[PinkFloyd]

Quote:

Originally Posted by mysticaldodo Its still working, but there's some distortion on one of the channesl. Have to double check

I strongly recommend you don't power the amp up until you get it repaired dodo, you've got 6 burnt out transistors and 3 fried resistors....... best to get these replaced ASAP.

 

[plibber]

Quote:

Originally Posted by PinkFloyd Give them a go I think you may like the sound, it's more open and very airy and "fleet of foot" more dancing like a ballerina than clumping about like a bricklayer...... the bass is much more musical and less ploddy sounding...... remember that the valves also play a part in the overall sound, the stock JAN philips are "ok" but they can really be improved on for not a lot of money. This is not just swapping out capacitors for the sake of swapping them out.... the reason I chose Panasonic FC is for their HF performance and they are very low ESR "equivalent series resistance" compared with the stock Jamicon 85C general purpose caps.... they really do sound better IMO.

I visited the RS Components site last night and was pleasantly surprised to find that they have an Australian branch. I ordered the Panasonic caps and happily found them on my doorstep this afternoon.

I've swapped out the caps and had a quick listen to make sure that everything works. I'll have to have a long listening session tonight and see how things have changed.

Thanks Pinkfloyd for your help. I can't wait to see what other mods you have up your sleeve to further improve this amp

Amperex NOS tubes with the beautiful gold and blue Panasonic caps in place.

 

[PinkFloyd]

Quote:

Originally Posted by plibber I've swapped out the caps and had a quick listen to make sure that everything works. I'll have to have a long listening session tonight and see how things have changed. Amperex NOS tubes with the beautiful gold and blue Panasonic caps in place.

Looking good! Give those caps a good few days to fully form, the sound should progressively open out over a period of a week or two

Another little thing you may want to try is removing the four 6.3V 220uF non polar output caps and replace them with two 1000uF non polar caps.

No output cap is best, one per channel is second best but two per channel is just horrendous IMO. The only reason they have fitted 4 x 220uF is "size" so they'll fit underneath the board which accommodates the pot and headphone socket, anything larger and they wouldn't fit (unless you lay the cap on its side

) You'll notice that the two 220uF output caps per channel are paralleled making a combined value of 440uF per channel..... after much testing with the WNA amp 1000uF was deemed the best value for the output cap and the same seems the case with the V3.

Whip those 4 x 220uF output caps out and replace with 2 x 1000uF non polars (I used 16V 1000uF) for better bass definition and a degree more clarity. You can just solder over the pads on the spare space for the other two caps or you can fit something like a polypropylene film cap which will bypass the non polar electrolytic output caps.

It's early days and there are quite a few possibilities at the output (no output caps at all for example) but for the time being two 1000uF non polar output caps and a couple of polyprop film caps sounds marginally better than it does with 2 x 220uF NP caps per channel. I haven't even got around to measuring the DC offset without the output caps in place yet.... if it's low enough then it's possible they can be removed and the pads jumpered together....... it's also feasible (enough room on the board) to parallel together a bank of film caps but I doubt the end result would be worth all the bother...... maybe just a 1000uF non polar per channel with a 4u7 polyprop in parallel would be the cheapest and best overall solution.

Anyways, it's well worth trying! All you need to buy are a couple of 1000uF non polar 16V caps (about 30p each) and see what you think.

Here are a few pics:

Remove the 4 x 220uF non polar output caps

Solder two 1000uF non polar caps in their place.... this leaves two spare spaces for caps which can either be left blank or used to house a couple of film bypass caps

spare capacitor holes shown.... either solder over them or fit bypass caps or another couple of 1000uF caps or whatever takes your fancy!

I've temporarily fitted a couple of polypropylene caps into the spare cap bays which are acting as bypass caps for the non polar output caps.

Lots more to come soon........

 

[adhoc]

looking great pinkie.

just curious though - what do you intend to replace the 2 bypass polyprops with? something polystyrene?

 

[mysticaldodo]

Ok, just send it in for repair. I should get it in 2 weeks time as he to complete other prior jobs first. The technician said he's gonna remove the carbon from the board (where the burnt resistors are) and he's gonna replace the 6 resistors (R214/215/216 and the other 3, not sure of the designation) with TKD resistors and he's gonna fit them high enough just like Pink's XCan. He checked the resistors and said 214 - 3.3ohm, 215 - 33ohm and 216 - 3.3ohm . Has MF changed the specs for the newer revisions of the XCan?

I complained about the slight sibilance and metallic tinge of the XCan even after I tube rolled with EI tubes and changed half of the caps to BG, the other half are still Jamicom. I must admit it was still a huge improvement compared to the stock Jamicom and JAN. He told me one cause of the sound was the cheap metal resistors being used. He said he could replace all the resistors with carbon types and get a warmer sound but lose some resolution. I decided to try the TKD, which are metal but better quality then the stock resistors (they-TKD are suppose to be transparent and without the metallic sound) to replace those 6 resistors to see how they go and might consider changing all the resistors.

I'm reconsidering changing the rest of the caps to BG or maybe just Panasonic? I'm not sure whether the increased in sound quality will justify the
price. BG will be damn expensive but he stated if the caps are good enought and you don't need a high uF.

Can anyone enlighten me or is this all BS?

