Non parafeed Paramount

[xcortes]

What changes in addition to removing the plate choke and parafeed cap would be recommended to modify a Paramount (2A3 soft start) to series feed? I am in the process of getting a DS 025 transformer. Thanks

[vetmed]

Paramour or Paramount? In either case I would measure the DC resistance of the choke and the primary of the DS 025 and see if this makes a significant difference to the plate voltage.

Robert Lees

[xcortes]

Paramount. Corrected the original post.

I don't have the 025s yet. Mike will build me a very special and unique pair. In any case the difference from the plate choke I don't think will be much more volts and the soft start driver provide for adjustable voltage so dialing up is easy. But do I have to do something with, for example, the ps caps?

Thanks

[johnsonad]

Give us the details on that iron my friend!

[Paul Joppa]

You do not HAVE to make any other changes.

But for the best sonics, I would do the following:

1) replace the 270-ohm power resistor in the power supply, with a filter choke such as the good old C7-X. For you Xavier, see if you can find one of the made-in-Mexico Triad ones!

2) For the last PSU capacitor, replace the two electrolytics with a 630-v film capacitor of 20uF or greater, and take the negative end to the hum pot center terminal (the effective cathode connection) rather than to ground. This capacitor carries the signal current, and thus has a similar effect to that of the parafeed capacitor.

[xcortes]

@ Aaron: the all silver version of the QS 025 doesn't have 4 ohm taps so Mike will build me an all silver pair with 4 ohm secondaries.

@Paul I already have MQ filter chokes BMC8 I think so point A has bee taken care of. As for point B let's see if I uderstood correctly. I take out the two last filter caps (270uF) and install the new one from the + rail to the hum pot. And make it a nice one. Am i right?

Thanks a lot Paul.

Ps I'm at the storage facility leasing some space for the big horns, Karlsons etc. Didn't knew how big and sunny my living room is. Now the three pair of Paramounts will be different: one pair Ni tfa 2004, the second Co pinstripes 2004 jrs and the third series feed silver primaries and secondaries. Each game has different types of fun. Let's see for how long I can survive without the big sound.

[johnsonad]

Keep us updated as to which set of amps matches those WE's best!

[Paul Joppa]

...I take out the two last filter caps (270uF) and install the new one from the + rail to the hum pot. And make it a nice one. Am i right?

You're right.  Should be interesting!  :^)

[xcortes]

3 Pairs 3

[johnsonad]

Don't let go of those 2004's without letting me know please! (Not as if you will

[xcortes]

Nope. No intentions to let them go. With these two pairs I have everything to build (rebuild) two pairs of Parabees for the Quads.

I' also keeping the three pairs of tl404s. The day I get back to horns it will be with a revenge: sr45s.

[johnsonad]

I hope that you don't mind me inviting myself for visit at some point Xavier! I really would love to hear your system! You always have a place to stay in San Diego!

[xcortes]

Right now I don't have a system

But you're welcome any day. We have a guests' room and now that I rented some storage it may even come with a useable shower!

If things go well I hope to start renting a place in Coronado next year. I used to go to SD several times a year when my girlfriend (now wife) lived there. And subsequently for many years until my inlaws moved to Mexico about three years ago. Most of my BH kits and MQ iron went to their Chula Vista house.

[Grainger49]

Xavier,

I would imagine with that many tubes removed your living room is not only larger but cooler.

[xcortes]

Paul,

I've been studying your suggestion and I learned that what you suggest is an ultrapath topology. Thanks for the lesson!

BTW, would the change be the same for a 300B Paramount? How about a Parabee?

Thanks!