rumble issues - see old thread update

HI Dan

Richard Gray - my local tech and designer thought it probably is tone arm compliance - needing a little more weight

we will see where it goes from there

thanks

thanks everyone

I'll go through this thread with Richard

I do have multi weights for the triplaner and Richard and I are going to try this first- I also have the sb with the shim under the cartridge

Richard was over and said I definitely don't have an amp clipping issue - although some of the amps power is being robbed when feeding the low freq outbursts

there are some minor warped records that cleary set off pumping in the speakers, and some other's that it's so minor (but stil probably mucking up the low end) but probably still there

I want to get all the clarity out of my setup and maybe this is the limiting factor

as for suspension - I have the Silent Running Audio platforms and stand - and a very heavy platter - floor concrete - about as isolated as I can make it

it could be a room mode - I have a 14 by 27 room
long wall setup - at listening area - null against wall and reinforced 2 feet in. I've tamed slap echo with echo busters but no low freq suppression. CD's sound fine.
Table slightly forward of speaker ports which are 3' from back wall.

Perhaps if I placed the table closer to the wall on my seperate Billy Bags stand.

I'll try covering the speaker ports as well. Ports 2 2" at bottom of speaker. Jim Salk has not encountered this before with his speakers, then again, few owners with analog

Richard set this table up with a scope and the results are stunning other than the 'pumping' problem - which is there but only strong on high voumes and minutely warped records.

If this is truly a port / room issue then I'll have to look at placement of either the table or speakers. I'm a bit concerned that a subsonic filter might just mask a problem rather than correct.

Thanks

Tom

thanks guys

I'd hate to have to go to a another speaker, my friend has ported Salk's smaller

Dan_Ed - my Bat is on loan to a friend more than a few states away

Moscode 401 HR - I don't think it's clipping anymore but analog related

yes Doug volume is a culprit - increase it and more and slight warps in records.

never noticed this before, but I'm sure if things are not quite right even at lower volumes - the lower freq vail is affecting the sound.

45 rpm 180 gram blu note recordings sound fabulous
so maybe that has an effect

Room modes could be contributing. It does sound very resolving and no real flaws on cd, perhaps it sets up tone arm resonance issues. I'll try my Rives freq test and SPL if I can find them

ported speaker issue -
possibly - I'd hate to have to go to a another speaker, my friend has ported Salk's (a smaller model) and they pump all the time - he has a wood floor, not as well isolated and his speakers are close in to the back wall

sorry - floor carpet, thick pad, foundation is concrete

known as "sea meant" to the locals down here in Louisiana

diagnosis round II

Richard came over with his 'higher tech' scope

we found a little isolation issue caused by the light hollower SRA platform under the turntable - we replaced that with a 3 cm granite slab which isolated the table much more efficiently

the scope showed resonance problems in both channels around the 4-7 htz range - which Richard said were caused by a low mass arm being mated with an overly compliant cartridge. I told him that the ZYX and Triplaner often matched with great results - as many of you can attest to

we tried additional shims, counterweight options and also more and less weight to no avail
I typically run 1.75 g

he felt the high compliance of the cartridge and tonearm
combined with the highly resolving low end of the Dodd pre and Moscode amp were allowing the tonearm/cartridge resonance issues to be reproduced by the speakers

we checked the speaker baffle output and it wasn't sufficient to cause an issue

next step - Richard will bring a lower compliance cartridge to test out and see how it mates with the arm resonance wise

I'll call the various manufactures to get their input

any suggestions from others here on the arm / cartridge synergy would be very helpful

thanks

Tom

hit up an excellent website calculating resonance

http://www.gcaudio.com/resources/howtos/tonearmcartridge.html

I did a little research and calculations using the formula stated


check out the ZYX Universe site


http://www.sorasound.com/products/zyx/zyx-universe/

that's a pic with a triplaner from their beloved US dealer Mehran

ZYX universe specs

http://www.hifi.com.sg/products/cartridge/zyx/universe.htm

Universe specs

compliance
horizontal 15 x 10 -6 cm/dyne
vertical 12 x 10 -6 cm/dyne

I have the SB (0.24mv) version


Triplaner specs

http://www.triplanar.com/tonearm.html

11 grams

resonance freq = 1000/6.28 *suare root (M*C))

for vertical 12 compliance = 13.86 hz

for horizontal 15 compliance = 12.40 hz

these are both in the ideal range stated in the gc audio article

high enough to be out of the record warp subsonic stage but low enough to be out of the musical relm (well, most music these days)

so what gives?

