Original KB300 1983 model reverb?

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dak
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Original KB300 1983 model reverb?

Post by dak » Mon Feb 14, 2022 5:58 pm

Hi, in the KB300 (1983) circuit diagrams I find, there is a reverb unit with three drawn springs and the Peavey part number 71011130. In the 1989 schematics I only find the connector P101 with no reverb unit specified or drawn in.

My own amp is from 1986 according to the serial number and matches the old circuit diagrams. The reverb tank inside is a short 3-spring tank (accutronics 8EB2C1B) but has a part number of 71011142 printed on it. I definitely like the sound of this reverb better than that of a long 2-spring tank in a different older amp (not Peavey, from the 70s) I have. Are 71011130 and 71011142 indicating the same part, or has there been a change in production? I consider it unlikely to be an after-sales replacement since it does have a Peavey part number on it.

Just curious, no particular reason.

Thanks!

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Enzo
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Re: Original KB300 1983 model reverb?

Post by Enzo » Tue Feb 15, 2022 12:08 am

First, just because it has a PV part number on it, doesn't make it original. When I was a Peavey dealer/warranty-station I bought parts from them for stock all the time. Of course it sure can be original.

Different part number means different part.

Note the 1989 circuit is the standard Peavey 4558 rive circuit. The older unit from 1983 has additional drive stage after the op amp. I suspect you like the sound better because the pan is driven harder, Moreso than the short pan itself But two and three springers do sound different, as do short and long pans.

The 11130 is a lower impedance drive pan, like what Fender uses. I think the transistor drive stage likes that. I tend to think your EB pan is not original, maybe it was installed to replace a dead pan at some point. But the little solid state drive is not so picky. Just like you can use an 8 or 16 ohm speaker on a 4 ohm rated SS amp. The EB pan is happy enough.

8EB pan is the short 3-spring pan, the 9EB is the long three-spring. If it sounds good, it is good.

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dak
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Re: Original KB300 1983 model reverb?

Post by dak » Tue Feb 15, 2022 6:53 am

Enzo wrote:
Tue Feb 15, 2022 12:08 am
Different part number means different part.

Note the 1989 circuit is the standard Peavey 4558 rive circuit. The older unit from 1983 has additional drive stage after the op amp. I suspect you like the sound better because the pan is driven harder, Moreso than the short pan itself
Actually it's a bit irritating since adding reverb gives the sound a lot more presence (the piezo horns sound a lot better then). So the driver may be a bit over-EQ-ed for this unit? But the specs call for 6dB/oct and that's pretty much what I see..
But two and three springers do sound different, as do short and long pans.
I'm pretty sure that is what is irking me about the long two-spring in the other amp (a 4FB2A1C, driven by opamp): the echoes are just too distinct. More like a machine hall than a church.
The 11130 is a lower impedance drive pan, like what Fender uses. I think the transistor drive stage likes that. I tend to think your EB pan is not original, maybe it was installed to replace a dead pan at some point. But the little solid state drive is not so picky. Just like you can use an 8 or 16 ohm speaker on a 4 ohm rated SS amp. The EB pan is happy enough.
Would yield lower mechanical output though, so I'd get worse SNR, a smaller range of the controls, and a higher likelihood of picking up mechanical noise not coming from the transducer. In theory. In practice, "If It sounds good, it is good" is on the dime. If you think the original reverb likely was a long one, maybe I should check for retired screw holes.

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Re: Original KB300 1983 model reverb?

Post by Enzo » Tue Feb 15, 2022 2:07 pm

The original could even be one of those old OC pans. PV used them from time to time.

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dak
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Re: Original KB300 1983 model reverb?

Post by dak » Tue Feb 15, 2022 3:18 pm

OC?

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Enzo
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Re: Original KB300 1983 model reverb?

Post by Enzo » Wed Feb 16, 2022 1:09 am


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dak
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Re: Original KB300 1983 model reverb?

Post by dak » Wed Feb 16, 2022 7:09 am

Thanks, I wasn't aware of that. These days Accutronics seems like all one ever hears of in terms of older history, and the few remaining manufacturers seem to mostly follow their old model ranges and specs, with shorter 3-spring models nowadays appearing to be more common than in the early days.

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Re: Original KB300 1983 model reverb?

Post by dak » Wed Apr 06, 2022 9:50 am

dak wrote:
Tue Feb 15, 2022 6:53 am
If you think the original reverb likely was a long one, maybe I should check for retired screw holes.
Just had the thing open again today. Definitely no other screw holes, so there wasn't a long reverb from the start.

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