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Old 22nd November 2008, 12:30 AM   #61
N1ESE is offline N1ESE  United States
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yeah, may be able to dig up a DVD player. I just tried my iPod and I get the same max. volume as my PC.
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Old 22nd November 2008, 01:01 AM   #62
n_maher is offline n_maher  United States
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Opinions on the web vary but most have the output of the Ipod at (or less than) 1V RMS. That's probably less than half what you'd see from just about any commercial CD player and might go a long way towards your perceived low output. But it also might not explain it. It'd be nice to know what the rated efficiency of your speaker is. My 2 way bookshelf speakers are ~90dB/1W/1M, I'm hoping the simple is more than up to the task of driving them.
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Old 22nd November 2008, 01:12 AM   #63
N1ESE is offline N1ESE  United States
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Ok, all three of the following devices produce the same maximum volume on the amp:

Computer Line Out
iPod
Standalone DVD Player stolen from guest room TV

The sound quality is very good just not loud. I have no clue on the speaker specs. These were purchased from Radio Shack for $15 when they discontinued them about 2 years ago. I don't think they are very efficient. Although a picture doesn't mean much in this case, here is what it looks like:

Click the image to open in full size.

I'm an audio newb, I don't have any other speakers yet. I was going to start working on the speakers next if the amp worked out. Nate, can me and my amp come visit sometime?
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Old 22nd November 2008, 02:28 AM   #64
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The Simple SE which I built is very sensitive. In other words, it has a lot of gain. Mine requires very little input voltage to drive it to ear splitting levels. My complaint was that I can never get the volume knob past 9:00 without being too loud. My speakers are rated about 92 dB.

With that said, I've experienced big changes in amplifier gain by changing the output transformers. I used a pair of 6.6K:4 ohm transformers (Hammond 1620) on a PP EL84 amp. Swapping out those transformers for a set of Z565 replicas resulted in a big drop in gain. I had to turn the volume knob up a lot more to get the same kind of volume. I think the Z565 replicas are closer to 8K~9K on the primary side for the same 4 ohm secondary load.

You could also probably get more volume simply by switching to the next size secondary tap, if you transformer has them. For example, the 8 ohm tap should be louder than the 4 ohm tap. My Simple SE has Transcendar 5K:8 transformers, and they only have the 8K tap on the secondary.

Which CXSE did you purchase? If you have the cathode feedback connected, it should get louder if you disconnect it. If you haven't hooked up the UL tap, it should be louder in UL mode (although you may want cathode feedback if you are running UL).
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Old 22nd November 2008, 02:31 AM   #65
N1ESE is offline N1ESE  United States
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Yeah, thanks Ty. These Edcor CXSE's only have an 8-ohm tap unfortunately.
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Old 22nd November 2008, 02:35 AM   #66
N1ESE is offline N1ESE  United States
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How much would the driver tube impact the gain? I supposedly bought an EH 12AT7 but I honestly have no clue what it is because it has no markings on the tube at all.
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Old 22nd November 2008, 02:36 AM   #67
n_maher is offline n_maher  United States
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Perhaps it's time for a picture of how you have the output trafos wired? Don't be shy, I can pretty much guarantee I've done something dumber as a part of a build.
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Old 22nd November 2008, 02:37 AM   #68
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Quote:
Originally posted by N1ESE
How much would the driver tube impact the gain?
A lot. A 12AU7 would result in relatively low overall gain. A 12AX7 would give much higher gain, but probably won't tolerate the 10 mA drive stage current for very long.
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Old 22nd November 2008, 02:40 AM   #69
N1ESE is offline N1ESE  United States
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Quote:
Originally posted by n_maher
Perhaps it's time for a picture of how you have the output trafos wired? Don't be shy, I can pretty much guarantee I've done something dumber as a part of a build.
Here you go. I just switched to UL mode to see if it made much of a difference but not really. It might be a little bit louder but nothing really noticeable.

The red wire is B+, Blue is the Plate, White/Blue is UL tap.

Click the image to open in full size.Click the image to open in full size.
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Old 22nd November 2008, 02:47 AM   #70
N1ESE is offline N1ESE  United States
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Quote:
Originally posted by Ty_Bower
A lot. A 12AU7 would result in relatively low overall gain. A 12AX7 would give much higher gain, but probably won't tolerate the 10 mA drive stage current for very long.
So I could have a bum 12AT7 then or not even a 12AT7 at all then, eh? Maybe I should invest in a known good, quality, 12AT7 from someone like Jim McShane then.
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