[nikongod]

Quote:

Originally Posted by oinkbanana /img/forum/go_quote.gif nikongod: i switched the tubes around, same results. i didn't try the "gain 10" setting.. should i? i assume that's the louder output.

the sound stayed lower on the same side. bummer. perhaps it is the cable.

I would not try the higher gain setting, I thought there may be a LOWER one than you have now, which dosnt appear to be the case.

 

[DoYouKnowJim?]

Quote:

Originally Posted by oinkbanana /img/forum/go_quote.gif when i switch the left and the right endpieces of my balanced cable, it is still the "black" end that i have problems with. the cable maker is shipping me a NEW cable tomorrow. he had soldering issues with his last batch, so mine wasn't the only problem. i mentioned the poor heatsink/burnmarks, so hopefully the new one will be done with care.

As I mentioned - if I'm reading this correctly and the lower level and cut-outs follow the black connector line, the balance a problem with the cable. I mean, if one side has both cut-outs from jiggling the connector and lower level, why would someone begin his/her investigation at anything other than the cable itself? The imbalance is probably caused by a poor connection or a mis-wire (reversed polarities).

 

[apatN]

Can anyone explain what a mis-wire -as stated by "DoYouKnowJim?"- will do when you are running balanced?

Anyway it looks like the cable is the culprit here. Strange, because cables are more likely to cut out entirely instead of a lower volume. Maybe your cable maker cooked the cardas connector.

 

[cafe zeenuts]

Quote:

i switched the tubes around, same results. the volume knob is comfortable in the noon position (which is the middle) both internal gain settings are set to "gain 5",

Quote:

i didn't try the "gain 10" setting.. should i? i assume that's the louder output.

So you have switch around the tube and the result is lower sound on the same side of the headphone. I'm pretty sure its the cable. Regarding Alex (APS) taking longer than the normal 14-21 days, thats normal too I wait 5 weeks for my cable.


With the gain at 5, volume knob in the 12 o'clock position this amp would blast the HD650 to the moon. I've never turn over 10 o'clock position and my normal listening level is just below 9 o'clock on the dial. And there is no need try "Gain 10" unless you running K1000.

Btw what pre-amp tube are you using, 6SL7 or 6SN7???

FYI the 6SL7 will have a higher gain than 6SN7...

 

[glitch39]

if you happen to have a multitester handy, check the resistance on the cables between the connection points.

a badly soldered cable can introduce unwanted resistance.

 

[jerry1130]

Remove the grill of your headphone and check if the drivers are secure. I had the same problem when one of the drivers came lose from its socket. It drove me crazy before I figured out what was causing it.

 

[FallenAngel]

You can easily swap the connectors between left/right on the headphones, if the same side is quieter, it's the headphone, if not, it's the cable.

I'm sure it was stated, but the usual etiquette around these things is to contact the seller and have them fix it, not post photos of their faulty work.

 

[oinkbanana]

The only person I named was Alex (aPureSound) because I'm NOT having these problems with him. I'm just typically not used to waiting longer then the longest quoted waiting period, i cancelled the order, he refunded, everything went smooth (aside from expiring my 30day refund period for the amp). maybe in hindsight I should have returned the amp, or maybe just waited for the cable I might not have the problems I currently have.... I'm learning the etiquette as I go.

I'm not interested in flaming the cable maker that I'm currently dealing with. I posted photos to find out if it was shoddy work or not, maybe it's common, opinions seem split. This is the first 'custom' cable I've purchased. I'm just asking this community for advice on dealing with this problem.
Yesterday he said he'd mail me out a new cable today, which pleased me. But today I've gotten a new email "oh crap... but its going to take a few days".
i figure the profit margin on these items are high enough to merit A+ customer service... I don't want to get frustrated, but "excuses" are too common. I'm honestly embarrassed to have to deal with this situation.
I still don't know if this damaged my tube amp when i ran it with No LOAD? I can't even check the amp without a 4pin cable.. i'm stuck. it's frustrating.
How Do i make sure everything works out smoothly?

if I'm crossing the etiquette line, someone PM me and i'll be glad to edit my posts.



