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 ?

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 ?

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

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.

Just proved that see thru iron trick today when I found a penny next to a bottle cap..AWESOMENESS..Love my 77B PRO

reddogpatch said:

Just proved that see thru iron trick today when I found a penny next to a bottle cap..AWESOMENESS..Love my 77B PRO

Click to expand...

what is this 'see thru iron trick' ?

filternozzle said:

reddogpatch said:

Just proved that see thru iron trick today when I found a penny next to a bottle cap..AWESOMENESS..Love my 77B PRO

Click to expand...

what is this 'see thru iron trick' ?

Click to expand...

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

straker said:

filternozzle said:

reddogpatch said:

Just proved that see thru iron trick today when I found a penny next to a bottle cap..AWESOMENESS..Love my 77B PRO

Click to expand...

what is this 'see thru iron trick' ?

Click to expand...

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

Click to expand...

Thanks Straker.

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).

Tom_in_CA said:

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).

Click to expand...

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.

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.

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.
[size=large]Melbeta[/size]

I just found my old posting, read it, and still it is absolutely true. Now the entire industry, is oriented to VLF machines, not the older TR machines, they use phase shift discrimination, and go deeper, find more trash, and I use an special audio amplifier, I go below the trash level, while everyone else detects and discriminates the trash level. Is that smart? Who knows??? I do not tell...

So who finds the most? I remain silent on that question. I find a target, I seek the faint smaller deeper targets, that are slight whisper sounds, but the audio amplifer found them as a loud sound, so I had to switch into bypass mode. Why??? Well I had to see if it was a faint whisper sound. If it was, I dig and pocket it. If still loud sound, I walk on by. I only dig up faint,deeper, whisper signals, that are from the bypass mode, of my audio amplifier unit...

But, fairly often, not always though, just as I am getting ready to dig it up, someone comes with a newer flashy VLF detector, with phase shift discrimination in it! They, seen me digging and pocketing, was curious seeing me on my knees, digging, and they usually swing their beautiful newer unit, over my target, says "nothing there".

You see, he is using a VLF with trash filters in them, so he is correct, to his machine there is nothing there, but with mine, I go down and pocket it. He wants to see the target, I tell him I am searching for and digging up nothing targets.

You see, his machine told him "Nothing there"... He gets a bit irritated with me, and leaves, and I continue with finding and digging up "nothing there" targets. I wear an trash apron, put the real trash in the apron, and put the "nothing there" targets in my pants pockets...

I do what I do, others do what they do. Neither they or myself, would get along so don't swing over my target and just let me continue digging up targets that are not there with my older souped up machine.

Okay, I said all I will say right now, on the subject of "nothing there" targets..... Am I dumb digging up targets that "aren't there"? Yes I am dumb. Just let me do my stupid thing and go use your newer VLF with the phase shifting technology... Just let me waste my time, chasing and digging up small, faint, deep, whisper sounds, and I will let you go on with your newer, VLF, discriminating out trash... You do your thing, and I will do my stupid thing too...

Download photos??? Why would I post a photo of "nothing there"??? I am dumb, but I am not "that dumb"!!!

Oh??? You insist??? Well, just this one time, of only some dumb "nothing there" stuff.... It is in an .pdf file below.
Melbeta