Grand Wazoo Posted January 5, 2011 Share Posted January 5, 2011 Ok, here is the situation. I own 3 combo amps as follows: 1 x 500W Promethean P5110 with detachable head. The Promethean is very tasty little amp, I have bought it for portability reasons as I take it with me on long trip on my ship when I am away at sea. The only nag I have about this combo is the 1 x 10 speaker which is a bit of a compromise, similar to Pavarotti singing in falsetto. 1 x 500 Mark Bass CMD102P fitted with a Little Mark Tube 500W with a 2 x 10" cab - Super Dooper Combo and a force to be reckon with, plenty power, plenty volume and all the colour of the rainbow of tonalities. Last of the bunch is a 30W Ashdown Drophead prototype (it's basically aLittle Bastard Head without the lid), no serial number with detachable head and 1 x 15" cab, in fact its just like one of those Ampeg B-15 flip-top jobbies. True Vintage vibes, extremely warm deep low and capable of crunchy powerful distortion, an amazing little amp worth the £1200 price tag. today I have tried the following experiments all but one of them were successful. In order to accertain if the Promethean head would sound good through a larger set of speakers, I set about trying that head connected the other 2 combo's speakers: the Mark Bass 2 x 10" and the Ashdown 1 x 15" I've removed the Promethean Head and plugged this from the speaker output into the Mark Bass 2 x 12 cab input, gorgeous powerful sound, very pleased, definately an option to consider on gigs. I did the same with the Promethean Head into the 1 x 15" Ashdown cab again, blinking thunderous sound, warm and phat, loud as @#£$ I then did the same experiment with the Mark Head into the 1 x 15" Ashdown cab and hell YEAH! Deep subsonic lows, with plenty of clarity thanks to the VLE and VPF filters. The best of the bunch. and my last test didn't work out. I tried to connect the 30 Watt all tube Ashdown head in to the Mark Bass 2 x 10" speakes and no sound came out, yes I made sure it was plugged properly and the stand-by was on rather than off. Still no sound. Can anyone explain why? the Ashdown head has 2 speaker outputs one marked 4 ohms and the other 8 ohms as in the pic below but neither output gave the Mark Bass 2 x 10" speakers any sound. Any idea why? The Ashdown head was plugged back into its own 1 x 15" cab and it worked fine I'd just like to know why it wouldn't work with the Mark Bass cab. Is it because both the Mark Bass and the Promethen are "class 5" amps whereas the Ashdow it's a based on an old fashion design all on tubes? Thanks Quote Link to comment Share on other sites More sharing options...
LawrenceH Posted January 5, 2011 Share Posted January 5, 2011 (edited) [quote name='Grand Wazoo' post='1078464' date='Jan 5 2011, 12:29 PM']The Ashdown head was plugged back into its own 1 x 15" cab and it worked fine I'd just like to know why it wouldn't work with the Mark Bass cab. Is it because both the Mark Bass and the Promethen are "class 5" amps whereas the Ashdow it's a based on an old fashion design all on tubes? Thanks[/quote] If the MB cab is 4 ohms then you definitely need to use the 4 ohm output, don't use the 8 ohm or you rist damaging the Ashdown head. There's no reason why an all-valve amp couldn't power these speakers, getting the ohm load right is pretty much all that matters. Given that both the Markbass and the Promethean use speakon outputs (I think?) as opposed to the jack on the Ashdown, I'd suggest that a dodgy speaker cable is your most likely explanation. Edited January 5, 2011 by LawrenceH Quote Link to comment Share on other sites More sharing options...
warwickhunt Posted January 5, 2011 Share Posted January 5, 2011 I'd tend to agree that it is a duff lead as there is no apparent reason why it shouldn't have worked. Quote Link to comment Share on other sites More sharing options...
Grand Wazoo Posted January 6, 2011 Author Share Posted January 6, 2011 [quote name='warwickhunt' post='1079075' date='Jan 5 2011, 07:51 PM']I'd tend to agree that it is a duff lead as there is no apparent reason why it shouldn't have worked.[/quote] No it's not the lead, it's a brand new heavy duty speakon to 1/4 inch jack high quality and I have tested it with the volt meter it's fine. I just need to check the 4ohm thing. Quote Link to comment Share on other sites More sharing options...
essexbasscat Posted January 6, 2011 Share Posted January 6, 2011 Was a different cable used to connect the Ashdown compaired to the other two ? what was different between the tests ? what factors were the same ? Quote Link to comment Share on other sites More sharing options...
