Resistors - opinions

[fabiomayo]

I know this has been discussed already but I 'd like to get fresh opinions.

Other than the 'standard' Vishay/Dales on the TS slopes and Plates,
what resistors do you use in the signal path? Most I've seen are 1W
Carbon Film and I realize 1W Carbon Comp wouldn't probably add any
good... Perhaps 1/2w or 1/4w in some points could add to the tone?


(I'm just a top ace when it comes to second guess myself )

[dogears]

Carbon film is good. Dont' use CC as they drift and have horrible tolerences. Plus, they will not add to the tone since the plates are most likely the only place you will hear resistor differences.

[groovtubin]

Carbon film is good. Dont' use CC as they drift and have horrible tolerences. Plus, they will not add to the tone since the plates are most likely the only place you will hear resistor differences.

The ONLY place i`ve EVER seen them drift bad enuff to scrap is in the power supply, plates/cathodes, etc. It musta worked good in signal path for Howard on the early 60`s models. he used CC`s on the GRIDS of the preamp tubes as you well know. Nuthin wrong with trying them, you afraid someone might like them? lol!!

[Funkalicousgroove]

use Metal film and carbon film , that seems to be what the big guy used on more recent amps, and they sound good.

[fabiomayo]

Thanks for your replies.

Second guessing phase is thru

groovtubin, with so many tweaks to try and tuning the amp I think for now
I'll use the common 1w carbon film. Later on I may be willing to try new things...

All the best

[groovtubin]

Thanks for your replies.

Second guessing phase is thru

groovtubin, with so many tweaks to try and tuning the amp I think for now
I'll use the common 1w carbon film. Later on I may be willing to try new things...

All the best

that is DEF the BEST thing to do, i DID THAT as well, I BUILT for DIAZ AMPLIFICATION< totally diff animal, but i`ll tell ya what, all them BIG Allen Bradley CC`s sounded UNREAL!!!!!! Read the reviews at Harm Central. My FIRST one was used by Warren on the Conan O`Brien show 3/15/04. Built Warren Haynes ( 2) amps, the distortion is AWESOME as well as the CD-100`s, not FAR from Dumble in response and sustain, infact i believe the distortion in a Diaz is better if you want a cross btwn Marshall and boogie, it`s ONE fine amp. I OWN a Diaz Classic Twin, everyone who plays it is floored.. I`m no expert, but i have built some cool amps for REAL pros..... Most of all have fun!

[fabiomayo]

That's cool, groovtubin. I had already read here on the forum 'bout you
being a Diaz builder, and having built Warren's... That's cool!

I'll just try to get the amp up & running noisefree first, than I'll do the
tweaking to my tastes... Your suggestion is certainly on the line...

[tonelab2]

I've used AB CCs in the signal path no problems.
For a 'D' clone stick to what others have said, CF and MF go well in this amp.
The new CC made in Asia somewhere is total crap.
CFs I consider to have no tone what so ever but are cheap also have as much hiss as a 1watt AB in some builds.
MFs are ok but they sound metalic to my ears , no escaping it.
These are only opinions ( worth less than .02)so YMMV.

+1 all them BIG Allen Bradley CC`s sounded UNREAL!!!!!! I agree 100%
a great organic sound ( i don't really know how to describe it).

[Sven]

Greetings,

Although this thread is about resistors, in order not to start a new thread about capacitors, I shall mention them here with hope that someone shall reply.

It is stated that these amplifiers should be built with Orange drop PS series caps. It is not clear what is the meaning of ¨6PS¨ series, since in SBE (company that makes them) spec. sheet there are only ¨PS¨ series radial caps, made as Film & Foil types with polystirene dielectric.

Since it would be preferred in these quarters to build an amp with axial type of capacitors instead of radial, I have seen that SBE makes also axial type of Orange drop capacitors, same Film & Foil with polystirene dielectric ... as it seems that except for the axial construcion, they are pretty much the same as the favored ¨PS¨ series. Those axial types are listed as 470p (round) and 471p (pressed) series.

Has anyone had opportunity to use those axial Orange drops, and what types of axial caps would be recommended in general, more so since SBE 470p and 471p axial Orange drop series do not seem to be available for purchase, as I have looked on the Internet ...?

As for the second cap mentioned here as favored, Xicon MPP series, I read that they are metallized polypropylene types, with radial leads.

