[Amps] Advice

[Roger]

Paul Decker wrote:
> When I was writing the original reply I was thinking more along the lines of different tubes for example a single 8877 requires more airflow and has more back pressure than two 3cx800's. 
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> Agreed, two tubes of the same type would require more airflow than a single tube.  However, I think we could assume that two tubes of the same type would produce 2x the power of the single tube amp.  
>   
I could easily run the legal limit with one FU728F, 8877, or 4CX-1500B 
but with a pair of them still running the legal limit they will take a 
little more volume, but not require near the back pressure of one tube 
running the same power as each tube is only running half the power of 
the single tube.

I've been making the assumption that the builder is not going to try and 
run twice the power. OTOH the original post was a bit 
"tongue-in-cheek".<:-))

73

Roger (K8RI)
>  If the twin tube amp were run at the same output as the single holer, it would also follow to reason the airflow requirements could for the two holer could be reduced because each tube is only being driven to a reduced output. 
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> Paul 
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> ----- Original Message ----- 
> From: "Gary Schafer" < garyschafer at comcast.net > 
> To: < dezrat1242 at yahoo.com >; < amps at contesting.com > 
> Sent: Saturday, December 05, 2009 11:04 AM 
> Subject: Re: [Amps] Advice 
>
>
> There is no free lunch. While it may seem like you could get by with less 
> air flow it doesn't follow. 
> A pair of tubes will require twice the air flow at the same back pressure as 
> a single tube. Tubes being the same of course. 
>
> 73 
> Gary  K4FMX 
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