total of 12 batteries to fit inside the machine. And the exterior battery check function clearly says : 6, 6, 6, on the 3 selections of battery check. Presumably for 6 volt + 6 volt + 6 volt.

But on the 77iB machine I have, I notice that the space inside for the batteries does not allow for 3 packs of double A's to fit inside . In the plastic sleeve where they intended for the batteries to fit. And on the outside, on the battery check control, it says: 6, 9, 9. I'm guessing this is because this machine is made to take a single pack of four AA's (6 volts total), and two 9 volt batteries.

Here's a pix of the outside of each. Notice that while they are both 77's, yet the battery check label is labeled differently



And the "leads" to the batteries don't tell me anything about intention. Because the connection for a 9 volt battery, is identical to a connection intended to a 4 pack of AA's:



So are there some 77's which were made to accept 9 volts batteries, while others were intended to take only AA's ?


Re: Followup question:
Posted by: fowlercharles
Date: September 08, 2016 09:10PM
Hi Tom, wasn't there also some differences in the Coils on the very early I b machines? As I recall from some Pics I saw somewhere, with descriptions I think maybe by Monte (I could be wrong) mentioned the coils being stationary, and not adjustable. I think there was one on Ebay fairly recently that bore that out also. I've never "seen" any version of the 77b /ib . I have a 94B and a couple of Coin Hustlers, and they being later of course have the adjustable coils. Just thought I would mention the coils so we could round all the bases. HH, Charlie

Re: Followup question:
Posted by: Tom_in_CA
Date: September 09, 2016 07:16PM
Hello there fowler charles . Yes, there was incompatible coils from when they evolved from iB to B. That was in about 1974. The newer coils are no longer compatible with the older ones UNLESS you are able to go inside the machine (or chord or coil, or something) and do a minor alteration. So they can be made to be compatible, but not without a little alteration of some sort.

And yes: When that changeover of coil types occurred, the new coils have adjustable angles, while the old ones were "fixed" position.

The newer B versions went a bit deeper, rejected iron better, etc.... But both of them could still do the "see through iron" trick, from what I'm told.

Re: Difference between the 77b and 77IB is ??
Posted by: reddogpatch
Date: October 30, 2016 02:03AM
Just proved that see thru iron trick today when I found a penny next to a bottle cap..AWESOMENESS..Love my 77B PRO

Re: Difference between the 77b and 77IB is ??
Posted by: filternozzle
Date: May 28, 2017 07:15AM
Quote
reddogpatch
Just proved that see thru iron trick today when I found a penny next to a bottle cap..AWESOMENESS..Love my 77B PRO


what is this 'see thru iron trick' ?



Happy Hunting
Nautilus DMC-IIB now retired, Nexus MP & Minelab GPX-5000

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Re: Difference between the 77b and 77IB is ??
Posted by: straker
Date: May 28, 2017 09:59AM
Quote
filternozzle
Quote
reddogpatch
Just proved that see thru iron trick today when I found a penny next to a bottle cap..AWESOMENESS..Love my 77B PRO


what is this 'see thru iron trick' ?

The Compass Yukon (77 series in this case) used 100 khz. This high frequency tuned out iron and responded well to non ferrous items.

Re: Difference between the 77b and 77IB is ??
Posted by: filternozzle
Date: May 28, 2017 12:56PM
Quote
straker
Quote
filternozzle
Quote
reddogpatch
Just proved that see thru iron trick today when I found a penny next to a bottle cap..AWESOMENESS..Love my 77B PRO


what is this 'see thru iron trick' ?

The Compass Yukon (77 series in this case) used 100 khz. This high frequency tuned out iron and responded well to non ferrous items.

Thanks Straker.



Happy Hunting
Nautilus DMC-IIB now retired, Nexus MP & Minelab GPX-5000

Re: Difference between the 77b and 77IB is ??
Posted by: Tom_in_CA
Date: May 28, 2017 03:13PM
Or put another way, try this real world example: Take ANY of today's normal discriminators. Eg.: explorer, CZ6, varieties of whites, varieties of Garretts or Fishers, etc... Take any of the normal coin-hunting machines of today:

Take a rusty nail , put it on the ground, and wave over it. You will get the reject or null sound when in disc. Right ?

Ok now put a penny directly underneath that rusty nail and wave over it. What do you get ? It will "mask", right ? Or give a cruddy signal that you'd likely pass, eh ?

