[BoilermakerFan]

Quote:

Originally Posted by UglyJoe /img/forum/go_quote.gif Question about the power transistors. I'm building a BG Max with the VitQ bypasses, and unfortunately the suggested 2238/968 BJT's aren't available right now. TomB suggested to use the 2344/1011 transistors as a replacement, and I am fine with that, however I wanted to take the opportunity and ask what others thought as well. I'm willing to trade some detail for a little extra bass, but only SMALL amounts of detail. I want something that the BG's will make worthwhile. Anythoughts? Also, I noticed that the lead time on arival of new 2238s at MCMinone is like 17 days now. Is it worth it just to wait and go with the tried and true? Or is there a good possibility that that lead time might be incorrect and the wait might be longer anyway? Thanks guys.

Are you using the Hoffman enclosure in the BOM? Is this your first build?

If this is your first build, I might suggest saving the BGs and using the Muse ES/Vit Qs with the 2344/1011s. You'll get 90% of the BG/2238 combo and have a lot less invested in the MAX. BUT, you'll have a great MAX to enjoy now instead of having to wait.

The problem Tom has had with the 2238s is actually receiving genuine 2238s. Even if they come into stock, there is no guarantee they will be genuine 2238s.

There are a few other BJTs that have not been tested and one set that needs to be re-evaluated in the MAX since Steinchen's web site comments were based on open-air transistors at very low bias levels. If you can be patient for a few more weeks, there may be some very good news coming forward. I personally have 4 different sets of "untested" BJTs on the way and I will make sure Tom receives the same sets from me for his comparison as well. I can't speak for Tom, but I know he is busy so we may not be able to report back within 4 weeks.

Edit: So with the 5 sets I already have, and the 4 on the way, I'll have a "few" to choose from.

 

[tomb]

To echo Boilermakerfan, I have had a standing order with MCMinone for six months. They've attempted delivery of 2SC2238's twice during that period, but they were stamped and made by CDIL. Needless to say, they've moved that expected date so many times I can't count it anymore.

I don't blame them, really. At least they stand behind the fact that they want to sell only genuine Toshiba 2SC2238's. Counterfeits are rampant on ebay and elsewhere and many of the other reputable transistor dealers (BDent) have stopped trying to carry them altogether. The plain fact is that I suspect most of us may never see genuine Toshiba 2SC2238's again.

 

[UglyJoe]

Considering that waiting appears not be an option then, what is my best "other" option. Again, I understand that the 2344/1011 are a good replacement for the 2238/968; are they the only pair that makes sense with BG caps now, or does anyone else have another option that they like, that might have slightly less detail but something else going for it?

 

[Iniamyen]

Well, I'm having some issues desoldering one of the panel LED holes, and I still haven't done any casework, but it works (and beautifully I might add!!)

I'm using the can't miss build #4 setup (WIMA + Muse ES + 3422/1359) with the 12AE6 tubes and I'm definitely loving the sound. Very smooth presentation, nice midrange, and nice punch to the bass. Definitely less harsh than my PIMETA with AD8610's with some music.

Thanks for all the help! I'll *definitely* be building more of these for friends/family/myself so it's safe to say you guys have gained another fan for life!

EDIT: And holy crap that Vreg heatsink gets hot !

 

[BoilermakerFan]

Quote:

Originally Posted by UglyJoe /img/forum/go_quote.gif Considering that waiting appears not be an option then, what is my best "other" option. Again, I understand that the 2344/1011 are a good replacement for the 2238/968; are they the only pair that makes sense with BG caps now, or does anyone else have another option that they like, that might have slightly less detail but something else going for it?

Well, I'll assume it's your first MAX, so you do not have a baseline to compare too. If a Porsche GT is 95% of a Ferrari Enzo, but you can't buy/drive/ or ride in an Enzo, are you going to be disappointed you had to "settle" owning and driving a Porsche GT?

You could use the BGs/VitQs with the 2344/1011s and enjoy the best "other" known/proven option at this time. Once Tom and I have had a chance to do listening comparisons of the 4 other sets, then we can report our findings to everyone and make recommendations. Tom's will probably be based on using them with 1" or 1-1/2" heatsinks and BGs or Muse ES caps. Mine will be based on using a different case with 2-1/2" heatsinks so I can run a lot higher bias current with Muse ES, Silmic IIs, and/or Cerafines. I will probably start with Muse ES caps since I have (3) sets of them from Beezar and they are easily sourced from there so I try to keep a known baseline and only change the DB transistors. If we find a set that we both really like head and shoulders above the current offerings, then you could swap out the 2344/1011s for this new set.

But perhaps you should let us know what type of music you primarily enjoy and what headphones you have or plan to purchase. That may change everyone's recommendations for you.

 

[UglyJoe]

Thanks, Boilermakerfan. I am not trying to be rude or ignore you, in case that is how it's coming across.

