Discussion: Tweedle Dee Deluxe and Tweedle Dee Champ

[Schmirleroo]

Hey all,
First off.. love this site!
Questions:
The reasoning for the 110K resistor as a slightly different size and colour on the layout as the 100K beside it?
I'm assuming just to bring to attention that its a different value.. all the BOM I can find show it as a carb/film?

Has there been any problems with the Traid PT running a GZ34?
It looks like that particular TX would be under rated at only 100mA

Any benefit to stacking those cathode biasing resisters?
It seems like a bit of over kill IMHO... a single 250ohm at 10 watts would suffice

Thanks!
RJ

[pompeiisneaks]

First, welcome to the forums
Second, I moved the thread to the discussion section. Please note the stickied separate top thread that says to not post commentary/discussion in the Files section, and instead use the Discussion section.
Finally, that's to show via color that it's a different type of resistor. If you want to be true to the original you'd use a metal film resistor there, as that's what dumble used. Other resistors that are brown are carbon composite, and the tan ones are carbon film. You can even go so far as to look to find NOS resistors of the type dumble used, but that's becoming a quite expensive endeavor nowadays.

I don't know for sure about the transformer, I'd need more detail than 'a triad PT'. But if it has 100mA of current avaialble on the HT winding, it shoudl be fine. on a datasheet I looked at the max current for 2 6V6 in push pull, cathode biased at 400V, and it's saying at 100% diss it's going to be 30mA per tube, so 60mA total. on top of that a few milliamps for the 12AX7's and you're fine, but I'm not an expert at speccing transformers.

As for the cathode bias resistors, again, if you want to build it like he did, then yes do so, if not, you're right a single 10 watt resistor should work fine, the original only used a 5W. OTOH, we don't know if he only had those on hand, or if he was trying to do something like reduce the heat by massively over speccing that part, for some specific reason... maybe he found that the cathode biased amp was quieter, or performed differently with an overspecced resistor there. I'm not sure. I did it just because I wanted to try to be closer to the original. (OTOH I didn't use the carbon comp or the like, I used all carbon film resistors in my build).

Hope that's helpful.

~Phil

[Schmirleroo]

Thanks for all of that..
To continue, I am working with a board that has the single 33K resistor feeding V1a (from the 5C3 design.
My thoughts were to have another 33K feeding from the low jack (non switchable jack) to the high jack as the chassis is a 4 holer.
Thoughts anyone?

Cheers

[pompeiisneaks]

Thanks for all of that..
To continue, I am working with a board that has the single 33K resistor feeding V1a (from the 5C3 design.
My thoughts were to have another 33K feeding from the low jack (non switchable jack) to the high jack as the chassis is a 4 holer.
Thoughts anyone?

Cheers

If you put in another 33k and just another lead in, you don't get a Hi/Lo type setup, that's just two 33k inputs, both being identical, which doesn't gain you much, but if that's fine with you, go for it. I'd guess it might give you more options if you wire it like the typical fender Hi/Lo jacks with two 68k resistors, so you have the two types of inputs, but then you're deviating more from the original tweedle dee deluxe. Again that just depends on how 'true to the original' you're trying to be.

~Phil

[Schmirleroo]

Having a 4 hole chassis is the problem. Im basically making a 5E3 'Dumble as opposed to the 3 hole 5C3.
I have a modulus 'Dumble' board that's layout only has turrets for the single 33K. I may just stake another turret below and run it with 2 68K's
I'm also using Kemet 33uF Caps and a WGS ET65 in the design.
I'm hoping it'll be 'close'

[Charlie Wilson]

Hello, the 110k is a metal film Roderstein Mk3. I believe he used that resistor for two reasons, he wanted a 110k that actually measured 110k and using the metal film gives a bit clearer top end. Notice that he used metal film for the power tube 1k5 grid stoppers as well. The stacked cathode resistor thing, again in my opinion, was to have a very heat stable cathode resistor in an amp with a lot of current and heat. Not sure how the Triad power transformer is holding up in the original as I haven't seen it in several years. My advice on the power transformer is do not use one with anything higher than 355v unloaded. I think you want to keep the B+ 400v or less. Oh yeah, just use the two 68ks. Greenback may be a better choice for the speaker.
CW

[Schmirleroo]

A strange thing here.. I have ordered 2 and 1 watt metal film resisters @ 1% from mouser
They are smaller then an ant.. tiny little things..
I'm about 90% complete in parts.
I do have the choice of running a PT that has an unloaded output of 660 as opposed to the 710 of the Triad (I will not be using a Triad)
The OT is a 8K primary @ 15 watts

[Schmirleroo]

Hello, the 110k is a metal film Roderstein Mk3. I believe he used that resistor for two reasons, he wanted a 110k that actually measured 110k and using the metal film gives a bit clearer top end. Notice that he used metal film for the power tube 1k5 grid stoppers as well. The stacked cathode resistor thing, again in my opinion, was to have a very heat stable cathode resistor in an amp with a lot of current and heat. Not sure how the Triad power transformer is holding up in the original as I haven't seen it in several years. My advice on the power transformer is do not use one with anything higher than 355v unloaded. I think you want to keep the B+ 400v or less. Oh yeah, just use the two 68ks. Greenback may be a better choice for the speaker.
CW

Charlie,, I have been using (99%) the layout and schematic that you hav graciously offered up on this site.
Is there a master BOM with resister/Capacitor types, makes etc?
My plan was to use CDE Orange Drops, Xicon 1/2 watt, Xicon 1 Watt (power) Vishay 3 and 2 watt (filter/power) and Kemet 33uF Caps, and Kamaya CarbComp for signal...
I have an original english Greenback (G12M) and/or a Weber silver bell at 50 watts... Thoughts?

[norburybrook]

I've settled on a Celestion Cream Alnico for my Tweedle Dee. Nice speaker

Here's some sound clips of the tweedle dee with the celestion Alnico cream.


https://soundcloud.com/marcus-cliffe/se ... sound-clip




M