Amp upgrade with Canton speakers: Feasibility study

[arj]

If Arj was referring to power amp tubes making the most difference - I will second that

My Bad..Thats exactly what i meant

 

[arj]

@ Asit :

my experiences with JJ are that

-- They excel in the Low Frequency department, giving you unexpected bass drive from vacuum tubes.
-- Whilst excelling in low bass performance, they have this uncanny ability to give a nice midbass lift to the sound, adding warmth and a BIG tone.
-- Very good wideband midrange.
-- Extended High Frequencies that are not glaring.
-- Extremely rugged tube.

!

I have been hearing reports on the QC of JJ not being very good and some tubes just bursting...in fact Jim McShane one of the more renowned tube vendors openly does not stock them
not sure of how true these reports are though

 

[arj]

The only reason I am not revealing their names here is because I do not want them to be made fun of as was done in a thread where some tweaks were discussed in the past.

Asit the things I have tried for Isolation has even left my wife staring at me thinking I have finally lost it hyeah: but yes..it does make a difference to me and one does not always have to spend too much money if you keep an open mind

 

[Asit]

Great reply everybody.

Audio_engr, thanks for that recommendation of the JJs. I have read some similar reports.

Prem, I also have heard/read great things about the Gold Lion tubes.

Viren, a special thanks to you for explaining to me the self-biasing and tube-matching. I have these BEL tubes also in mind. Is it possible to get them also matched? The ones Rajiv has are probably not matched. BTW, when you are stressing the need for matching, are you talking about 2 pairs of matched tubes or a matched quad?

The strengths of the Leben are its very well balanced sonics: excellent tonality, tonal balance across the freq range, high level of clarity, separation and imaging, good dynamics (including excellent microdynamics), yet having excellent pace and timing and above all a sense of fluidity, musicality and immediacy. I am extremely happy with the amp and the Sovteks are doing a great job. It's very hard to point at a relatively weak area of this amp. Now among the 3 tubes that are in consideration, which will have all these atrtributes in a balanced approach? For example, I would not like to sacrifice the clarity of this amp in an attempt to go for something else and so on.

Regards.

 

[arj]

hehe!! I lost a CDP 15 yrs back when the temporary pneumatic rig with sandtray CDP tumbled all the way to the floor ..... :lol: :lol: and some 5-7 kgs fine sand going into the CDP..... hyeah:
:

:lol: Good Lord..in my case Molten wax (Dont even Ask ) caused me to jerk and a rack of CDs were on the floor...Broken Jewel Casings still bear witness.

 

[viren bakhshi]

Hi Asit,

More important to have the pair in the same channel matched.

However, in cost, a matched quad is probably no more than two matched pairs!

Viren

 

[gobble]

Curious - how is placing a marble slab under an amp going to isolate it?

Regards

 

[Asit]

Sridhar, Thanks for the confirmation. It gives me great relief.

Viren, let's see what is the premium to be paid for the matched pairs or a quad. Where can I get matched BEL tubes in India? Should these be available in Chandni market (local electronics market) for example, and would they have the tools to find a matched quad?

Arj and Audio_engr, I have no idea what you guys are talking about ... sand and molten wax. Wow!

Regards.

 

[Asit]

Hi gobble,

I guess it's not isolation that is in work here. It is the transmission of any mechanical energy that is in the amp into something else. It's a bit like my speaker stands. They are taking away any residual vibration of the speaker cabinets (while not contributing any of their own, by being absolutely dead) and ultimately transmitting them into the floor. At the same time since they make contacts with the floor only through the cones and therefore at points, no or negligible vibration from floor can get transmitted into the stands. I believe it's the same principle here too (the unpolished marble slabs would be ideal if they had no resonance of their own, but I suppose they are not perfect, but they work to an extent as I see). That's why ideally they also should be placed on cones. Whether perfect or not, they would sure alter the sound and you may or may not like it.

I did not quite understand the underlying working principles of the vibrapods, and that's one more reason why I did not go that way.

Regards.

 

[arj]

I did not quite understand the underlying working principles of the vibrapods, and that's one more reason why I did not go that way.

Regards.

i believe those aree used to dissipate the vibration out usually used to isolate out components like transports which can pass on vibrations to a rack. they convert all the mechanical energy (From and To the component ) to heat and dont allow th rest of the components to feel it..similiar to rollerblocks. Also some speakers (Audio Note/Harbeth/snell etcc) which need to dissipate energy prefer such materials with Lossy stands instead of damped /inert stands.

I have never tried it, but Vibrapods/Squashballs sandwiched between 2 marble/granite slabs should do a good job ?..maybe my next experiment

 

[viren bakhshi]

Asit,

I doubt that you will find any such sophistication in Chandni market - more like a bunch of tubes thrown into a carton! Buy double the quantity of EL84s than you need (they should run you between Rs.100-200 each).

