Magnetic Compnents inc universal transformer thread

[ClassicTone]

Bram,

I see what you are saying now. Yes, the 40-18069 and the 40-18026 should work well together. The problem may be with mounting the 40-18069 in the Metro chassis as it appears to have a cutout hole where the PT should be mounted to accommodate a more historically accurate laydown style PT. Since the 40-18069 is a fairly large and upright style PT, you may have some problems mounting it in your existing '68 Metro 100W Plexi chassis. You might need a different chassis to accommodate the PT such as a plain chassis without a cutout hole. I'll contact our distributor Triode Electronics and see if they have a suggested chassis that may work better for your application.

Joe Janisch
ClassicTone By Magnetic Components, Inc.
http://www.classictone.net" onclick="window.open(this.href);return false;

[BAinFL]

Thanks Joe. I've already placed my order for the 12000 chassis so don't go out of your way chasing another chassis for me at this point =)

Out of curiosity to the original designers of this PT: Why was the standup orientation chosen over a laydown style? I know you can't please all the people all the time, but it would have seemed more likely that 12000 builders (EVH tone chasers) would be the most likely target audience for the dual voltage feature and thus would be more inclined to prefer a laydown style. Not questioning the logic, but just curious to why a standup was spec'd for the initial spec.

In any case, Joe thanks for all the help.

[ClassicTone]

Hi Bram,

It was discussed and decided by members of both the Metro forum and Sloclone forum that an upright PT would be most desired. Please read following quote from a member of this forum and was stated earlier in this thread.

a stand up transformer has the most advantages (no chassis cutout= more usable room inside the chassis for several rectifier & filtering boards etc.) with very solid (Marshall- like) reinforcement brackets.

It was a pretty nice process actually in which everyone had some positive feedback on what they would like to see in a 100W power transformer.

Thanks Bram!

Joe Janisch
ClassicTone By Magnetic Components, Inc.
http://www.classictone.net" onclick="window.open(this.href);return false;

[Roe]

I heard triode planned to make a dynaco A451. will you be making it?
should be perfect for Sunns, dumble SSSs and other big amps

[ClassicTone]

Hi Roe,

No, I have yet to hear anything from Triode on the A451.

Joe Janisch
http://www.classictone.net" onclick="window.open(this.href);return false;

[joey]

Thanks Joe. That answered a lot of my questions.

On your recommendation for the CT laydown PT, could you elaborate on why? Was your suggestion based on historical accuracy of the '68 plexi? Or something more physical in nature (size weight orientation etc)? The main attraction to the 40-18069 for me was the dual power which I'm interested in for an EVH sound using George's "virtual variac" circuit. I'm looking to build an amp that has a great sound, the '68 model authenticity is not an important factor to me. I know Heyboer has a laydown PT with dual voltage (which is to George's specs) but right now that iron is a bit out of my price range...and I'm already convinced you guys have some amazing sounding hardware, excellent reliability and care about your customers! I'm sold on MC...just want to order the right hardware and get some idea of what issues I'll need to navigate to incorporate it in my build.

Again, I appreciate your comments/suggestions and your interaction here on the forums. Many thanks!

-Bram

If I may interject, the 40-18069 was not designed to have a virtual variac type application, it was designed to have a tap more suited to reduce strain on common power pentodes, and beam pentodes, but also to have a slightly higher voltage tap more suited to some kinkless bottles.

All that said, Having a lower hv tap will not give you a variac operation anyway. what a variac or autoformer does is affect whole primary voltage into the pt, which not only affects hv, but the whole reflected secondary including the heaters, in which reduced thermionic emissions play a huge role in the variac sound.... No transformer Solely with dual hv secondaries will mimic this.

this transformer is monstrous, and will most likely cover up the laydown punch with it's footprint if you want to give it a go, I garauntee you will not find a better PT especially for that money.

[baron55]

Yes it is monsterous


If you use an aluminum chassis I wouyld make sure it is at least .09 or thicker. Now if the amp is for personal use, then you could maybe go lighter since you won't be movng the amp around a lot in shipping or touring.

[ClassicTone]

Thanks Joey and Baron for helping clarify the chassis issue a little for Bram.

Joe Janisch
ClassicTone By Magnetic Components, Inc.
http://www.classictone.net" onclick="window.open(this.href);return false;

[BAinFL]

Thanks Joey and Baron for helping clarify the chassis issue a little for Bram.

Joe Janisch
ClassicTone By Magnetic Components, Inc.
http://www.classictone.net" onclick="window.open(this.href);return false;

+1

[BAinFL]

...the 40-18069 was not designed to have a virtual variac type application, it was designed to have a tap more suited to reduce strain on common power pentodes, and beam pentodes, but also to have a slightly higher voltage tap more suited to some kinkless bottles.

I'd throw it out there then with all the interest in 12000 series builds and EVH tone chasers that maybe Mag Comps *next* project style PT would incorporate dual voltages that would incorporate "normal voltages" for typical EL34 type output tubes and then a *lower* voltage section to really brown things out. And of course keep it laydown style for the 67/68 chassis.

I guess what I didn't recognize that the range of voltages in this particular PT was more like normal + high, I just heard dual voltage and incorrectly assumed normal + low. Some of this stuff is starting to make sense to me now =) Thanks for everyone's patience.

[joey]

...the 40-18069 was not designed to have a virtual variac type application, it was designed to have a tap more suited to reduce strain on common power pentodes, and beam pentodes, but also to have a slightly higher voltage tap more suited to some kinkless bottles.

I'd throw it out there then with all the interest in 12000 series builds and EVH tone chasers that maybe Mag Comps *next* project style PT would incorporate dual voltages that would incorporate "normal voltages" for typical EL34 type output tubes and then a *lower* voltage section to really brown things out. And of course keep it laydown style for the 67/68 chassis.

I guess what I didn't recognize that the range of voltages in this particular PT was more like normal + high, I just heard dual voltage and incorrectly assumed normal + low. Some of this stuff is starting to make sense to me now =) Thanks for everyone's patience.

Well the thing is Bram, you will not get a variac type sound with just lowering the HT voltage, And if you just wanted to lower the HT voltage of any transformer, you don't need dual taps to do so, it can be done very effectively by a few different means.

1) a cheap easy MOSFET source follower circuit designed to operate on pulsed DC, which is exactly the principal behind "power scaling"(thats all powerscaling really is), just without the massive range that the powerscale circuits typically use. (Don't worry you will never hear the mosfet in your circuit). This method will give you a huge range of adjust, deciding on what you choose.

2) using a small transformer out of phase in parallel on the primary taps to acheive a true variac vibe. you don't even need to put it in your amp if you don't want to, it can be in a separate small chassis.

3) an autoformer, like the Blues Sarencino amp does.

[BAinFL]

Thanks Joey. Those are some interesting ideas. I'm just looking for a good mix of EVH sounds and classic plexi in my first build. The more I go doen this rabbit hole, I think I'm just going to build a pretty conservastive '68 spec for now...only mod I think I'll add is a LarMar MV. Thanks for the explanations...maybe I'll try something down the line. I guess I thought the Virtual Variac and a dual voltage PT was all I needed for the sound I wanted. Gonna build the first one and tweak from there.