Tan Music Man

[martin manning]

Ok, in this post from that thread TM says these specs (same as Tony posted above) are not for the 130W. The 265-0 loaded voltage mentioned would produce ~750V on the plates, which is too high, isn't it?

Thanks for the info. Are you using an original transformer or a replacement?
I found these specs for a Schumacher replacement but am still looking for the actual transformer.

Music Man 130 (model 2275 4-10)
High Voltage Sec #1 Sil Voltage Doubler (F.W.) (2) 100mfd
Brn - R/Y 710vdc @ .100a 660vdc @ .275a
Red- R/Y 440vdc @.275a
Low Voltage Sec #2 org - yel- org
Sil. Bridge (2) 150 mfd cap + - 42 V 0A 60V CT @ .1 RMS
Filaments (2) 6.3V @ 6 A grn- grn/yel

That Schumacher is the wrong MM PT for the 130W model, see my post above. The link you posted to the TAD HD 130 model was the correct design/layout. However, it's a tad hot at 285V. That TAD model would be about 804V unloaded and around 765V-plates/383V-screens loaded, whereas the MM was 265-0.

If you wanted to clone the stock H/Lo power setup,then the HT secondary winding would be laid out as follows; 265,180-0

First HV build was a stock replacement because I talked myself out of my own design, all others my own design.

TM

[martin manning]

The 270k resistors across the reservoir caps are bleeders, not balance resistors. Musicman amps had them, and for very good reason. In the D amp those caps can discharge through the preamp voltage divider and the B3 filter balance resistors. That would take some time, though, so I now think that including them was a good idea. In the PS design I drew up, the preamp divider is only a total of 265k, so they are not necessary.

Here's MM 200-130 HV supply. Note 1k5 screen resistors, each one shared by a pair of opposing power tubes.

[ToneMerc]

Ok, in this post from that thread TM says these specs (same as Tony posted above) are not for the 130W. The 265-0 loaded voltage mentioned would produce ~750V on the plates, which is too high, isn't it?

[quote=ToneMerc post_id=322640 time=<a href="tel:1415454063">1415454063</a> user_id=6557]

Thanks for the info. Are you using an original transformer or a replacement?
I found these specs for a Schumacher replacement but am still looking for the actual transformer.

Music Man 130 (model 2275 4-10)
High Voltage Sec #1 Sil Voltage Doubler (F.W.) (2) 100mfd
Brn - R/Y 710vdc @ .100a 660vdc @ .275a
Red- R/Y 440vdc @.275a
Low Voltage Sec #2 org - yel- org
Sil. Bridge (2) 150 mfd cap + - 42 V 0A 60V CT @ .1 RMS
Filaments (2) 6.3V @ 6 A grn- grn/yel

That Schumacher is the wrong MM PT for the 130W model, see my post above. The link you posted to the TAD HD 130 model was the correct design/layout. However, it's a tad hot at 285V. That TAD model would be about 804V unloaded and around 765V-plates/383V-screens loaded, whereas the MM was 265-0.

If you wanted to clone the stock H/Lo power setup,then the HT secondary winding would be laid out as follows; 265,180-0

First HV build was a stock replacement because I talked myself out of my own design, all others my own design.

TM

[/quote]

FYI this is powersupply of Bruno Super100 with EL34...

Thanks for that, Tyler. I guess that's another vote for stacked filters all down the line.

As far as the screens go! Dumble uses 150 ohm 3 watt on the screens of the 6L amp, Music man uses the typical 1K5.(total) My guess would be due to the lower voltages (less protection needed) any other thoughts on why he might have lowered them down that far?

So which is which? I can't make sense of what you wrote there. I thought 470Ω for 6L6 amps ala Fender, and 1k or so for EL34. Above there is mention of 150Ω for the MM power supply.

On screen voltage in general I think it's about getting the load line to pass through the knee, and that is often made to occur dynamically. The 350V static screen voltage puts the load line well below the knee, and that's why I say I would like to see what happens if the screen voltage were lowered.

