Akai cr80dss mod

[Quadchuck]

Sometime back I connected the tape head of the Akai to the tape head connections of my Teac mk424.
while this sounded good and bypassed all the noisy Akai circuits it made my teac unusable for cassttes.
I returned teac to normal . Listening to my recordings of early 2000s I am disappointed that some are not as good as they could be but since I sold 1/2 of my tapes back when Ebay was not so stupid.
I now have a different idea inspired by the program DC 8. The program has filters you can apply to recordings one such filter is NAB tape. I am recording from Akai head to mic input of teac with no eq then recording to computor and applying filter after. Here are pictures of results using a teac test tape with 15 frequencies across spectrum 14k to 40hz. the first pic is the teac tape with no filter, also I cleaned up noise and next pic is applying DC8 filter NAB. You can see highs are not very even. The program lets you make your own curves so I made one that better gives all 15 more even levels, about 2 db of the lowest to the highest 1k.
I have made short test with Seals and Croft Q8 and it sounds good , I'll have more

 

[Quadchuck]

The MK424 sits atop Akai , and soundcard VU's show -20db playing a Seals & Croft Diamond Girl tape. The same VU's with no visable reading is tape removed. While VU shows no signal,
there is faint circuit noise with monitor volumn all the way up.
Another VU read shows left channel as Akai would output with no tape inserted and right side
shows lower noise floor with mod.
The DC 8 program shows the Akai playback of Teac test Frequenciy tape and it is quite good
small rolloff at 14k and low side. The dip is frequency 63hz and it must be nead what they call head resonance.