[Harp-L] Tube Help for Harmony H-400C

[Dina Janzen <dlj@xxxxxx>]

Willie Harp Boy-

This amp does not have a power transformer, and accordingly uses tubes 
that are different from amps that have a power transformer.   It will 
probably sound good with the tubes it has.   I think there is scant 
info regarding tube subs in an amp like yours.

The biggest concern is making the amp safe to use, as it may not be 
possible to ground the chassis.  A line power isolation transformer is 
needed.  Some amps have them, some don't.  If your amp has two 
transformers, one is probably an isolation transformer and one is an 
output transformer.   If it has just one transformer, it is an output 
transformer.  Personally, I would not use an amp like this without an 
isolation transformer and grounded chassis because of shock risk.

Jim


On Jun 17, 2005, at 11:14 AM, harp-l-request@xxxxxxxxxx wrote:

> Message: 12
> Date: Fri, 17 Jun 2005 06:28:57 -0700 (PDT)
> From: Aaron kazmer <gripwillie@xxxxxxxxx>
> Subject: [Harp-L] Tube Help for Harmony H-400C
> To: harp-l@xxxxxxxxxx
> Message-ID: <20050617132857.21597.qmail@xxxxxxxxxxxxxxxxxxxxxxx>
> Content-Type: text/plain; charset=iso-8859-1
>
> Hi  all.
>
> I am new to tube amps and was lucky enough to get a
> Harmony H-400C for only $30.00 buck Cdn in almost mint
> with Harmony tubes. And It works great. I would love
> to get some help/info about swapping tube to make it
> the best little Harp Amp I can.
>
> As it is the tubes are (looking into the back from
> L-R) 35W4 - 12AU6 - 50C5. It also has a Jensen 6"
> speaker that looks original.
>
> Any help would be great.
>
> Thanks so much in advance
>
> Aaron "Willie Harp Boy" Kazmer