Does anyone have details on the Musicman power transformer? I would like to know the DC resistance of the HV secondary. I can't believe or don't understand the specs posted above, since the current rating has to be quite high to work with the doubler. Maybe that's DC current listed?

Martin, go back and look at my build thread, a 265-0 PT works. FWIW, you are correct about the HT rating needing to be higher in current. AFAIR, from my research the smallest MM power transformer was almost 600mA, the PT's I use are almost twice that.


I have built at least 4-5 amps with this power topology core; the most basic method of stare and compare while copying Dumble works.I did the radials across the string at the suggestion of Andy Fuchs, stacked at only B3 like HAD and of course the classic style also done by HAD.

TM

[ToneMerc]

Martin
One of the main reasons why I have been hesitant until now to post any layouts of the MM info is due to the higher voltages in this amp I would just feel awful if someone tried to build this amp with my layout without taking the proper precautions or make a slip up that could seriously injure themselves or worse!!..So needless to say this one will be filled with warnings and precautions. Thanks as always for running the numbers for us to help make sure we all build us a safer great sounding amp!!


Tony

Tony you are right, 750V is no joke. I got bit by 579 in my first build. I put warning stickers on the chassis and on the power board!

TM

[talbany]

Martin
Yes I know about the 1K5's on the MM amps..I was wondering if you had any idea why he might have used such a low value for the screen supplys (on the same amp we analized the PS in) that's all

BTW!.The DC resistance on the HV winding of my 200-130 is 4.0 ohms! Hope this helps!

Thanks Mike for the info
Those were the only specs I had on the MM transformers in my 130 folder Too many different MM power transformers out there
BTW.Did you have yours custom wound or was it a replacement!

Thanks Tyler for the Pics! Big help!

From what I am hearing the SL-100 is an exact replica of the Ultrasound amp..I am waiting on some pics to confirm a few things.



Tony

[talbany]

Martin
One of the main reasons why I have been hesitant until now to post any layouts of the MM info is due to the higher voltages in this amp I would just feel awful if someone tried to build this amp with my layout without taking the proper precautions or make a slip up that could seriously injure themselves or worse!!..So needless to say this one will be filled with warnings and precautions. Thanks as always for running the numbers for us to help make sure we all build us a safer great sounding amp!!


Tony

Tony you are right, 750V is no joke. I got bit by 579 in my first build. I put warning stickers on the chassis and on the power board!

TM

Damn right AC will knock you on your ass but DC won't let go until your good and dead!
Sorry you got BIT!

[martin manning]

Martin, go back and look at my build thread, a 265-0 PT works. FWIW, you are correct about the HT rating needing to be higher in current. AFAIR, from my research the smallest MM power transformer was almost 600mA, the PT's I use are almost twice that.

Indeed 1200 mA is what I estimated for full load. The 265-0 you quote is at idle load? That means you would see 750VDC (less a few for ripple) at idle. Seems like you'd have to be be well over 700V.

Yes I know about the 1K5's on the MM amps..I was wondering if you had any idea why he might have used such a low value for the screen supplys (on the same amp we analized the PS in) that's all

That small value isn't going to produce much screen voltage sag when driven hard, it's more likely just to serve as a stopper. One can only assume that HAD liked the sound better that way. Thanks for the MM PT DCR!

[Mark]

Transformer sets might be hard to find. The Mojotone set isn't the 130 watt set as far as I can tell. Mercury do make a set but ...$$$

I have asked Classictone if they do a transformer set. I'll report back when I hear from them.

[martin manning]

I'm pretty sure Heyboer would have the specs, and can make them on request.

[talbany]

Ok, in this post from that thread TM says these specs (same as Tony posted above) are not for the 130W. The 265-0 loaded voltage mentioned would produce ~750V on the plates, which is too high, isn't it?

