[Trapper32]

Quote:

Originally Posted by sinisterm /img/forum/go_quote.gif Strange how everyone seems to like them. I have two pairs and don't like their sound at all. Guess they don't like Grados too much. Though the guy I bought my Grados from adviced me to try those. Both burned for ~100 hours. I prefer these Russians over them any day. Just ordered quad of Sylvania JAN 6AK5 and a matched pair of Tung-Sol 6AK5W 5654 from Yen. Gonna post my thoughts about them as soon as I have some hours on them.

Of course everyone's got different ears ....but I bet u're gonna like those Tung-Sols with the Grados....Let us know how they turn out....

 

[esirex]

Hi there, do we need to do a mod if I wanna change the power tube to 6H30Pi-EH Electro Harmonix? Or is it a direct swap? Just like to make sure b4 purchasing it. On yen audio its said a direct replacement.

 

[Trapper32]

Quote:

Originally Posted by esirex /img/forum/go_quote.gif Hi there, do we need to do a mod if I wanna change the power tube to 6H30Pi-EH Electro Harmonix? Or is it a direct swap? Just like to make sure b4 purchasing it. On yen audio its said a direct replacement.

Its a direct swap for the MKIV but for the MKIII you'll need to do a resistor mod.

 

[Trapper32]

Just managed to pick up some EF92 Bugle Boys on eBay.....been looking for 6 months....can't wait to hear if they're as good as everyone says...

 

[sinisterm]

Quote:

Originally Posted by Trapper32 /img/forum/go_quote.gif Just managed to pick up some EF92 Bugle Boys on eBay.....been looking for 6 months....can't wait to hear if they're as good as everyone says...

Lucky you. Give em to me, I order you!

 

[esirex]

Quote:

Originally Posted by Trapper32 /img/forum/go_quote.gif Its a direct swap for the MKIV but for the MKIII you'll need to do a resistor mod.

Thanks for the info trapper...

 

[Pricklely Peete]

Well this isn't exactly a tube roll...but it will sure help those tubes to sing....latest mod on the MK III.....resistor changed to 120 ohm for use of 6H30Pi power tube, PIO bypass caps on 3 x 270uf 250V filter caps in power supply section, PIO bypass caps on 2 x 220uf 200V caps....and Teflon bypass caps (.1 uf 600V DC 5% tol) slung on the underside of chassis. PIO cap values are .033uf 500V 10% (all 5). Teflons bypass 3.3 uf 50V WIMA MKP 1 output coupling caps.

Sounds great so far...NOS Telefunken CV4015 drivers ( note Sylvania black plate 6AK5WA's in photos), Sovtek 6H30Pi power tubes. Tubes have less than 100 hours with cap mods less than 10 hours.

Really impressed with the immediate improvement in SQ.

Heres a couple pics....

Underside shot showing huge Teflon caps attached with zip ties through stock chassis holes. The cap bodies have been wrapped in electrical tape ....they are aluminum casings...so they had to be insulated from the chassis bottom.

Last shot showing just how tight this little chassis is, hard to believe I stuffed 5 PIO bypass caps in there

The end result ? Well worth the effort IMO. Total cost of upgrade is around 80 dollars including a set of matched Sovtek 6H30Pi's

A bargain by any standards these days....Burn in is going to be a long wait I'm afraid, min 250 - 350 hours...sigh...

Peete.

 

[dgbiker1]

Has anyone else noticed a VERY faint hum, sounds like a quiet ground loop buzz but it's heard from the case, not through the headphones. I have to listen for it to hear it, but when I do hear it I can detect it from across the room.

I first found it when I was doing the "smoke test" on my Opus, listening for anything going awry. The opus passed, but I picked up on the hum from the MkIII for the first time.

 

[Pricklely Peete]

Quote:

Originally Posted by dgbiker1 /img/forum/go_quote.gif Has anyone else noticed a VERY faint hum, sounds like a quiet ground loop buzz but it's heard from the case, not through the headphones. I have to listen for it to hear it, but when I do hear it I can detect it from across the room. I first found it when I was doing the "smoke test" on my Opus, listening for anything going awry. The opus passed, but I picked up on the hum from the MkIII for the first time.

Transformer making noise/vibrating perhaps ? I have no hum whatsoever, what's the mains line voltage out in your neck of the woods dgb ?

How are you doing these days ? Nice to see you again

Peete.

 

[dgbiker1]

Wow peete, those are some impressive mods on your MkIII. I'm hanging in there, it's been an insane few months (finished school, wrote my thesis, started my job, moved three times, etc...). My poor MkIII hasn't been seeing much upgrade/rolling love lately since I've been spending my money on building an opus dac, and now an M^3 amp (a SS amp, but I love the look of tubes so it'll have a nixie tube vu meter

)

Yea, I'm thinking it's the transformer too, but I don't know if I'm within spec or if it should be silent. It's a good excuse to buy tube dampers and some of those spiked feet and cork for the amp

Mains voltage should be about 120VAC, but I've never bothered to stick my dmm in the socket to check. I'm moving next weekend, so it'll be interesting to see if the problem persists.

 

[Penchum]

Quote:

Originally Posted by dgbiker1 /img/forum/go_quote.gif Wow peete, those are some impressive mods on your MkIII. I'm hanging in there, it's been an insane few months (finished school, wrote my thesis, started my job, moved three times, etc...). My poor MkIII hasn't been seeing much upgrade/rolling love lately since I've been spending my money on building an opus dac, and now an M^3 amp (a SS amp, but I love the look of tubes so it'll have a nixie tube vu meter ) Yea, I'm thinking it's the transformer too, but I don't know if I'm within spec or if it should be silent. It's a good excuse to buy tube dampers and some of those spiked feet and cork for the amp Mains voltage should be about 120VAC, but I've never bothered to stick my dmm in the socket to check. I'm moving next weekend, so it'll be interesting to see if the problem persists.

Thats a very cool VU meter idea! Please keep us posted!

 

[Danika k]

Hi I see that the Yen Audio store on ebay are listing 408A tubes as compatible with little dot amps, will they work with my MkIII? How do they sound?

eBay Store - Yen Audio: Little Dot Upgrade Tubes: Westinghouse 408A Little Dot I Amp MATCHED PAIR 6028

 

[dgbiker1]

Quote:

Originally Posted by Danika k /img/forum/go_quote.gif Hi I see that the Yen Audio store on ebay are listing 408A tubes as compatible with little dot amps, will they work with my MkIII? How do they sound? eBay Store - Yen Audio: Little Dot Upgrade Tubes: Westinghouse 408A Little Dot I Amp MATCHED PAIR 6028

They don't work. I tried WE 408As, I got silence.

 

[Trapper32]

Quote:

Originally Posted by Danika k /img/forum/go_quote.gif Hi I see that the Yen Audio store on ebay are listing 408A tubes as compatible with little dot amps, will they work with my MkIII? How do they sound? eBay Store - Yen Audio: Little Dot Upgrade Tubes: Westinghouse 408A Little Dot I Amp MATCHED PAIR 6028

They're compatible with the new LD 1+

 

[PascalT]

I have a question.. about 2 weeks ago I received 2 sets of Sylvania tubes. I put one in, sounds awesome, great. I then try another set of tubes but decide to go back to the Sylvanias, but they really don't sound nearly as good as before.

What gives? Can burning in those tubes actually make them sound bad? I put the set i hadn't used yet in just now, and it sounds just as good as originally. There is a huge difference in the soundstage between the two sets, it's like night and day.

Question is.. are those tubes known to "close up" and muddle up the sound after burning in? It just seems weird to me that the sound would degrade after some use.

thanks for any insight.