OPT options for a 10\50 SET

Design and use of the various types.
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Maven86
Posts: 2
Joined: Mon Oct 11, 2021 3:57 pm

OPT options for a 10\50 SET

Post by Maven86 »

Hi Dave,

I purchased a pair of your 49% Ni interstage transformers for a 10\50 SET build and am now considering going nickel for output transformers as well. I wanted to start a conversation with you about the various options I have and to figure out what would be the best fit. I guess it's best to start with a few questions\comments:



1. Ideally I would have liked to have both 8 and 4 ohm speaker outs as well as a headphone jack but after reading around, having more secondary outputs may not sound as good as sticking to one output? If this is the case then I'll stick with an 8 ohm secondary.

2. As far as operating points go, I don't plan on squeezing the 50 for all its juice so I'd be alright with something in the 3.5 W range.

3. I'm not rigid on using the 10 for a driver but figured I'd want to experiment with DHT drivers (specifically thoriated tungsten variants). If you have any suggestions for something better that still works optimally with my interstage transformers, I'd definitely be open to exploring those options as well.

4. I know it's hard generalizing differences in sound given the impact of other components\variables in the system but what can I expect in terms of subjective differences in presentation between something like 49% nickel vs 80%? I would guess that the 80% would give me that more "musical" tone (which I'm looking for). But I'm wondering if there were other tradeoffs such as clarity, resolution, detail ect. when increasing the Ni content.

5. In terms of sound goals for this design. I'm going more towards the musical, engaging\soul grabbing direction as opposed to the hyper detailed analytical route. I have another amp using amorphous cores and I love it for what it does well. However, tone wise I want this to go in the opposite direction while not giving up too much in terms of "technical" performance (if that's even possible).

I'll start here for now but I'm assuming there's a lot more information needed to fill the gaps for a design. Please feel free to steer the conversation in that direction.

Thanks,
Merv
dave slagle
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Re: OPT options for a 10\50 SET

Post by dave slagle »

Hello Merv,

I will answer your questions inline below.
Maven86 wrote: Mon Oct 11, 2021 7:33 pm 1. Ideally I would have liked to have both 8 and 4 ohm speaker outs as well as a headphone jack but after reading around, having more secondary outputs may not sound as good as sticking to one output? If this is the case then I'll stick with an 8 ohm secondary.
I like to the load from the speaker impedance reflected to the tube by the turns ratio squared. The speaker numbers are "fixed" and the actual load the tube sees is somewhat soft. If you want 6K, anything in that vicinity will be fine. Lets assume a transformer with possible turns ratio possibilities of 27.5:1 32.3:1 and 39:1. With a 4Ω and 8Ω load the reflected loads possible are:

8Ω 8325Ω 6060Ω 12144Ω
4Ω 4162Ω 3030Ω 6072Ω

this configuration will give a 6K load for both and as a plus there are a few other options available to experiment with. The headphone jack is more problematic since there is such a wide range of possibilities but have found that the increased reflected load from using one of the speaker taps is a benefit and adding another specific winding introduces too much compromise. In reality the choice of load for the tube has more to do with required power output and I find higher value loads always sound better until you run out of power.
3. I'm not rigid on using the 10 for a driver but figured I'd want to experiment with DHT drivers (specifically thoriated tungsten variants). If you have any suggestions for something better that still works optimally with my interstage transformers, I'd definitely be open to exploring those options as well.
Just be aware that if you use the 10 you will need 6-8V of drive.
4. I know it's hard generalizing differences in sound given the impact of other components\variables in the system but what can I expect in terms of subjective differences in presentation between something like 49% nickel vs 80%? I would guess that the 80% would give me that more "musical" tone (which I'm looking for). But I'm wondering if there were other tradeoffs such as clarity, resolution, detail etc. when increasing the Ni content.
80% isn't an option at this time so the choice would be between 49%, amorphous and Nano. I find the 50 mates with nickel wonderfully. Amorphous seems to rob the tube of all of its natural tone and nano fits in between the two.
5. In terms of sound goals for this design. I'm going more towards the musical, engaging\soul grabbing direction as opposed to the hyper detailed analytical route. I have another amp using amorphous cores and I love it for what it does well. However, tone wise I want this to go in the opposite direction while not giving up too much in terms of "technical" performance (if that's even possible).
I think from a technical perspective equivalent transformers can be made with all three core types. The decision here ultimately comes to the voicing of the amp.

dave
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Maven86
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Joined: Mon Oct 11, 2021 3:57 pm

Re: OPT options for a 10\50 SET

Post by Maven86 »

I think the 49% Ni core with the 6k primary sounds like it would work. If anything, I would also be able to use these for 45s or paralleled 801As I'm guessing?

I'll shoot you an e-mail about pricing and such. Thanks for the information.
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