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Post by Deleted on Feb 24, 2009 12:03:29 GMT
HOWDY TO ALL,,,,,,,, CHARLIE ,you may recall my having a 15'' & a 12'' speaker's [now in a cab with open back now as a speaker box only etc..  Well I have wired up a switch to give all combination's & found the 15'' on its own to be the better sound ,[more vintage] , but the 2 together are a little bit brighter  ??.. I will now fit the ''LPAD'' 8ohms to the 12'' as to add as more or less & try that as well... Saying that how are you finding the ''15'' in you project-amp? .. Mine seems to give that ''woodier'' type sound & the 2 in series or parallel is hard to pick any difference at home volume about 25 watts? & just to add the 12'' is quite bright on it's own!!!!!!! AND my cab is not covered & is finished in ''nitro-cellulose''& tilted off the floor at the front... CHEERS ............barry..  |
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UK Brian
Member
I have my sound, and I luv it
Posts: 440
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Post by UK Brian on Feb 24, 2009 12:16:27 GMT
Hi barry, sometimes when practicing, and feeling to d**n lazy to hump stuff around I will use a keyboard amp that seems to stay in the ehearsal room, that has a 15" speaker and I must say it has a rather pleasant full sound, I have to wind all the bass ofof it tho'
Cheers
Brian
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Post by Charlie Hall on Feb 24, 2009 15:33:40 GMT
Hi Barry,
Most 15" speakers will have a bit less high end than a 12" speaker. My 15" is bright but mostly at around 2KHz which can make it sound a bit harsh, because it has a metal dome as it is a copy of a JBL.
It could be that you need to tame down the treble content of your amp by modifying it. However if you do that, you might need to modify the tone stack as well.
Regards,
Charlie
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Post by Deleted on Feb 24, 2009 19:50:07 GMT
HI brian ,that may well be the type of amp-speaker combo to use your tone-lab with ?. Are you well enough to still be doing your ''gig's'' yet ? ,well the weather up there has warmed up a bit I hear to a comfy 8degcel,''BRRRRRRR'' dam cold mate it too cold when your'e not at your best [health] .. & still waiting for you to post that ''PIC'' of the 69 quid aria!!!!!!!!! WELL the valve amp has changed thing's here a bit ,as the sound is so much different to my s/state yamaha , and I am trying different thing's as the ''fet'' box I built etc .....
A surprise to me is the t/lab prior to echo unit sound much better through this amp than I thought it would as I tried it just last night & got a surprise !!!!!!!!
Well mate take it ''easy'' & by the way if you can have a listen to P/KORVING"S version of the quo's ''down-down''....................cheer's ...........barry..
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Post by Deleted on Feb 24, 2009 20:23:17 GMT
HI CHARLIE ,,you are right on modifying the amp ,as it is geared for the modern-market & has a dedicated very dirty channel, the clean channel is not too bad but I will do something about it as soon as possible as I have yet to look inside.to see how the preamp board is built I am hoping it uses normal component's & not smd ,I will soon have look .. charlie I know you are a busy man but if you would take a look at the circuit & offer some suggestion's that would be great ,looking at it myself it has relay switching & thats ok as long as they stay trouble-free? ? it is all valve opperation apart from the reverb solid state driver &preamp [reverb only] & that's ok as I wont have use for that reverb,,,.. THE 15'' I have sound's good to me& the12'' is ok but brighter as you would expect!! It's just that the amp itself could be toned down a bit more as the treble has to be almost off & the middle does bring up the treble as well ,I think that the coupling caps early in the preamp should be increased in value? ?? cheer's charlie & all ,...................barry... |
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Post by Charlie Hall on Feb 24, 2009 23:54:13 GMT
Hi Barry,
I've had another look and can't decide where to start! I have broken the clean side down into sections mentally but having trouble deciding which tonestack is the clean side, I think it might be the lower one on the diagram. There is a presence circuit with an unusual bootstrapping analog chip in the feedback loop, not sure exactly what that does yet but might be for tightening the low end, so that is another area that can be looked at. Leave it with me and I'll see if I can go further.
