[rollei_list] Re: Completely OT- Loudspeaker info a pop up question

  • From: Akhil Lal <alal@xxxxxxxxxxxxx>
  • To: rollei_list@xxxxxxxxxxxxx
  • Date: Thu, 17 Feb 2005 17:36:31 -0500 (EST)


Have you any information on the torodial output transformers made by 
GenRad? I believe they were used in Kron-Hite amps.


On Thu, 17 Feb 2005, Richard Knoppow wrote:

> ----- Original Message -----
> From: "John Jensen" <jwjensen356@xxxxxxxxxxxxx>
> To: <rollei_list@xxxxxxxxxxxxx>
> Sent: Thursday, February 17, 2005 8:20 AM
> Subject: [rollei_list] Re: Completely OT- Loudspeaker info a
> pop up question
>> I don't think that Altec Lansing had a Peerless line
>> of speakers.  However, there was a highly regarded
>> transformer maker named Peerless that was acquired by
>> Altec Lansing.  Peerless output transformers were
>> highly regarded back in the golden age of audio.
>> Then along came David Hafler and Herbert Keroes
>> (spelling?) and formed Acrosound with their
>> transformers.  Hafler later spun off from Acro forming
>> Dynaco making audio output transformers which seemed
>> to be a knockoff of Acros.  Acro and Dynaco output
>> transformers were also highly regarded.
>> John
>   Acro transformers were excellent. In fact, they were used
> in the amplifiers of the Westrex Stereo disc cutting system.
> Haffler was one of the first to understand than the inherent
> bandwidth of feedback amplifiers had to much wider than the
> "usable" bandwidth. A powe amplifier with 20 db of feedback
> (typical) must have a bandwidth of around 100khz to cover up
> to 20khz. Few output transformers prior to the Acro would do
> this. Frank McIntosh was another who understood the
> requirement for transformers in feedback systems. His real
> contribution was the design of an economical winding method
> that allowed very tight coupling and very low parasitic
> reactances in a transformer. The split load idea of the
> McIntosh amplifier was actually an old idea. The Acoustical
> Quad amplifier beat him to a commercial version of this.
> McIntosh was able to run his first amplifiers in class B
> because of the transformer but this really not a good idea
> when feeding loudspeaker.
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@xxxxxxxxxxxxx

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