Blowing speaker drivers upon turn on

[S Clark]

I've got an audiophile friend that keeps blowing drivers upon turn on... three times in the past 12 months.  He gets in a hurry and forgets his sequence.  He's using an older AR tube preamp..not sure which amp he has in at the moment.
I've never had this issue.  All my amps have a delayed start.  Would this feature fix his problem?
My preamps are Dodd battery models. 

[Nick B]

Yikes, 3 times in a year? I’m not technically inclined, but I’d think a delayed start would be helpful. Why not have the instructions on his phone, tablet so he can refer to that each time.

[S Clark]

Yikes, 3 times in a year? I’m not technically inclined, but I’d think a delayed start would be helpful. Why not have the instructions on his phone, tablet so he can refer to that each time.

He knows the sequence, he just gets absent minded (as do I occasionally).  In my system, it's the phono pre that I have to watch out for.  But amp first in, last out is what I've always heard is best the least likely to cause a loud surge.   

[GDHAL]

Correct procedure is power amps being turned on last, and off first.

Either way though it shouldn't blow speakers. At worst there should be an audible and unpleasant noise from the speakers. And typically the noise is emanating from the bass drivers, which by design can handle more current.

In my particular case I power on off at will in whatever sequence and it has no effect unless I deny my speakers power with out them letting them go out of standby on their own but that's a different story because they have their own amps built in.

Best.

Hal

Edit: this is the source of my info https://forum.audiogon.com/discussions/amplifier-power-versus-maximum-speaker-input-power/post?highlight=Power%2Bdown%2Bsequence&postid=221638#221638 read the post from almarg. If you don't know who he is and think you know better, think again.

[GDHAL]

I'd like to apologize for my previous post. Upon rereading it I'm of the opinion it comes across as being disrespectful. I shouldn't underestimate anyone's knowledge.

Hopefully I'll be forgiven. Thank you all.

Best.

Hal

[S Clark]

I'd like to apologize for my previous post. Upon rereading it I'm of the opinion it comes across as being disrespectful. I shouldn't underestimate anyone's knowledge.

Hopefully I'll be forgiven. Thank you all.

Best.

Hal

No problem.  On the wonderful worldwide web, you can find what ever advice you'd like to take. 
My amps all have delays, so it makes little difference in my case. 
My friend is using an AR D300.  Don't think he has a start relay.   
Just looked at that manual, recommends preamp first, amp second. 

[Nick B]

I'd like to apologize for my previous post. Upon rereading it I'm of the opinion it comes across as being disrespectful. I shouldn't underestimate anyone's knowledge.

Hopefully I'll be forgiven. Thank you all.

Best.

Hal

Hal,

There is a Modify function on these posts so you can redo/restate your comments if you wish.

Nick

[GDHAL]

I'd like to apologize for my previous post. Upon rereading it I'm of the opinion it comes across as being disrespectful. I shouldn't underestimate anyone's knowledge.

Hopefully I'll be forgiven. Thank you all.

Best.

Hal

Hal,

There is a Modify function on these posts so you can redo/restate your comments if you wish.

Nick

I realize that, Nick. And the thought crossed my mind to remove my post or portions of it. Thing is I realize many folks are quick to read posts here on the forum and elsewhere. So it wouldn't be fair, so to speak. I'd rather leave it and apologize than delete it and pretend I hadn't written it to begin with.

[Nick B]

I'd like to apologize for my previous post. Upon rereading it I'm of the opinion it comes across as being disrespectful. I shouldn't underestimate anyone's knowledge.

Hopefully I'll be forgiven. Thank you all.

Best.

Hal

No problem.  On the wonderful worldwide web, you can find what ever advice you'd like to take. 
My amps all have delays, so it makes little difference in my case. 
My friend is using an AR D300.  Don't think he has a start relay.   
Just looked at that manual, recommends preamp first, amp second.

Since these appear to be aged/mature AR pieces, the circuits may well be lacking soft start or other current protective measures. Does your friend have the money or desire to hire a tech to possibly install a relay or simple circuit to fix or improve this problem? I’d think with the audiophile network we have, there would be some good techs.

