eetechTom
2 posts
Apr 11, 2015
4:38 PM
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Bought a cheap(but mint) Mura dual impedance mic on ebay so you know what comes next. Found a deal on a 90's Fender Sidekick SS, 1x10 bass combo. Cheap Taiwan electronics in this amp to be sure, but am going to build a tube amp to drop in the cabinet. The cabinet is built like a tank, and has 2 ports in the front with the stock 10" speaker.
I'm looking for advice on opening up the rear panel of the sealed cabinet. Curious how having ports on the front and an open cabinet in the back is going to affect the sound. Suppose I could plug the front ports if i feel a need. I'm basing the amp on the N5X schematic from the ampmaker website. This is a 5 Watt amp, with adjustable plate/grid voltage. Also has two separate output tube sockets to work with a single EL84/6BQ5 or a single 6V6.
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rainman
175 posts
Apr 12, 2015
9:40 AM
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If I was looking for a small tube amp I would look no farther than the Lone Wolf Harp Train 10. With the intro offer of $300.00. It has 8 watts, designed for harp by one of the best. It would take away a lot of guess work and if for some reason you didn't like it it would re-sell for close to full price.
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Bilzharp
54 posts
Apr 12, 2015
10:02 AM
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To address the original question, I don't think the ports will be doing much of anything if you open up the back. Plug them or leave them open, I don't think it makes much difference. Given your forum name, I'm guessing you're into the challenge of building a tube amp. One potential issue in adapting a S.S. chassis is making sure that the large speaker magnet doesn't interfere with the hanging components (tubes & output transformer) that you'll be adding. I'm not familiar with the N5X amp but I'm not sure I see much use in having an adjustable plate voltage in a 5W amp. The separate output tube sockets also seems unnecessary but admittedly kind of cool. Good luck and keep us updated.
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Barley Nectar
757 posts
Apr 12, 2015
1:23 PM
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Hmm, I'd probably just put the jig saw to it. I wonder if that cab is made of wood or some composite material. As a bass cab, those ports may be interesting but then the amp needs cooling air which presents another aspect of consideration. I agree with Blizharp's post.
I too, am unfamiliar with the N5X amp. Randy Landry's Lone Wolf site has some excellent harp circuits. The Valve Junior preamp worked very well for me in a build. What ever you do, you will enjoy the effort. Good luck...BN
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eetechTom
3 posts
Apr 12, 2015
2:09 PM
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Thanks for the input. I do have 30+ years of experience in electronic repair, and repaired a handful of home audio tube stuff back in the 80's. The explanation on the site with the N5X amp is that you could dial down the voltage to get good distortion at reduced power levels but now that I think about it I hear what you are saying Bilzharp. Maybe that feature would make more sense if you had a 50W gigging amp you wanted to use at home as well. Part of the deal is I've just always wanted to build a tube amp. I did see the stuff on the Lone Wolf site that looked good so maybe I should make things less complex and go that route.
BN, It's 5/8 particle board all around, except for a thinner back panel and some pine bracing here and there.
I'll post some pics when I get this thing finished but may be a month or more down the road.
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HawkeyeKane
2767 posts
Apr 13, 2015
6:59 AM
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I'd say go for one of the Lone Wolf single-end project amps. Either the 6L6SE or the 3X6V6SE. Very simple circuits and they'd both get you a nice sounding medium size harp amp.
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Hawkeye Kane - Hipbone Sam
Can I go home now...???
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