Grand Wazoo Posted January 6, 2011 Author Share Posted January 6, 2011 [quote name='essexbasscat' post='1079548' date='Jan 6 2011, 10:05 AM']Was a different cable used to connect the Ashdown compaired to the other two ? what was different between the tests ? what factors were the same ?[/quote] I've only got one speaker cable to my name, normally the Promethean and Mark bass' heads connect to their cabs with a short cable that sticks out of the cab. The only combo with a long detachable speaker cable is indeed the Asdown Drophead. So now 1) if I plug the promethean head through the mark bass 2 x 10" cab it works. 2) if I plug the promethean head through the ashdown 1 x 15" cab it works. 3) if I plug the mark bass head through the ashdown 1 x 15" cab it works. 4) if I plug the ashdown head in the mark bass 2 x 10" cab it doesn't work. (now I have not tried 4 or 8 ohms so next time I am ashore I'll give it a go). Quote Link to comment Share on other sites More sharing options...
mart Posted January 6, 2011 Share Posted January 6, 2011 What happens if you plug the Ashdown head into the Promethean cab? Quote Link to comment Share on other sites More sharing options...
Grand Wazoo Posted January 6, 2011 Author Share Posted January 6, 2011 [quote name='mart' post='1079848' date='Jan 6 2011, 01:54 PM']What happens if you plug the Ashdown head into the Promethean cab?[/quote] Didn't try that, as I wasn't that bothered about that particular option I wanted to hear the Ashdown head through a 2 x 10" but I'll try when I am home just to see if it works. Cheers Quote Link to comment Share on other sites More sharing options...
mart Posted January 6, 2011 Share Posted January 6, 2011 Since the Markbass cab worked fine with your Prom head, it must be something to do with the Ashdown head. I can only think that the head has some kind of protection built in to avoid you turning the amp on without a (sufficient) load connected, and that, for some reason, the Markbass cab isn't "looking" like a proper load to the Ashdown head. How does the Ashdown cab connect to the head - just by a mono 1/4" jack? Or a stereo jack? Is there any other wiring linking the head and the cab? Sorry, I'm just brainstorming here ... don't mind me .... Quote Link to comment Share on other sites More sharing options...
Musicman20 Posted January 7, 2011 Share Posted January 7, 2011 [quote name='mart' post='1080075' date='Jan 6 2011, 04:32 PM']Since the Markbass cab worked fine with your Prom head, it must be something to do with the Ashdown head. I can only think that the head has some kind of protection built in to avoid you turning the amp on without a (sufficient) load connected, and that, for some reason, the Markbass cab isn't "looking" like a proper load to the Ashdown head.[/quote] I think this might be correct. I cant see why the amp would work fine with its own cab, but not with another, unless its an ohms issue. GW - Make sure if you are connecting it to try this, that you dont leave it plugged in without a 'load'. You probably know, but tube amps need to see a speaker load otherwise it can damage the transformer (I think thats correct, anyway). Im uber careful with my Orange. Although, if its physically plugged in, Im sure its fine! Ill dig around the internet to see why this is happening...hope it sorts itself. Quote Link to comment Share on other sites More sharing options...
Musicman20 Posted January 7, 2011 Share Posted January 7, 2011 [url="http://www.ashdownmusic.com/tech/manuals/valve_series_manual.pdf"]http://www.ashdownmusic.com/tech/manuals/v...ries_manual.pdf[/url] - Close enough! Just read your post again, and as you have the 8 ohm and 4 ohm outlets, I see no reason why you cant use it with another cabinet. If the MB combo cab is 8 ohms, then 8 ohms plug from Ashdown to input of Markbass combo cab (as you know Markbass amp NEEDS disconnecting). If the MB combo cab is 4 ohms, then 4 ohms plug from Ashdown to input of Markbass combo cab (as you know Markbass amp NEEDS disconnecting). Im pretty sure the MB combo cabinet is an 8 ohms 2x10, so this doesnt apply. Check the Asdown 8 ohms into the Promethean cabinet. If this works, its a problem with the Markbass combo cab eg possibly the connector needs replacing or just cleaning perhaps. If the Ashdown doesnt work into the Promethean cabinet, then, and if you Ashdown cabinet is 4 ohms, there is a problem with the 8 ohms output on the Ashdown amp. Lastly, it COULD possible be a speaker lead problem....maybe it has a slight kink in it and at certain angles the wire inside isnt connecting. Phew! Firstly, Id email Ashdown. Seems odd that there would be an 8 ohms problem as it has the outputs on the back! Quote Link to comment Share on other sites More sharing options...
