|
Post by PinkFloyd on Apr 18, 2008 19:08:06 GMT
Forum member Rossman sent me his 336 to get bypass caps fitted.... in they went, had a listen and (nope) didn't do it for me so whipped out those two banks of 3 x 10uF outputs caps and replaced with 1 x 100V / 220uF Nichicon (bitumen blob damped) in their place (only 70V present here folks so fine to use 100V caps) what an improvement.... a lot better with one solitary cap in this position plus you have the added benefit of hardly any roll off in the bass if using low impedance 'phones. With the standard 30uF (3 x 10uF) the cut off frequency is 165Hz if using 32ohm 'phones..... with 220uF the cut off frequency is 21Hz so a lot more bottom end when using low z 'phones. In fact the stock 30uF is really only suited to 'phones of 300ohm and above. Anyways.... I much prefer the one non polar cap than those three film caps that are stitched together.... if they sounded any good I could see the point but they don't in this instance (IMO) Running her at the moment with a NOS Tronal 6SN7GT at the front and a General Electric 6080 in the back..... very nice Anyways Rossman.... hope you like it and cheers for the remote control I may do a bit more to it before you return from Australia Horrid things: Gone: By the way...... still have to tidy that section up and secure it. The bypass caps (Samwha VA series 100uF / 35V low ESR 135c temp rating) The glowing bottles: By the way Rossman..... bloomin' good job I keep a truckload of these kind of valves about the place else I would have been caught short..... turned out good though
|
|
|
Post by PinkFloyd on Apr 18, 2008 23:01:18 GMT
Mike, do you by any chance have a Ken Rad VT231? They are expensive and hard to find in the USA. Sorry My friend..... No, I don't..... if I did you'd be the first to have a pair. The chips arrived the other day BTW...... more on them later after I've soldered them onto the B-Dogs..... many thanks Miguel, I'll have fun roadtesting my new specs (spectacles)
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Apr 19, 2008 11:01:57 GMT
|
|
|
Post by rossman on Apr 25, 2008 3:16:28 GMT
Mike, many thanks for the work you have done, I am really looking forward to hearing the amp again when I get home. I was using a GE 6080 with excellent results. It had been partnered with a Tung Sol 6SN7GT until recently when I got a Teonex 6SN7GT it is really quiet even before the mods. Now I will be able to try the other variants that I have. Mrarroyo, I might be able to arrange something with you on a Ken Rad VT231 as I have a couple of them at the moment, although I want to hang onto 1 of them. I am back on May 12th so if you PM me after that we will be able to discuss further.
|
|
|
Post by rossman on May 16, 2008 20:06:37 GMT
Now that I have been back for a few days and my source has started to come back on song I am very happy with the work that Mike has done There was a slight problem with the power indicator not lighting up but Mike's technical advice has solved the problem (give it a wiggle ;D) All of the valves that I have tried have been silent which was the main point of the exercise as far as I am concerned. There is also greater spaciousness to the soundstage. The PS1 probably has another couple of days of improvement if past experience of listening from cold is anything to go by so I am expecting the amp to show up even more improvements, Again many, many thanks Mike.
|
|
|
Post by PinkFloyd on May 17, 2008 22:16:41 GMT
Now that I have been back for a few days and my source has started to come back on song I am very happy with the work that Mike has done There was a slight problem with the power indicator not lighting up but Mike's technical advice has solved the problem (give it a wiggle ;D) All of the valves that I have tried have been silent which was the main point of the exercise as far as I am concerned. There is also greater spaciousness to the soundstage. The PS1 probably has another couple of days of improvement if past experience of listening from cold is anything to go by so I am expecting the amp to show up even more improvements, Again many, many thanks Mike. Nice one man, glad you like it! It will also be better with 32ohm 'phones now as the bass will not roll off anymore..... those 220uF Nichicon non polar caps are really nice sounding IMO and leagues better than the stock 30uF film caps. Have you tried that Tronal valve as yet?
|
|
|
Post by rossman on May 18, 2008 12:32:13 GMT
Yes I've tried the Tronal, it seems a bit "thicker" than the Raytheon that I have in at the moment, especially in the midband. I will have another listen later.
Still, the good thing is that I can now try valves without worrying about them humming.
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on May 19, 2008 2:46:11 GMT
Found some surprising (to me) news at the Triode systems site : "The problem with most china made audio can be the voltage requirement being set at 220V. This was the case for the Mr Liang 845 amplifier. Do not believe the voltage written on the back of most china hifi. Mr Liang was marked as a 240V unit but checking the 6.3V heaters showed them to be running at 6.85V. This means all the voltages are 8 to 10% higher including that lethal 845 HT !!
A higher voltage may not be an issue for a transistor amplifier or CD player that is well made with over rated components. However with tube amps the heater voltage can be a problem in that it will shorten the tube life if they are running 'hot"not knowing if this is common or not or even if it has been an issue I still think it is worth noting to at least know it is potentially a problem.Better to run heaters slightly low than "hot' or even at spec www.triode-systems.com/?q=node/4
|
|
|
Post by dmsims on May 21, 2008 9:43:09 GMT
|
|
|
Post by PinkFloyd on May 21, 2008 10:25:45 GMT
If you are using RS-1 then their impedance is 32 ohm. The 332 has 33uF output caps so the cutoff frequency is around 150Hz which is FAR from good! you want to remove those 33uF caps and fit something along the lines of 220uF non polars which will give you a cutoff frequency of around 22Hz. You could always keep the 33uF and use them in parallel with the 220uF non polars, this would give you 253uF per channel and the cutoff frequency would then be around 19Hz with 32ohm 'phones and 2Hz with 300ohm 'phones..... The 33uF caps are not good with low Z 'phones.
|
|
|
Post by dmsims on May 22, 2008 8:35:48 GMT
PinkFloyd:
can you supply these caps ?
and thanks for the info
|
|
|
Post by PinkFloyd on May 22, 2008 9:42:54 GMT
PinkFloyd: can you supply these caps ? and thanks for the info I have a few left, yes
|
|
|
Post by haha161 on Oct 17, 2008 19:50:14 GMT
hi,i'm a newbie for diy and modding amps.i own a darkvoice 336i with senn600, would like to replace those "two banks of 3 x 10uF outputs caps" as you did,can you show me the rating of the replacement cap require,is it ok to replace with blackgate caps or elna caps? and explain more detail step what to do?? thx very much
|
|