Problem is, when looking online I can't seem to find a large selection of 4 ohm 8 inch speakers billed as either "full range" or "for bass guitar". Also, if I screw it up, at least it's not my original one that I love. ![]() I'm not a super techie guy, but it doesn't seem like it would be that hard to do. Since it was a cheap find, I may just go ahead and experiment with a replacement speaker. I think this new one I got must be one of the later ones that was not made in USA, and I can definitely hear the difference. I can post pictures of the two if people are interested. And if so, could anyone reccommend one? The power rating on the amp is 25 watts ohms. I'm also wondering if replacing the speaker might help. ![]() I'm wondering if years of sitting in that box in that warehouse took its toll. Also, there is an almost undetectible hum that I can hear that accompanies the sound (only) when I play a note. In addition to those differences (which are interesting but don't really bother me), the speaker distorts as soon as I get over 5 on the volume knob and hit the E string on the bass. The knobs are a slightly different style. The "new" one just says "Dean Markley" in the same spot. Right under the headphone jack, next to the power switch, the old one says "Made in USA". For example, the box is exactly 1/2 inch shallower than the old one, as if they decided to cut costs by using just a fraction less material. There are some interesting very minor differences between this "new" one (made in 1993) and my old one (from about 1989). For 55 bucks (which included the shipping cost) I couldn't pass it up. Recently I found a seller on Ebay who had several K20-B's unopened/unused in the original box. I love it - I've had other amps over the years, but this was my first, and still my favorite. Nice clean sound, surprisingly loud for its size, tough and durable. I've had it for about 30 years, since I was 14 years old. I have a Dean Markley K20-B (The Bass version of their K20). I do like to work on, and learn whatever I can about gear, too.Looks like this thread might still be active. I’m sure it has to be rebiased, and thoroughly checked. The first two GTs have all 8 pins, the rectifier has 6 pins, and the last GT has 6 pins, and the last one is the one that appeared to have had the pins intentionally removed, or they broke.Ĭan I purchase 4 new 6L6 tubes, and replace them? I have no problem bringing it to a reputable repair shop, here in Nashville. I quickly powered down!!īack to the tubes: from left to right, the rectifier tube is 3rd from the left. And, it just sounded wrong- I know what the amp can do, and how it should sound. Plugged a guitar in, and it’s back to where it was, the night I first swapped the speaker. It came on, and I could hear the amp stages revving up. Today I put the head back in, reconnected speaker, reverb, foot switch, and for ****s and giggles fired it up. When I initially swapped the speaker, I first noticed I couldn’t play the amp at 50%. I put everything back together, fired up the amp, and now it’s working? Kind of. I am getting all new tubes, but how could it have worked all this time, with a ripped speaker, and jacked up tubes? I don’t know if I need to get the amp biased, either. ![]() I can now see a little glimmer of metal where the pins broke off, in the damaged tube. At first I thought that was ok, because the no name tube appears as if there never were pins in 1 and 6. Upon closer inspection, pins 1 and 6 have been broken off. The HCD each have 8 pins, but the BDF has 6 pins, as does the no name tube. What’s strange is, 2 of the Groove Tubes have H5 HCD handwritten on them, and the other Groove Tube has H5 BDF on it. ![]() My tubes that have been in the amp are wonky? There’s 3 GT-6L6B Groove Tubes tubes, and one I assume is the original stock tube. I verified the meter on a known working 8 ohm speaker. I broke out my TOA impedance meter, and realized the new Eminence is 12 ohms, not 8. Replaced it, and it powers on, but there’s no sound at all. Waited, tried again, and found the main fuse blown. Sounded ok ish…THEN, a very loud hum started coming from the amp, tubes started glowing, so I quickly unplugged it. No output unless I cranked the gain and the master? Lowered everything, put it on 100% and was able to hear and play. I turn the amp on, and immediately realized I couldn’t use my standard 50%. Then things went slideways- The amp was working fine before I jacked it all up! I purchased an Eminence Man o War 12” 8 ohm 120 watt speaker, and put it in. I decided to clean her up, and realized the stock 12” Magnum had a rip in it, and was beyond weathered. Glad I found this forum, hopefully somebody can help! I’ve had a Dean Markley CD-120 for a lot of years, that’s been nothing but faithful.
0 Comments
Leave a Reply. |