1N4007 vs. UF4007?

[El_Martin]

TNX for the info, Larry!

Filters are F&T, cathode bias.
Going to try the poly caps.

Ciao
Martin

[JimiB]

Yes, I have a .1/1100V Polypropylene directly on the diodes from plus to minus and another .047/1100V after Standby just in front of the choke.

Larry do you have a drawing or can you clairfy this a bit?

[novosibir]

It's already clearly explained!

Just a Polypropylene from B+ right after the diodes to ground, to the diode's minus side. And the same after the Stby again from B+ to ground.

Larry

[ampgeek]

Hey James,
I belive that Larry is describing the cap addition to a bridge type rectifier plan.
Dave O.

[novosibir]

I belive that Larry is describing the cap addition to a bridge type rectifier plan.

... to the diode's minus side.

Yes, that's valid for a bridge rectifier pattern. If you have the two row rectifier (don't know the exact description in English), the type with the CT to ground, then the cap has to be placed between B+ and ground, in this case as close to the CT's ground as possible, to enhance its efficiency.

BTW: The only rectifying w/o any switching noise (and where an additional cap isn't necessary) is a tube rectifier - but only a 'real' tube rectifier, not the Weber copper caps.

Larry

[ultramega]

[quote="Normster"]Totally off topic, but every time I see one of Larry's builds I want to hang up my soldering iron and call it quits. Beautiful work!!![/quote]

Wow. just had a look at Larry's amps. They look amazing!
That Dino is just gorgeous

[drhulsey]

Totally off topic, but every time I see one of Larry's builds I want to hang up my soldering iron and call it quits. Beautiful work!!!

Those gut shots look like an artistic composition rather than an electronic layout

[Analog Assassin]

Very important! Don't forget the UF also for the bias supply!

Larry

I was going to ask that. I recently rebuilt my bias supply. I've got a tube rectifier, and I was wondering if better diodes made a difference there.

[sebastian]

It's already clearly explained!

Just a Polypropylene from B+ right after the diodes to ground, to the diode's minus side. And the same after the Stby again from B+ to ground.

Larry

Hallo Larry!
Marshall uses a kind of this configuration on JCM/JTM60 range,and in JCM2000 DSL use a 1nF across each rectifier diode.
I also build amps with strong marshall sounds,I play hard rock and heavy metal so I prefer 80' and 90' Marshall.My impressions:

A bit OT....

I use only for real Marshall tones ARS 50+50mF capacitors.I tried JJ,FT,TAD ecc ecc but no one match the sound of the ARS,very close to the old LCR's (there are also some LCR nos in the market?????? ??? )
I use custom wound transformers,some build with vintage specs and some custom builded with respect to inductance,CC resistance,iron grade but with more modern interleavings,as in JCM900 OT.The sound is wonderful,only more midrangey and a bit bright.Here in Italy I don't find any builder that use 1.5" (38mm) iron lamination because the standard in Europe is 40mm.Changin the width of the core I have reach good results fortunately.In Germany there is Shinrock but Ingo is not very serious and I'm waiting a transformer from 1 year (already payed) !!!!!

All the info about power transformer for a 100 watt classic 70-80 Marshall amp in internet,aren't very correct.The exact voltage of HT winding in early 70 late 60 of some Marshall PT was 180+180 volt with a lot of current.Modern replacement are very weak,175+175 volt (that are fine) 0.58-0.6 Ampere.Biasing a 2203 correctly,with this kind of trafos,make the B+ go down until 420 volt !!a bit low in my opinion.I tend to use 350 volt center tap (that often I don't use) 0.7A-0.75Atotal ,that is correct for the Dagnall T4145 80's specs and the B+ stabilize itself on about 435-440 volt.Only with a strong secondary of 380 volt center tapped rated at about 0.9-0.95A the B+ raise at 470-475 volt under load!! the current is the current of the full HT winding. What do you think about the HT secondary current for a "good" 2203 replica (that I will add with a hot rod mod,for Slash style sounds,or add a tube for select from 2203 std/2203 hotrodded)

2203 rulez!!

Not OT :
I also used some 5408 instead 4007 and the sound is more clear,but sweet,despite I don't use UF type....
I try this UF .....

Sebastiano

[Trace]

Try the Polypropylenes, as suggested above and maybe better go with F&T's or Sprague's as for the filter caps.

I tend to hear and feel a pretty big difference between the F&T's and the Sprauge's. I prefer the F&T's as they feel more open and smoother, perhaps less grainy? It's hard to put into words but there is a big difference in the feel of the amp when A/B'ing different filter caps.


In my humble opinion
Trace

[novosibir]

I use only for real Marshall tones ARS 50+50mF capacitors.I tried JJ,FT,TAD ecc ecc but no one match the sound of the ARS,very close to the old LCR's

ARS I've never tried yet, but found out, that F&T's come closer to the LCR's soundwise and concerning the amp's behaviour than TAD's or JJ's

(there are also some LCR nos in the market?????? ??? )

If I still haven't buyed it
Yes, I may be lucky, since I still have a whole bunch of the NOS LCR's from the early 90' Shure, they require a long forming process, before you fire up the amp the first time, but they are an essential part of the amp's tone and barely compensable with another electrolytic.