mart Posted January 7, 2011 Share Posted January 7, 2011 All good sensible points from Musicman20. Buuuuut .... [quote name='Musicman20' post='1080913' date='Jan 7 2011, 12:01 PM'][url="http://www.ashdownmusic.com/tech/manuals/valve_series_manual.pdf"]http://www.ashdownmusic.com/tech/manuals/v...ries_manual.pdf[/url] - Close enough![/quote] I don't know if that is close enough. I had a look for the Ashdown manual, but of course this is a new prototype, so may well have all sorts of differences to their current range. It may be the same, or it may not!! [quote name='Musicman20' post='1080913' date='Jan 7 2011, 12:01 PM']..... Check the Asdown 8 ohms into the Promethean cabinet. If this works, its a problem with the Markbass combo cab eg possibly the connector needs replacing or just cleaning perhaps. ....[/quote] Not necessarily. GW has already pointed out that the Markbass cab works with the Prom head: [quote name='Grand Wazoo' post='1079614' date='Jan 6 2011, 11:00 AM'].... 1) if I plug the promethean head through the mark bass 2 x 10" cab it works. ....[/quote] So if the Ashdown head works with the Prom cab (and I suspect it [i]won't[/i]), then it'd be puzzling, and a result of some curious mismatch between Ashdown and Markbass. [quote name='Musicman20' post='1080913' date='Jan 7 2011, 12:01 PM']..... If the Ashdown doesnt work into the Promethean cabinet, then, and if you Ashdown cabinet is 4 ohms, there is a problem with the 8 ohms output on the Ashdown amp. Lastly, it COULD possible be a speaker lead problem....maybe it has a slight kink in it and at certain angles the wire inside isnt connecting. Phew! Firstly, Id email Ashdown. Seems odd that there would be an 8 ohms problem as it has the outputs on the back![/quote] +1 to all those points. I'm beginning to think that in this new prototype Ashdown are trying out some clever technology to prevent people running the head with no load, and that the technology is maybe too clever, so doesn't work with the Markbass cab. That's just a wild guess, but it fits the observations. Quote Link to comment Share on other sites More sharing options...
obbm Posted January 7, 2011 Share Posted January 7, 2011 Another quick check would be to do the "forbidden" and connect the Markbass cab to the Ashdown with a short instrument lead just to verify that the outputs work. Is the Speakon a 2-pole or 4-pole? If the latter is it wired correctly? Quote Link to comment Share on other sites More sharing options...
Grand Wazoo Posted January 15, 2011 Author Share Posted January 15, 2011 [size=7][b][font="Times New Roman"][i]CONFESSIONS OF A 24 KARAT PLONKER = ME![/i][/font][/b][/size] i.e. [b][font="Times New Roman"][i]MEA CULPA[/i][/font]![/b] (Latin for my fault) I have sorted the problem, I had overlooked the obvious and the reason I couldn't plug the Ashdown head into the Mark Bass combo is because the MB cab does not have an amp input as such, what it does have, it's a little male jack that comes out of it's speaker and go into the speaker output of the MB head!! Now what I did that obviously didn't work was to try and plug a speaker cable coming from the Ashdown head into the other head of the MB i.e. I was being a total PLONKER. DOH!! Now, thanks to a bit of late wit I realized the mistake and got a speaker cable with a female / male where I can get the output from the MB connected with the male from the MB speaker and all works well. So yeah call me a plonker, I just didn't have my thinking head on that day. All is well what ends well Quote Link to comment Share on other sites More sharing options...
mart Posted January 17, 2011 Share Posted January 17, 2011 Tee hee! But now I am puzzled: how did you get this: [quote name='Grand Wazoo' post='1079614' date='Jan 6 2011, 11:00 AM']..... 1) if I plug the promethean head through the mark bass 2 x 10" cab it works. ....[/quote] to work? Quote Link to comment Share on other sites More sharing options...
Grand Wazoo Posted January 29, 2011 Author Share Posted January 29, 2011 [quote name='mart' post='1092155' date='Jan 17 2011, 09:09 AM']Tee hee! But now I am puzzled: how did you get this: to work?[/quote] that's easy even for a plonker like me, ok.. follow me: the promethean head can be detached from the cab by undoing these 2 great big thumb screws, ok? So it removed it and sat it on top of the Mark Bass combo, I then unplugged the speaker lead from the back of the Mark Bass head and plugged it in the speaker output of the promethean, and hey presto. Quote Link to comment Share on other sites More sharing options...
mart Posted January 29, 2011 Share Posted January 29, 2011 [quote name='Grand Wazoo' post='1106927' date='Jan 29 2011, 01:47 AM']that's easy even for a plonker like me, ok.. follow me: the promethean head can be detached from the cab by undoing these 2 great big thumb screws, ok? So it removed it and sat it on top of the Mark Bass combo, I then unplugged the speaker lead from the back of the Mark Bass head and plugged it in the speaker output of the promethean, and hey presto.[/quote] So the lead coming from the MB speaker was long enough to reach the Promethean head, but you couldn't get the Ashdown head close enough for it? Ok, I think I understand now! Quote Link to comment Share on other sites More sharing options...
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