Beer of the Bass

It would be an interesting experiment to glue a couple of housebricks inside a 2u rack case with a bog-standard ICEpower module to see whether bass players coo over the "heft" of the sound!

A little more progress - vane braces glued to back panels: Back panel glued into cabs. Nice healthy glue squeeze-out here! I've used some woodscrews through the outside to hold things together (in lieu of clamps) while gluing - I'll remove these and fill the holes when the glue is dry.

The concept is a good one, since I find Musicman basses aesthetically pleasing and they make lovely necks, but I've never quite got into the whole active thing. So I guess these are aimed at people who feel the same way. It would have been nice if they had a few more nods to the classic stingray/sabre style visually though.

[quote name='Twincam' timestamp='1453394620' post='2959129'] Very very cool. Any pics of its internals? [/quote] I haven't taken any internal pictures of mine, but there are some of the same model here: [url="http://www.radiomuseum.org/r/dynacord_eminent_ii_2_t.html"]http://www.radiomuseum.org/r/dynacord_eminent_ii_2_t.html[/url] It's quite a tight layout in there - servicing it will be interesting...

I've always enjoyed having interesting old valve amps around, but I've been without one recently. I had a smaller Dynacord Bass King T for a little while, so when I spotted this Dynacord Eminent II on eBay, I decided to go for it. It's an unusual design; intended as a PA mixer amp, it has transistor preamps with a valve phase inverter and power stage. Even more unusually, it runs a high plate voltage of around 750 volts in order to achieve an output of 80 watts from a pair of EL34 valves, which would typically be used at around 400 volts in a 50 watt amp. They were made in Germany from the late 60s to the end of the 70s - this one is dated May 1978. It has the benefit of being very compact for a valve amp of this output and having a perspex front panel which is illuminated in green when switched on - I'm a sucker for that sort of kitsch! I was fairly lucky considering that I bought it unseen. It arrived in working condition; there are no issues with hum or noise, it has the correct fuses and the valves are not red-plating or microphonic. The valves are a Telefunken ECC81 and a pair of Hoges EL34, which I gather are re-badged RFT EL34s. I haven't had the chance to check voltages or bias yet, but I will do that. While the amp doesn't seem to require troubleshooting, I still intend to replace the filter capacitors for the HT and bias supplies and replace the bias trimmers with more modern types just to make it a little more reliable. One section of the can capacitors has been disconnected and replaced with a pair of lower voltage rated capacitors in series, though from the appearance of the capacitors this must have been done more than 20 years ago, as the replacements were made in West Germany. I have only had a quick play through it so far, but it sounds good - very clean and clear. The input impedance is low by modern standards so it can sound dull when plugging a passive bass straight in, but a simple buffer such as a Boss tuner on bypass sorts that out. I might add a direct input to the power amp section so that I can build a B15n style preamp in a small box to use with it - this feels less invasive than replacing the preamp section of the Dynacord (which I've heard of other people doing). The cab in the photo is a small DIY 1x10" which I use for quieter settings, though the Dynacord will mostly be used with the pair of 1x12" cabs I am building at the moment.

I think the big neck is to be expected if they're going for a pre-war sort of feel. My 1936 Kalamazoo archtop has a neck so big that I had great difficulty finding a capo that worked! I have to use the cheap nylon strap kind as nothing else will fit...

I stuck my head in the Cash Converter/Cash Generator place just down from the Queen's Hall today, and they had a 90s Peavey Mark III head in very clean looking condition for £44.99. I don't need it, but if anyone in Edinburgh is looking for a cheap backup/rehearsal room/house backline sort of amp I thought they might appreciate the heads-up.

A little more progress; they're starting to look box shaped. I'm using ordinary PVA woodworking glue, with screws through the corner batten because I don't have many clamps. I used 20mm square softwood in the corners, largely because it was in the bargain bucket at Wickes and the other sizes were full price. The back is going to be glued in, but I'll keep the baffle removable, with a 20mm wide flange along the inside for it to screw to which will be sealed with gasket tape. I need to take about half a mm off one end of the back panels before I glue them in, as it turns out they're very slightly oversized. I might fit the vane braces to the back panels before gluing them in, as it would save some faffing around in a confined space. The back panels are a very snug fit, so I reckon I can get a decent glue joint without using battens along the back edges. Henry the hoover gazes on in admiration:

My double bass has at least 100 years on it and has had years of running repairs though never a full restoration job. If it gets scratched or chipped I'm barely going to notice and if anything bigger happens insurance should cover the repairs. I like the thought that it's been a useful, working instrument for so long, so I try not to be shy about taking instruments out and using them.

