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Post by jimbo on Feb 19, 2022 15:51:18 GMT
I have always been slightly concerned that my Croft amplifier cases although perfectly adequate for the job are made of fairly thin steel especially the top lid which has slots cut into it to allow valve ventilation. However because the top lid is thin it vibrates both from airborne sources and very slightly from a buzzing toroid.
Anyone got any suggestions of what I can use on the inside of the steel lid to dampen it down? My current solution is to put something heavy on top.
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Post by alit on Feb 19, 2022 15:54:11 GMT
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Post by alit on Feb 19, 2022 15:54:34 GMT
Wow, some URL.
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Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,398
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Post by Bigman80 on Feb 19, 2022 16:03:32 GMT
Spot on Al. That's good stuff indeed. |
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Post by firebottle on Feb 19, 2022 16:25:48 GMT
I've got some Dynamat here James, can spare some to do your lids no problem.
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Post by rexton on Feb 19, 2022 16:37:51 GMT
+1 for dynamat. It's a sod to remove, however.
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Post by jimbo on Feb 19, 2022 17:01:44 GMT
I've got some Dynamat here James, can spare some to do your lids no problem. Thanks for the offer Alan but i might try some of the other stuff . cheers |
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Post by jimbo on Feb 19, 2022 17:02:51 GMT
I will just check I have enough clearance between lid and top of toroid to fit some of this stuff. many thanks. |
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Bigman80
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The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,398
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Post by Bigman80 on Feb 19, 2022 17:06:18 GMT
I will just check I have enough clearance between lid and top of toroid to fit some of this stuff. many thanks. Just Fit it where you can. Some will help! Keep any ventilation clear and it should be ok. |
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Post by jimbo on Feb 19, 2022 17:09:16 GMT
I will just check I have enough clearance between lid and top of toroid to fit some of this stuff. many thanks. Just Fit it where you can. Some will help! Keep any ventilation clear and it should be ok. Cheers , I see its military grade too so maybe used in tanks!   |
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Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,398
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Post by Bigman80 on Feb 19, 2022 17:10:14 GMT
Just Fit it where you can. Some will help! Keep any ventilation clear and it should be ok. Cheers , I see its military grade too so maybe used in tanks! I like Mil-Spec.....even if it's damping material! |
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Post by brucew268 on Feb 19, 2022 18:14:12 GMT
I have always been slightly concerned that my Croft amplifier cases although perfectly adequate for the job are made of fairly thin steel especially the top lid which has slots cut into it to allow valve ventilation. However because the top lid is thin it vibrates both from airborne sources and very slightly from a buzzing toroid. Anyone got any suggestions of what I can use on the inside of the steel lid to dampen it down? My current solution is to put something heavy on top. Hi James,
Send me your address and I'll post an A4 sheet of Silent Coat to you. It's basically the same as Dynamat and that first link above... and should be used judiciously. You'll probably only need one or two 10mm discs.
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Post by jimbo on Feb 19, 2022 18:20:31 GMT
I have always been slightly concerned that my Croft amplifier cases although perfectly adequate for the job are made of fairly thin steel especially the top lid which has slots cut into it to allow valve ventilation. However because the top lid is thin it vibrates both from airborne sources and very slightly from a buzzing toroid. Anyone got any suggestions of what I can use on the inside of the steel lid to dampen it down? My current solution is to put something heavy on top. Hi James,
Send me your address and I'll post an A4 sheet of Silent Coat to you. It's basically the same as Dynamat and that first link above... and should be used judiciously. You'll probably only need one or two 10mm discs.
Thats very generous of you. Thank you. I will send you a PM. |
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Post by hifinutt on Feb 20, 2022 15:28:38 GMT
would a dc blocker help ?
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Post by jimbo on Feb 20, 2022 17:31:32 GMT
would a dc blocker help ? That has been suggested and certainly may do. The case is mainly vibrating through airborne vibration I think but a DC blocker would cure the toroid buzzing. |
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Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,398
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Post by Bigman80 on Feb 20, 2022 17:32:13 GMT
would a dc blocker help ? That has been suggested and certainly may do. The case is mainly vibrating through airborne vibration I think but a DC blocker would cure the toroid buzzing. It may not. |
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Post by sq225917 on Feb 20, 2022 18:04:14 GMT
It's probably just a rattly case. Mount the mains traffo remotely, bolt it to a perspex disc and glue that to 10mm thick foamed neoprene rubber with pu glue, and glue the whole thing to the chassis.
That's how the traffo in my neurochromes are mounted, absolutely zero chassis vibration.
I wouldn't throw them about, but short of leaving them upside down I'm not worried about them coming unstuck.