In general, as we know. valve guitar amp builders do prefer Film & Foil type of caps, although metallized film types such as Mallory 150 series are also very favored. So, which ones are preferred,

A -- Film & Foil or Metallzed types
B -- Polypropilene or Polystirene

or a mix, a happenstance, an ¨accident¨ ... that one type seems to work better ?

Once again, what would be the choice of AXIAL capacitors, especially since some people like their guitar valve amplifiers with axial caps, ... just for the sake of pleasure or whatever the reason might be ...?

Last, quite frankly I really do not understand how capacitors influence the sound in the case when many brands of capacitors pretty much have very similar/same characteristics. I know that some capacitors can and some cannot pass high frequencies that well as others ... and perhaps some people like that performance of not passing very high frequencies from polystirene caps (Mallory 150) ... or am I wrong ?

My quiest is for an excellent AXIAL capacitor for the singal flow ... of course, rather obviously ... are there any suggestions?

All the best,

Sven

[Funkalicousgroove]

Sven,

Obviously you've never held a type PS orange drop in your hands, what we all do is take our favorite plyers and carefully bend the leads out, in essence making them an AXIAL cap. 6PS refers to type PS caps with a 600v rating.

You can try as many types as you like, but REAL Dumbles have the 6PS caps, with a few here and there utilizing small brown caps (NTE).

To my ears the type 715 OD's are brash sounding and a bit gritty, the M150's are a bit too Dark. I like the 225p(400v) and the type PS. I've also found that using different types of caps throughout the amp generally results in a more "Euphonic" tone.

Funk

[Sven]

Greetings,

Thank you for your prompt reply. Well, I did not work with Orange drop PS caps, but they are radial caps as any other ...

However, it is true that if the original amplifiers used those caps, than, obviously, it is best to use them. But, what I really asked was this, let me clarify again:

1. SBE Orange drops ¨PS¨ series are Film & Foil capacitors with polyester dielectric, and with radial leads.

2. SBE Orange drops, ¨470p¨series (as well as 192p series) are listed by SBE specification sheet also as Film & Foil capacitors with polyester dielectric, but with the AXIAL leads.

So, my question is this:

Aren't PS series and 470p (and also 192p, perhaps) series, actually the same capacitor by all other parameters, except that PS are radial, while 470p (and 192p) are axial ? Is the design of their leads the ONLY difference between those series ? According to the SBE list, that might be the case. Has anyone asked SBE company about that?

Here is the link: http://www.sbelectronics.com/productlines.htm

Thank you.

Sven

[Funkalicousgroove]

According to the data sheets they are very similar, however, I've never found the 470p series for sale. there are pictures on this site of amp #124 with all the goop removed, and all but the bass cap are 6ps.

[fabiomayo]

I always find these cap discussions interesting...

I asked this before with no replies. Have anyone tried paper-in-oil capacitors
in this design?

[Sven]

I always find these cap discussions interesting...

I asked this before with no replies. Have anyone tried paper-in-oil capacitors
in this design?

Greetings,

In order to achieve certain goals, a certain performance from this particular type of design, it is indeed best to use Orange drop capacitors, no doubt about it ... since there are idiosyncracies in valve amplifier designs that are simply beyond measurements and various purely scientific and engineering criteria. That is why I really do not question use of SBE Orange drop PS series capacitors, as well as highly recommended Xicon MPP series. I am merely trying to see if the ONLY difference between PS series and 470p series is in insertion of leads, radial vs. axial -- and that is a question that I shall e-mail to SBE company, and HOPEFULLY get some reply from their people ... and report to this forum.

As for paper-in-oil capacitors, it does not seem that this is the type of amplifier that needs that profile of a singal capacitor ... on the other hand, one can alway experiment and try to find out what it is like to use those PIO caps ... with my personal observation that there is no need to spend the extra money for that type of ¨charisma¨.

All the best,

Sven

[tonelab2]

I always find these cap discussions interesting...

I asked this before with no replies. Have anyone tried paper-in-oil capacitors
in this design?

I have a few spragues and other brands I've been saving for a build but haven't tried them as yet. From what I have read over the years from other builders is that PIO caps usually don't sound that great in medium to high gain circuits but do well in clean and low gain amps. I recall a couple of builders mentioned that they gave a cranky tele type country sound (whatever that means) in a high gain circuit . Other experienced users will more than likely pipe in. Perhaps you can try and let all us know, I'd be interested in the result.
cheers