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Post by johnnydeadstring on Apr 2, 2006 12:49:04 GMT -7
Hi. I have just got a 1997 carmen ghia head. My vox ac10 is far louder which is very disappointing to say the least. I have tried different valves without much success. It is slightly louder with a 12ax7 in v2 but still unusable. I was really looking forward to cranking this amp up and was worried I might have to use an attenuator but it sounds like it already has one built in. Any help would be much appreciated Thanks
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Post by pedalcr8z on Apr 2, 2006 13:38:02 GMT -7
Something is wrong...........list the tubes being used and what speaker and impedance. It should be much louder than a AC-10!
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Post by johnnydeadstring on Apr 2, 2006 13:55:10 GMT -7
I have ruled out any speaker or valve problems as I am lucky enough to have a lot of spare gear. I have tried various celestion and jensen speaker combinations 4 8 and 16 ohm. The amp only has a 8ohm output but is supposed to cater for all. I wonder is the bias circuit faulty. The amp is not making any strange noises and has a healthy hiss when turned up full. I have modified the vox ac10 so it is very usable for most gigs and had the pleasure of being asked to turn it down by a sound man last week. I didn't of course. Tried with my strat and gibson es355. I have checked some voltages but I don't have a schematic. Thanks John
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Post by bustertheboy on Apr 2, 2006 14:15:53 GMT -7
interesting- my ghia through greenbacks (not most efficient speaker- 98db) is as loud as my fairly hot blackface vibrolux but not quite as loud as my son's boogie subway blues (22w) all are loud enough for most stages interested in this healthy hiss- mine is about the most silent amp i've ever played also voltage of 300v on 5y3 - check with miles on the section at the top of the opening menu an AC15 is a fairly loud amp but i'm not aware of the ac10- when you say modded- in which way there is no bias circuit on these- self biasing which leads me to wonder whether you should try the advice above and change valves- the el84 output valves can make a difference as the bias is affected by the output valves themselves and can make a big difference is the valve section v1-12ax7,v-2 5751 or 12BH7, 5y3 then two el84s? all the best and keep trying you have a potentially brilliant giant killing amp brett
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Post by zdogma on Apr 2, 2006 17:18:25 GMT -7
With a 100dB speaker, like a v30 or g12H it should be just a hair more volume than the AC10 if all is well. You really have to double the wattage to elit a noticable voume change. The older ghias were 15 watts or so. Shouldn't be quieter, though.
My ghia has about the same output as a standard ac 15 in good condition, with identical speakers.
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Post by G'OlPeachPhan on Apr 3, 2006 8:01:23 GMT -7
Did you buy it used? Definitely increases the chances that it was abused somewhere along the way. Almost sounds like it could be an issued with either the power or output trannies, but that's a SWAG for sure... (swag = scientific wild arse guess)
If you know a thing or two about electronics, you could (CAREFULLY so you don't electrocute yourself) always pop open the hood and take a look... if not, better to send it to a qualified tech. What city/state do you live in? Chances are someone on this forum could recommend a good tech.
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Post by billyguitar on Apr 3, 2006 8:44:42 GMT -7
A bad output tranny can do that. Hope it's something cheaper.
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Post by bustertheboy on Apr 3, 2006 23:00:10 GMT -7
i know it's a dumb ask, but have u substituted el84 s from a known good source? as i said above these amps are greatly affected by tubes- self biasing circuits it should be a loud amp- all they lack is clean head room what they have is mighty grunt and the purest and most present harmonics around
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Post by johnnydeadstring on Apr 4, 2006 1:23:11 GMT -7
Hi everyone Thanks for all your help. I am in Belfast Northern Ireland. I have left the amp with an amp tech. He was delighted to see a DR Z. They are not to common in these parts. He said he was knocked out when he saw Buddy Whittington play Belfast last year and has done a bit of research on the Carmen Ghia. He is a good guy and I trust he will fix it. I can remember going to see Jeff Healy play Belfast about 10 years ago and the guy beside me drooling saying "Thats a DR Z he's using". I did as much as I could and think maybe its a preamp component fault. I was only getting about 1 watt output. Quick test on output transformer was ok but I only read the resistances across primaries and secondary. They were within tolerances.(Torres Inside tube amps). I will keep you informed and thanks again for all the interest that you have taken in my amp. I can't wait to get it back at full throttle. John
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dave
New Member
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Post by dave on Apr 4, 2006 4:06:56 GMT -7
hi johnnydeadstring
Welcome to the UK chapter of Z brethren! We are now 3! The UK brethren turned out en mass to the BW gig in London last night. The good news is the Bluesbreakers are properly touring the UK in the autumn so very good chance BW will be over your way later in the year.
