[poo]

Quote:

Originally Posted by chobint /img/forum/go_quote.gif If you guys can deal with a standard pot, instead of a stepped attenuator...

I've never been a fan of the stepped attenuator, or understood it

I've always much preferred a smooth action... but is there a reason stepped is better, or is it down to preference?

 

[johnwmclean]

Quote:

Originally Posted by poo /img/forum/go_quote.gif I've never been a fan of the stepped attenuator, or understood it I've always much preferred a smooth action... but is there a reason stepped is better, or is it down to preference?

It’s has much better control, say if you want to return to the music you heard the day before you can get an exact volume match. Also you can adjust the steps exactly to your liking when building. For example when Serk got the M^3 built he put in a gradual increase until the 3 o clock position, then increases significantly up till the 6 o clock position. You don’t want to be stuck with a smooth volume pot that is useless after 10. You want nice incremental steps that can be reliably repeated.

 

[chobint]

stepped attenuators provide better channel matching. As in they can match the impedance of each channel within 1% (or however good the resistors are) at a reasonable cost. Traditional volume pots typically cannot match the channels nearly as well (10% maybe) and are very expensive then they are well matched.

 

[Corky]

Quote:

Originally Posted by johnwmclean /img/forum/go_quote.gif Welcome Corky, you’ve been added to the list (opening post) Your advice and help along the way would be really appreciated.

if and when needed i will happily lend a hand or words of encouragement

attenuation wise i have a Buffalo for my source and i plan on using the Joshua Tree for attenuation once it comes out again.

 

[minivan]

i read from somewhere amb (ti kan) does not encourage people to use joshua tree, because it's only 10k impedance, it's preferable to use 50k volume pot, may want to ask amb to confirm this

 

[jantze]

Quote:

Originally Posted by minivan /img/forum/go_quote.gif i read from somewhere amb (ti kan) does not encourage people to use joshua tree, because it's only 10k impedance, it's preferable to use 50k volume pot, may want to ask amb to confirm this

Interesting. What would be the ultimate stepped attenuator for balanced b22 then? 24 steps is not enough.

 

[JamesL]

Actually, I think the JT has variable input impedance

If you want best quality, a ladder attenuator would be best, such as the dact series... would provide constant impedance, and excellent channel matching even compared to other series type stepped attenuator.

Theres also the RK50 >=] ... infinite number of steps.

Several more options similar to the JT
Dantimax - several different chip and relay based attenuators.

Jos van eijndhoven - looks like the JT

welborne labs - Another shunt attenuator..

 

[johnwmclean]

Could anyone who’s definitely interested or if you’ve changed your mind, please post back and let me know. As we don’t have a builder some of you may have chickened out

, thats ok, just let me know! But just so everybody knows there’s lots of help at hand and lots of support from the DIY community just reading through these posts reassures me

Also include exact configuration needed.

I would like to get the order ready for Jeff, for the B22 amp kits and S22 psu kits. On the AMB site you may have read about device matching, Jeff does this for the major components as follows from Jeff:

“I match the 2SJ74 and 2SK170 into quads with 0.25 mA Idss match (within +/- 4 to 2%) better with higher current. The other parts are not matched but there are enough parts to get a close group for Q9- Q12. The most important parts are matched.”

Let me know if you want to get more of a certain part to work on matching and I’ll let Jeff know. I am personally satisfied with this.

NOT INCLUDED: Connectors, jacks, stepped attenuator, knob, feet, wiring and chassis and other things that may pop up.

Once I have an exact order I can get a price, you should all have an idea of the ball park price with around 5 - 10% discount for a group build. Get your orders in!

 

[nsx_23]

Quote:

Originally Posted by Daveze /img/forum/go_quote.gif I'd almost be inclined to put my hand up but I'm about to begin the 70-80 hour weeks that are the lead-up to Christmas. If you're happy waiting until a bit into the New Year, I might be more available... If you're not feeling all that confident with DIY, I recommend heading down to your local Jaycar and picking up their headphone amp kit. Its dead easy to make, cheap and there's plenty of scope for you to frig around with mods to increase your understanding and DIY-ness. Extensive support threadhere.

Not to go off topic here, but I didn't want to start a new thread over something this small. Is that jaycar kit easy even for a noob to build, and how does it sound? I'm interested in some kind of home amp for my AKG K601, but am very limited in money at the moment ($100AUD-ish).

 

[Zorander]

Quote:

Originally Posted by johnwmclean /img/forum/go_quote.gif Could anyone who’s definitely interested or if you’ve changed your mind, please post back and let me know. As we don’t have a builder some of you may have chickened out , thats ok, just let me know! But just so everybody knows there’s lots of help at hand and lots of support from the DIY community just reading through these posts reassures me Also include exact configuration needed. I would like to get the order ready for Jeff, for the B22 amp kits and S22 psu kits. On the AMB site you may have read about device matching, Jeff does this for the major components as follows from Jeff: “I match the 2SJ74 and 2SK170 into quads with 0.25 mA Idss match (within +/- 4 to 2%) better with higher current. The other parts are not matched but there are enough parts to get a close group for Q9- Q12. The most important parts are matched.” Let me know if you want to get more of a certain part to work on matching and I’ll let Jeff know. I am personally satisfied with this. NOT INCLUDED: Connectors, jacks, stepped attenuator, knob, feet, wiring and chassis and other things that may pop up. Once I have an exact order I can get a price, you should all have an idea of the ball park price with around 5 - 10% discount for a group build. Get your orders in!

I have no plans to build this myself (only willing to pay the extra bucks for someone to build for me) so, without a prospective builder, I will have to pull out.

Cheers!

 

[elliot42]

Just had a read of the thread, and while I won't be buying a kit (I've got a BantamDAC, CKK3 and parts for some cables on the way that will need attending to), I could lend a hand at a DIY get together. I don't have the experience (or time) to fully build and number of B22s, nor am I great at debugging electronics. But I am alright with a soldering iron and think it would be fun to get together and do some DIY.

So give me a buzz if and when you decide to meet up and do some soldering, I could help out or even just watching a B22 being built could be fun.

 

[fordgtlover]

Quote:

Originally Posted by nsx_23 /img/forum/go_quote.gif Not to go off topic here, but I didn't want to start a new thread over something this small. Is that jaycar kit easy even for a noob to build, and how does it sound? I'm interested in some kind of home amp for my AKG K601, but am very limited in money at the moment ($100AUD-ish).

Hey NSX_23, you should check out this thread. That Jaycar amp (with a few tweaks) has a very keen following.

 

[minivan]

the jaycar headamp sound as good as the solo, i know because i built one of these and i own a solo in the past

 

[Zorander]

Quote:

Originally Posted by minivan /img/forum/go_quote.gif the jaycar headamp sound as good as the solo, i know because i built one of these and i own a solo in the past

You, sir, piqued my interest. I shall walk into a Jaycar store and pick up one of them.

 

[amb]

Quote:

Originally Posted by minivan /img/forum/go_quote.gif i read from somewhere amb (ti kan) does not encourage people to use joshua tree, because it's only 10k impedance, it's preferable to use 50k volume pot, may want to ask amb to confirm this

The Joshua Tree is an excellent attenuator, but it has low input impedance (IIRC much lower than 10K, depending on attenuator setting). As long as you understand the implication of this and use a source or preamp that has 1/10 (or preferably lower) output impedance than that, then there is no problem using it. This is not just for β22, but is a general consideration for any amp.