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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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21st Sep 2019, 3:19 pm | #81 |
Dekatron
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Re: Convert Vintage Valve Radio to Guitar Amp
Excellent.
Lawrence. |
21st Sep 2019, 3:35 pm | #82 |
Pentode
Join Date: May 2017
Location: Ware, Hertfordshire, UK.
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Re: Convert Vintage Valve Radio to Guitar Amp
hello all, just watched the video ,,impressive
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21st Sep 2019, 4:03 pm | #83 |
Retired Dormant Member
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Location: Cambridge, Cambridgeshire, UK.
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Re: Convert Vintage Valve Radio to Guitar Amp
Amazingly, I measured 106 dB 1 metre away from the speaker (albeit using a phone sound app, so probably not the most accurate).
Quite how such a low power amp is capable of putting out that sort of power, I don't know! |
21st Sep 2019, 8:27 pm | #84 |
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Re: Convert Vintage Valve Radio to Guitar Amp
It's a matter of having a much more efficient speaker than you may be used to. High quality speakers are monumentally inefficient so what a speaker optimised for efficiency can do is surprising.
As a reference, a trombone played flat out is pretty noisy, and the acoustic power out of it is about half a watt. David
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21st Sep 2019, 10:52 pm | #85 |
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Re: Convert Vintage Valve Radio to Guitar Amp
Cheers!
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21st Sep 2019, 11:03 pm | #86 | |
Pentode
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Re: Convert Vintage Valve Radio to Guitar Amp
Quote:
To put this into context it takes an increase in SPL of around 10dB to produce a perceived doubling of volume (dB is a logarithmic scale) so by changing the speaker in an amplifier from a 90dB to a 100dB you can double the volume. To achieve the same doubling of volume by increasing the amplifier power you would need to increase the power by a factor of 10 so if your original amp was 5 watts you would need to increase that to 50 watts to double the volume. |
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22nd Sep 2019, 1:53 pm | #87 |
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Re: Convert Vintage Valve Radio to Guitar Amp
That is one vintage radio that will get used unlike most restorations where the "it's going now" is all that happens.
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27th Sep 2019, 7:35 pm | #88 |
Octode
Join Date: Nov 2011
Location: Manchester, UK.
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Re: Convert Vintage Valve Radio to Guitar Amp
That sounds great!
I too would be interested in what set of valves your Cossor uses. I have a 501 in use and a 500 (the woodie) non-worker for spares which might be interesting to apply to this purpose - I think both of mine use rimlock valves. |
27th Sep 2019, 8:45 pm | #89 |
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Re: Convert Vintage Valve Radio to Guitar Amp
Interesting explanation of power, volume and sound pressure levels here.
http://www.sengpielaudio.com/calculator-levelchange.htm Mike |