(AK) classA HA/Preamplifier.

[Deleted]

Shall we start looking into a GB Chris?

I'd like a few more to play with

[Deleted]

Apr 9, 2013 22:59:14 GMT @shaun said:

Shall we start looking into a GB Chris?

I'd like a few more to play with

But you could start by trying a 47pf polystyrene on the IP to start with assuming that you have a 50K Volco. If you are using something lower value let me know as I have some spare 100pf of that type.

sorry I’d love to say that the foils sounded bad and my pocket would be happier but ain't so.

Take care

[Deleted]

Let's go down the slippery slope
www.studiozey.com/zeyresistor/index.html
Then
www.studiozey.com/invisistor/index.html

[Deleted]

Hi Greg
It's now the 10th of April, not the 1st.
They might do wonders for the DX though.
Try posting that link in DIYA.

Regards
Alex

[Deleted]

Apr 9, 2013 23:23:13 GMT @gregerskine said:

Let's go down the slippery slope
www.studiozey.com/zeyresistor/index.html
Then
www.studiozey.com/invisistor/index.html

Hi Greg

They look a touch pricy and fugly for me but let us know how they sound.

take care

[Deleted]

Apr 9, 2013 23:50:33 GMT @shaun said:

Apr 9, 2013 23:23:13 GMT @gregerskine said:

Let's go down the slippery slope
www.studiozey.com/zeyresistor/index.html
Then
www.studiozey.com/invisistor/index.html

Hi Greg

They look a touch pricy and fugly for me but let us know how they sound.

take care

Hi Shaun
A small group buy of the previously mentioned Vishays may be worthwhile ?
Perhaps also the other resistor in the feedback network (4.7K)too ?
It could be worthwhile doing the same with the different values at the same locations in the 15W.
Kind Regards
Alex

[Deleted]

Apr 10, 2013 1:49:32 GMT @sandyk said:

Apr 9, 2013 23:50:33 GMT @shaun said:

Hi Greg

They look a touch pricy and fugly for me but let us know how they sound.

take care

Hi Shaun
A small group buy of the previously mentioned Vishays may be worthwhile ?
Perhaps also the other resistor in the feedback network (4.7K)too ?
It could be worthwhile doing the same with the different values at the same locations in the 15W.
Kind Regards
Alex

Hi Alex

I was looking at that 4K7 resistor in the FB loop and also the 100R on the base of the 337/327 but wanted to try to do things gently in stages to have a grip on the effect of the changes. Could be that using a quieter 4K7 in that spot would make some difference so I’ll be up for trying that along with the 100R once the dust has settled on the work so far.

a GB may be good and I’ll have a closer look at it but from the States it's going to incur import/VAT and handling costs which I suspect is going to push the price up to somewhere near the Charcrofts. I’m not sure how friendly Nick from Hificollective would be to a discount for a larger order but I suspect that the price break would come with more units than we are likely to need.

As I said to make a GB viable from Texas where those parts are a little less pricey

We need is a Stateside member to help with the order but the down side is that we have no amps in that part of the world.

But the easier to find and cheaper Vishay Standard bulk foil resistors may be worth thinking on but they are ¼ W units compared to the 0.4W charcrofts. ¼ should be fine but a little room to move is always nice.

Greg has also found some interesting resistors. I like the look of the paraffin soaked ones but after a trawl round I’ve read that they have a slight woodiness to their sound.

Take care

[Deleted]

But the easier to find and cheaper Vishay Standard bulk foil resistors may be worth thinking on but they are ¼ W units compared to the 0.4W charcrofts. ¼ should be fine but a little room to move is always nice.

Hi Shaun
.25W would be fine at all those locations.
Regards
Alex

[jonclancy]

Apr 9, 2013 23:23:13 GMT @gregerskine said:

Let's go down the slippery slope
www.studiozey.com/zeyresistor/index.html
Then
www.studiozey.com/invisistor/index.html

Whaaat> Only 4N silver. Dang it, I use 5 or 6N all the time!

