What's in a Mars Specialist?

[The New Steve H]

Friend of mine thinks he wants a Mars Specialist, which is an 18-watt amp with two 6V6 tubes. It is rumored to be based on the 5E3, but it has a 6SL7 in the preamp.

Does anyone know what's inside this thing? If it's just a 5E3, cloning should not be a problem.

[The New Steve H]

Also wondering if there is a way to get better control over the volume without messing up the tone.

[harryk]

I do not know anything of Mars Specialist, but I have done several modified 5E3 amps and installed VVR power scaling to a couple of them. With this amp, when there is no master volume, I ended scaling the whole amp, which seems to work the best way in this case. I have used VVR power scaling in many amps and mainly used it to scale PA only. In that case it is better to have somekind of MV also.

I have installed VVR to 5E3, AC30 and some other cathode biased amps without negative feedback and it seems that it works best in this kind of amps compared to fixed bias ones. Maybe somebody can help and explain why .

[The New Steve H]

We may take a whack at it.

[Zippy]

Friend of mine thinks he wants a Mars Specialist, which is an 18-watt amp with two 6V6 tubes. It is rumored to be based on the 5E3, but it has a 6SL7 in the preamp.

Is this the same "friend" that has come up with all the other projects you've tackled? Or is this yet another voice in your head?

It's hard to "clone" something if you have no idea what it sounds like or its topology. Please gather some more info - gut shots rule but knowing its controls, tube complement, transformer numbers, and characteristics go a long way to getting started.

[The New Steve H]

Please gather some more info - gut shots rule but knowing its controls, tube complement, transformer numbers, and characteristics go a long way to getting started.

Perhaps this why I posted the question?:idea:

I'm sorry my friends get on your nerves. Maybe I should give you their email addresses. As it happens, this is a friend who thinks the other friend is taking too long to get moving.

[The New Steve H]

Maybe the problem is that people can't imagine me having more than one friend.

[Zippy]

Maybe the problem is that people can't imagine me having more than one friend.

It's easier to imagine you having more than one voice in your head.

Where did your "friend" hear the Mars Specialist? Do you have any more info to share? Could your "friend" take a look inside the cabinet to get some trannie numbers? That could lead to sussing the voltages.

[The New Steve H]

Let me see what I can do with him. He sent a shot of the back opening of an amp he said was a Specialist, but it didn't have the Filmosound box. It looked pretty weird. The power tubes were by the PT, but the OT was between the power and preamp tubes.

A Mars demo video says it has a 6SL7 preamp, with a 12AX7 inverter and 6V6 power tubes. The rectifier is a 5Y3. The only pots are volume and tone. It has 16 and 8 ohm jacks in the back.

It ought to be a very quick project, provided I don't decide to mill a chassis out of an old fire hydrant or something.

[Cygnus X1]

A Mars demo video says it has a 6SL7 preamp, with a 12AX7 inverter and 6V6 power tubes. The rectifier is a 5Y3. The only pots are volume and tone. It has 16 and 8 ohm jacks in the back.

Almost sounds like a variant of the 6SC7 Deluxe 5C3.
A lot of hybrid stuff going on there.

It ought to be a very quick project, provided I don't decide to mill a chassis out of an old fire hydrant or something.

You been sleeping in my "bed of knowledge"?
Sounds like one of my bright ideas!

[The New Steve H]

Sounds like you're not familiar with my somewhat unusual chassis designs! Perhaps best to keep it that way.

[Cygnus X1]

Sounds like you're not familiar with my somewhat unusual chassis designs! Perhaps best to keep it that way.

Well, yes I am.
Fun stuff.

[d95err]

http://www.atmarsamps.com/products/index.html

No mention of octal preamp tubes on the website. Also says it has an "uncommon" phase inverter. Now what could that be. Paraphase?

[The New Steve H]

Here's the shot of the rear opening. If this is the right amp, it shows that it has a big tube in the preamp area, which is presumably the 6SL7.

Not exactly a gut shot.

[C Moore]

http://i1132.photobucket.com/albums/m57 ... G_0055.jpg
http://i1132.photobucket.com/albums/m57 ... G_0056.jpg
http://i1132.photobucket.com/albums/m57 ... G_0057.jpg
http://i1132.photobucket.com/albums/m57 ... G_0053.jpg
http://i1132.photobucket.com/albums/m57 ... G_0052.jpg
http://i1132.photobucket.com/albums/m57 ... G_0051.jpg
http://i1132.photobucket.com/albums/m57 ... G_0050.jpg

I found these on TGP. No gut shots that I saw. You may have to copy and paste each link into the address bar. Looks to be all of the same amp, with maybe a:
5Y3
2x 6V6
2x 12AY or AX7 I guess.
Neat looking amps.....not sure how they sound or what they sell for.
Wonder what the story is behind the company name.? Is it related to the film industry.....?
Best