The 77b nulls (rejects) the nail, yet when you put the penny under, gets the beep :) In fact, up to 2, or even 3 or 4 nails at a time (depending on size of nails and how-they're laying and placed, etc....

A close 2nd of today's regular machines are the Whites "Classic" series, & some of the 2-filter Tesoros. Like Silver Sabre, Bandit, and so forth. Of course the downsides are that the depth on those 2-filter machines isn't too good. And ability in minerals wains, etc... Some would argue the Deus is a nail-see through machine. Although I saw one get spanked, so I have yet to see in-person the fame for-nails/iron that is supposed to get. But despite that some modern "relic" machines are renowned for ability in iron, I don't think any of them can beat the # of nails per-a-target that the 77b could handle.

The benefits of the 77b ended there though. In all other ways they are a dinosaur : No other form of disc (foil and silver dollars all sound the same), a bear to keep balanced, poor in minerals, not-much depth (compared to today's power-houses).

Re: Difference between the 77b and 77IB is ??
Posted by: Ipooponyou
Date: May 31, 2017 12:03AM
Quote
Tom_in_CA
Or put another way, try this real world example: Take ANY of today's normal discriminators. Eg.: explorer, CZ6, varieties of whites, varieties of Garretts or Fishers, etc... Take any of the normal coin-hunting machines of today:

Take a rusty nail , put it on the ground, and wave over it. You will get the reject or null sound when in disc. Right ?

Ok now put a penny directly underneath that rusty nail and wave over it. What do you get ? It will "mask", right ? Or give a cruddy signal that you'd likely pass, eh ?

The 77b nulls (rejects) the nail, yet when you put the penny under, gets the beep :) In fact, up to 2, or even 3 or 4 nails at a time (depending on size of nails and how-they're laying and placed, etc....

A close 2nd of today's regular machines are the Whites "Classic" series, & some of the 2-filter Tesoros. Like Silver Sabre, Bandit, and so forth. Of course the downsides are that the depth on those 2-filter machines isn't too good. And ability in minerals wains, etc... Some would argue the Deus is a nail-see through machine. Although I saw one get spanked, so I have yet to see in-person the fame for-nails/iron that is supposed to get. But despite that some modern "relic" machines are renowned for ability in iron, I don't think any of them can beat the # of nails per-a-target that the 77b could handle.

The benefits of the 77b ended there though. In all other ways they are a dinosaur : No other form of disc (foil and silver dollars all sound the same), a bear to keep balanced, poor in minerals, not-much depth (compared to today's power-houses).

Look at the Nexus MP with 24kHz concentric coils.

Nexus MP Target separation test.

Nexus MP Monte Berry nailboard test

After these tests MP goes very deep with another search coil in the set.

Nexus MP depth test.

Re: Difference between the 77b and 77IB is ??
Posted by: Tom_in_CA
Date: May 31, 2017 04:56AM
awesome videos ! That would mimic the 77b, for sure. All the iron-see-through tests were done at depths which would mimic depths of no more than a few inches . Notice he never lifts up the coil more than a few inches off the tests. Versus the last video, which is strictly for depth tests, is NOT being done with iron covering at those depths. But that's understandable that super depths, you're not going to be "seeing through iron at the same time". And the 77b could never replicate those depths. Ie.: you're not going to perform both tricks at the same time with ANY machine.

For most american SW ghost towns, (desert like conditions) you don't need much depth anyhow. The objective would be iron-see-through. Even if that meant compromising depth.

That was pretty impressive. The person testing commands a knowledge of the "gotchas" that a potential viewer would be thinking in his mind . Eg.: "why didn't he do this?" or "why didn't he do that?" and "how do we know such & such?". He seems to cover many varieties of bases to mimic real-world scenarios.

thanx very much for posting those links.

Re: Difference between the 77b and 77IB is ??
Posted by: Melbeta
Date: July 22, 2017 10:24AM
I was a Compass metal detector dealer in those days. The difference is that the 77IB was an older circuit design, and in 1976 Compass came out with the Yukon B series. This newer series had a newer larger circuit, with more electronic parts, thus the necessity of a larger power supply. Also the older coil with the solid shaft was set aside, and a new coil with an adjustable shaft was incorporated. Now there is a story that the two coils are not interchangable, and that is true, when you use them "as is". If you re-wire the older IB to the B series they will interchange and are then interchangable. And of course, vise versa. If you re-wire the B series coils, to match the wiring of the IB coils, they are then also interchangable.
Melbeta

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