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Old 21st August 2003, 07:22 PM   #21
Kyle K is offline Kyle K  United States
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The stock circuit runs 11mA of plate current, which exceeds the rating of the Hammond choke. Did you check how much current the 5687 draws after you put the choke in and adjusted the ps voltage?
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Old 21st August 2003, 09:59 PM   #22
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Kyle K

As I stated in my post the voltage and current draw were within reasonable bounds. The power supply voltage was slightly lower than with the plate resistors. Yes, the current draw was at 7mA. Given these factors and the tubes response I can only draw two possible conclusions.
1.) 5687 tubes are junk 2.) These cheap $10.00 power supply chokes are junk and totally unsuited for this task.

Now, I tried several 5687 tubes. I tried different brands and several of each. I did not however try more than one set of chokes because I only have one set. I guess there is a possibility that I got a bum set of chokes. I doubt this however.
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Old 21st August 2003, 10:09 PM   #23
316a is offline 316a  England
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Default Easier way !

Quote:
Originally posted by Bandersnatch
Hey-Hey!!!,
I just wound some center tapped chokes for loading a PP driver stage, similar circuit to one of Brook's. It was wound pie style with each half in a partition on the bobbin form and had in the first version one AC end up against the core. I got a distinct improvement when I wound with both halve's center windings at the core and the AC carrying ends at the outside of the bobbin.
Female vocals were lost the schreeeechy tone, silibance I think it is called, with that single change, same amount of Cu and Iron but change the winding geometry and it was a whole different animal. Makse me scared about the stuff involved with the permutations and combinations involved with OPT's
regards,
Douglas
...errr , there's an easier way ! Find a humble mains toroid with split 115/115 primary , and just use this (unwinding of the secondary is optional and can be left 'flapping') . I have measured in excess of 100H for 50VA units , higher for smaller core sizes . Transformer winding is a strange art , I hope you get good results . Have you managed to measure your home-grown unit on the bench or in circuit ?

316a
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Old 28th August 2003, 11:10 PM   #24
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just tried a second(replacement set) of chokes with the 5687. It works without ringing. Running roughly 7mA as before. The sound is good but I seem to prefer the higher plate voltage and the plate resistors to the choke setup. It seemed have lost the impact it had before. With it running at around 130-145 on the plate and about 11mA it seems to sound the best.

Joe
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Old 28th August 2003, 11:53 PM   #25
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Hey-hey!!!!,
I did some measuring, al at 60 Hz though. I got 85 Hy per half, and 4x this across the whole winding, all with more than 10 mA of DC through it The sound is slightly better with DC balanced. Since both hlaves have exactly the same DCR, I just twiddle the adjustment until the plate voltage is the same to a few tens of mV.
Sooner or later I will do a maore comprehansive set of measurements, but not just yet.
regards,
Douglas
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Old 4th September 2003, 01:52 PM   #26
JBasham is offline JBasham  United States
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Joe:

Sorry, my man. I wasn't disrespecting you.

I was reacting to Frank's statement: "Joe, I hate to say to people "I told you so". You know what I mean, don't you?"

I think a statement like that could deter people from trying PS chokes as plate chokes in other applications. Many people who try it will find it suits their tastes just fine. When they're looking for suggestions to improve their sound later, they might try spending money on a better plate choke.

I think you did exactly the right thing to try the choke yourself and see if it would work notwithstanding Frank's advice. Sometimes, that's how you find out something works great -- as I think you know better than many people. So sorry if it came out the other way 'round!

As for the Bottlehead Paramour, it costs something like $550 now, which is most definately "entry level" admission price for a SET. I built one a while ago so I would have something done quickly, to listen to while I was working on my new scratch-built 300B's. I sold it at a profit a couple weeks ago, as I had planned all along.

If you ever hear one, I think you might be impressed. It's just my opinion, but they sound better than much of the scratch-built SET and PP stuff I hear at club meetings. Douglas is a PP guy, but he's probably the most knowledgeable guy on this forum, and I think he would agree that these things are a surprise for an entry level item with $15 worth of output iron.

But here's the punch line: guess what's the first thing you have to fix to upgrade the Paramour into something really top drawer?

Replace the Magnetek choke with a proper plate choke and upgrade the output transformer! Hahahahahaha!
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Old 4th September 2003, 02:36 PM   #27
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Hi,

Quote:
I think you did exactly the right thing to try the choke yourself and see if it would work notwithstanding Frank's advice.
And what was my advice, you think?

You can't possibly know that since it was given in a private e-mail exchange.

I never even insinuated anything other than what I had predicted would happen, again you can't know that either.

I feel you're reading things that just aren't there; so let's give it a rest and move on nicely.

Cheers,
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Old 4th September 2003, 09:26 PM   #28
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JBasham

No apology needed. As a matter of fact it is I that should apologize for the crude reply I posted. Your reaction to Frank's statement is incorrect. Frank has had nothing but good intentions and has helped me a long way. I can always count on his wisdom and guidance when I need it. Frank knows how to teach me the best and that is by letting me try something when I have an idea. Granted, he will tell me ahead of time that it usually won't work. He is always right too.

Please accept my apology Frank, JBasham, and anyone else that I offended in this post/topic.


Joe
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Old 10th September 2003, 04:28 PM   #29
JBasham is offline JBasham  United States
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Thanks, Joe.

Frank, back off a bit. I don't care what your PM to Joe said. I was refering to your post, which says PS chokes are not linear enough to use as plate chokes. But for some people, they will be a good compromise. And you don't have to listen to their amps.
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Old 11th September 2003, 12:09 AM   #30
dhaen is offline dhaen  Europe
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Hi,

This thread has become a little overheated.
We have had some discussion about cheap chokes used in anode circuits before, resulting in a similar impasse.
To be blunt, when using a component in an application that it is not designed for Eg PS chokes in anodes, there will be a great variation in results. For the lucky ones they will work, and for the rest of us, be a disappointment.
However, that should not stop us from experimenting. Great things come from trying ideas, and learning.
Don't forget also, that we have differing expectations. What's acceptable to one, is not to all.

Cheers,
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