Even I don't have a tube tester. I just measure the tubes in circuit - in my Integre Two amp, and mix and match. If you want, I can do that for you - measure and mark the tubes and send them back.

Viren

 

[gobble]

Sorry for posting OT but a quick question - I'm interested in getting a pair of "mullard" tooled BEL 12AU7s. Where can I get them in Bangalore? I think they are manufactured locally correct? :licklips:

I also heard they use Philips tooling ... so all BELs may not be "mullard-ised"


Cheers

 

[Asit]

Asit - being a physicist should be able to throw some light as to what is happening in the case of Leben sitting on marble.

audio_engr,
I have already explained my understanding in this post http://www.hifivision.com/amplifier...speakers-feasibility-study-57.html#post115376

The only thing I did not say there what happens to the energy when it gets transmitted into the slab. I would think because of the heavy nature it acts as a heat sink, that is, absorbing that energy into itself, which would mean in this case that the dominant part of the energy getting transmitted into heat. This is a natural consequence of a law of thermodynamics wherein all organised mechanical energy ultimately gets transformed into random mechanical energy which is basically heat. There could still be some residual bodily movement of the slab (organised mechanical enegy) which could have been transmitted into the rack through the use of cones (which I do not use). I believe it's good that I do not use cones because in that case the rack also needed to be better (that is, each shelf then should have been isolated from each other). If the rack is very heavy, it again would again act as a sink of all mechanical energy.

Regards.

 

[Asit]

Hi Viren,

Thanks for your very generous offer. Since Sridhar says the tubes do not need to be matched, your method is good enough for me. Let's see the situation locally. If I am not able to find them to my satisfaction here in Kolkata, I would request you or Rajiv to send 4 such tubes to me, and of course I have to say this (please do not mind), I shall pay whatever price plus the postage. I know that all the help from the forum members are truly priceless, I'll not be able to pay for that (goes without saying).

Thanks again and regards.

 

[arj]

Tubes are microphonic in nature. Mounting and shock absorption may be voodoo but definitely work in the case of any electro-mechanical devices (turntables, tubes, CD lenses) in an environment where you are basically causing the air to vibrate for your listening pleasure

I believe the transport section of CDs ie the lenses are particularly sensitive. since it is based on the principle of reflection any small jerk causing a error of x degrees causes and impact of 2x degrees.

 

[Rajiv]

I also heard they use Philips tooling ... so all BELs may not be "mullard-ised"

Hi,

Philips was the parent company.It owned the name/company Mullard,among several others Valvo,Dario,Amprex etc

@Asit.

Please PM me your mailing address and I will send you the EL84's.Let me see what other brands of EL84's I have in the tube box.

I have a set of BEL EL 84's in the Leak amp which are within 10% when I checked them in circuit.They are used but test as good as new.

Viren's method of testing tubes in circuit is the best method as it gives the test readings in actual working conditions.

Regards
Rajiv

 

[Asit]

Thanks Rajiv, I'll send you my address.

Regards.

 

[hifiashok]

Hi folks,

While the discussion is on for the tube-rolling, here I want to share my recent experiments with a few tweaks I have tried in my set-up.

Ashok's (hifiashok) post (http://www.hifivision.com/amplifier...-speakers-feasibility-study-52.html#post95532) in this thread regarding my rack got me thinking. He was commenting on upgrading my rack, after the speakers were placed on such aesthetically and functionally wonderful stands. I knew my rack did not provide proper isolation/damping for the sources (CDP and Cassette deck) and also for the valve-amp. I know all valves (even the best built ones) would have some microphonics (undesirable transformation of mechanical vibration into noisy electrical signals, however small) and that an isolating/damping platform was essential. I had a few private exchanges with Ashok on vibrapods and such isolating equipments. I did an extensive net-study of these things, but in the end was left with a mixed feeling. Moreover, these are not the cheapest tweaks, and did not want to buy them without trying out. Nobody I knew in Kolkata had them.

One distinguished forum member suggested I tried out unpolished marble slabs under the amp/CDP since a few of his friends had good results with such tweaks (ideally the marble slabs should then rest on cones). He was due for a visit at my place and when he came, to my surprise brought along a small marble slab just big enough to be put under the feet of my CDP/amp. I have had 3 racks before, at least two of these were very decent (bought abroad from hi-fi gear stores) and never really worried about these things before in my life. So frankly, I did not know what to expect. When we put it under my amp and everything was turned on, lo and behold, there was a marked change in the sound. The sound became more focussed (more PRaT), for lack of a better word. We also tried the slab under the CDP. However, although initially I liked this for instruments alone, I did not like this arrangement with vocals which got receded noticeably with respect to other things. I invited another distinguished forum member for a listen and he also agreed. Then I got another similar slab (call me mad or completely crazy or whatever, but these are quite inexpensive, Rs 100-150 for a slab) and we tried all possible combinations, and ultimately settled for both the slabs under the amp.

