[Daveze]

Hmm, tough. I'd say go with the mini, If you're anything like me you'll love the custom case.

I think you need to get up to speed with the new boards: opamps (OPA627, etc) are out, discrete buffers are in. Indulgence.

 

[acvtre]

Quote:

Originally Posted by Daveze /img/forum/go_quote.gif Hmm, tough. I'd say go with the mini, If you're anything like me you'll love the custom case. I think you need to get up to speed with the new boards: opamps (OPA627, etc) are out, discrete buffers are in. Indulgence.

Actually I would prefer a complete kit with pcb and other stuff needed and also the case ready. I think I have to wait beezar.com

 

[Beefy]

Quote:

Originally Posted by Daveze /img/forum/go_quote.gif Ah, sorry, I think I wasn't clear. The Mosfet Max is best for low impedance, Mini Max is best for high impedance.

I see what you are saying, but in all fairness...... if you are dropping out of Class A with BJT's at 50mA with *any* impedance phones, there is a good chance you have just deafened yourself.

 

[acvtre]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif I see what you are saying, but in all fairness...... if you are dropping out of Class A with BJT's at 50mA with *any* impedance phones, there is a good chance you have just deafened yourself.

So you say minimax and MM are equal, in the sens that you don't have to bother about the impedance?

 

[Beefy]

Impedance is something you shouldn't ever worry about in the real world. There are very few scenarios where it is actually important.

 

[acvtre]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif Impedance is something you shouldn't ever worry about in the real world. There are very few scenarios where it is actually important.

Great, so since the MM is bigger, this means easier to populate, I think I'll go for the MM mosfet and hopefully also the Bantam DAC. Good choice?

 

[tomb]

Quote:

Originally Posted by acvtre /img/forum/go_quote.gif Great, so since the MM is bigger, this means easier to populate, I think I'll go for the MM mosfet and hopefully also the Bantam DAC. Good choice?

I think what Beefy is saying is that to distinguish between the designs is splitting hairs to a certain extent. Although, the MOSFET-MAX can power some desktop speakers fairly well - I wouldn't recommend that for the MiniMAX.

Ultimately, the MOSFET-MAX is a more "advanced" build: temperatures are hotter, options are more numerous, so therefore, you need to make intelligent choices, etc. The MiniMAX is the better choice starting out, most likely.

 

[Beefy]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif I think what Beefy is saying is that to distinguish between the designs is splitting hairs to a certain extent.

That one

 

[acvtre]

Ok, now the problem is, beezar sells only the minimax PCB or also the kit as for the SSMH?

EDIT:
omg but it's terribly expensive. Absolutely impossible, ok now the choice is...the millet hybrid maxed or the SSMH? the others are really too much expensive.

 

[tomb]

Quote:

Originally Posted by acvtre /img/forum/go_quote.gif Ok, now the problem is, beezar sells only the minimax PCB or also the kit as for the SSMH? EDIT: omg but it's terribly expensive. Absolutely impossible, ok now the choice is...the millet hybrid maxed or the SSMH? the others are really too much expensive.

The custom case on the MiniMAX is only $40 more than the case you'd need on the MAX. Many spend that for a couple of two-inch long endplates from FPE.

That's the only thing you'll save over the MAX. Plus, the MAX will have a more expensive parts set due to the number of relays included (3 as opposed to 1 on the MiniMAX).

No doubt, the Starving Student is less expensive ... but as I've said before, proportionally so, I think.

 

[acvtre]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif The custom case on the MiniMAX is only $40 more than the case you'd need on the MAX. Many spend that for a couple of two-inch long endplates from FPE. That's the only thing you'll save over the MAX. Plus, the MAX will have a more expensive parts set due to the number of relays included (3 as opposed to 1 on the MiniMAX). No doubt, the Starving Student is less expensive ... but as I've said before, proportionally so, I think.

Ok, maybe there's something that I don't understand because the BOM on DIYforum.org says that I would spend over 230$ for the mini and 150$ for the max, so the difference is not of only 40$. Consider that the stuff in europe is not as cheap as in USa. In addition, I don't know why, the maxed it seems to me to be easier, maybe it's only an impression.
Actually I don't know what to do, I'm going crazy. Actually, I can't see or understand a reason to spend more money for the minimax, the only problem for the maxed would be the casework for me. My real intention is to simply populate the PCB, that's all.
Nobody sells a kit with all the needed stuff?

 

[tomb]

Quote:

Originally Posted by acvtre /img/forum/go_quote.gif Ok, maybe there's something that I don't understand because the BOM on DIYforum.org says that I would spend over 230$ for the mini and 150$ for the max, so the difference is not of only 40$. Consider that the stuff in europe is not as cheap as in USa. In addition, I don't know why, the maxed it seems to me to be easier, maybe it's only an impression. Actually I don't know what to do, I'm going crazy. Actually, I can't see or understand a reason to spend more money for the minimax, the only problem for the maxed would be the casework for me. My real intention is to simply populate the PCB, that's all. Nobody sells a kit with all the needed stuff?