In Germany there is Shinrock but Ingo is not very serious and I'm waiting a transformer from 1 year (already payed) !!!!!

I've tried Shinrock's in the late 90' sometimes and it was me, who turned Ingo into the right direction at all, how to build 'correct sounding British iron' - and I still have some of his experimental OT's sitting on my shelfes, just good for keeping books upright. But even after his irons were right, you can't drive a business with a supplier, who promises 6 weeks and delivers after 4 months and tells you the blue from the sky, what all has happened.

Meanwhile I've heard, that one of his daughter does have very serious health problems, what of course takes his energy. Furthermore keep in mind, that Ingo has a regular job at the police and therefore can wind transformers only in his leisure time.

Larry

[novosibir]

It's hard to put into words but there is a big difference in the feel of the amp when A/B'ing different filter caps.

True words!

Once I've tried the in HiFi circles high regarded Mundorf electrolytics in one of my British Purist - and was extremely disappointed of the result.

All the electronically parameters of these caps have measured great and promising, but the amp was dead after the swap

A sound - nice, clean, free of any ghosting, literally like 'polished', but way off of any kind of vintage sound, no character, no raunch, no grind - nothing has remained. Still in the same night I've swapped back a fresh set of LCR's into the amp - and after the forming process I've been happy again. The furry, woody sound with the chunk & grind and the nice shimmering sparkles on top of the notes was back again - aaaaahhh

Larry

[Trace]

True words! Once I've tried the in HiFi circles high regarded Mundorf electrolytics in one of my British Purist - and was extremely disappointed of the result.

I can relate to this as well. This is hard to put into words but in my experience; Having tried high-end products (IE: caps, transformers, etc) that are intended/manufactured for the hi-fi world, seldom seems to work in guitar amps. Granted there is cross over with some components and I support using high quality products in guitar amps however the results can be too serial or uninspiring.

I have gotten good results with using certain Scott output transformers in guitar amps but then again back-in-the-day Scott amps were not consider top-of-the-line in the hi-fi world so perhaps this explains it however on the opposite side of this I have used certain Macintosh OT's with great success though these were custom builds. Granted you had to be much more fussy/particular with all value selections in the circuit. These are rare examples where the cross over from hi-fi to guitar amp yielded great results.

I suppose it stands to reason that the over all concept of hi-fi is to try and replicate everyone as accurately as possible where as guitar amps do not follow the same concepts. In the end it's all about what ever works best to achieve what ever goals you are trying to attain (IE: the end justifies the means).

All the electronically parameters of these caps have measured great and promising, but the amp was dead after the swap

Agreed and more times than not this is what I also have experienced.

A sound - nice, clean, free of any ghosting, literally like 'polished', but way off of any kind of vintage sound, no character, no raunch, no grind - nothing has remained. Still in the same night I've swapped back a fresh set of LCR's into the amp - and after the forming process I've been happy again. The furry, woody sound with the chunk & grind and the nice shimmering sparkles on top of the notes was back again - aaaaahhh

Again I agree with you. For the characteristics that we look for (or rather what you have described) we prefer to use F&T's. They seem to give the best of both worlds. They are not as cost effective/cheap as other filter caps but they do seem to be the best over all and they work very well in a wide variety of different amps. Hopefully they will not follow the path of modern tube manufacturing and change the design after a few years (ha, ha).


Have a great day
Trace

[Analog Assassin]

I've never heard of F&T's. Where do you get them?

[sebastian]

FT in my opinion sounds a bit more rounder and darker than LCR'S but are great caps!! I use ARS from arselectronics,the same that Marshall uses on handwired series,on 2203x,1987x ecc ecc.ARS are bright sounding but with the complex mid range and tight bass very similar to LCR.LCR are a bit (very few...) darker and with better midrange but ARS sounds great and seem to improve the power and clarity of any amp only changing filter caps (compared with amps with NEW capacitors).ARS seems to have some little problems of ghost notes in some fret positions but in the end are good!!
I tried TAD gold caps(standard in a Marshall 2203x from 2000 to 2002) ,sounded bad,spongy!!! I don't know if Gold caps were made by FT in germany or Ruby in china....Then I tried JJ 50+50mF 500 volt,and puahhh...
ugly caps,the sound at low levels is very warm but lacks detail,the bass is confuse,mids are scooped and highs began piercing .Very low in current capability,low power perception,I think that I lose about 10-20 watt from power amp with JJ caps!!!

If I have to make a good sounding amp without turn to madness to search good caps,or spend a lot of money and duty taxes buying ARS from California,I prefer to use some "internal mounted" Panasonic ,Nichicon or Samwha capacitors,sounds A LOT better than JJ or TAD and are cost effective.