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Post by dougal on Nov 2, 2018 10:00:23 GMT -7
Hi all,
I've dropped a few posts in the Carmen Ghia section about a new amp I've just got.
As a brief summary, I'm in the UK and recently purchased a Carmen Ghia head from the UK dealer, Peach Guitars.
I received it yesterday, and it blew a fuse immediately after turning it on the first time. Peach sent me out a new fuse and replacement rectifier and power valves.
I got those this morning, so went through the troubleshooting process mentioned on the Doc's page. Disconnected everything, pulled all the tubes, replaced the fuse, connected to speaker and power, then turned the amp on.
At this point, the amp turned on fine. So I powered it off, disconnected everything, popped the new rectifier valve in, connected back up, powered on, and it blew the fuse again immediately.
I've been in touch with Peach and they are arranging for collection, but due to the weekend it will now be on Monday.
Was wondering if anyone had any suggestions of anything I might be able to try/check over the weekend?
Kind regards
Steve
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Post by bgkyt1 on Nov 2, 2018 14:26:26 GMT -7
is it a brand new amp? the amp is built for 230v, correct? you're sure you didn't mistake the old rectifier valve for the new one? was the speaker plugged in when testing the rectifier?
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Post by dougal on Nov 2, 2018 18:27:32 GMT -7
Aye, it's a brand new amp. Not sure if its just to the amount that get sold over here, but it's actually dated 2015. I knew this before purchasing and wasn't really concerned about it, though it does potentially mean its been stood for about 3 years in a warehouse.
Peach test before shipping, so they'd had it working ok.
I hadn't checked the voltage of the amp, just assuming it was UK spec coming straight from a dealer. I had the amp all packed up, but curiosity got the better of me, and I unboxed it again to check.
Can confirm it is 230v so that's ok.
99.99999% sure I didn't put the old rectifier back in, and it was definitely connected to a cab.
I had actually ordered a rectifier tube and extra fuses myself before Peach had said yesterday they were going to send me one, and these came after I had already boxed the amp back up after checking it with the stuff Peach sent me.
Well, as the amp was out, and I had a few more fuses handy, I thought I'd check some more. So back to the beginning with a new fuse in:
All tubes out - powered on fine Popped my new (3rd one) rectifier in - powered on fine! Switched it off and on again a few times with just the rectifier in - powered on fine each time. Popped the original power tubes in - fuse blown..... Replaced fuse Started with just the latest rectifier in - powered on fine as it did before. Switched it off and on a few times with the rectifier in - fuse blew.... Had more fuses so not giving up, replaced fuse again With just the rectifier in - powered up fine Off and on a few times - powered up fine each time Popped the power tubes in that Peach had sent me today (these hadn't been in the amp yet) - powered on fine!! Progress! Did start getting a bit weary at this point, so I went whole hog and popped both pre amp tubes in - powered up fine!
I've had about an hour on the amp now, intermittently powering it off and on (giving it a few mins off before turning on again each time), and it's still working, and oh my days, even at 1am volumes it's sounding glorious.
So, I'm a bit puzzled what to do now. In summary, it has blown the fuse once as mentioned with this 3rd rectifier, but after replacing that fuse, I was able to get the rest of the valves in and have been using the amp, with no unexpected noise or crackles or anything.
I guess the question in the back of my mind is could I just have been a bit unlucky with the valves, or is there potentially something up with the amp that was causing this.
I'll be having a chat with the guys at Peach in the morning to see what they think.
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Post by premiumplus (Dave) on Nov 2, 2018 19:13:42 GMT -7
It's possible that you had a bad power tube and a bad rectifier tube as well. Sounds like you have it working, play it and let us know how it goes. You won't hurt anything.