 

[mysticaldodo]

Quote:

Originally Posted by PinkFloyd Get that back to the guy ASAP for repair and ask him "why" he has removed C211 & C111.... it also looks like he's swapped out some of the diodes.

For the output caps. I changed it to 2 BG caps (470uF, not sure about voltage and can't check as the board is not with me) if not mistaken. Had to cut the board connected to the front panel so that the caps can fit. He said 4 220uF BG caps are more expensive then 2 470uF caps.

My technician also said that the 'Blue' Alps Pot could probably cause some harshness to the sound. Is this possible? I thought the pot was for volume control only.

 

[adhoc]

Quote:

Originally Posted by mysticaldodo My technician also said that the 'Blue' Alps Pot could probably cause some harshness to the sound. Is this possible? I thought the pot was for volume control only.

yep, it is - anything in the signal path would cause some change to the sound.

however, whether this change is perceptible is debatable imo - and imo especially so when it starts the various brands of metal film resistors get involved.

 

[PinkFloyd]

He checked the resistors and said 214 - 3.3ohm, 215 - 33ohm and 216 - 3.3ohm . Has MF changed the specs for the newer revisions of the XCan?

The resistors are as follows:

213 / 113 = 10 ohm 214 / 114 = 32 ohm 215 / 115 = 10 ohm

Quote:

Originally Posted by mysticaldodo I'm reconsidering changing the rest of the caps to BG or maybe just Panasonic? I'm not sure whether the increased in sound quality will justify the price.

I've never tried the black gates in an X-can (way too expensive for what they are IMO) the Panasonic FC do a good job.

Quote:

Originally Posted by mysticaldodo He stated if the caps are good enought and you don't need a high uF. Can anyone enlighten me or is this all BS?

That "is" BS where the X-can is concerned..... if anything you want to fit "more" capacitance (ie: 3300uF instead of 2200uF) certainly not less. It was the MF technician who advised me to fit 2200uF instead of the stock 1000uF in the V2 and that reaped huge dividends in the sound stakes..... to fit "less" capacitance doesn't make any sense at all (whatever the brand of capacitor) and, as I say, fitting "more" is really the way to go in this design.

 

[mysticaldodo]

Lets say I changed the rest of the caps to Panasonic caps with higher uF (3300) but still retain the BGs (which have the same uF as the stock Jamicoms) is that going to be a problem?

I'll ask about the Panasonic low ESR caps when my amp is ready. (are the low ESR a special type or are all their caps like that?)

 

[adhoc]

Quote:

Originally Posted by mysticaldodo I'll ask about the Panasonic low ESR caps when my amp is ready. (are the low ESR a special type or are all their caps like that?)

low-esr caps are a special type.

what is esr? (scroll down to near the bottom of the page)

 

[mysticaldodo]

THX

 

[VR6ofpain]

So Pink, you going to sell this thing to me when you are done with it?

 

[PinkFloyd]

Quote:

Originally Posted by mysticaldodo Lets say I changed the rest of the caps to Panasonic caps with higher uF (3300) but still retain the BGs (which have the same uF as the stock Jamicoms) is that going to be a problem?

No problem at all but keep them matched per side as shown:

Quote:

Originally Posted by mysticaldodo I'll ask about the Panasonic low ESR caps when my amp is ready. (are the low ESR a special type or are all their caps like that?)

Panasonic "FC" have pretty low ESR.

 

[adhoc]

Quote:

Originally Posted by PinkFloyd Panasonic "FC" have pretty low ESR.

FWIW, iirc, the "FM" series has a far lower ESR. unfortunately their relatively low Vmax might prove to be a problem.

 

[PinkFloyd]

Quote:

Originally Posted by plibber I've swapped out the caps and had a quick listen to make sure that everything works. I'll have to have a long listening session tonight and see how things have changed.

Hi Plibber,

How's it sounding with the Panasonic FC's in place? If you bought them from RS then you've probably got 4 x 2200uF spare as you would have had to buy 10 from them. Why not fit the extra four 2200uF in place of the 4 x 1000uF and give that a go? I've got the extra 4 x 2200uF in place and things are certainly sounding a lot better than they did a couple of weeks ago when the amp was in its stock guise

10 x 2200uF now on board.

I've been doing a lot of listening the past few days and the biggest bottleneck in the amp has got to be the two 10uF "polar" input caps (yes "polar"! totally rancid!) What the hell were MF thinking here I wonder? Capacitors in the signal path are bad enough but polar electrolytics..... give me a break!

Terrible implementation as the cap is subjected to backwards voltages on half of every cycle of audio..... not good as far as sound quality is concerned! Far better to employ either a film cap or a non polar cap in this position..... I measured no DC across the input caps so you are safe to replace these with a 10uF non polar cap of your choice.

I had a couple of 10uF non polar electrolytics to hand so I replaced the 10uF polar electrolytics with these and bypassed them with some polypropylene film caps... quite an amazing improvement! Obviously you could replace them with film types for optimum sound quality or even remove them altogether if you wanted to play russian roulette.... whatever, this is one key area of the amp which can be improved upon and a simple cheap 10uF non polar cap bypassed with a polyprop sounds a lot better than the stock 10uF polar cap.... for sure

10uF non polar input caps bypassed with polypropylene film caps

10uF non polars

V3 next to guinea pig V2 (V2 sounds awesome BTW!)

Happy Mullards