sbelyo

I figured that

Do I want to ask what this is, or will I be hazed again?

Yeah, it's me. I never did get around to finishing the CD-Pro2M transport from diyhifi.net so I had to buy this in the mean time

My heavily modded Philips 963SA was acting up so I just pulled the trigger on the Music Hall CD25.2 player that PartsConnexion had in their autumn sale for $499.00 w/free shipping It has their level 1 mods: RCA jacks upgraded to Vampire Feet upgraded to sorbothane Chassis deadening Cap and resistors in output stage upgraded to audiophile level Output op-amps upgraded to OPA-627 Diodes and caps in PSU upgraded as well. Will post pics when it arrives

I need help deciding the gain and volume control values. I know that when you go blanced the gain is doubled. My first question is, what is the default gain when following the parts list? what resistors control the gain? I have Grados as well as high ohm cans so I need to find some sort of balance between gain and volume control knob sweep. Normally I use a 50K volume control but that only gives me less than half the knob sweep when using my grados with my original Dynahi. For that build I left the gain stock. I believe it was 10 or 11 I can't remember.

Got all my parts and boards ordered... Parts Bill so far is around $500 but this includes PRP resistors and a pair of Sigma22 board along with their components as well. My plan is to put the PSU and xformer in it's own case so there's some added expense in that. By the time I buy 2 cases, panels from FPE, and a volume control I would think I'm into it for just about $1K Could it be done for less, yes but I'm letting FPE and Par-metal do all the casework. I just don't enjoy that part anymore plus I want a gold point attenuator this time around. I figure go big, or go home

It's low 30 volts. I think I'll go with the amphenols. Thanks for the link

No speakers connected that way. I forgot all about those

ok, so I've been looking on and off for the last few days and I'm wondering what everyone else is using? I've looked at the amphenols, but what confuses me is the price point. I only need 6 connections and metal is not necesarry, but if the price is the same or close to plastic I'd go with that. Any reccomendations that Mouser would stock?

got it. we don't need them because of the opa445 can handle the 30 volts with no problem right?

I'm going to use the opa445 so I can omit the 7815 and 7915 regulators correct? If so, do I have to jumper the holes for the regulators or can I just leave them unpopulated?

That's pretty much what I thought... I'm gonna stick with the Panasonics. I think I used FM's in my original Dynahi. I thought the FC's had lower ESR and higher reliability. I'll have to read the datasheets again

I'm building a pair of the rev2 dynahi boards and a pair of Sigma22's and I wanted everyone's opinion on weather or not boutique capacitors make a difference in those boards. Since there's no electrolytics in the signal path (correct me if I'm wrong) I'm not so sure they would make a difference. And I think I remember somewhere that the boutique capacitors often have a negative effect when placed in those positions. My other option would be just to use Panasonic FC's

Perfect... Since I'm planning on using Grado's along with high impedance cans will I need to adjust the gain?

I've decided to use two sigma22's for the psu. One for each channel. How much DC current will one channel draw? I'm guessing it's based on what the load of the amp is so I'll be using it with 32 to 300 Ohm headphones

yep, they look to be almost the same size. max on the dales is 0.425 in length PRP is 0.400

will the 1/2 watt PRP's fit the board? I don't have mine yet so I can't measure

found: 8 2SK170 8 2SJ74 2 2SK389 All BL grade I was planning on using vishay-dale resistors except for the resistors on the output transstors. Would it be worth it to replace those with PRP? I contacted them and they will sell me 64 20R 1/4 watt 50ppm 1% at about $1.25 a piece lead time 6 weeks. Couldn't find 20R at Partsconnexion or soniccraft. I could also get IRC 20 ohms from mouser at around the same price and they are in stock. What do you all think?

I have to check what I have.... oy

ah, ok that makes sense. As far as the LSK389 you're right, the pakage is the same I just don't know what grade to use. Another question, the people out there with completed board are just using the 2SK170's and the 2SJ74's (matched pairs) ? If that's the case it's the only way to complete a board right now correct?

am I missing something or is the LSJ109 a single in a TO-92 package ? The board has it layed out for a TO-71. Was it available as a matched pair or something? Need some help on this part. Also, I can find the LSK389 in a TO-71 package, but what grade or letter do I use A B or C?

Wow... Thanks for trying that. It's good to know that it doesn't blow up. Alas, I think I'll just build it with a case and PSU that will support headphones for now, but it's nice to know I could power speakers with it

Thanks Pars.... I'd have to take the case off my original Dynahi to see what I used

It was just a thought. I was going to build something else for the speakers, but I thought it was worth an ask. I won't try to drive speaker with it then. So you think I would need a total of 4 sigma22's? One amp board is 2 channels right? Or did I misunderstand? I was thinking one sigma22 per board ie one for Left and one for Right. I'm guessing 30VAC output on the transformer. How many voltamps?

I was able to get a set of bords for the Dynahi rev2 from Tran. Hopefully I'll get them in the next two weeks. Until then I have a few questions before I start to buy parts. Would a pair of Sigma22's work for the power supply instead of the PSU borads that come with the set? Could I drive a pair of 8 ohm monitors with this amp as well as headphones? If so how much power will it provide? What are the reccomended specs for a power transformer if I'm going to drive speakers as well as headphones?