Pass B1

[john_k_antony]

Thanks Spirovious, I will try that. I need to make the same resistor network as you did . However I was hoping that I will get the same results with 330 ohm as you got with 306.5 ohms. Seems like its extremely sensitive to even a slight change in resistor value.

I am really surprised to know how sensitive is the sound output w.r.t moderate change in the output resistance.

Also do you guys think there will be any difference due to 1W vs 1/4W resistors ? What is the ideal rating BTW?

Thanks,
John.

 

[jls001]

Also do you guys think there will be any difference due to 1W vs 1/4W resistors ? What is the ideal rating BTW?

Using 1 Watt resistors is not required unless mentioned in the circuit design. The higher wattage means that it will carry high current and therefore heat up.

Some resistors do sound better than others. Or so I've been told That is why a Dale or a Caddock resistor will sell for a premium compared to a no-namer.

 

[john_k_antony]

Using 1 Watt resistors is not required unless mentioned in the circuit design. The higher wattage means that it will carry high current and therefore heat up.

Some resistors do sound better than others. Or so I've been told That is why a Dale or a Caddock resistor will sell for a premium compared to a no-namer.

Actually I was not using 1W on purpose. For 220 ohm, that was the only option available.

I know better quality resistors sound better for multiple reasons including the super narrow tolerance level . But for me all the resistors in the chain are same quality except for the fact that 220 ohms is rated at 1W and all the others were 1/4W. Also the 220 ohm resistor was much bigger in size due to its power rating of 1W.

The surprising thing was, I was expecting the sound to inch towards more brighter side when I was reducing the resistor value. And it indeed happen like that till 220 ohm. The moment I added the 1W 220 ohms, sound took a "U" turn and started sounding rolled off at the high end and narrow sound stage. But it was not bad at all, it was sounding more "warm" and "hefty". And I loved that sound for lots of the tracks .

-John.

 

[jls001]

Thanks Spirovious, I will try that. I need to make the same resistor network as you did . However I was hoping that I will get the same results with 330 ohm as you got with 306.5 ohms. Seems like its extremely sensitive to even a slight change in resistor value.

I am really surprised to know how sensitive is the sound output w.r.t moderate change in the output resistance.

Also do you guys think there will be any difference due to 1W vs 1/4W resistors ? What is the ideal rating BTW?

Thanks,
John.

@John: you must really try the 306 Ohm value. It is no doubt a serendipitous discovery by Spiro, but the result is quite amazing.

PS: after modding Rikhav's unit, I did the Spiro mod (strictly as per Sprio's recipe) on mine too and I really like what I hear. Had I not done this, I wouldn't have known that a Denon DL103 can dig out serious amount of details (Hypnotoad AD797 phono stage, Thorens TD 124 TT, & Origin Live Encounter Mark III arm).

I am now wondering whether it is worth changing the internal cabling (in/out RCA ports to circuit board), wires used in volume control (I still think the CAT5 cable I used earlier sounded better), and perhaps swap out the RCA sockets to Neutriks (from the MX that came as part of the B1 cabinet GB)? Any thoughts?

 

[rikhav]

@John: you must really try the 306 Ohm value. It is no doubt a serendipitous discovery by Spiro, but the result is quite amazing.

PS: after modding Rikhav's unit, I did the Spiro mod (strictly as per Sprio's recipe) on mine too and I really like what I hear. Had I not done this, I wouldn't have known that a Denon DL103 can dig out serious amount of details (Hypnotoad AD797 phono stage, Thorens TD 124 TT, & Origin Live Encounter Mark III arm).

I am now wondering whether it is worth changing the internal cabling (in/out RCA ports to circuit board), wires used in volume control (I still think the CAT5 cable I used earlier sounded better), and perhaps swap out the RCA sockets to Neutriks (from the MX that came as part of the B1 cabinet GB)? Any thoughts?

Hi Joshua
I am sure changing the RCA ports would be worth but then it would also depend on how good or bad MX rca ports are comparing the Neutrik ones

Same for the internal cabling, it will make a difference (by how much, that would be very difficult to predict)

 

[spirovious]

@John: you must really try the 306 Ohm value. It is no doubt a serendipitous discovery by Spiro, but the result is quite amazing.