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Post by rexton on Feb 20, 2022 19:20:00 GMT
DC blockers are not the be all and end all. They certainly kill musicality.
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Feb 20, 2022 19:28:06 GMT
I would not agree with that statement.
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Post by rexton on Feb 20, 2022 19:56:33 GMT
I would not agree with that statement. Horses for courses, tried several, killed musicality every time. |
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Post by sq225917 on Feb 20, 2022 20:33:26 GMT
Never heard them do anything other than reduce transformer noise, but I've only ever used bigguns that don't current limit.
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Post by brucew268 on Feb 20, 2022 21:57:38 GMT
When I first used one it seemed that a little of the edge sharpness was gone and I mentioned that to Nick @lda. He said it may be that what I was used to was overshoot and to listen for week or two before deciding. Of course there were capacitors to break in as well. I ended up agreeing that could be it and have been happy for years since whilst enjoying good handling of the leading edges.
From LC Audio it's a EUR30 experiment not like £700+ some are asking.
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Post by jimbo on Feb 21, 2022 7:32:43 GMT
I have heard arguments for and against DC blockers but i have never heard what one does in my system. Only then will I know the truth.
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Bigman80
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Posts: 16,398
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Post by Bigman80 on Feb 21, 2022 12:50:10 GMT
I have heard arguments for and against DC blockers but i have never heard what one does in my system. Only then will I know the truth. Is the transformer causing the case to vibrate? I may have missed that bit earlier |
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Post by jimbo on Feb 21, 2022 15:40:26 GMT
The transformer is only causing very slight vibration, most of the case vibration is coming from the speakers being close.
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Bigman80
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The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,398
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Post by Bigman80 on Feb 21, 2022 16:04:10 GMT
The transformer is only causing very slight vibration, most of the case vibration is coming from the speakers being close. A DC blocker wont do anything if it's being caused by the speaker. Also, the Transformer is likely to be vibrating due to the laminations. Could also possibly be from being rated for 230v and your home supply being at least 240v. Some transformers do not like more than 230v. I would suggest using that damping mat and seeeing how you get on. If you can hear the traffo buzzing away, change them for proper spec ones. It's the only real long term cure, and i expect the Crofts are going to be long term in your system. |
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Post by brucew268 on Feb 21, 2022 17:01:04 GMT
The transformer is only causing very slight vibration, most of the case vibration is coming from the speakers being close. Oh, that's good to know. The transformer is only causing very slight vibration, most of the case vibration is coming from the speakers being close. A DC blocker wont do anything if it's being caused by the speaker. Also, the Transformer is likely to be vibrating due to the laminations. Could also possibly be from being rated for 230v and your home supply being at least 240v. Some transformers do not like more than 230v. I would suggest using that damping mat and seeeing how you get on. If you can hear the traffo buzzing away, change them for proper spec ones. It's the only real long term cure, and i expect the Crofts are going to be long term in your system. Of course a DC blocker is only if the vibration is from the transformer and if it's due to a little DC on the mains. I didn't notice, is that a laminated core transformer next to the toroidals? I was thinking of toroidals, but in any case it seems there are several possibilities. |
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Bigman80
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The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,398
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Post by Bigman80 on Feb 21, 2022 17:27:52 GMT
The transformer is only causing very slight vibration, most of the case vibration is coming from the speakers being close. Oh, that's good to know. A DC blocker wont do anything if it's being caused by the speaker. Also, the Transformer is likely to be vibrating due to the laminations. Could also possibly be from being rated for 230v and your home supply being at least 240v. Some transformers do not like more than 230v. I would suggest using that damping mat and seeeing how you get on. If you can hear the traffo buzzing away, change them for proper spec ones. It's the only real long term cure, and i expect the Crofts are going to be long term in your system. Of course a DC blocker is only if the vibration is from the transformer and if it's due to a little DC on the mains. I didn't notice, is that a laminated core transformer next to the toroidals? I was thinking of toroidals, but in any case it seems there are several possibilities. Torroids do it too. |
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Post by hifinutt on Feb 22, 2022 17:56:51 GMT
DC blockers are not the be all and end all. They certainly kill musicality. not always . they have different effects . i once had a puresound L10 and it made a really big enjoyable difference to its musicality [ isotek syncro ] i agree though its not always the answer and i have had 4 isotek syncro in my time |
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Post by jimbo on Feb 23, 2022 16:08:58 GMT
Silent Coat now installed in Croft pre amp. Thank you Bruce!
The case certainly rings less when tapped and airborne vibration much reduced to the point it barely perceptible. Good result.
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