About a choke

[pjd3]

Hello,

Onto project #3. - I'm trying to figure out if I can use a choke I have for proj #3. It was originally from Bogner Alchemist that ran using 2 6L6GC's.

The choke's ratings are 67 ohms / 13 henries. I didn't use this choke for the 6V6GT plexi due to replies that thought the DCR was a bit low - And i couldn't argue with that because most chokes in the amp power nodes I see like this had DCR's more along the lines of 160 ohms or so (so I bought those). I gathered that the screens would have a happier lower voltage due to this DCR - that there wouldn't be enough plate/screen voltage difference using the 67ohm/13H choke.

But, on this next third project I will be using a 43% Ultra-linear output transformer. In this case, since the KT88 pair will be receiving their voltage from the OT UL primary taps, is it then more feasible that this 67 ohm choke could be a contender? I was also worried about current rating but considered that this choke will not be providing current to the power tube screens as it did in its previous life in the Bogner Alchemist.

So do I seem to be thinking up the right tree at all on this?
Thanks everyone. - oh yeah, and I do plan on a pair of KT88's for around 60 watts or so.
Best, Phil D.

[Phil_S]

How are you using it? L-C or C-L-C? Any idea of it's mA rating? How was it used in the donor amp?

[pjd3]

Hi Phil,

It will be used in a C-L-C configuration i'm nearly positive. For some reason, these transformers in the Bogner Alchemist do not show specs. I've spent hours on line searching for the model numbers written and came up with nothing. They are the only pieces of elecronics that I failed to find specs on. Line six actually manufactured that particular model and don't devulge alot of the inside stuff on the Alchemist.

I'll have to go back and look at the schematic to see how it was used. I personally have never seen a guitar amp that was L-C so I did assume it was C-L-C

The BOM did have the Henries value and I measured the dcr myself. I'll go check the schematic and see how the choke was configured.

thank you for the inquiry. I'll be back!

Best,
Phil D.

[sluckey]

I'll go check the schematic and see how the choke was configured.

That'll give you more info about how you can use it than chasing spec sheets. Post the schematic.

[pjd3]

I'll re-train myself how to post pics. what I will also do is bring it into work tomorrow and put it on the LCR meter. That won't tell me anything about the current handling max but it will give me precise L and R. I think I was wrong on the L value. I'll know more tomorrow. Perhaps I can have an engineer look at it and judge current according to the wire gauge and choke resistance? Not sure if it entirely works like that but maybe something can come out it .

thanks guys,

Best,
Phil D.

[Phil_S]

It will be used in a C-L-C configuration....

If the donor amp used a pair of 6L6 and the choke was configured C-L-C, then you should be able to use it in any 40-50W amp and certainly in lower powered amps. I suggest you are overthinking this.

[pjd3]

Thanks Phil,

I'm quite fine with over thinking. At least it means I'm thinking and that occasionally leads to learning something new.
Yup, your comment on things of the choke make sense to me.
I did also compared H, DCR and weight to offerings from Hammond, classic tone, and there appears to be a loose but consistent correlation with those specs to current handling. Sure its not exacting by any means but was enough to add some confidence that the choke will be enough to handle what gets thrown at it.

For this project the plan is to build the amp in a 19" rackmount with tubes, transformers and maybe caps on the top of the rackmount chassis for all to see. Yeah, I'm selling into vanity on this one, at least visually. So, I want the components to look just a little nice.
Just yesterday I ordered one of those "gloriously beautiful" Edcor power transformers. This choke from the Bogner, although not wonderful Blue is at least in a nice glossy black housing that looks better than an open raw naked choke. The nice looking Edcor chokes were $40 - $60 which would have been a more difficult battle to win.

And from what can tell, the presence of an Ultra linear OT should make life even easier on a choke, current wise. Hope so.
Thanks so much for your input, I feel confident to go forward with the choke in this one!

Best,
Phil D.