Pass B1

[rikhav]

As I told joshua when he visited me we have still not used anything very exotic in crtical areas
Wondering what level the b1 go to if we used exotic components whereever neceassry

Joshua, the cd you gave me is sounding so natural and real, its unbelievable

 

[jls001]

To continue from here, I finally completed the build of the Pass B1 as I was inspired by how good Rikhav's system sounded after he introduced the B1 in his chain.

My initial experience wasn't smooth as one channel of the audio was louder than the other. The funny thing about this was the imbalance gets introduced after the B1 has been kept powered on for some time (like overnight or full day). Sometimes when it sounded unbalanced, I switched off the B1 and switched it on again, and it started playing normally, but it would become unbalanced after some time. Coupled with another observation that after initial power on it played fine, so I left the B1 off when not in use, instead of keeping it powered on constantly.

The chain was my Lenco L75--> Pearl II phono stage --> B1 --> power amp.

Some days back I swapped out to another source (Thorens TD 124 --> Hypnotoad AD797 phono stage --> B1 --> power amp) as that was the easiest thing to do, and got balanced sound. But last night the imbalance cropped up even on this source. It had been playing fine for the last few days. So I repeated the usual rigmarole of off-on, and it started playing fine.

Now I am stumped! I need advice on how to troubleshoot this problem. Right now my suspicion is on volume pot. I will need to experiment a bit more as the above mentioned two chains need different pot positions for equal loudness. I don't know if my pot is "sticky" at some position or positions. May be a reflow of solders on the wirings will help?

 

[sachu888]

I suspect a dry solder on volume pot or at PCB side, pl check RCA also.

Regards
Sachin

 

[rikhav]

To continue from here, I finally completed the build of the Pass B1 as I was inspired by how good Rikhav's system sounded after he introduced the B1 in his chain.

My initial experience wasn't smooth as one channel of the audio was louder than the other. The funny thing about this was the imbalance gets introduced after the B1 has been kept powered on for some time (like overnight or full day). Sometimes when it sounded unbalanced, I switched off the B1 and switched it on again, and it started playing normally, but it would become unbalanced after some time. Coupled with another observation that after initial power on it played fine, so I left the B1 off when not in use, instead of keeping it powered on constantly.

The chain was my Lenco L75--> Pearl II phono stage --> B1 --> power amp.

Some days back I swapped out to another source (Thorens TD 124 --> Hypnotoad AD797 phono stage --> B1 --> power amp) as that was the easiest thing to do, and got balanced sound. But last night the imbalance cropped up even on this source. It had been playing fine for the last few days. So I repeated the usual rigmarole of off-on, and it started playing fine.

Now I am stumped! I need advice on how to troubleshoot this problem. Right now my suspicion is on volume pot. I will need to experiment a bit more as the above mentioned two chains need different pot positions for equal loudness. I don't know if my pot is "sticky" at some position or positions. May be a reflow of solders on the wirings will help?

Most simple solution according to me just to troubleshoot and actually know your b1 is the problem before opening it up

Take my B1

As it is I am so busy with work I don't think I would be able to listen to my setup for next 4 or 5 days

 

[jls001]

Thanks, Sachin for the pointers. A quick and dirty check revealed the source of the problem to be a nearly broken wire that connects the pot's wiper of one channel to the board. I repaired that and both TTs are now singing sweetly. I love the tonality and the resolution. I am guessing the highs will smoothen out further.

I guess this is one of the troubles with using CAT6 solid core wires for circuit cabling - the unintentional cut to the copper wire while unsleeving can cause brittleness and eventually a breakage.

The gain of the Pearl II is way too low for the cartridge I'm using so I need to jack up the default gain of 55 dB to about 62 dB (as per my calculation). Now I need to swap out a different resistor for the gain setting on the Pearl II. With the current gain, I find it lacks the slam compared to the Hypnotoad AD797 phono pre.

 

[jls001]

Take my B1

Thanks for the kind offer. I guess I have resolved this problem. Anyway, we need to make your resistor mod permanent so do drop in with your B1 when you have the time. Don't forget to bring along the resistors you received from Sachin

 

[jls001]

Bad connection problem cropped up again on the B1, marring my enjoyment of the music. So instead of applying patches and band aids, I replaced all the internal wiring where I had used CAT6 cables, with multi-strand silver coated copper wires. I used CAT6 as I had some broken 4 foot Ethernet patch cords. I had read of other using it with great success in similar application. I have no complaints with the sonics but for some reason they lose continuity randomly. May be I didn't do it right.

