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A little bit of explanation before I ask my question.

I have an Allen Accomplice it supports either 6V6 or 6L6 tubes. If 6V6 are in it the ohm switch is a 8\16 ohms setting. For 8 ohm speakers use 8 ohm setting. For 16 ohm speaker use 16 ohm.
If, however you are using 6L6 tubes, which I am, the ohm switch becomes 4\8 ohm. 8 ohm speaker use the 4 ohm setting, 16 ohm speaker use the 8 ohm setting. These instructions are marked on the back this way and the amp is designed this way.
The speaker extension jack is wired in parallel. I have an 8 ohm speaker in the combo. If I connect a cabinet with an 8 ohm speaker, do I still use the 4 ohm setting or is 2X8 ohms too much load? Like does it split it down to 2 ohms? I am not sure how series and parallel work so just wanted confirmation.
2 speakers 8 ohm would normally be 16 ohms divided by 2 for an 8 ohm setting. but with this amp the way it works I'm thinking it would be 4 ohms.

I did send an email to David Allen but mistakenly thought the amp had a 16 ohm speaker and that is what I told him. This was his answer. So now that I found out that the internal speaker is actually 8 ohms and I should match the extension cabinet with an 8 ohm speaker it seems I should be using the 4 ohm tap. But just want to be sure I'm not missing anything.

If you could use a 16 ohm extension speaker cabinet along with your internal 16 ohm combo speaker, then the amp would see those two in parallel or 8 ohms. In that case your amp would be matched with the impedance switch set for 8 ohms (up). It would also divide the power equally if each is 16 ohms.

David
 

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Hey Google: "Two 8 ohm speakers wired in parallel will have a net impedance of (8 divided by 2) 4 ohms."

So I would set to 4 ohms.
 

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Discussion Starter #3 (Edited)
Hey Google: "Two 8 ohm speakers wired in parallel will have a net impedance of (8 divided by 2) 4 ohms."

So I would set to 4 ohms.
Thanks. The amp is really confusing me. If 2 8 ohm speakers in parallel are 8 divided by 2 = 4 0hms then why does David Allen tell me also 4 ohms for 1 - 8 ohm speaker?

I have been running it as 8 ohm all this time (for months) until the previous owner sent me the manual today and I saw that I'm supposed to be running it 4 ohms setting with 1 8 ohm speaker. So I switched it today and I have more volume, more clean headroom and less compressed sounding.
The way Allen has designed these amps is really confusing. Alot of people think that an 8 ohm speaker should have the 8 ohm setting selected. But not when in use with 6L6 is used. It is to be set to 4 ohm as thats the load that the tubes wants to see. I am just confused as to what to do when using the parallel jack with an 8 ohm cabinet. It seems to me it would further divide it to 2 ohm load to the amp. Not sure. I sent a question off to David Allen for confirmation. Hopefully he'll respond.
 

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If, however you are using 6L6 tubes, which I am, the ohm switch becomes 4\8 ohm. 8 ohm speaker use the 4 ohm setting, 16 ohm speaker use the 8 ohm setting. These instructions are marked on the back this way and the amp is designed this way.
No. You are somehow misunderstanding (the part I bolded). Where does it say this? For a 4 ohm load have the switch in the 4 position, for an 8 ohm load have the switch in the 8 position. I'm talking the 6L6 labelling. Ignore the numbers in brackets (6V6 settings). Better yet, put a piece of tape over the 6V6 numbers. :)
You have an 8 ohm internal speaker. Use an 8 ohm ext. cab along with it and set the switch to the 4 position.
 

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No. You are somehow misunderstanding (the part I bolded). Where does it say this? For a 4 ohm load have the switch in the 4 position, for an 8 ohm load have the switch in the 8 position. I'm talking the 6L6 labelling. Ignore the numbers in brackets (6V6 settings). Better yet, put a piece of tape over the 6V6 numbers. :)
You have an 8 ohm internal speaker. Use an 8 ohm ext. cab along with it and set the switch to the 4 position.
You will never go wrong when setting the amp to match the total speaker Ohms ... "it is known".
G.
 
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If you are using 6L6 tubes you can switch between 8 and 4 ohm speakers or loads. If you are using 6V6 tubes you can switch between 16 and 8 ohm speakers or loads.

The 8 ohm setting for 6L6 tubes is the 16 ohm setting for 6V6 tubes, and the 4 ohm setting for 6L6 tubes is the 8 ohm setting for 6V6 tubes. Generally, 6V6 tubes want to see twice the impedance of 6L6 tubes.

If you are using 6L6 tubes and you want to use an extension cabinet, you need an 8 ohm speaker in the amp and an 8 ohm speaker in the extension cabinet. You then choose the 4 ohm 6L6 setting because the two 8 ohm speakers make a 4 ohm load when in parallel.

If you are using 6V6 tubes and you want to use an extension cabinet, you need an 16 ohm speaker in the amp and an 16 ohm speaker in the extension cabinet. You then choose the 8 ohm 6V6 setting because the two 16 ohm speakers make an 8 ohm load when in parallel.
 
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