[Deleted]

Hi All

A quick update which starts with a question.

Do components need time to bed in?

Well in the case of the Charcrofts I’d say that the answer is yes. Most definitely.

I’ve heard caps burn in plenty of times and TBH sometimes they can sound worse after burn in.

Resistors IMHO can take a little longer and I remember those bulk foil vishays taking their time to settle down.

I’ve just had a full day with the Charcrofts and they have improved quite noticeably from yesterday.

Mmmmmmmmmmm

Even more clarity/focus and musicality.

In my experience it’s not tooo often that expensive components live up to their price tag but these do.

It’s pretty much like a front end upgrade to a much better CD player or Turntable.

Very impressed and hard to drag myself away from.

Shows clearly what a great job is being done by Alex developing this HA/PRE.

Happy

You bet

Take care

[jonclancy]

Hi Shaun,

Yes, I have heard that about Z-Foil resistors. I was warned that the implementation I have used with my attenuator would take a long, long time to burn-in.

What is the R... partname on the BOM (position) that you're looking at apart from the FB/IP/OP locations? The input/Output I can understand. I'll need to have a refresh on the schema to see where else I'd consider trying a film resistor.

Cheers

Jon

[Deleted]

Hi Jon

For a shunt pot I’d say that those naked foils are about as good as it gets with the only downside being a little mechanical fragility.

Just out of interest what I did was to use fine nosed pliers to grip the resistor leg near its body and bent the leg around the pliers to give the outward bend. Then I did the same thing for the downward bend. That gave less mechanical stress to the component and avoided unnecessary handling of the device.

Yup paranoia city but at the price I felt good about it. Just like the good old days of flaky Holco’s.

From my memories of using the box bulk foils I was kind of expecting a slow burn in process and was genuinely surprised to get such a good sound with the Z straight out of the bag so to speak. They are polishing up very nicely.

OK part numbers I’ll try but I don't have the boom to hand. Building from memory don't ya know?

What I have now is

R1 56K R2 220R IP

R11 10K FB

But I’m planning to go a little further at some point with R19 & 20 100R on the base of the 337/327 and 12 4k7 FB and the OP resistor.

But one has to wonder if those last parts I’ve mentioned are going to have the same impact as the ones I have already. Needs further thought I think.

Take care

[Deleted]

Hi All

Just something that may be of interest in the resistor ‘’sound’’ discussions.

www.sasaudiolabs.com/resistor.htm

take care

[Deleted]

Hi All

So this morning the last of the charcrofts arrived.

100R for the OP which are now fitted and burning in so I’ll come back to that once they have had a little time to mature a little.

I have tried replacing the 4K7 resistor in the FB loop with a 5K bulk foil box Vishay from my parts box but I changed it pretty quickly for a NOS 4k7 Holco H4 which sounded a little better with the HA IMHO. I’d still like to try a Tantalum resistor in that spot so that’s next on the list.

However

I have been having a little play with the last cap (100uf) on the JLH and also the 100uf PSU decoupling caps on the Mule.

So I have 8 100uf 35V Elna Carafine and 8 100UF 35v Elna Silmic2 with the decoupling caps bypassed with Arcotronics 100NF MKP polypropylene box caps.

I’ve only used the Silmics for Cathode coupling duties on some of my tube builds so was looking forward to trying them out with Alex’s superb HA. These caps seem to divide opinion somewhat and Leo’s Marmite comment is most appropriate with caps especially.

So in my set up with my Ears and IMHO.

OK first up was Silmic as the last cap on the JLH and Carafine on PSU decoupling duties.

Mmmm fresh out of the packet they sound as dry as a bone with a sort of grainy upper mid and top end that was quite a shock.

Quite nice bass though.

Ok on the cooker to burn in for 20 hours constant playback after which things had improved a little but the still sounded a little grey and anaemic IMHO.

