Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Paramount => Topic started by: Gerry E. on November 16, 2012, 06:51:34 AM

Title: A Paramount Suggestion and Question
Post by: Gerry E. on November 16, 2012, 06:51:34 AM
About a month ago I purchased a pair of 1952 WE 396As for my V1.1 Paramounts (NOS in original boxes).  I really like the sound of them.  They seemed to be more dynamic then the Swedish Ericsson 2C51s I was using.  Some people may prefer the more laid back sound of the Ericsson
Title: Re: A Paramount Suggestion and Question
Post by: Paul Joppa on November 16, 2012, 10:40:41 AM
The most effective place to insert a high-pass filter is at the amp's input (or the preamp's output).

Less effective is to change the interstage coupling capacitor inside the Paramount. That would relieve the output tube and the output transformer of some deep bass, but the driver would still have to handle the full spectrum.

There are a couple other considerations that complicate the decision:

1) Adding a capacitor at the power amp input is one more capacitor in the signal path. If the preamp has two outputs and has a capacitor at its output (such as the Foreplay III and the BeePre) then separate capacitors can be used for each set of outputs, eliminating this compromise.

2) The capacitor will be small and will increase the impedance levels, making the circuit more sensitive to picking up hum and noise from electric fields. If the preamp can drive lower impedances than the 249K stock input resistance, you might want to change that resistance in order to use a larger capacitor. I would not do this with the interstage capacitor since the driver relies on the high 249K 300B grid resistor to maintain ,ow distortion. In any case, be sure the capacitor is correctly oriented (outer foil to the source side) to provide the most effective shielding.
Title: Re: A Paramount Suggestion and Question
Post by: Gerry E. on November 20, 2012, 07:00:44 AM
Thanks PJ.  I keep coming up with ideas (like rotating the output tube sockets in another thread) that appear to be more trouble than they are worth.  I think I will leave things as-is.  Having said that, I may have a friend help me do the 300B-to-2A3 conversion in January.  This will allow me to hear 2A3 Paramounts for myself in my system.

On another note - I received my 1952 WE 2C51/396As from ROBTRAM yesterday.  They look just like the ones that I paid a lot more for and they test significantly better!  If anyone purchased a pair for their Paramounts, I would be interested in hearing your opinion of them compared to what you were using.  Thanks.

Gerry     
Title: Re: A Paramount Suggestion and Question
Post by: johnsonad on November 20, 2012, 09:14:19 AM
Hi Gerry.  Give the 1950's GE 5670's a try along with the Bendix if you can find a pair. Both sounded better to me than the WE tubes and I have eight pairs of them. Of the WE tubes, the very early JW (will be marked JW) sounded the best to me..
Title: Re: A Paramount Suggestion and Question
Post by: Roger on November 20, 2012, 10:26:58 AM
Hi Gerry.  Give the 1950's GE 5670's a try along with the Bendix if you can find a pair. Both sounded better to me than the WE tubes and I have eight pairs of them. Of the WE tubes, the very early JW (will be marked JW) sounded the best to me..

We obviously have different preferrences when it comes to tubes. I tried the Bendix 6385, and didn't like it. Found it to be very analytic and thin sounding. I ended up with Ericsson 2C51 gold pins.
Roger
Title: Re: A Paramount Suggestion and Question
Post by: johnsonad on November 20, 2012, 01:37:45 PM
Hi Gerry.  Give the 1950's GE 5670's a try along with the Bendix if you can find a pair. Both sounded better to me than the WE tubes and I have eight pairs of them. Of the WE tubes, the very early JW (will be marked JW) sounded the best to me..

We obviously have different preferrences when it comes to tubes. I tried the Bendix 6385, and didn't like it. Found it to be very analytic and thin sounding. I ended up with Ericsson 2C51 gold pins.
Roger

My experience was different.  Goes to show that tubes are only one small piece of the puzzle.  Those Ericsson gold pins are hard to come by.  I have about every other variant other than that one....  PJ did write that he voiced the amps to the GE 5670 plate curve and I found myself listening to GE tubes more than the others.