My cabinet is from the B1 cabinet GB, made by Bibin. It is designed to accomodate multichannel source selector circuitry too, but since I am not using that yet, the A and B source selection is achieved through a simple DPDT toggle switch. May be later I will incorporate the multichannel source selector. For now, I am making do with two sources. The holes meant to accomodate the selected source indicator LEDs are now unused and looking a bit out of place.

For some reason the hole of the volume knob (from the GB organised by Keith and Jayant), is smaller than the stalk of the pot. Since the knob is made of polymer, it was easy enough to simply use a drill bit of the required size and twist it (by hand) hard and carefully into the existing hole to enlarge it to the correct diameter. That done, the volume control now sports a knob

The next step is to find a bright nail polish (is there such a things as white nail polish?) to mark the dot on the volume knob, and also to mark the "Min" and "Max" points around the volume knob. Then I will be ready to fit the top cover.

 

[jls001]

So instead of applying patches and band aids, I replaced all the internal wiring where I had used CAT6 cables, with multi-strand silver coated copper wires.

Has anyone noticed change in sonics with change in internal cabling? I am not too sure if I am dreaming this, but the sound with the solid cored CAT6 cables was livelier than the multistranded cable I am using now. The bass was deeper too. Or do I have to wait for it to burn in and bed down?

 

[omishra]

Has anyone noticed change in sonics with change in internal cabling? I am not too sure if I am dreaming this, but the sound with the solid cored CAT6 cables was livelier than the multistranded cable I am using now. The bass was deeper too. Or do I have to wait for it to burn in and bed down?

No change IMO with cat 6 cable solid to multistrand but I definitely change after added shielded cable in signal jumps across RCA - PCB. But it's not measured, only perceived.

Please keep us updated with your findings.

 

[rikhav]

No change IMO with cat 6 cable solid to multistrand but I definitely change after added shielded cable in signal jumps across RCA - PCB. But it's not measured, only perceived.

Please keep us updated with your findings.

Hi Mishraji

I guess the multi strand silver coated cable Joshua has used Is also shielded if I am not wrong

In my experience silver coated cables take a long time to settle down (maybe 100-150 to 200 hours)

I have no article or measurements to prove my point but the IC's and speaker cables I use are silver coated multi strand copper

Based on what changes they have gone through wrt sound in a perio of 6 to 8 months I am having this opinion

P.S. During that time I was listening to my setup very less and hence such a long period

 

[jls001]

Some pics to make things clearer:

Below pic shows the wiring of the volume control and source selection switch. The blue, red and black wires are multistranded silver coated copper (teflon insulation, no shielding - it's just a plain wire)

Pic below shows the rear-panel input and output connections which uses RG-174 shielded coax:

And this is the front panel:

The red LED is NOT source indicator. I just extended the LED to that hole on the front panel to show that the unit is ON. The other holes are empty:lol:

 

[spirovious]

After reading about B1 mods,I tried myself.I got a modified kit from Sachin which included 221 ohms resistors and not 1K.When I finished B1,I felt that sound was very open,but some what thin.Bass was less.So I tried 1 k resistors and heard the original B1 sound.Yes bass improved and sound was lifeless or with less details.So I just followed the circuit path and found that output resistors(104 and 204)are the only which are making difference.Not other two suggested in the mod.So kept 102,202 as it is(1K) and used two 221ohm resistors in series.So effective resistance at 104 and 204 is now around 442ohms.Why around 442,I did not remove earlier 1K and its parallel to 442ohms.
Now I feel the overall sound is complete.Good Bass and certainly detailed sound.In my opinion,it outputs the original sound present in the recording.I thing this mod is midway to original B1 and modded by experts.
So its as followed-

102,202 = 1K
104,204 = 442 ohms.(if 1K in parellel,its 306.5ohms as final)

One must try and post their views.

 

[jls001]

So kept 102,202 as it is(1K) and used two 221ohm resistors in series.So effective resistance at 104 and 204 is now around 442ohms.

@Spiro: how do you arrive at the 442 Ohms value? Is it simply 2 x 221 or did you arrive at this number swapping out different values and listening to what sounds best?

You have done a very good experiment.

 

[spirovious]

@Spiro: how do you arrive at the 442 Ohms value? Is it simply 2 x 221 or did you arrive at this number swapping out different values and listening to what sounds best?

You have done a very good experiment.