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Post by purpletele on Nov 2, 2018 19:23:28 GMT -7
Aye, it's a brand new amp. Not sure if its just to the amount that get sold over here, but it's actually dated 2015. I knew this before purchasing and wasn't really concerned about it, though it does potentially mean its been stood for about 3 years in a warehouse. Peach test before shipping, so they'd had it working ok. I hadn't checked the voltage of the amp, just assuming it was UK spec coming straight from a dealer. I had the amp all packed up, but curiosity got the better of me, and I unboxed it again to check. Can confirm it is 230v so that's ok. 99.99999% sure I didn't put the old rectifier back in, and it was definitely connected to a cab. I had actually ordered a rectifier tube and extra fuses myself before Peach had said yesterday they were going to send me one, and these came after I had already boxed the amp back up after checking it with the stuff Peach sent me. Well, as the amp was out, and I had a few more fuses handy, I thought I'd check some more. So back to the beginning with a new fuse in: All tubes out - powered on fine Popped my new (3rd one) rectifier in - powered on fine! Switched it off and on again a few times with just the rectifier in - powered on fine each time. Popped the original power tubes in - fuse blown..... So you pulled these tubes?Replaced fuse Started with just the latest rectifier in - powered on fine as it did before. (Only the Rectifier?)Switched it off and on a few times with the rectifier in - fuse blew.... Had more fuses so not giving up, replaced fuse again With just the rectifier in - powered up fine Off and on a few times - powered up fine each time Popped the power tubes in that Peach had sent me today (these hadn't been in the amp yet) - powered on fine!! Progress! Did start getting a bit weary at this point, so I went whole hog and popped both pre amp tubes in - powered up fine! I've had about an hour on the amp now, intermittently powering it off and on (giving it a few mins off before turning on again each time), and it's still working, and oh my days, even at 1am volumes it's sounding glorious. So, I'm a bit puzzled what to do now. In summary, it has blown the fuse once as mentioned with this 3rd rectifier, but after replacing that fuse, I was able to get the rest of the valves in and have been using the amp, with no unexpected noise or crackles or anything. I guess the question in the back of my mind is could I just have been a bit unlucky with the valves, or is there potentially something up with the amp that was causing this. I'll be having a chat with the guys at Peach in the morning to see what they think. Dougal, I have had similar issues with new amps that I have built. I have also had a similar issue with a new amp. You have been real logical about the sequencing, but I had a question about one of the moves. However, it may not make any difference. You have had the power tubes take out the fuse and then you replaced fuse, but were the power tubes still in when you powered up again? I have gone in a cyclical failure loop, where one thing trips another, just as you have described. And I solved it as you have described and have been fine. Just to hear it from across the pond for reassurance, 99% of the time it's a tube issue. My experience since then has been the amp has never had temperament problems again. If it turns on and plays after you finally sleep, then I wouldn't ship it back. You will go into a circular loop with that as well if you ship it back. Meaning, you will not have an amp for a few days longer, and you may have a similar or slightly different tube issue if you get another new amp. Especially if the package carriers drag their knuckles. It seems that in all of my new amps that I have purchased and had shipped I had rouge tube issues within a few hours, my new Z-Plus and EMS was not an exception. I'm betting that you are good to go for many years with the configuration that you have described.
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Post by dougal on Nov 2, 2018 19:40:37 GMT -7
Hey Purpletele, Yeah sorry if my post was a bit unclear, I can definitely ramble at times! At the point the original power tubes were in and the fuse blew, yes I took those tubes out, so I was left with just the new rectifier, and then popped a new fuse in. At one point after this, with just the new rectifier in, it did blow a fuse, but as it had been working ok with this rectifier in, I left it and replaced the fuse and then the amp powered on fine again with just the rectifier in. Then from that point, I was able to put the rest of the tubes back in as described, and have an hour playing it. So essentially, i'm on the 3rd rectifier, 2nd set of power tubes, and on the 5th fuse! Been quite a night. But, it was solid during the hour I was on it after all this. I clearly need to spend hours on it over the weekend and give the neighbours a listen too Will be interesting to see how it handles a zVerb too. Will report back and say how things go. Thx all!