So time to change places.

Carafine on the JLH and silmic decoupling the PSU.

Interesting as they sound just totally different (but as we know they all sound the same really NOT). These sounded a little over rich to me with quite a heavy bottom end. Ok another 20 hours of slow cooking and well. They sounded really bad.

Soggy and lifeless like a wet blanket had been thrown over the music.

Rats

I almost ripped them out there and then but I’d read that these caps really do need to be well done so another 20 hours of roasting commenced.

And

On with the cans again

And
They really have opened up the sound with the upper mid and top end catching up with the lower mid and bass. So much more even but at the same time smooth and detailed. Who hit the large button I asked myself? The head stage is pretty enormous to my ears but at the same time solid and well filled (if that makes sense).the system seems much more able to differentiate between changes of cable and front end.

I had Panasonic FC in originally and IMHO they are a good cap (but the suntans in my original build are better). Caps can be quite a personal thing in much the same way as cables so it pays to try a few types to see what you like. What I do try to avoid is using the same caps throughout the system as this can lead to an ‘’over egging effect that can be a bit too much of one thing. Nope I like to mix em up where I can which can lead to a more balanced sound.

Much more like it and now I’m quite enjoying them.

As a whole I’ve been pretty satisfied with the few small changes that I’ve made and learned a few things along the way.

Happy
Yup

Take care

[Deleted]

Hi All

1) www.hificollective.co.uk/components/prp_pr9372_metal_film_resistors.html
PRP PR9372 Series resistors ¼ W AND ½ W used


Alex
You asked a question on how nonmagnetic resistors sound which was an interesting question.

Ok I’ll have a go at answering it.

I’m not so sure that the nonmagnetic properties have an influence on the sound per say but I do suspect that the kind of materials used in their construction does.


Usually copper leads and end plates are used and with these resistors I have a noticeable reduction in sibilance and glare. Whilst that is really under control with the original it’s more natural and in keeping with the recording with these resistors in place IMHO. So the question maybe is would we use steel for our IC/LS cables?






2) www.hificollective.co.uk/components/elna_capacitors.html
Elna Silmic 100uf 35V.


Ok just a word on the Silmics
Anyone who does not believe that capacitors need time to form and change in SQ as they do so needs to be forced to listen to these babies run in. they start of sounding pretty good but go bright and bass less pretty quickly. After 20 hours or so running in they hit a kind of bland stodgy fuzzy stage which I found horrid. They need to have at least 40 hours to become listenable and after sixty the bass is back and they are starting to sound really good.


3) www.hificollective.co.uk/components/car_resistors.html
Charcroft Z-Foil Resistors for Audio which I’ve used for the IP OP and FB.
4) www.hificollective.co.uk/components/shinkoh_resistors.html
Shinkoh Tantalum resistors which I’ve used in the FB loop.

5) www.hificollective.co.uk/components/polystyrene.html
I’ve changed to 47nf polystyrene for the front end cap.
6) Lastly I’ve bypassed the silmicks with 100nf Arcotrinics polypropylene box caps.

Overall the sound I’m getting now with the above changes in place is really detailed /dynamic with great bass which is fast and tuneful. I’m finding it easier to forget that I’m wearing headphones and with the right recording it’s more like sitting in a bubble of sound.

But note that I’m using the K701 and others using other HP may want to try other caps and what not.