Thanks for the info. Are you using an original transformer or a replacement?
I found these specs for a Schumacher replacement but am still looking for the actual transformer.

That Schumacher is the wrong MM PT for the 130W model, see my post above. The link you posted to the TAD HD 130 model was the correct design/layout. However, it's a tad hot at 285V. That TAD model would be about 804V unloaded and around 765V-plates/383V-screens loaded, whereas the MM was 265-0.

If you wanted to clone the stock H/Lo power setup,then the HT secondary winding would be laid out as follows; 265,180-0


First HV build was a stock replacement because I talked myself out of my own design, all others my own design.

TM

Mike & Martin
Here is the service manuals and specs for the 2275-75

It's showing both 50w and 100w used either 2X6L6’s or 4 6L6’s
depending on the primary voltage used the numbers are

100-65 65w-75w,100-125VAC
100-65-250—56w,75w,220-250VAC
200-130—-100W,150w 100-125 VAC
200-130-250—-100w,150w, 220-250 VAC

All of these transformers delivered 700V (mine was 702) on the plates under load

These were the same transformers used in the 200-130 100w models which looks like the same tranny I have

2475-75_&_2275-75.pdf

The only ones I noticed with the higher voltages were the Type 2 that ran 725 on the plates and 360VDC on the choke.
Which of these models again you think run high unloaded?

Tony

[67plexi]

Mojotone has the 65 watt in stock.

http://www.mojotone.com/amp-parts/Transformers_1#/

I built a low plate with a Drake 1202-132 OPT way to loud but it does sound like the MM sound clips posted.

[Mark]

I received a reply from Classictone and they don't make a Musicman transformer set.

[martin manning]

Which of these models again you think run high unloaded?

I was questioning the 265VAC loaded Mike mentioned for a MM-type PT he had wound. It would make sense if it was meant to be the unloaded voltage. Did I misunderstand?

[Charlie Wilson]

Here is Mercury Magnetics HD130.
CW

[talbany]

After digging through the Music Man Manuals here is what I think is going on with the Specs posted earlier:?

The 130 is a fairly standard X-former used in many of the 100/110W US with 120 Pri hybrid MM models with both 6L's and or 34's w/Hi/Low switch!
The manuals don't exactly specify a 130-type 2 (with choke) however these type 2 transformers seem to run 25V higher on both plates and screens loaded..(There is no MM amp that I can find that runs at 765V under load)
The specs I posted came off an older MM forum supposedly from a reputable source however the 130 HV winding for us should read
Brn-R/Y---265-0-265 VAC Unloaded which would give us 747VDCno load in the amp and 702VDC under load @ 25 mA bias @ idle (filtered 100uF) for the 130 type

The bias tap Org-Y-Org winding delivers 33-0-33 (no load) Dumble utilizes only 1/2 the winding to get his 47.5 -DCV which should be enough to bias a quad of 6l's or 34's since they require a lower idle bias setting of around 25Ma. per tube.
The 130 also has 2 separate 6.3V filament windings,1 to run the heaters another running through another voltage doubler powering a pair of 12V relays.
If you get a replacement 130 from a reputable supplier that does not have separate 6V filament winding you can split the 33-0-33 winding gnd the CT use the negative side for bias supply and use the positive side to power a 12-V regulator (and a dropping resistor) to run the relays. The winding has enough current that the bias will not change when the relays are turned on and off (use low current relays)

So from what I can tell as long as you use the 130 (type 1 PT) designed for the hybrid 100/135 watt MM amps, it should work in a Dumble MM PS w/700V on the plates Under load!..This is however not to say some other manufactures winding X-formers might spec something totally different and tell you it will work in a Music Man (TAD)..

That's what I got..Feel free to double check my numbers as some of this was taken from specs I remember 100 Cheeseburgers ago )

BTW.I don't ever remember having a current rating issue with my 130 in the high plate.She always ran cool as a cucumber
Tony