perhaps dampening trough needed?

hi guys

just reading your insightful posts

latest update

less woofer excursion after using granite slab under table on craz rack - it eliminated or greatly reduced isolation
slightly warped records set it off, but most have much more minimal speaker pumping (I can live with if not damaging cartridge)

craz platform is floating and works great with electronics but not with turntables - I could tap it and get noise through the speakers - not now as I replaced it with 3cm granite

pumping is more pronounced on outer portion of record which fits with the warpage scenario
so I may have similar observations as what you saw at Doug's (room and port elements may add to this)

the arm is still resonating (as seen on the scope) - calculations and your experiences as well as Mehran's and Thom Mackris say this should work and it seemed to till I got a low end pre amp -the doshi

weight 1.75 ish - have the shim and adding a quarter on top of the cartridge didn't work either
I tried the mass counterbalance variations along the arm

room 15 by 27
I have system/speakers on long wall using Cardas nearfield setup
There is a dip in volume om the back wall behing the couch - increases two feet into the room
speakers 3 feet into room. CD's sound great in the room with no noticable freqency humps

haven't tried the speaker placement
do have some echo buster type iso panels I could stick between speakers and equipment

alignment is dead on as shown by scope with test records and hearing music

I have a heavy anvil I can use on the top of warped records
is the clamp more effective

the pumping at present isn't really audibly effecting the sound anymore or minimally except for warped records

Richard is also going to bring over a few other cartridges with lesser compliance and see if we can remove resonance

this may be as dan and bob suggested - live with it

I think I'm getting closer, just want to isolate this and tweak everything out of my system

enjoy music tolerate equipment ...

thanks for all the helpful insight,
much appreciated

hi guys

thanks for the further tutorials
this hs spinned into a very insightful thread

Richard is Richard Gray of the Power Company fame
he is an electronics guru and has set up a wide range of tables, arms and recognizes issues via scope, test records, etc

the Craz rack is fine - minimal suspension pads under denser surface material, titanium in the frame. It's the SRA VR platform above it that was causing the problems - these work miracles on amps, pre's, cd's etc but as we found out - the floating element is transmitting too much to the turntable

we replaced it with 3 cm granite and much lower resonance and speaker pumping. SOme in sync with the music, some not and probably in sync with the record. Sound doesn't seem to have added a shrill mid range

I also have a Billy Bags turntable stand my loricraft sits on - that sounds like some lugging I don't want to try

someone at a NOLA audiophile meeting last night suggested eccentricity in the spindle/bearing - but those Galibrier tables are built like a tank. I thought I heard the sligthest squeak the other night on a quiet passage - once a revolution. Do I need to re-oil it Dan?

low freq pre relates to it passing a lower freq signal - lower than my prior Dodd and Arc LS5.

salks ruler flat to 34 hz f3 under 29 hz f10 23 hz

I'l call Thom Mackris and Kevin at SRA for starters

I'll have to look into the record clamps
and yes I don't use the anvil but have seen records that it hurts on warpage more than helps

as Doug suggests - you get to the point where you are hearing all the eccentricities in musical reproduction

or as Richard said - compliant arm, compliant cartridge, comp pre, comp amp, etc - you are going to hear everything - warts and all

thanks

Finally resolve what was wrong

the feather test - moving a feather lightly against the cartridge parallel to the record should move  the headshell

If not the tonearm bearing isn't moving properly


The tonearm bearing wasn't moving suficiently so the cantilever was moving up and down causing all the pumping

had the bearing fixed