I like and maybe I should call it the SE edition (Subjectivist’s Extravaganza)

Take care

[Deleted]

Hi Shaun
It seems possible to me that the MF resistors that Jaycar are now selling, as supplied by their offshoot Soanar. may sound closer to the better types as they no longer use copper coated steel leads and appear to be non magnetic.
With recent problems now hopefully resolved, I may be able to concentrate on and finish my build of Will's 15W Class A PCBs in the coming week. I now have the PCBs 60% complete, but I will be using 2SA1943 and 2SC5200 output devices ,as I have 2 pairs that are reasonably well matched. Initially, I will use the existing PSUs so that I can better judge the performance of the new PCBs.
Kind Regards
Alex

[Deleted]

Apr 26, 2013 12:34:10 GMT @sandyk said:

Hi Shaun
It seems possible to me that the MF resistors that Jaycar are now selling, as supplied by their offshoot Soanar. may sound closer to the better types as they no longer use copper coated steel leads and appear to be non magnetic.
With recent problems now hopefully resolved, I may be able to concentrate on and finish my build of Will's 15W Class A PCBs in the coming week. I now have the PCBs 60% complete, but I will be using 2SA1943 and 2SC5200 output devices ,as I have 2 pairs that are reasonably well matched. Initially, I will use the existing PSUs so that I can better judge the performance of the new PCBs.
Kind Regards
Alex

Hi Alex

Those copper resistors that you have mentioned from Jaycar where on my mind when I posted. It may also be worth finding out what metal they are using for the end caps just to have a full picture as I think that may also have some bearing on the SQ. those red jobbies that I’ve posted too seemed to further tidy the top end so I think that for the little cash involved they were GVFM.

Let us know what you find out about the construction of those Jaycar resistors as at the right price they may be worth thinking about for the PA also. That’s what I’m thinking on ATM.

Yes I have the 2SA1943 and 2SC5200 in my Build of your lovely PA and they sound pretty good to me.

Take care

[Deleted]

Hi Shaun
I won't be able to directly compare both types of resistors, as I am using a mix of old and new stock. They are the same types at the same locations on both PCBs though
Kind Regards
Alex

[Deleted]

Apr 26, 2013 21:35:18 GMT @sandyk said:

Hi Shaun
I won't be able to directly compare both types of resistors, as I am using a mix of old and new stock. They are the same types at the same locations on both PCBs though
Kind Regards
Alex

Hi Alex

No worries on that but if you have a spare of the copper lead variety then you could just put a magnet to one end to satisfy curiosity.

Take care

[jonclancy]

Seems I was ahead of myself when I built up my boards as I had already incorporated 120R (R18 and output to match K701)and SF12. I've just installed 100R on my spare boards and will drop them into the chassis sometime. IIRC, it's 68R for output as standard, 100R for pre and 120r for K701 etc. Looks like 100R could be a nice compromise and would be cheaper than doubling up resistors to have 120R for heaphone and 100R for preamp use (as my setup is build for dual use).

[Deleted]

Looks like 100R could be a nice compromise and would be cheaper than doubling up resistors to have 120R for heaphone and 100R for preamp use (as my setup is build for dual use).


Hi Jon

yes that was my take.

take care

[jonclancy]

Apart from D1, where are you guys using SF12? In the JLH as well?

Cheers

Jon

[Deleted]

May 9, 2013 5:01:15 GMT jonclancy said:

Apart from D1, where are you guys using SF12? In the JLH as well?

Cheers

Jon

Hi Jon
Apart from the front end balance,I am also using them in the bridge rectifier section of the Jaycar PSU PCBs for the preamp.

Kind Regards
Alex

[Deleted]

X2

[FritzS]

Are using single contact-pins (like as in good DIP sockets) are a good choice for those components, which are changeable? After testing, this could soldered too. Looks like this at.rs-online.com/web/c/steckverbinder/leiterplattensteckverbinder/leiterplatten-steckverbinder-kontakte/

I buy'd MRS25 resistors - but which are recommend to use HOLCO or similar resistors like this www.hificollective.co.uk/components/prp_pr9372_metal_film_resistors.html?

For C1 100pF I have film capacitor, polypropylene (Mouser 505-FKP2100/100/2.5),
for C2 68pF I have MICA (Mouser 598-CD15ED680GO3F) in my stock - are this OK?

I seen now about MICA I got an answer from Alex rockgrotto.proboards.com/post/121894/thread