First - yes, I sell kits for the MiniMAX, but it's not "official." (maybe that just changed

)

Second - if your "... real intention is to simply populate the PCB, that's all.", then you'll never have a working amp. We're proud that the MAX/MiniMAX family has as much or more onboard components than probably any other DIY PCB design - pot, headphone jack, power supply, etc. However, that's still a far cry from being able to complete a working amp. There are switches, power jacks, tip jacks, RCA jacks, wiring, knob, etc. All of these are needed to get a working amp in order.

Third - yeah, there are differences in the BOM of the MAX and MiniMAX. Both amps evolved over time. The MAX was first and although the BOM was very complete for most of amps of the time period it came out, there are many more components listed in the MiniMAX BOM. The MiniMAX BOM is the BOM for a complete kit, period. There are tip jacks, RCA jacks, a machined knob, more expensive capacitors, the 12FM6 tubes (rarer and more $$), and even a DMM and trimmer adjustment tool. These add up to ~$30 in extras. Combined with the $40 difference for the MiniMAX case, that's approximately the same for the MAX - it would be the same for the same parts, iow.

Now - anymore questions about pricing ... please address them to me in a PM or e-mail. I suggest that you study these designs further before you turn this into a window shopping discussion again. No offense, but that's not what these threads are about.

 

[acvtre]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif ...cut... Now - anymore questions about pricing ... please address them to me in a PM or e-mail. I suggest that you study these designs further before you turn this into a window shopping discussion again. No offense, but that's not what these threads are about.

So sorry, that wasn't my intention.
However with "My real intention is to simply populate the PCB, that's all" I mean that I just wanna completly build the amp and don't take technical decisions because I can't, unfortunately.

About the third point: basically you say that the hybrid maxed is older and the minimax newer and better. So it's better if I chose between the MM mosfet, not the hybrid maxed, and the minimax, is that right?

Big noob question: what is the tube bias? (right, ground, left) what is supposed to plug in there?

 

[tomb]

Quote:

Originally Posted by acvtre /img/forum/go_quote.gif So sorry, that wasn't my intention.

No problem. It's just that much talk of pricing and selling will get me banned as a Member-Of-the-Trade. We have to respect the rules that Jude and the Mods set if we want to participate in Head-Fi.

Quote:

However with "My real intention is to simply populate the PCB, that's all" I mean that I just wanna completly build the amp and don't take technical decisions because I can't, unfortunately.

I understand, but it should be a learning experience. Have you read and understood the MAX/MiniMAX websites? That should be the first step. Quote:

About the third point: basically you say that the hybrid maxed is older and the minimax newer and better. So it's better if I chose between the MM mosfet, not the hybrid maxed, and the minimax, is that right?

No one said "better." Assuming we get the new MAX V1.2 PCB in production (It's not available right now, so some of these questions are moot.), the same parts = the same performance.

The MiniMAX was designed later. The purpose being to cram as many through-hole parts into as small a PCB space as we could, and design what we think is the best custom-case offering available. Along the way, we also addressed the original MAX power supply and improved it on the MiniMAX so that it has major-league quieting and ripple performance. The whole thing ties up into a neat little package that many have enjoyed building.

When the MAX V1.2 board is ready, it will have more features (like a board-mounted Bantam or Grub DAC), but still, equal parts = equal performance. The one distinguishing difference is that the MAX will allow the use of MOSFETs. You see, MOSFETs require a certain minimum of current bias to operate correctly (and to even turn on). That current bias is high enough to need 1-1/2" heat sinks. That size heat sink will not fit in the MiniMAX. So, if you want to use MOSFETs, the MAX is the only option.
Quote:

Big noob question: what is the tube bias? (right, ground, left) what is supposed to plug in there?

A DMM plugs into the tip jacks so that you can measure bias. Bias on a vacuum tube determines the center point of the zero voltage reference for the music signal. The tubes work on positive voltage being supplied to the tube. However, music needs both negative and positive voltage to create a music signal (a sine wave that fluctuates between negative and positive).

The way we do this on a tube is to elevate a bias point for the grid so that there is a voltage difference above and below the music signal as it exits the tube. The Millett Hybrid/MAX/MiniMAX works on a 24-27VDC power supply. So, we set the tube bias at 13.5VDC if the power supply is set at 27VDC. That centers the music signal at 13.5VDC and allows the tube to amplify the music signal from +13.5V (27VDC) to -13.5V (0VDC).

In the case of the Millett Hybrid/MAX/MiniMAX family, there are three tubes that can be used - 12AE6, 12FM6, and 12FK6. Each tube will have an entirely different adjustment to set that tube bias. In fact, each tube within the same type will have a different adjustment on the trimmers to set that 13.5V bias. So, we provide the tip jacks in the design so that these changes can be easily made at any time. After all, tube rolling is one the more fun things about tubes. You don't want to have to take the case apart every time you change a tube.

Hope that makes a little sense. It's complicated, I know - more reading will help.

 

[BoilermakerFan]

Decided to do my V1.2 proto as a MOSFET-MAX. Checking to make sure I have all the parts and transistors I need before I start building.

EDIT: V1.0 kit is sold...