I thank these distinguished forum members for their help as always. Folks, these people have solid shoulders on which their heads rest, but this time they had to go with my madness a bit and play on, I suppose. Any way, I am happy now. The only reason I am not revealing their names here is because I do not want them to be made fun of as was done in a thread where some tweaks were discussed in the past. I have revealed Ashok's name because he openly has recommended isolating accessories in the forum. I hope he does not mind me taking his name here.

happy to contribute even in the slightest (or off-handish) way to your final pleasurable outcome.

Anyway, I now believe letting any unwanted vibrations die out is a must for a tube amp, and perhaps also very important for source equipments. We are discussing a tube equipment here, the build quality of which has been praised by everybody in the world. Hence I'd consider it a must for all tube based gears. I have used only crude methods here and am not going to try too much I suppose, but it was a revealing experience for me. When we move to a new apartment next year, I'd definitely think about a new and nice rack (but not too expensive, one I'd be able to afford easily) which would pay attention to the issues discussed here.

Regards.

 

[Asit]

Hi all,

It's been more than 3 years now with this wonderful amplifier. Now it's high time I tried a few other tubes. I have been very happy with the sound produced by the stock tubes, but then after all, tubes have a life span beyond which they would simply give up. Tubes in my amp have not reached that stage - actually in my estimation they are far from reaching that stage because my use has been quite light.

Any way, I have been itching to try a few different tubes for quite some time. I have a pair of Electro Harmonix 12AX7 (pre tubes) given to me by Vasu (member 'myriad') to try out. I also have a quad of BEL EL84 (power tubes) that Rajiv sent to me for free. These tubes have been with me for a long time. Once,about a year ago, I decided to try out the EH pre tubes. The result was nothing to write home about - the sound became quite muddy, the clean crisp sound that is a signature of my amp was nearly gone. So I put back the stock pre tubes (GE 5751 5 star), and the magic was back. Well, that was the end of my experimentation with different tubes - I did not manage to gather enough courage to try out the BEL power tubes although they came highly recommended by Rajiv.

My son recently spent 3 months at the U of Chicago as an undergraduate intern (fully paid). I decided I'd take this opportunity to get a few tubes through him. Arj suggested in this thread the 6P14P tubes (equivalent to EL 84) made at the Reflektor plant in Russia in the 1970's. Rajiv also suggested the EL84M (military grade tubes) by Sovtek. I found out that, most probably in the early 80's, the Reflektor plant was bought over by Sovtek and the EL84M tubes were most probably the same or very similar to the Reflektor 6P14P-EB or 6P14P-EV (the higher, more durable and less microphonic versions with capability of withstanding higher voltages). These higher grade Reflektor 6P14P tubes are cheaper than the Sovtek EL84M and the reports are excellent - as a result prices are slowly rising. Some say, these are quite similar to the NOS Mullard at a small fraction of the price. Well, whether or not they sound like NOS Mullard, they appeared to me as great bargains, so I ordered a matched quad and a matched pair (6 in all, extra 2 as spares) and got them delivered to my son's Chicago address.

I was more undecided about the pre tubes (5751 or equivalently 12AX7), not because I did not know which were the better tubes, but because they are really expensive. My first choice were the early Telefunken 12AX7, and quite up there were the GE triple micas. Finally, I settled for the NOS Telefunken, however, not for more expensive black plates, but the ribbed plates. According to my sources, ribbed plates are equally good, and actually has a fuller lower mid than the black plates - something that may go well with the rest of my chain according to my estimation.

My son came back on the night of 31st July and literally brought back the light to all of us (remember the black out of the Eastern grid that day). The very next morning I put in the matched quad of the Reflektor 6P14P-EB tubes. I have now only a few hours on them, so my impression on them will be brief and only the initial thoughts.

These are really really quiet tubes - that is the first thing that comes to my mind. The separation of instruments and different vocals in a large chorus is also noticeably improved, although it was already very good. The mid is already unbelievably good and very natural. Previously, my top had a bit of bite, not quite bright, but could be just a tad forceful at times. That is now completely controlled - I'd like it to open up just a bit though. The bass was not good for the first hour - by that I mean it was not well defined, a bit loose and a bit boomy at times, but it was never harsh and tuneless. After that first hour, it has now improved a great deal, but still not quite the very tight well defined tuneful and musical bass I am used to. Would the tube experts comment on this? Is this quite normal and can I expect the bass to improve gradually to a state that I have no complaints about?

I have not yet tried the Telefunken pre tubes. I may just try them out briefly just to test them, but I will wait till the power tubes settle in. Only that way I will learn about the sound they produce.

Regards.

 

[arj]

. Would the tube experts comment on this? Is this quite normal and can I expect the bass to improve gradually to a state that I have no complaints about?

hi asit, i am not sure if they change too much after the 1st hour or so..(at least in my experience). could you also try changing the speaker impednce in the back of the amp to around 6 ohms ?