The DISCO DESTOROYAH getting the test tape treatment

[Cpl-Chronic]

My latest goal is to go through my collection & run my trusty 3000Hz test tape on each deck to set speed properly & do light maintenance to keep them turning proper & sounding crisp. It's been a while since I pulled this beast of a DISCO mod off the shelf & do a checkup etc. The tuner is shot & needs replacing but otherwise it sounds quite good with the BOSE 2 OHM woofers & JVC M70 tweeters loaded into the horns. Both decks play well, including the relay play feature. I even added Conion C-100 LED meters to display the wattage output of the center Super Woofers & a few bumper bars to protect the front, in case of a forward fall.

I want to shout out to Caution for giving me advice on how to adapt the C-100 LED meters to the Super Woofer outputs. Without his valuable advice I could not have added them to the DISCO-DESTOROYAH!! Thanks again Caution.

Enjoy it in HD:

 

[rivetmaster]

Awesome. Great choice of tunes too. I love me some Thomas Dolby

 

[Transistorized]

I am the same way when it comes to my cassette playing at the correct speed. I don't have a test tape so what I end up using is a new factory tape that I also have the CD for as well. I play them both on the same song and sync the cassette to the CD. Seems to get me spot on, or close enough

Edit: Love those C100F LED's at the bottom. Very cool

 

[Cpl-Chronic]

I am the same way when it comes to my cassette playing at the correct speed. I don't have a test tape so what I end up using is a new factory tape that I also have the CD for as well. I play them both on the same song and sync the cassette to the CD. Seems to get me spot on, or close enough

Edit: Love those C100F LED's at the bottom. Very cool

Yeah, I did the same using a digital source & comparing an exact copy on tape I would make with my Denon 3-head deck. It took hours to get it as close as possible to match. Using the test tape, I found out that tuning by ear would get varying results & my closest tuning by ear was dead on @ 2998-3001Hz. Some of my ear tuned decks were out by as much as 50Hz roughly( 2950 or 3050). It was because I spent less time splitting hairs on adjustments & did a fast & dirty ballpark adjustment that sounded good to my ear. I would have to adjust, back & forth with a jeweller's screwdriver, trying to get only so close. Using a test tape & WFGUI also gives you W/F measurements & shows you that decks will often start out a bit faster & then settle into their real speed after a bit of playing time, usually 30 seconds to a minute. The real frustrating part is that sometimes, when you have the boombox apart, making adjustments until it is spot on for speed, when you get the box back together, the speed changes by as much as 30Hz difference & you have to take it all apart again & adjust it accordingly, knowing it'll change by that amount again, once it is all back together again.

That's why unless you have a test tape & a WOW meter of some kind, spend literally hours tuning & comparing, you'll be surprised by how far out of spec your deck will be, even if it sounds correct to your ear. I've read that really good experienced musicians can actually hear a difference of about 10Hz between being 'in tune" & "out of tune" as far as the music scale. All quite interesting stuff.

 

[Transistorized]

I used to be obsessed with tape speed. I still try my best when I am doing repairs but what cured me trying to make them perfect was knowing that is impossible. Belt / tape stretch and wear of the mechanical components will eventually skew what once was a spot on speed setting. I am sure this is the byproduct of lower quality belts but, I have found that most decks will run too fast after a few hours of tape play with a new belt. I used to adjust my M70s slightly slower just so I didn't have to tear it all the way down to recalibrate after a few hours of use. I still think JVC should've made that radio easier to adjust. Its a chassis removing process to adjust tape speed on that model.

 

[Cpl-Chronic]

....I have found that most decks will run too fast after a few hours of tape play with a new belt. I used to adjust my M70s slightly slower just so I didn't have to tear it all the way down to recalibrate after a few hours of use. I still think JVC should've made that radio easier to adjust. Its a chassis removing process to adjust tape speed on that model.

Yeah, I would agree that you can go mad sometimes chasing that perfect speed but I do want my decks within 10Hz of reference if at all possible. So far my experience has heen that most decks can get within 10Hz of spec & anything more than 15Hz out is considered by me to be out of spec & needs adjustment. My Technics double auto-reverse deck is the worst offender, riding around the 2975 mark one way & 3008 in the other direction, on deck 'B'. Only one speed adjuster as far as I can tell on the mainboard for each deck.