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Post by dcarver on Nov 2, 2018 20:15:48 GMT -7
You fixed it ! Sounds like you had a bad rectifier, a bad power tube, and possibly a bad fuse. Play the bajeezus out of it. If anything blows, you can jump off that bridge when you get to it. Kidding mate. Glad you got it working.
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Post by dougal on Nov 3, 2018 16:33:53 GMT -7
Well, is there anything as irritating as thinking something was fixed, then having the same problem again... It's been almost 24 hours since I got the amp working, and in that time I've probably had it on a dozen different times and it had been fine. Then, I come to have another blast on it this evening, and the darned thing was dead again. Checked, and the fuse had gone. Replaced it yet again, and it's fired up ok again, but I'm very wary now that something just doesn't seem right. One thing I have noticed from the Carmen Ghia user manual on the web site, is that it states to use the type of fuse that's labeled on the back of the amp, but then in brackets it says 1A 250V Slo Blo. Now on my amp, the label says 1A 250V AGC, which as I understand it is the normal/fast blow type. I've dropped a mail through to Dr Z repairs just pointing this out and questioning it, and asking if there's anything else I can check. Otherwise, it's going to have go get sent back, but with it working OK for me for a while, who's to say when the retailer gets it back and checks it that it'll blow a fuse. Really frustrating, as there has to be something amiss. Will see what happens.
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Post by KeithA on Nov 3, 2018 16:40:49 GMT -7
Well, is there anything as irritating as thinking something was fixed, then having the same problem again... It's been almost 24 hours since I got the amp working, and in that time I've probably had it on a dozen different times and it had been fine. Then, I come to have another blast on it this evening, and the darned thing was dead again. Checked, and the fuse had gone. Replaced it yet again, and it's fired up ok again, but I'm very wary now that something just doesn't seem right. One thing I have noticed from the Carmen Ghia user manual on the web site, is that it states to use the type of fuse that's labeled on the back of the amp, but then in brackets it says 1A 250V Slo Blo. Now on my amp, the label says 1A 250V AGC, which as I understand it is the normal/fast blow type. I've dropped a mail through to Dr Z repairs just pointing this out and questioning it, and asking if there's anything else I can check. Otherwise, it's going to have go get sent back, but with it working OK for me for a while, who's to say when the retailer gets it back and checks it that it'll blow a fuse. Really frustrating, as there has to be something amiss. Will see what happens. I always use slo-blow. The 1950's technology in tube amps will take out fast-blo tubes more often than not. Fast-blo are intended for fragile, consumer-type electronics. I remember once I lost a fuse and the only local shop open (on a Sunday) only has normal fuses. I blew two more before I got slow-blo fuses on the Monday. Never had a problem after. However, that doesn't mean there's not something wrong with the amp from a rough shipping experience. Edit-I just checked the back of a few of my Z's and they all call for Slo-blo
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Post by purpletele on Nov 3, 2018 18:16:37 GMT -7
Douglal,
I bet you have a grid resistor that was failing or failed due to the One of the factors.
You are best to work an exchange with Peach.
in the future if you run into that situation please do not try a new fuse more than twice. I have taken out an output transformer doing that very thing.
i bet that the original power tube short weakened that resistor, and it did its job very well by failing.
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mully
New Member
Posts: 4
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Post by mully on Nov 4, 2018 2:37:13 GMT -7
going to check out a used Carmen Ghia Anniversary model in germany today. The seller says he has had the same problem with it. Fuse blowing all the time. He brought it to a music store and they built a bigger fuse into it and he says it's been fine since. Maybe the fuses used are not really meant for 230V usage? Or maybe the music store put in a super big fuse which won't act like a fuse anymore because when it blows it might be too late.