What's the status of Picato strings at the moment? I know that Innovation double bass strings, which were made in the Picato factory, have had availability issues recently because the factory was closing. They have said that Innovation production will continue at a new site, but I don't know what that means for the Picato lines. Perhaps Daf Lewis could clarify, since he has worked with Innovation/Picato.

Bits of plywood! Left to right are my top/bottom, sides and baffle/back pieces. I ought to take some more photos than this, but this morning I did some marking out and cut the corner battens to size. Hopefully tomorrow or Tuesday I'll have them looking like a box, then it will be on to bracing and cutting out the baffles. I'm using Edinburgh Hacklab, a shared workshop space, as I don't have the sort of work space to do this stuff at home.

I reckon you're thinking of the Fearful cabs, which are available as plans for DIY'ers or from approved builders, and do have some design similarities with the earlier ranges of Barefaced cabs. [url="http://greenboy.us/fEARful/"]http://greenboy.us/fEARful/[/url]

[quote name='Manton Customs' timestamp='1452860718' post='2954150'] That's probably a good idea if you buy an unfinished one - and it need not be Fender. A Nitro finish will naturally relic/age much nicer than the Poly on most of the alternatives. 90% of companies that offer a Nitro finish these days are actually Nitro sprayed over a Poly base coat, so they will not age and check in the same way old finishes do. [/quote] I'm not massively knowledgeable about old Fenders, but I'd read that they have been using a thick polyester sealer as a base coat since some time in the 60s at least, so finishing that way might be appropriate for a 60s style instrument.

Yes, there's only about 1dB difference in the size of the midbass bump between the two tunings, which is going to be very subtle if I can hear it at all. There isn't much difference in the steepness of the roll-off below that either. I can fit three 64mm ID ports in a box this size at 50Hz (four ports work out longer than the box depth) and it looks like I'd be likely to exceed the driver Xmax before the port air velocity gets high enough to be problematic. My old cab which I wound up selling (which these are replacing) had similarly low mechanical power handling at 30Hz and was even limited at 40Hz, but in practice this didn't cause me problems with the amps I use and volumes I play at.

[quote name='mcnach' timestamp='1452731530' post='2953043'] Ha ha! No, bass and shoes stay red When will you build yours? It would be fun to check them out side by side. [/quote] I'll hopefully have one of the DIY cabs at a rough n' ready testing stage over the next week or so, and the pair of them properly finished another couple of weeks after that. I'm aiming to use one or two at a gig in mid-February. They'll also be blue, though a slightly darker shade, with a sparkly cloth grille.

Ooh, nice colour! Does this mean you'll need a blue bass and some blue shoes to complete the set? I'll be interested to hear how you get on with them.

I've picked up my plywood. It came from MKM Building Supplies, who are at my end of Edinburgh. They ordered in a sheet of 12mm birch for me which looks to be really good quality with even plies and no visible voids. They cut it to size on their big table saw too, which was well worth the extra couple of pounds as it's accurately cut with square edges and saves me from faffing about with an 8x4" sheet. It was £45 for the sheet, not the cheapest I've seen but not outrageous either. I have four pieces each of 520 x 330mm, 370 x 330mm and 496 x 370mm, plus enough offcuts to use for bracing etc. Next I need to pick up some softwood for the corner cleats and a length of tubing for the ports.