Yes,it was just trying some combos(resistors)wondering why would the sound signature change a lot with mod to original B1 and trusting ears,finding micro changes in sound(with headphones)during changes helped me to find it.

 

[keith_correa]

I am now wondering whether it is worth changing the internal cabling (in/out RCA ports to circuit board), wires used in volume control (I still think the CAT5 cable I used earlier sounded better), and perhaps swap out the RCA sockets to Neutriks (from the MX that came as part of the B1 cabinet GB)? Any thoughts?

If the CAT5 sounds "better" to you then I see no reason for you not to change to it. Unsolicited tip: don't tin the bare copper for any more than needed - tends to make the wire brittle.

 

[spirovious]

After playing with 306 ohm mod for long,I felt that still input signal sounds marginally different.Especially vocals showing little different character.So decided to try some more mods.
Just added 18ohm in series with 306 mod.So now total resistance is 324 ohms. With this,vocals were stronger and better.Listen it for long ,still not satisfied.Overall sound became warm.Treble now was softer.So not a positive achievement.So removed 18 ohm and replaced by 10 ohms.This was a plus.Now I am getting sound similar to DAC output.306 is really good one,still for getting better vocals and overall exiting sound,I changed it to 316ohm by adding 10ohms in series.
That 10ohms really making good difference on positive side(no placebo effect). Sound stage may be narrow marginally.But getting near perfect analog out from B1 was my target.Bass also improved further a bit.Treble is clean and rounded.So one can really try this mod and post their views.

 

[Dr.Bass]

Hi Guys,
I request some advice here.

I am looking to buy a First watt B1 directly from the US dealer (Reno hifi). It is a factory built unit. Considering that people are still playing around with various resistors and may be caps etc, is there anything special I should demand the US dealer to get done for me within the B1 before he ships it across ? I do not have the skills to go DIY so I am relying on the fact that Mr.Pass will do a good job with his own design especially since he is selling it under his brand. Is it a good idea to buy direct from Pass ?

If I get the preamp, it will replace a $6k Lamm preamp. While the Lamm is a terrific preamp but I still can hear a bit of "tube warmth" which I would ideally like to get rid of. I have tried a pure passive preamp and I liked the tone-neutral sound from it except that as with most passives the overall presentation lacked solidity. Bass lacked the authority. I expect the B1 to do what a good passive does in terms of tonal neutrality but without letting go of the solidity. Am I expecting too much ?

 

[jls001]

@Dr Bass: the B1 keeps showing up in the For Sale section here. To build it from kit, it should cost 10K-ish (the INR variety). I'm not sure how much Reno charges.

For my personal taste, the stock B1 is super clean, perhaps tending to the clinical. After the resistor mod, the mids become fuller, bass tightens up substantially, and it sounds more tube-like. The mod is really simple and I can tell you how to do it with just a nose plier and no solder. If you don't like the sound of the modded one, simply use stock values.

B1 has been compared to many big dollar pres and has come away in shining colors.

PS: all connections are unbalanced. Do take note.
PPS: there is (not so new) kid on the block that has displaced the B1 from its perch - the Direct Coupled B1 from Salas. It is nothing but a B1 with the Salas power supply which can be biased to a tame B1 like value, or one or two steps higher for better sound. But step two and three needs substantial heatsinking.

 

[hifiramr]

@Dr Bass: the B1 keeps showing up in the For Sale section here. To build it from kit, it should cost 10K-ish (the INR variety). I'm not sure how much Reno charges.

For my personal taste, the stock B1 is super clean, perhaps tending to the clinical. After the resistor mod, the mids become fuller, bass tightens up substantially, and it sounds more tube-like. The mod is really simple and I can tell you how to do it with just a nose plier and no solder. If you don't like the sound of the modded one, simply use stock values.

B1 has been compared to many big dollar pres and has come away in shining colors.

PS: all connections are unbalanced. Do take note.
PPS: there is (not so new) kid on the block that has displaced the B1 from its perch - the Direct Coupled B1 from Salas. It is nothing but a B1 with the Salas power supply which can be biased to a tame B1 like value, or one or two steps higher for better sound. But step two and three needs substantial heatsinking.