When resistors are in series,the total resistance is addition of the values.
221 + 221 = 442ohms.

 

[rikhav]

After reading about B1 mods,I tried myself.I got a modified kit from Sachin which included 221 ohms resistors and not 1K.When I finished B1,I felt that sound was very open,but some what thin.Bass was less.So I tried 1 k resistors and heard the original B1 sound.Yes bass improved and sound was lifeless or with less details.So I just followed the circuit path and found that output resistors(104 and 204)are the only which are making difference.Not other two suggested in the mod.So kept 102,202 as it is(1K) and used two 221ohm resistors in series.So effective resistance at 104 and 204 is now around 442ohms.Why around 442,I did not remove earlier 1K and its parallel to 442ohms.
Now I feel the overall sound is complete.Good Bass and certainly detailed sound.In my opinion,it outputs the original sound present in the recording.I thing this mod is midway to original B1 and modded by experts.
So its as followed-

102,202 = 1K
104,204 = 442 ohms.

One must try and post their views.

Hi spiro
Am little confused

When you say you finished b1, is it the new kit you got from sachin you are talking about?

For the new kit you felt the sound to be thin and lacking in bass?

Then you have written that you removed the 221 ohms resistor and in place put the original 1k resistors?

I am not that technically sound so maybe I am little confused

For me, changing all the resistors made hell of difference in stage, details, bass and overall resolution (sound was way more resolving)

It would be interesting to know how is the sound with the mods you have suggested

 

[TheCoolestOne]

After reading about B1 mods,I tried myself.I got a modified kit from Sachin which included 221 ohms resistors and not 1K.When I finished B1,I felt that sound was very open,but some what thin.Bass was less.So I tried 1 k resistors and heard the original B1 sound........
102,202 = 1K
104,204 = 442 ohms.

One must try and post their views.

Interesting experiment and thanks for sharing. Should give it a try. I too had felt that with the Mod there was a change in Bass and found it to be thinner too.

 

[spirovious]

Hi spiro
For the new kit you felt the sound to be thin and lacking in bass?
Then you have written that you removed the 221 ohms resistor and in place put the original 1k resistors?
I am not that technically sound so maybe I am little confused
For me, changing all the resistors made hell of difference in stage, details, bass and overall resolution (sound was way more resolving)
It would be interesting to know how is the sound with the mods you have suggested

Let me post some photos.I soldered resister on back like SMD which is easy to replace.I got mod kit and so wanted to try original too.Also wanted to try better and balanced mod.So please see some pictures and don't laugh at my soldering art.

Actual resistance is less than 442ohms as you can see 1k is still there.If we calculate,actual resistance is around 300ohms.How?
Those blue resistors are 221ohms each.They are in series.So combined resistance is 442ohms.Now 1 k is parallel,so calculations goes like this-

If R is final resistance across (104,204) and R1 is 442, R2 is 1k then its like this

1/R = 1/R1 + 1/R2

1/R= 1/442 + 1/1000

R= 1000/442000 + 442/442000

1/R= 1442/442000

1/R= 1/ 306.5

So final value of R is 306.5 ohm.

Experts,please correct me if my calculations are wrong.Logically R will be less than 442 as 1K is parallel.So looks correct.

 

[omishra]

306.5 ohm is correct.

 

[rikhav]

So spiro in short what it means is that for you it worked when you kept original value of 1k ohms at 2 positions and 306 ohms at other 2 and it worked better then changing resistors at all 4 positions from 1k to 221 ohms

For you sound was lean with less bass when changing all 4 to.221 ohm?

How was the sound with all 4 resistors being 221 ohm comparing it to stock values I.e. 1k ohm at all 4 said positions

Excuse me if my queries are childish

 

[spirovious]

So spiro in short what it means is that for you it worked when you kept original value of 1k ohms at 2 positions and 306 ohms at other 2 and it worked better then changing resistors at all 4 positions from 1k to 221 ohms

For you sound was lean with less bass when changing all 4 to.221 ohm?

How was the sound with all 4 resistors being 221 ohm comparing it to stock values I.e. 1k ohm at all 4 said positions

Excuse me if my queries are childish

When I used 221ohms in all recommended positions,I found thin sound with less bass.Sound was lively.But found that actual sound in recording was little different.
When I used all 1K,Bass was there,but no attack.Also lot of detailing missed which was there in 221 ohms X 4 mod.So started to find the midway solution and probably better one.I found that output resistor is actually changing sound signature and not the other two.So I tried different combinations and found this as balanced.