[Nick B]

I'd like to apologize for my previous post. Upon rereading it I'm of the opinion it comes across as being disrespectful. I shouldn't underestimate anyone's knowledge.

Hopefully I'll be forgiven. Thank you all.

Best.

Hal

Hal,

There is a Modify function on these posts so you can redo/restate your comments if you wish.

Nick

I realize that, Nick. And the thought crossed my mind to remove my post or portions of it. Thing is I realize many folks are quick to read posts here on the forum and elsewhere. So it wouldn't be fair, so to speak. I'd rather leave it and apologize than delete it and pretend I hadn't written it to begin with.

Understand your rationale Hal 👍

[S Clark]

Since these appear to be aged/mature AR pieces, the circuits may well be lacking soft start or other current protective measures. Does your friend have the money or desire to hire a tech to possibly install a relay or simple circuit to fix or improve this problem? I’d think with the audiophile network we have, there would be some good techs.

Yep, he's got the resources, it's just a royal pain in the butt when there are no reliable techs in the area.  There's a guy in Dallas that might be able to add a soft start circuit... 200+ miles away.   It might be a better option to simply sell the AR and buy another amp.   He's great guy, and loves his gear, but he's tough on it.   

[Jack]

If that amp is Direct Coupled it would make the problem even worse with a tube preamp.

[P.I.]

This:

https://neurochrome.com/products/intelligent-soft-start

Tom's devices are crème de la crème... The man is a wizard!

This will work.  Bullet-proof design, immaculately implemented.

[Nick B]

Since these appear to be aged/mature AR pieces, the circuits may well be lacking soft start or other current protective measures. Does your friend have the money or desire to hire a tech to possibly install a relay or simple circuit to fix or improve this problem? I’d think with the audiophile network we have, there would be some good techs.

Yep, he's got the resources, it's just a royal pain in the butt when there are no reliable techs in the area.  There's a guy in Dallas that might be able to add a soft start circuit... 200+ miles away.   It might be a better option to simply sell the AR and buy another amp.   He's great guy, and loves his gear, but he's tough on it.   

Well, having the resources is a good start. Some things in life are inconvenient, a big pain, like me driving to Vegas tomorrow to simply get 2 new replacement drivers soldered. I told the guy I’d like to wait for this simple and quick job. If he’s in a good mood, he likely won’t charge me the customary $50 up charge to jump ahead of his other customers. If I was blowing up drivers a few times a year, I’d do whatever it took to resolve it.

As an aside, it was over 25 years ago that a friend invited me over to her neighbor’s place in a very upscale neighborhood in so. California. He had an AR pre and amp and a vinyl rig that sounded so sweet I can still appreciate it all these years later. The guy was also a rich, handsome guy in his 40s who had a beautiful 20 something year old living with him. A very nice lifestyle, indeed 😎

[steve]

I am going to give away a simple mute circuit I designed for an SP-3 preamplifier output.
The circuit can be used in almost any tube preamplifier with DC filaments, with simple modifications.

Using the DC filament supply is important.

The circuit (relay) is designed to short the outputs to ground for approximately 45 seconds
before the contacts open.

The circuit can be made using perf board, terminal strips etc. Attached is the schematic.

The diodes D2 - D6 in series at the top are used to drop the 12 volts to a reasonable figure
for the zener and 5 volt relay coil.

A 6 volt filament dc supply would require no diodes D2-D6 in series.
R5 should be changed to 470 to 1k ohms for zener current.

D1 shorts the timing capacitor through the tube filaments, C1 to near zero volts upon
power off. D1-D6 are simple 1 amp, or 2 amp general purpose diodes.

IRF is static sensitive.

R1 can be whatever value that prevents oscillations. I had plenty of 2.4k ohms.

R5 was 2.4k as I had plenty of that value resistor. Used for zener diode voltage reference.

R2, R3, R4 are timing resistors.

Zener is 5.1 volt reference voltage for timing circuit.

Modified for clearer explanation.

Good fortune Scott.

steve