How you compare original nelson pass b1 with Direct Coupled B1 from Salas can you explain the sound signature when compared with original version

 

[jls001]

How you compare original nelson pass b1 with Direct Coupled B1 from Salas can you explain the sound signature when compared with original version

I'm yet to build the DCB1 though I have the kit. From what I read, the second level of biasing is supposed to substantially improve the tone and soundstage.

 

[captrajesh]

@Dr. Bass, before sinking in your top dollars, why don't you borrow a fully made DIY preamp and see if it floats your boat? Unfortunately, you are in Singapore and shipping it back and forth would cost a bomb.

 

[dheerajin]

Hi Dr Bass,

I want to narrate my experience here-

Pass B1 with Integrated NAD 375BEE amp

Sound signature got changed and it was jawdropping performance i should say.
I had mentioned the same experience in my thread

http://www.hifivision.com/preamplifier/52335-pre-amplifier-my-system-8.html

POST#72

Pass B1 is transparent equipment and its performance can be easily compared to expensive preamplifiers.
It amplifies noise too as being transparent , hence it is very good equipment to compare two source(CD/DAC) for noise levels.

Second part-

Pass B1 with Integrated YAMAHA A-S2000 amp

Here the situation takes abrupt turn

Sound is same as before but dont know why it is not matching the finesse of YAMAHA amp as a standalone integrated amp. May be impedance mismatch but since it is active buffer, should not happen the same. I even tried 3 different interconnect to check.
May be experts chime in and give reason behind this difference in sound.
As per reviews available on the net, this piece of YAMAHA is on altogether different level
and termed as"affordable high end". May be this is the reason of sounding not better with Pass B1 due to very good pre-amp of Yamaha.

So as Captain suggested , before taking plunge , borrow it from someone to test it with your power amp.

For both the situation above I was using power amp section of both the integrated amp.

 

[jai1611]

Pass B1 with Integrated YAMAHA A-S2000 amp

Here the situation takes abrupt turn

Sound is same as before but dont know why it is not matching the finesse of YAMAHA amp as a standalone integrated amp. May be impedance mismatch but since it is active buffer, should not happen the same. I even tried 3 different interconnect to check.
May be experts chime in and give reason behind this difference in sound.
As per reviews available on the net, this piece of YAMAHA is on altogether different level
and termed as"affordable high end". May be this is the reason of sounding not better with Pass B1 due to very good pre-amp of Yamaha.

The Yamaha performs better with balanced inputs. Unfortunately the preamp-in is single ended so cant match the performance of the internal balanced pre

 

[spirovious]

The Best is that with the change in resistor value,you can improve the sound as desired.
http://www.hifivision.com/diy/21036-pass-b1-158.html

check my post 1573 and onward.

 

[shafic]

So as Captain suggested , before taking plunge , borrow it from someone to test it with your power amp.

I want to narrate my experience here!!

Pass B1 with McIntosh MC 2505 power amp

.

Some months back Joshua had brought the pass B1. We heard it with my McIntosh MC 2505 power amp. The sound was very clean and clinical but lack of BASS. My Lyrita tube pre amp gives warm tube sound with the same power amp. I like the pass B1 for it's clean notes.

regds,
shafic

 

[shafic]

The Best is that with the change in resistor value,you can improve the sound as desired.

Is this applicable for vintage amplifiers too?

 

[gobble]

I have the B1 kit with lightspeed attenuator and r-core trafo lying around - I purchased from OMisra but don't plan to build it anymore. but its with one pcb. You need a second one to put in front of the attenuator.

G0bble

 

[rikhav]

I want to narrate my experience here!!

.

Some months back Joshua had brought the pass B1. We heard it with my McIntosh MC 2505 power amp. The sound was very clean and clinical but lack of BASS. My Lyrita tube pre amp gives warm tube sound with the same power amp. I like the pass B1 for it's clean notes.

regds,
shafic

Hi shafic sir
It was my b1 which joshua got to your place.
I can confidently say after the resistor mods the bass, overall weight in the sound has improved quiet substantially along with very good details in the highs
So while retaining the original positive point of having a very clean sound, the sound now has more weight in the mids and good bass as well

Bass further improved after changing resistor value according to mods suggested by FM spiro