Yes, this is my first Max (I've had 2 boards since the original group buy and simply haven't stuffed them yet). The reason I waited so long is because I wanted to build the BG version... maybe it's silly, but I hate to have spent all this time waiting to get the cash to build a BG Max and then not do it because the recommended transistor pair isn't available anymore.

As far as musical tastes I like everything, but mostly listen to rock. I have a set of sr125's, and my next plan of purchase is either HD650s or K701s, if I can get a listen to them sometimes soon. I want something else to contrast the in-your-face grado sound, with a bigger soundstage, and the K701 seems to fit that bill; plus I seem to remember that the k701 pairs nicely with a Max.

As far as what I like to get out of sound, detail is obviously extremely important. I don't mean to make it sound like I'm willing to completely sacrifice detail for bass... on the contrary, I'd be extremely disappointed with booming sloppy bass and no detail. However, I understand that the 2238/968 pair is sensational at detail and maybe not so strong in the bass, and that the 2344/1011 pair is like the toshibas, only not as good. My question was only if I had to lose a little of the detail of the 2238/968 pair already, if there might not be another pair with a little less detail but better payoff in bass or some other aspect than the 2344/1011 pair.


EDIT: More than likely I'll order the 2344/1011 pair, as that seems to be the default BG build recommendation now that the 2238 is disappeared; I just wanted to get anyone else's thoughts on other possibilities that might work as well or better.

 

[Beefy]

Quote:

Originally Posted by UglyJoe /img/forum/go_quote.gif EDIT: More than likely I'll order the 2344/1011 pair, as that seems to be the default BG build recommendation now that the 2238 is disappeared; I just wanted to get anyone else's thoughts on other possibilities that might work as well or better.

I really suspect that the new MOSFET Max will become the de-facto pairing with Black Gates, based on AMB's simulations. Wait just a week or two, and tomb will hopefully have the MOSFET site up and post some comparative listening impressions.

(And no, this IS NOT meant as a hurry up to tomb!

)

 

[BoilermakerFan]

Quote:

Originally Posted by UglyJoe /img/forum/go_quote.gif Thanks, Boilermakerfan. I am not trying to be rude or ignore you, in case that is how it's coming across. Yes, this is my first Max (I've had 2 boards since the original group buy and simply haven't stuffed them yet). The reason I waited so long is because I wanted to build the BG version... maybe it's silly, but I hate to have spent all this time waiting to get the cash to build a BG Max and then not do it because the recommended transistor pair isn't available anymore. As far as musical tastes I like everything, but mostly listen to rock. I have a set of sr125's, and my next plan of purchase is either HD650s or K701s, if I can get a listen to them sometimes soon. I want something else to contrast the in-your-face grado sound, with a bigger soundstage, and the K701 seems to fit that bill; plus I seem to remember that the k701 pairs nicely with a Max. As far as what I like to get out of sound, detail is obviously extremely important. I don't mean to make it sound like I'm willing to completely sacrifice detail for bass... on the contrary, I'd be extremely disappointed with booming sloppy bass and no detail. However, I understand that the 2238/968 pair is sensational at detail and maybe not so strong in the bass, and that the 2344/1011 pair is like the toshibas, only not as good. My question was only if I had to lose a little of the detail of the 2238/968 pair already, if there might not be another pair with a little less detail but better payoff in bass or some other aspect than the 2344/1011 pair. EDIT: More than likely I'll order the 2344/1011 pair, as that seems to be the default BG build recommendation now that the 2238 is disappeared; I just wanted to get anyone else's thoughts on other possibilities that might work as well or better.

It didn't come off that way. But if you have two boards and those cans, then I why don't you save the BGs for a MOSFET build and use the Muse ES caps/VitQs with the 2344/1011s and 12FK6 tubes? Personally, I think that setup would rock with the Grados since the Muse ES are bass caps and the VitQs keep the highs. The resolution and detail with the 12FK6 tubes is better too. Then build the MOSFET with the BGs and 12AE6A tubes for the K701s or K702s when they are finally released.

I'm planning to buy K601s now, then K702s when they hit the streets...

 

[bhjazz]

Quote:

Originally Posted by Iniamyen /img/forum/go_quote.gif I'm using the can't miss build #4 setup (WIMA + Muse ES + 3422/1359) with the 12AE6 tubes and I'm definitely loving the sound. Very smooth presentation, nice midrange, and nice punch to the bass. Thanks for all the help! I'll *definitely* be building more of these for friends/family/myself so it's safe to say you guys have gained another fan for life!

Beautiful build, Iniamyen. Nice work!

BTW: where is this "can't miss build" description you speak of? I have a max board waiting and I'd like to rough out my options. Thanks!

Also, since you are near Seattle, you're in for a treat. There is a Head-Fi meet in Seattle on June 21. We'd love to meet you! Here is the thread if you want to browse.

http://www.head-fi.org/forums/f24/ju...eattle-311361/

Welcome to Head-Fi!