I've tested the headphones with my single ended cable, and that works 100%
I've switched the red&black (left&right) headphone end connectors, and it's the black end that keeps giving me problems. the black connector is the right, but it doesn't cross out the possibility that I have a problem with the right side of my amp.

I'll get back to this thread when/if I get a working cable.

 

[FallenAngel]

Black is actually left.

It's good you confirmed it's the cable at fault. Get it cleared with the seller, they should take care of it.

Almost all amps (except for a few tube amps) will have problems with no load.

Being an idealist, there should never be any problems with build quality, though they sometimes happen and any responsible DIYer should quickly get those resolved. Good luck with your situation.

 

[oinkbanana]

I hope my problem is:
there was a partial short on one channel, which would cause the amp to see a different impedance than it would if the cable was good, which would explain the volume differential between channels.


but typically i'd assume since I also got signal dropping out (volume cutting) completely .. no load = bad!! amp damage.
:deep breath:

but i don't know enough about fully balanced amp design to make that assumption.

 

[nikongod]

Quote:

Originally Posted by cafe zeenuts /img/forum/go_quote.gif Btw what pre-amp tube are you using, 6SL7 or 6SN7??? FYI the 6SL7 will have a higher gain than 6SN7...

I would be supercareful swapping 6SN7 and 6SL7. Although they are pin compatible an operating point for 6SN7 dosnt really work right for a 6SL7, and vice versa.

With the common plate resistors used for a 6sn7 & reasonable B+ (less than about 320V) 1/2 to 2/3 of the gain of the 6sl7 disappears attempting to drive a hopelessly small plate resistor. Running a 6sl7 in a circuit designed for a 6sn7 generally winds up eeking less than 3db more gain out of the tube and putting WAY too much current through it. You dont get much more gain in parctice, and put excessive stress on the tubes.
Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif Almost all amps (except for a few tube amps) will have problems with no load.

In headphonia its not that bad: there are very few headphone amps that are not stable with no load.

White cathode followers, simple cathode followers, and plate followers with gobbs of global feedback as used in headphonia are generally are stable into an infinite load.

The buffers on the outputs of tube/SS hybrid amps are generally stable into an infinite load.

The VAST majority of transformer coupled tube amps are stable into an infinite load unless you go crazy and CRANK the volume without a headphone attached; even then you may still be OK. There are a couple in this category that do rely on the load for stability, but there are only a couple (like 2 and nobody around here has mentioned them on this site since about 2006) and when necessary they come with DIRE warnings not to run them unloaded.

SRPP amps are also generally stable into infinite loads although certainly "out of their element" being run into an impedance more than a few times away from their optimization points.

The "pure" SS amps are also generally stable into infinite loads.

Some amps run into trouble hard core style when the outputs are momentarily shorted plugging in/out. In these amps it is not the fact that they are run unloaded that causes fireworks, but the shorted output.

To be sure there are a couple headphone amps that are NOT stable with no headphone connected, but they are rare enough to be considered the exception rather than the rule. The warning is to insure that the 2 or 3 amps known for blowing up when the headphones are plugged in/out hot dont get plugged hot.

Quote:

Originally Posted by oinkbanana /img/forum/go_quote.gif but typically i'd assume since I also got signal dropping out (volume cutting) completely .. no load = bad!! amp damage. :deep breath:

The output stage on the LD6 is a simple cathode follower. It is totally OK to run with no load.

 

[glitch39]

When I got my MkVI, I checked with David and verified that the amp is able to run 6SL7 and 6SN7 tubes. The prototype actually used 6SN7's. I thought the gain loss will be huge because of the mu difference between the two. I was prepared to put the amp on "high" setting. But I was mistaken - the difference on the pot setting for the same volume when I switched the two tubes was minimal. I confirmed that the 6SL7 was not really being driven to its max mu of 70.

Since I had a bunch of 6SN7's, I picked and paired the best of the bunch and ran with that. I ended up using Raytheon VT-231's for the gain stage.

 

[glitch39]

To the OP: did the issue get fixed after putting the "proper" cables and you are now getting balanced level on each channel?

I hope you get the original issue fixed with your custom cabler