It has been a month since I installed the WGS Black Hawk HP100 in the Mark IV. This speaker would sound perfect in a Mark V combo. The Mark IV combo I have is not as satisfying as the Mark V head. Something is just not right with the Mark IV. May have something to do with it falling over and punching in the speaker jack through the chassis while I was playing through it at the same time. (Do not move the amp while it is operating, the casters are not very stable on carpet). I was able to repair the physical damage and straighten up the wire tree on the power section that got pushed over when the speaker plug broke the jack. (the original 90 degree plug shorted out long ago so I had a straight plug in its place. I changed that too after the incident. This all happened while I had a Fane Studio speaker installed and I was trying to find out where the rattle was coming from ( amp or the metal ducts under the floor).
The WGS Black Hawk is definitely a step up from the MC90 in tone. After a month of break-in, the highs and lows are more pronounced. Definitely a great AC/DC or Lead Zep tone. I fabricated a large plate that will provide clearance for the handle on top of the MKIV so I can place the MK V on top without fear of it falling. I did this so I can hear the difference between the two amps. If I had a Mark V combo this would be an option as a speaker replacement. Why just an option? The Mark IV is only 85W and it seems to overpower the speaker to the point the voice coil begins to smell hot. I believe the enamel is getting burned off of the windings. The next step would be to try the Jensen Black Bird since it has similar power rating @100WRMS, with a 200W music program rating. WGS does not have other rating but the 100WRMS which I think is over rated (I believe it more to be a 75WRMS speaker than a 100WRMS). Then again, the Mark IV may be under rated, perhaps there is more power at the lower frequencies that the WGS speaker can handle. I would rather pay the extra $20.00 for more power.
The WGS speaker provided plenty of room to change all tubes in the rear mounted configuration. Since I am uncertain what speaker will finally end up in the Mark IV, I modified the baffle hole so I can front mount the speaker. With the Fane speaker mounted, that gave me 1/2" clearance for the power tubes. That was definitely needed. The Fane speaker so far sounds the best at volume settings of 3 or higher. So if the WGS burns out before I get another speaker to try, at least the Fane will fit. Another note: the grill needs to be offset by about 1/4". I also changed how the grill is attached, now screwed in from front. I really love the tone and character of the WGS speaker especially when driven by the Mark V. That by itself sounds way better than the 412 with EVM12L at medium volume settings. I did try to mount the WGS speaker in a sealed 1x12 cab, it just did not sound good. I believe the resonant frequency of the cab is not suitable for guitar frequencies, it sounded worse with the back off. The WGS speaker is at its best in open back, Combo amp. Perhaps if you have a 1x12 combo, if it is under 60W this speaker would be perfect. Would also kick -*** in a 2x12 at 100W. Since the WGS Black Hawk HP is a reverse engineered version of the Jensen Black Bird, I will have to give the Black Bird some consideration since it may be able to handle more power.
On a side note: The WGS Black Hawk may be similar to V30 and or the MC90 in that it has a cloth dust cap. However, the voice coil is larger (2") and does not seem to have the HF beaming effect prone with the V30. Perhaps it is due to cone shape, seems to be more shallow than the V30, similar to the MC90. Cone shape is closer to an EV. The FANE has the shallowest cone, that speaker really projects (when you are close to the amp it does not sound as loud, move back a few feet and BAM there it is.