 

[Beefy]

Quote:

Originally Posted by bhjazz /img/forum/go_quote.gif BTW: where is this "can't miss build" description you speak of? I have a max board waiting and I'd like to rough out my options. Thanks!

Millett Hybrid MAX Boutique

I built #2.

 

[tomb]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif I really suspect that the new MOSFET Max will become the de-facto pairing with Black Gates, based on AMB's simulations. Wait just a week or two, and tomb will hopefully have the MOSFET site up and post some comparative listening impressions. (And no, this IS NOT meant as a hurry up to tomb! )

I didn't take it as one. Nevertheless, I suspect what else you state is probably the case.

Boilermakerfan -
Please don't take this in any way as discouragement.

While I agree in principle that there may be a slight chance that we can discover a diamond in the rough with some of the other less-known transistors, I wouldn't get your hopes up too high.

All of the recommended transistors and even their replacements are very well known to some, especially Steinchen. Note that his reviews were developed from a wide range of his experience in building just about every major solid-state DIY headphone amp ever designed. It's possible that we could find another transistor pair to be preferrable. So far, however, I've tried almost all of them and haven't found any of them to deviate very much from Steinchen's stated sound characteristics.

I would suggest, like you did, that perhaps UglyJoe try the 2SC2344/2SA1011 pair. Those are about 90-95% of the Toshibas. Plus, it's not an impossible job to change them out for another set sometime in the future.

 

[Iniamyen]

Quote:

Originally Posted by bhjazz /img/forum/go_quote.gif Beautiful build, Iniamyen. Nice work! BTW: where is this "can't miss build" description you speak of? I have a max board waiting and I'd like to rough out my options. Thanks! Also, since you are near Seattle, you're in for a treat. There is a Head-Fi meet in Seattle on June 21. We'd love to meet you! Here is the thread if you want to browse. http://www.head-fi.org/forums/f24/ju...eattle-311361/ Welcome to Head-Fi!

Thanks for the link! I'm glad I posted this, cause otherwise I wouldn't have known about it. It sounds like a pretty big deal

 

[amphead]

Great work Iniamyen! Those white leds are a nice touch. Hope you are enjoying the sound.

 

[BoilermakerFan]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif I didn't take it as one. Nevertheless, I suspect what else you state is probably the case. Boilermakerfan - Please don't take this in any way as discouragement. While I agree in principle that there may be a slight chance that we can discover a diamond in the rough with some of the other less-known transistors, I wouldn't get your hopes up too high.

I'm optimistic, and stubborn, so it definitely won't be taken as discouragement.

In order to facilitate swapping transistors, could I use these on the PCB?
310-13-164-41-001000

My thought is to mount the transistors to the heatsinks on the correct sides for their pinouts with the Thermasil pads and then "plug" them into these socket strips for evaluation. The socket spacing is within the range for the BJTs and I'm switching to screw-mounted heatsinks so they will have support. I'll go through about $10 in Thermasil pads, but hey, that's 2 beers at a bar or just over 2 gallons of premium fuel.

My question is, how far could I push the bias before the pin and socket mounting would be a concern? Would 100mA really be pushing it or do you think that would be fine (heatsink size is not the concern, only the socket junction with the BJT)?

This would allow me to populate (3) MAX boards, one each with Muse ES, Silmic II, and Cerafine caps, all bypassed with VitQs running 12FK6 tubes initially. Then I can swap the BJTs between the boards, bias, and listen. Then I would repeat with 12AE6A tubes. The only variable I can't keep constant in these tests would be variations between the tubes on the different boards, until I narrow down the preferred BJTs with each set of caps, then swap tubes around to make sure it's the BJT/cap combo and not just golden tubes.

I think this is as easy and reliable as I can make it.

 

[tomb]

Quote:

Originally Posted by BoilermakerFan /img/forum/go_quote.gif I'm optimistic, and stubborn, so it definitely won't be taken as discouragement. In order to facilitate swapping transistors, could I use these on the PCB? 310-13-164-41-001000</snip>

I'm not too fond of Mil-Max sockets when they're not supported by additional cross-members as in DIP-sockets. They're not very stable, as anyone who's tried to use them as resistor sockets can attest. One is usually better off chopping up a DIP-socket, instead.

I don't think Mouser has them, but DigiKey has a Molex-type socket made specifically for TO-220 transistors. I had some discussions with Colin early-on about this, but decided to build separate MAXes for each transistor type, anyway.

Here's a pic:

That's a Molex #10-18-2031, DigiKey part #WM2551-ND. Datasheet drawing here.

The disadvantage I believe, is that you need some side clearance to manuever the transistor into the socket. So, the middle two sinks may be an issue for the inside transistor. Plus, you have to trim the legs so that their height is correct for the heat sink mount with the added length of the socket. That makes them useless for regular soldering. There's no reason why you can't solder on some spent leads if you decide to mount them permanently, however.

P.S. The rest of your strategy sounds good.