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Post by brendanp on Nov 4, 2018 3:07:47 GMT -7
Hi Dougal
When I first got my Maz 18 NR combo, I bought it from the previous owner who said it had died. His amp guy claimed the amp "just needed new tubes". Nobody sells an amp because it needs new tubes. So, I bought it anyway, bought a fresh complement of tubes and it also kept blowing fuses once the new tubes were in. I could also see that fuse holder had seen a few screwdrivers already. Took it to my amp guy and after a few experimental checks on components and a few more blown fuses he did another chopstick test - basically, moving each wire near each connection point to find any shorts and, sure enough, there was a spark and the telltale fuse death. Once that connection was resoldered, everything's been fine. I think it's worth taking a poke around just to see what happens (if you have some spare, backup fuses with you). Could be movement, temperature, anything that can cause a surprise cold joint.
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Post by dougal on Nov 4, 2018 6:38:24 GMT -7
Thanks for all the input guys.
I think in the grand scheme of everything, I'm best off now letting Peach collect it and give it a once over. I don't mind swapping tubes and fuses, but with it being brand new, I think if anything needs looking at inside it's far better off with the dealer.
Might be a while now before I can report on anything further, but thank you all once again for your input.
Steve
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Post by headshrinker (Marc) on Nov 4, 2018 7:32:33 GMT -7
There might be a problem with the power switch where sometimes when you flip it it shorts and other times it doesn't. Had that problem with a Mesa many years ago. Replaced the switch and all was well.
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Post by Chilly Gibbons (Todd T.) on Nov 4, 2018 9:07:48 GMT -7
Let us know what they discover.
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Post by premiumplus (Dave) on Nov 5, 2018 6:50:34 GMT -7
You may as well send it back, but I'm surprised that it isn't slow blow type. I can't remember the last time (if ever) I've seen a fast blow fuse in a tube amp. Unless it was a separate HV fuse for output tubes. If you sent a PM to the Z shop on Saturday, you'll hear from them today. I'd at least wait until then.
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Post by doctorice on Nov 6, 2018 12:02:37 GMT -7
I think in the grand scheme of everything, I'm best off now letting Peach collect it and give it a once over. I don't mind swapping tubes and fuses, but with it being brand new, I think if anything needs looking at inside it's far better off with the dealer. Steve, rest assured that Dr Z and Peach will get it sorted out. On the rare occasions when I've had a problem with a new amp, Z has always made it right.
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Post by dougal on Nov 6, 2018 13:24:19 GMT -7
Cheers again for all the input guys.
It had already been arranged for the amp to be picked up yesterday, so rather than doing anything else, I let it be collected as I didn't want to be poking and prodding and do anything that might make things worse.
I did have a reply from Don after the amp had been picked up saying that a 1A slo blo could be tried, but for peace of mind that nothing else is wrong with the amp, I'd prefer to let Peach give it the once over. Would hate to think I popped a slo blo in there and it then caused some other issue if indeed the fuse had been failing for a specific reason.
I can see from tracking that they've had it delivered today, so hopefully I'll hear something from them tomorrow or Thursday.
Not having the best of luck with gear at the moment hah. Also waiting on a 000-28 re-imagined from my local store, but they seem to keep having delays with getting the guitar from the distributors here in the UK. Been about a month so far, and it's now estimated to be towards the end of this month. Will just class it as a really, really late birthday/early Christmas present!
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Post by dougal on Nov 9, 2018 7:24:20 GMT -7
Well, brief update. Just been speaking with Peach, and after they popped a new fuse in (fast blow), they have not been able to replicate the issue I was having! They were not able to find anything wrong with the amp (which is both good, but also slightly frustrating as it wasn't working well for me!), and they are wondering if there could be a slight difference in mains voltage in my area that might have caused it. I'm around 200 miles away from Peach, so I guess it's a possibility, but it's a bit odd that I have a couple of other Z's and a few other amps and never really had a problem like this. I have picked up some slow blow fuses, and have discussed with Peach if they are happy for me to try those (as they are technically different to what's specified on the back of the amp). I did explain that the response I had from Don was to give these a go. Just waiting on a call back now to sort out how to proceed. Unfortunately with the time it is now, I'm not expecting being able to get this back for the weekend
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Post by dougal on Nov 13, 2018 12:43:14 GMT -7
Latest update for anyone who's not yet bored with me!