My plywood is in stock at the timber merchant and I'm going to pop round with my cutting list later on. I've been looking at the different options for porting, whether to tune relatively high at 50Hz, low at 40Hz or somewhere in between. Tuning at 50Hz produces a bump of just over 2dB at around 120Hz and improved power handling from 50-100Hz where a lot of the energy in a bass signal lives. The downside is that the power handling at 30Hz is very low, which is likely to be fine in practice but could be risky if I ever turn up the bass knob and really hammer the low B string. Tuning at 40Hz reduces the bump to a little over 1dB and improves the power handling at 30Hz, but lowers the power handling from 50-100Hz. I've taken some screenshots from WinISD to illustrate this. 50Hz is in blue and 40Hz is in green. [b]Frequency Response[/b] [b]Maximum Power[/b] [b][/b] [b]Cone Excursion[/b] This shows the cone excursion at 120 watts. The red line shows Xmax, and Xlim is at 11mm. This shows that if my GK MB200 somehow ended up producing its full output at 30Hz, the driver could be damaged with the 50Hz tuning. However, this seems unlikely given that it will be receiving a bass signal rather than a sinewave generator. With the 40Hz tuning, it exceeds Xmax but stays within Xlim, so would distort but be less likely to be damaged. At present I'm most inclined towards the 50Hz tuning, unless anyone wants to convince me otherwise. Although I play 5-string, I rarely play the lowest notes and I'm not playing styles involving heavy bass boost. If I ever get into playing in louder situations with a more powerful amp, I would look at introducing a high pass filter into the setup. Another option would be to use multiple ports and plug one to alter the tuning - with some fiddling in WinISD it looks like I could use three 64mm ports 21cm long for a 50Hz tuning, and with one port plugged the tuning would drop to approximately 41Hz. It might be worth doing this and spending an hour or so playing through it at reasonable volume before deciding which tuning to keep.

Nice. I still kinda regret missing out on a silver Hayman that was nearly my first bass when I was a teenager. It would probably have got me some funny looks in the school big band I was playing in though...

[quote name='sarah thomas' timestamp='1452526396' post='2950810'] You might look at J tone pick ups - [url="http://basschat.co.uk/topic/107646-j-tone-electronique-db-pickups/"]http://basschat.co.u...que-db-pickups/[/url] [/quote] I have a J-Tone pickup, mine is the single element, rubber sleeved model, and I would quite cheerfully recommend them to anyone starting out. It's not the last word in realistic acoustic sound (no bridge wing pickup is), but it's a good solid, balanced sound which is feedback resistant and I like it better than some other more expensive bridge wing pickups. It's not especially finicky about input impedance and sounds fine straight into the 1Mohm input of my GK MB200. I've no experience of the clicky models, as slap is not my thing. I do think his jack mounts are a bit inelegant though - I use one of these with mine; [url="http://www.kontrabass-atelier.de/pickups_e.html#clamp"]http://www.kontrabass-atelier.de/pickups_e.html#clamp[/url]

The Teisco S110F is very close in architecture too, though I never had the chance to compare it when I owned the Teisco.

Have Bass Gear magazine ever reviewed the Tonehammer? It might be worth checking, as they often measure the frequency response of amps and include the graphs with their review. That seems like a surprisingly low frequency to be boosting, since there are other amps which start rolling off around there. You'd think it would be asking a lot of the speakers!

I'm still waiting on my plywood, but I've been looking some more into covering materials in the meantime. I've worked out that I would need at least 2 metres of Tolex and it isn't cheap, plus thinking back to the number of bad DIY tolexing jobs I've seen makes me think it might take some practice to do well. I'm leaning towards the Turbo Blue Tuff Cab paint, plus a cloth grille using the Fender style silver, perhaps with some piping around the grille. I've also got my cutting list together for the panels. I'm going with external dimensions of 52 x 39.4 x 33cm, which is just a touch larger in one dimension than the commercial cab I was comparing it to, but I'm constructing it with corner cleats which take up a little extra volume compared to other joints. I wanted to keep it that width so that if I change amps in future, a typical 19" wide amp won't look daft perched on top. With the baffle recessed by 25mm for the grille the gross internal volume works out at 51.57 litres. The pair of cabs fit onto one full sheet of ply, leaving some offcuts for bracing and grill frames.

I bought some strings from Mark. The price was right, he sent them out quickly and all was well.

I have an old Slingerland/Concertone short-scale open-backed tenor banjo which is setup for Irish GDAE tuning. It's a fun instrument, but I haven't quite bonded with it somehow. I haven't had it out very often in the last couple of years as I prefer to play mandolin or mandola when in folky mode. I keep thinking of selling it to fund some bass gear, but my wife likes it and won't let me!