[roger_s]

I'm happier with my 336i now that it's running DC heaters. Much, much less hum regardless of whose 6SN7 I run it with.

Now I'm giving some thought to those 10uf caps. They're paralleled to 30uf. I'm thinking a single 33uf Obbligato film cap on each side would be a major improvement. Before diving in with soldering iron and solder sucker I thought I'd check in here and see what others thought.

A audio taper volume pot follows that mod. And then I think I'll be done. Unless I decide to go after the caps in the power supply....

Thanks,

Roger

 

[adamus]

I doubt a major improvement but there should be some.

You issue will be the 33uf obbligatos are massive.,

 

[roger_s]

Thanks, adamus. Those 10uf caps in the 336i are pretty massive already. I suspect the obbligatos will fit with room to spare. I won't do the surgery unless it's going to have a significant improvement in SQ. I'm pretty happy with it right now--other than that linear pot. I'm thinking that should be next instead of the caps.

 

[adamus]

the caps are 11cm long, i cant see you getting them in the darkvoise without some case work.

 

[roger_s]

Are you sure? The DIY Hi Fi page says that they're 80mm long. That's just a bit over 3 inches. Two should fit fine.

 

[adamus]

Obbligato Film Oil 30uF 630V
Submitted by admin on 10 June, 2008 - 12:47.

* Obbligato Film Oil Caps

OBO-30

115 x 52 mm
Price: USD $19.00


= MASSIVE.

 

[roger_s]

Wrong caps! I'm talking about their premium film caps, not the film oils. Here's the dimensions and prices for the film caps:


value D x L (mm) US$
0.047uF (630V) 15 x 18 $4.50
0.1uF (630V) 15 x 18 $4.90
0.15uF (630V) 15 x 25 $6.00
0.22uF (630V) 15 x 25 $7.00
0.33uF (630V) 15 x 30 $7.80
0.47uF (630V) 20 x 30 $8.50
0.68uF (630V) 20 x 35 $9.00
1.0uF (630V) 20 x 35 $10.50
1.5uF (630V) 20 x 40 $12.20
2.2uF (630V) 20 x 40 $14.00
3.3uF (630V) 25 x 50 $16.50
4.7uF (630V) 30 x 55 $18.50
6.8uF (630V) 30 x 60 $20.00
10uF (630V) 30 x 75 $22.00
15uF (250V) 30 x 60 $20.00
22uF (250V) 35 x 70 $23.00
33uF (250V) 40 x 80 $28.00
47uF (250V) 40 x 80 $36.00

 

[adamus]

ah ok, sorry about that, i didnt realise the premium films went that high.

if you can fit them it it will eb an improvement. I put obbligatios in my soha last night, they are super smooth (perhaps too smooth, slightly plastic at the moment). I will put some time on them, sure they will open up.

 

[roger_s]

No problem! Nothing like a breakdown in communications....

I'm still kicking around the idea. I just have to work up the energy to tear into the DV again. Thanks for your input. I'll be interested in your opinion of the obbligatos after they've run a while.

 

[Jo6Pak]

Quote:

Originally Posted by roger_s /img/forum/go_quote.gif A audio taper volume pot follows that mod. And then I think I'll be done. Unless I decide to go after the caps in the power supply....

Roger -

Have you found a suitable, drop-in replacement for the stock volume pot? There was someone else here who replaced theirs, but had to fabricate a new ckt board to accommodate the new pot (one of the two pots had extra pins, as I recall).

I would have replaced mine long ago, if not for that. I would appreciate knowing what your game plan is.

THANKS!

 

[roger_s]

I plan on either a Noble or more likely an Alps Blue Velvet. I'm not sure the circuit board is really necessary. I've not taken a hard look at it I didn't see any obvious need for that circuit board. And I've read here that others simply replaced the stock pot with an Alps sans board.

Quote:

Originally Posted by Jo6Pak /img/forum/go_quote.gif Roger - Have you found a suitable, drop-in replacement for the stock volume pot? There was someone else here who replaced theirs, but had to fabricate a new ckt board to accommodate the new pot (one of the two pots had extra pins, as I recall). I would have replaced mine long ago, if not for that. I would appreciate knowing what your game plan is. THANKS!

 

[Jo6Pak]

Apparently, the stock vol pot is not located on the main board, rather a small board off the main. I will try to locate the thread I was referring to. It may help you (us). Thanks for responding. BTW - I believe the replacement was an ALPS of some sort.

 

[Jo6Pak]

Here it is:

http://www.head-fi.org/forums/f5/vol...e-336i-236934/

Now that I have read it again, it appears that the fabricated board may actually have been for convenience/preference, rather than necessity.

Roger - Please keep me posted as to your vol pot mod (parts, methods, etc) as I am very interested in doing the same to mine. PM me if you prefer. THANKS!

 

[roger_s]

I'll keep you posted. I've had that amp on the bench so many times that it deserves a vacation from my soldering iron torture!

 

[roger_s]

The pot's been replaced and man what a difference! And what an experience! I picked up an ALPS 100KAX2 via eBay. I got one with solder tabs instead of the PCB bins to make it a bit easier to wire up. Turns out the stock ALPS in the 336 is smaller than the KAX2 and its alignment tab is in a different spot. And the hole for the alignment tab is smaller than the alignment post on the KAX2. Drilling out the hole from the inside of the chassis was not fun and I had to drill a bit more of an angle than I'd liked but it worked.

While removing the stock pot I noticed that the wire from the input RCA jacks was coax and that the shield was being used to carry the signal ground. I figured that could not be good since the coax runs right next to the B+ power supply. I decided that the cable needed to be replaced along with the pot. I replaced it with a link of Mogami 2893 (two twisted pairs and a shield).

Now it gets fun. The RCA jacks are on a small PCB and the wires are strain-relieved via a very hard plastic-like glue. No amount of digging was getting that stuff off. Say hello to Mr. Heat Gun. Came right off after that. No the problem is there's no way to remove the PCB without major surgery. After un-soldering the original coax I saw that there was generous amounts of solder remaining on the PCB. I decided to just tin the Mogami, lay it on the blobs and let that suffice for mounting it to the PCB. The Mogami's shield I soldered to the chassis ground connected to the PCB.

How's it sound after an hour of fitting all of that together? Wonderful! The original pot's linear. The amp's turned all the way to 11 at about the 10 o'clock position. It's pretty silent up to about the 9 o'clock position without it's not be fed a signal. Not so with the KAX2 and the Mogami. Loud hits about 12:00 and blasting is at about 1:00 - 1:30 with my RWA iMod 3G. With the player on pause I have to crank it all the way up just to hear the tube hiss!

If you do nothing else, change out that pot and strongly consider replacing the cable feeding it from the input jacks.

Oh yeah. The stock knob is a push on affair. Doesn't fit the KAX2. I swapped it out for a large brass knob I'd bought on eBay but never got around to using. Looks pretty good and has some nice heft to it compared to the metal clad plastic knob that comes with the 336i.