So after another palaver, finally got the amp in my hands today. As previously mentioned, Peach have advised they've checked the amp and all looks ok, and they couldn't replicate the issue.
So...first time I switched it on, guess what happened? Yup, the regular fuse they had put in and had been testing with blew.
Half expected that, so I popped in a slow blow.
Didn't blow! Amp powered up, though something was still a little odd. First time powering up with the slow blow, I had a bright glow from the rear of the amp. Only for a split second, then it went and the amp warmed up and worked fine.
Switched it off and on a couple of times over a 30 min period and it was ok each time, no more glowing.
However, I then left the amp off for 10 mins. Switch back on while I was watching the back of it, and had the glow again - the power tubes lit up like a light bulb for a brief second, before dimming back to normal. The amp warmed up ok and worked fine.
Never had that with an amp before, and I'm assuming it isn't normal for a Carmen Ghia to do that. I've written to Don at Dr Z repairs for his take on the situation, so will see what he thinks.
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Post by KeithA on Nov 13, 2018 13:00:37 GMT -7
I've had that happen before. It's tube related.
Switch the two (2) eL84s and see if the bright glow follws the tubes switch. It did twice I had similar issues.
Obviously you'll need to do the switch and wait a while for the amp to power down fully so that the glow will resurface.
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Post by dougal on Nov 13, 2018 15:37:20 GMT -7
I've had that happen before. It's tube related. Switch the two (2) eL84s and see if the bright glow follws the tubes switch. It did twice I had similar issues. Obviously you'll need to do the switch and wait a while for the amp to power down fully so that the glow will resurface. Good shout on swapping the power tubes. Tried a new rectifier first just in case it was that, but got the same thing happen with the power tubes. Dug out a fresh pair of Sovteks, and touch wood, so far they haven't flared up on power on like the JJ's that were in. They are just a tad longer than the JJ's though, so the darn retainers won't fit over !!! On the retainer clip though, I can see what looks like two possible pairs of holes in the base of the clip that the wire clip part attaches to, with one pair of holes effectively lengthening the clip by a couple of mm which I think is all that's needed. Looks like I should just be able to move the clips to these holes to give me that bit extra length on the clip that it looks like I need. Don't want to get too excited about it all possibly being fixed.....will see how it behaves itself over the next 24 hours.
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Post by zpilot on Nov 14, 2018 15:43:03 GMT -7
I don't want to advocate redesigning or modding a Z amp but I have installed thermistors in amps a couple of times when the owner was having problems related to inrush current. There is a downside to these though which is the reason (I believe) most amp builders don't use them. Improper operation such as rapid turn off/on can cause them to fail which would entail warranty issues.
Still, there are too many of these amps out there and for too long for there to be a design defect causing this.
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Post by digs57 on Nov 15, 2018 16:02:05 GMT -7
Never want to use a pair of power tubes that red plate...even if just for 3 seconds...it will fail and burn transistor as zpilot explains...
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Post by zpilot on Nov 15, 2018 19:35:21 GMT -7
I don't think the tubes are redplating. It's not the anodes glowing. It is probably the heater filaments. As I understand it the filaments of the suspect tubes flash brightly because they are conducting too much current. As the all of the tubes warm up the resistance increases and the current decreases.
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Post by zpilot on Nov 16, 2018 15:44:29 GMT -7
Here's a good explanation and demonstration of filament flash. Watch up to 4:54. After that is a work-around which I don't recommend doing to your Z amp. The real work-around is not to use tubes that do this.
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Post by dougal on Nov 17, 2018 10:58:17 GMT -7
Thank you everyone for your input, but following a further blip yesterday, I'm sending the amp back for a refund. Unfortunately I've got a bit too much going on personally to possibly go through this with a replacement, and I've just got to the end of my tether with this particular amp now. Still got my MAZ 18 and Wreck to fall back on, so all's not lost.
Once things have settled down at home, I might look at this again, but for now, unfortunately I think I'll have to call it a day.
Mods please feel free to mark this as closed.
Kind regards
Steven
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