Good luck with getting the Ghia fixed. If you need tubes call Derek at Watford Valves. He sent me his 'recommended' set for the Ghia and a) they made a real difference to my allegedly 'newly retubed' amp and b) they got the BW 'seal of approval for good tone' last night. I dont think anyone hearing him would argue with that.
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Post by johnnydeadstring on Apr 4, 2006 5:19:34 GMT -7
Hi Dave Great to be a Z man. Thanks for the welcome. I know of one more owner here in NI. I will get him to join up. Will look out for the Bluesbreaker tour. Have to dig out my Hard Road album. I will be ringing derek this week I am sure although I have amassed a large hopefuly useful collection of oldies.
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Post by bustertheboy on Apr 4, 2006 14:17:22 GMT -7
great book that torres one- really helped with my old vibrolux and good for understanding the self bias thing glad you are persisting- as an owner in australia i understand the bit about feeling a bit isolated- i've only had one sound man even recognise 'wow that's a dr z i think i've heard about them!'
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Post by johnnydeadstring on Apr 7, 2006 13:02:26 GMT -7
Great news from my friend Tony the amp guru of Belfast. It is the conjunctive filter. Both resistor and capacitor are burnt out. He played me the amp without this filter and it is fantastic and that was only half way up. I have emailed DRZ to get the values of these components and it will be as good as new. Have any of you used the amp without the conjunctive filter. Woud it give it a bit more volume or is it better to have it installed. John
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Post by billyguitar on Apr 7, 2006 14:39:15 GMT -7
In the thread "Is This A Tube Problem" also under Carmen Ghia, G'Olpeachplan talks about it.
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Post by bustertheboy on Apr 7, 2006 17:15:25 GMT -7
MAYBE A TINY BIT MORE BUT LESS STRING TO STRING BALANCE- A LITTLE LESS EVEN
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Post by bustertheboy on Apr 7, 2006 20:26:04 GMT -7
got the values for the conjunctive filter from inside my recent ghia resistor reads 5w 10k and capacitor reads 2200m 6kv all the best ps i tried a similar mod on an old fender which was designed to even out frequency response etc- i liked it better on let us know if you like it better on or off brett
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Post by BW on Apr 8, 2006 4:36:04 GMT -7
Johnny, Dave's Ghia is WAY louder than mine, or at least it seemed that way down in the echoey bowels of the 100 club. I ran it thru my Swamp Thang, which is also a bright, LOUD speaker. Let us know how you come out, OK? You should be really diggin' that little screamer.
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dave
New Member
Posts: 7
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Post by dave on Apr 8, 2006 7:30:49 GMT -7
Way louder? Well, interesting. When I first got it I commented how bright it seemed, I was expecting a darker sounding amp than the Z-28. I set the tone normally about 2-3 o/c, I noticed you had it set around 2 o/c - is that the same as with your Ghia? Did you cut back any tone on the Lenz?
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Post by BW on Apr 8, 2006 8:50:27 GMT -7
I think I run the tone on my Ghia at about 12 o'clock, give or take an 'hour'. Yours might be a little brighter, but not a lot. On the bridge pickup, I always have to roll the guitar tone control back to the sweet spot when I have the guitar turned up for crunchy rhythm/solos. When I'm playing clean rhythm, I almost always have it all the way open, or at its most bright. Seemed like your Ghia had quite a bit more headroom than mine for some reason, its of about the same vintage, with only the 8 ohm output jack. Might be the output tubes in yours, I have GTEL84's (#6) in mine, half of a quad that I would have used in my 38. I'm using mine tonight w/ the Swamp Thang at Cachonga's, probably with a piece of plexiglass in front of it so as not to sterilize the front row (that is, the ones that ain't ALREADY sterile...;^)
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