Regards,
Charlie
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Post by Deleted on Feb 25, 2009 1:07:02 GMT
THANK'S for that charlie please take your time with it as I am sure you've plenty to do!!!!!!!!!! It shure has some component's in it,& I will look at the actual board & see how it is constructed it shure is wide enough in that part of the chassis it maybe spread-out a bit? ?? I do have a lot of spares as I bought enough to build at least2-3 amp,s that is resistor's & cap's 630 volt polyester & a good range of electrolytic's & matched EL34's etc,etc.. cheers barry.. |
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Post by twang46 on Mar 2, 2009 0:20:30 GMT
Hi all Just been given a HH Bassmaster (100w combo bass amp 15" speaker tranny amp, late 70's ??) from a guy I was doing a bit of wiring for in his garage conversion. Nice well made amp but weighs a ton early thoughts are to try the speaker & a-b it with the 15" I bought a while ago from the well known auction site to see which suits my amp better (2 x 6l6, about 25w) & use the cab to make a satisfyingly wife annoying large combo ;D So in due course there will be a 100w chassis up for grabs if anybody is interested Now Barry 2 x 15" cab sitting in my 9ft x 9ft room together with my other stuff, 2 love birds, table & 2 seater sofa, could be interesting  Cheers Dick ps.............. sun was shining today in Geordieland ;D |
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Post by Deleted on Mar 2, 2009 2:42:51 GMT
HI Dick well good new's on the ''sunshine''' mate you'll have to don-the-shades..
well mate I like the 15'' that I have as it's quite bright for a 15'' as it is a ''musical instrument design & not geared for bass only,as some are....
well you'll have to build a ''music-room '' or completly take over that room you have HA>HAAR..
THE music is the-most important thing is'nt ''IT''toss all the non musical item's somewhere-else HA.HAAAAR..,,,,,cheer's mate.................barry..
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Post by Charlie Hall on Mar 2, 2009 4:38:14 GMT
Hi Barry,
About your amp, try changing the clean sound's tone stack treble capacitor from 470pf to 250pf, and the 33K tone stack resistor to 56K or 68K. Leave the overdrive tone stack as it is for now.
That should do for a start, then we can see were we should go from there.
Regards,
Charlie
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Post by Deleted on Mar 2, 2009 6:20:51 GMT
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UK Brian
Member
I have my sound, and I luv it
Posts: 440
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Post by UK Brian on Mar 3, 2009 16:38:59 GMT
Ha Haa is it a typo or is there such a thing as a "2 metre red kangaroo"....... ;D ;D
Brian
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Post by Deleted on Mar 3, 2009 22:32:30 GMT
HI brian well she told me it was 2 metres & where she hit it was very remote part,of the bush ,between ,wilcania & broken hill , & you would find big red's there ,, brian 6ft,, for a kangaroo is not uncommon,,in my area we see plenty of grey's & they are mostly 4-5ft tall ,&they make mess of your front end if hit at speed ... www.koalaexpress.com.au/kangaroo%20facts.htm''HEY"" what did you get for your birthday-mate..........cheers to ALL.. barry.. |
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Post by Deleted on Mar 17, 2009 22:17:41 GMT
HI ALL ,,,well I can now say the 15'' speaker is the best & or both together!!!!!the efficiancy of both are good [very easy to drive] but the 12'' on its own lacks the warmth .. And I have found after blaming other unit's in front of my valve amp of having an inicial ''clip''apon a heavy ''pick'' ,I was not using the amp correctly that is having the drive pot set too high ,but now have set the master full on & adjust the drive to suit & is a better sounding amp altogether,& have decided to just add an ''EF86'' channel to it when I find the time I have all the nessasary bit's etc ,,& would I just copy the circuit from an ac15? ?? & would I use dc for the heater as the first 2x12ax7's in this amp use DC heater current? ??& why do they do that? as in my youth when building crude amps all heaters were ''AC'' ? ''ANY TIPS on the ''EF86'' mod would be appreciated !!! CHEERS TO ALL ,,....................barry.. |
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Post by Charlie Hall on Mar 18, 2009 3:58:07 GMT
Hi Barry,
I would use DC for the EF86 heater if the supply is already there, assuming that it will cope with the extra current. There will be (at least in theory) less hum when using the DC heater.
You can just copy the 1960 AC15 EF86 circuit but you might need to use a larger HT dropping resistor to get the HT about right (I don't know the correct HT voltage, maybe it is on the circuit diagram, it is probably around 250 to 300 volts).
Regards,
Charlie
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Post by Deleted on Mar 18, 2009 8:26:59 GMT
HI ALL & THANKS charlie ,I have yet to ''look'' inside the amp as yet it will be next week later in the week ,I need to look at the circuit again but i may be able to do away with some sections ,when using the EF86 [''switch'' the heater feed from 1 to another valve ,as well as the coupling to the appropriate feed point at the same movement..
I have a hand drawn schematic of ''paul's'' ac15 that he built, and a jennings one as well...
I will assertain the correct voltage at the plate as well..
I hope your weather is improving in the UK,,, as down here it's nice at the moment but we could really do with some rain good sleeping-weather!!!!!!!!!!!....
THE 15'' speaker is ''great'' charlie ,,cheers......................barry..
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Post by Charlie Hall on Mar 18, 2009 11:53:39 GMT
Hi Barry,
I'm not so sure that switching heaters will be a good idea because it could cause cathode stripping while HT is applied and the heater is not connected.
Regards,
Charlie
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