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Author Topic: '69 Sceptre help needed!  (Read 2116 times)

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Phi

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'69 Sceptre help needed!
« on: March 29, 2009, 07:31:07 am »

Hello everyone, I just registered in the forum. I'm a very happy owner of a '77 Model T and I just bought a '69 Sceptre (the one without the mid-boost switch) in a very bad condition, as a project. I need to get the lady back on stage and make her sing loud, but I need some infos in order to do this.
Will anybody please help me?
What I need to know is what kind of reverb unit would fit the amp. I know, or at least that's what I've heard, that Sunn amps mounted Gibbs-Hammond model F units in those years, but I still have to confirm this information, and even in case I can't find any specs about these units.
Does anybody know what kind of reverb tank is recommended for my amp? Input/output impedance?
In case I couldn't find a vintage unit, I know Accutronics produce many kinds of spring reverb units that match old amps, does anybody know which one is the best choice?
Thanks in advance for your help!

Phi

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Re: '69 Sceptre help needed!
« Reply #1 on: April 01, 2009, 06:36:18 pm »

Hey is anybody there?

EdBass

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Re: '69 Sceptre help needed!
« Reply #2 on: April 01, 2009, 07:29:47 pm »

I would try to help, but I don't know squat about reverb units, most of my "guitars" have 4 strings. As you can tell by the traffic numbers, this is a very low volume site. It may take a little while, but someone will come along with some useful info!

noel

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Re: '69 Sceptre help needed!
« Reply #3 on: April 03, 2009, 09:30:53 am »

I'd forget finding a vintage unit.  I guess the chances of that are slim and you'd probably just get the amp with it too.  I'd focus on finding a suitable acutronics replacement.  Just google spring reverb impedence to get an idea of the prodecure.  Basically, you need to measure the DC resistance to get you into the ballpark.  I've seen people have issues with this method on other message boards so you might just email acutronics directly.  They could probably guide you through the selection process.  All you have to figure out is: physicial dimensions (if this is a constraint...I don't remember how much space you've got to work with), input/output impedance, connection type (RCA probably...just figure out if the sleeve is grounded to the chassis or floating etc.).

I hope that gets you in the right direction.  Naturally, somebody with the exact part could probably help more but the Sunn board is notorious for "lurkers".

cheers

Isaac

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Re: '69 Sceptre help needed!
« Reply #4 on: April 04, 2009, 04:46:45 pm »

I did get a reverb tank that was represented as being the right one on ebay. Looks to be the right size, but I'm saving it for a Sceptre I also bought to fix up.
Isaac

Phi

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Re: '69 Sceptre help needed!
« Reply #5 on: April 08, 2009, 02:23:33 am »

@ Noel: Thanks for your answer, I'll try to measure impedance myself as soon as I solve a couple of electronic issues, while I wait I'll try to gather other infos.

Maybe it will be useful in the future for someone else so I'll share with you the infos I already have.

I've been told Hammond Gibbs F units are quite a standard for old amps and they can be replaced by type 4 Accutronics units, so I think the Accutronics code for my amp should be something like 4XY2A1A.

4 = model number
X = input impedance
Y = output impedance
2 = Medium decay time (1 or 3 should be fine as well, it just changes reverb decay time)
A = Input and output grounded (my amp has RCA connectors)
1 = No locking device (it's the only option for this model)
A = Orizontally mounted with the open side up

Still have to figure out input/output impedances.

@ Isaac: any information about your unit? Thanks!

noel

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Re: '69 Sceptre help needed!
« Reply #6 on: April 08, 2009, 09:33:39 am »

Looks like you're on the right track.  I believe the impedence is the only issue remaining.  In addition to measuring your unit I'd just check what Accutronics has available.  They usually only have a couple choices so that'll probably narrow it down.  You might find that based on the information you've already got combined with the standard models there is only 1 unit...that's your guy then!  Just a thought. 
cheers,
Noel

measurestaken

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Re: '69 Sceptre help needed!
« Reply #7 on: April 08, 2009, 10:33:00 pm »

I have nothing useful to add except that I own an old Sceptre and will refer to this thread if/when my reverb goes wonky.
thx, phi
Change the world, it needs it. - Bertolt Brecht

Phi

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Re: '69 Sceptre help needed!
« Reply #8 on: April 09, 2009, 11:32:06 am »

I was looking at the catalog thread and, just to be precise, I have to tell that the Sceptre I own must be a '68 later model, not '69 like I stated, and that because of the absence of the midboost switch.

Moreover, I emailed Accutronics and they said that they have a note about a Sentura II which confirms the fact that the reverb tank was a Gibbs F unit, and that it can be replaced by a 4AB2A1A Accutronics model.
Now, I don't know if input/output impedance was a standard at the times and so if that model will fit the Sceptre too, but it's some news at least.

Isaac

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Re: '69 Sceptre help needed!
« Reply #9 on: April 09, 2009, 06:30:30 pm »

@ Isaac: any information about your unit? Thanks!

Nothing handy. I'm in Portland, it's in Corvallis. Maybe I can get something over the weekend.
Isaac

Phi

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Re: '69 Sceptre help needed!
« Reply #10 on: April 10, 2009, 02:24:31 am »

Thanks, it would be great!