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5E3 Finalized--Finally + A Few Tweed Tips

1/7/2003 10:00 PM
Jason A
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5E3 Finalized--Finally + A Few Tweed Tips
All,  
 
What a cool amp. I originally built the 5E3 last year--and I screwed up in a few places the first time around. However, now it is definitely finalized and sounding killer. I stripped the chassis bare and rebuilt using dead stock circuitry except for the following: EMC 18 Watt OT--great Iron IMO, 4.7uF bypass for 12AY7/5751 first gain stage instead of the normal 22-25uF cap, and 100R/.5W "artificial ground" resistors tied directly to ground.  
 
The first build used teflon/silver wire, carbon film and metal film resistors, mallory poly caps, Angela tin/foil .022uF and .1uF for the PI, Jensen PIO caps for the first gain stage .1uF values, ATOM electros, 2W sealed carbon pots, and 100R/10 Watt wirewounds for the artificial center tap.  
 
The new [and superior] version uses uses the same parts except the following: .5W Allen Bradley carbon comps throughout except first gain stage plates which use Riken Ohm 1W 100k's, stranded cloth wire except for star ground runs which are still 22ga teflon/silver, and 100R/.5W carbon film for the artificial center tap.  
 
I also ordered a Weber Blue Dog--should be here in a couple of days time. I presently have a Jensen P12R reissue in the amp. This speaker is OK, but not incredible. It has finally broken in so it sounds worlds better than at first, however, I look forward to hearing the Weber--especially after breaking it in.  
 
I also wound up completely stripping the cabinet bare and completely redoing the entire thing. A set of dental tools [Sears] and a hairdryer makes removing the old tweed fairly easy if you are using DAP weldwood contact cement. Some tips for those who have to do like I did--if you use Weldwood contact cement [DAP] for the original tweed application and you want to remove excess glue after you remove the old tweed, try Citrustrip Orange stripper [outdoors only!!] and use a plastic knife to scrape the glue once the Citrustrip has activated [the manufacturer recommends non-metallic scrapers to be used with this product]. Milwaukee also makes a tirangular scraper with a wood handle that works really well for removing excess glue when used in conjunction with the hairdryer for the fine detail work after the citrustrip has been removed completely.  
 
I wound up re-tweeding and using Gerald Webber's recommendation on Minwax Polyshades Honey Pine stain/polyurethane. I'll tell you what--whatever some think about hsi opinions regarding electronics/amplifiers happen to be, his advice here is VERY nice. This is a really nice looking amp. After the tweed set up and the glue dried for about 3 days, I applied three coats of the Polyshades sanding lightly between coats using Scotchbrite/Green Scrubbies. I applied the Polyshades using a sponge brush. It was easy to work with, didn't smell TOO much, and the end result is pretty darn nice. The polyshades is both stain and polyurethane in one. I did not dilute or thin it. Looks wonderful right out of the can. BTW, when you first apply it, it looks really strange. It makes the tweed look dirty. This goes away after that coat dries.  
 
Also, regarding glue application--buy a wide roll of masking tape for making nice clean edges. This is also useful for "pre-applying" your tweed panels to the cabinet. I applied each tweed to the panel prior to gluing so I could cut the corners without making a mess. Wide maksing tape is a great thing to have onhand when applying tweed or tolex.  
 
You can find all of the cosmetic finishing items between Sears and Home Depot.  
 
Jason