Best Resistor type for TW builds.

[John_P_WI]

Make the amp work with current production tubes as NOS is going to deplete your amp building funds quickly.

Mark

+1

[selloutrr]

You can build a perfectly great amp with new production tubes, designing and voicing the amp around them. THe reason NOS tubes have become so popular is back in the day all those vintage amps were voiced with what was then new production tubes. now NOS tubes. Unless your tone is your living and you get paid to capture traditional amp tones. NOS tubes are just a bragging right not a requirement.

From my personal experiences in buying parts and building amps. I've found using top dollar super clear components actually made for a very bright and almost to clean of an amplifier for guitar. It made a great acoustic tone with the Gibson SST but lacked the "hair" of a traditional amp that made it great for a Les Paul. It did handle pedals well, like a Roland JC-120.

If you are a studio guy. simple put it's like a Grace 801 preamp A/B'd to a Neve 1073.

Most of these super spec parts are for hifi building where full frequency truly does matter.

[coolidge]

I use 1 watt PRP metal films, rated 500vdc, about 65 cents each, designed for audio and sound great. Its getting harder to source 2-3 watt power resistors with the required voltage rating, many of the 2-3 watts now are only rated 350vdc max.

[leadfootdriver]

I use 1 watt PRP metal films, rated 500vdc, about 65 cents each, designed for audio and sound great. Its getting harder to source 2-3 watt power resistors with the required voltage rating, many of the 2-3 watts now are only rated 350vdc max.

What are your experiences with metal films? What do they do, or don't do to the sound that made you choose them?

[diagrammatiks]

if you can afford and can source the koa spr's use them.

they are probably the best commercial production carbon films.

they make a great metal oxide as well.

prp's are pretty good for metal film. I haven't used them myself but I've never heard anything bad.

Another alternative is the IRC GS3. It's a thick film metal foil resistor that is a mix of characteristics from metal and carbon film.

[renshen1957]

You can build a perfectly great amp with new production tubes, designing and voicing the amp around them. THe reason NOS tubes have become so popular is back in the day all those vintage amps were voiced with what was then new production tubes. now NOS tubes. Unless your tone is your living and you get paid to capture traditional amp tones. NOS tubes are just a bragging right not a requirement.

Hi,

Not to hijack the thread, but I beg to differ on bragging rights being the reason for NOS tubes. NOS tubes in my experience last longer or is it that the new production don't last as long.

Read all the comments (negative) about Groove Tubes power tubes that Red-Plated, etc, these were supposed to be screened and tested new production tubes in several online forums. I have found this to be the case with power tubes, especially the OEM stuff that originates from China used by Fender, Peavey, Marshall, etc. as to shorter longevity.

In some cases, such as preamp tubes, a used but good testing old preamp tube lasts longer than some new product. Reliability hasn't been the greatest, although some strides have made been made.

And this isn't a big secret, either.

Purchasing NOS tubes depends on where and who you purchase them from. Ebay is a crapshoot unless you get to know the sellers.

I still purchase and use were appropriate New production tubes, as I do want the current manufacturers to keep producing as there is a finite quantity of NOS.

Here is a fact that might surprize you. The Hi-Fi community currently drives the Tube market, the Guitar Amp isn't as an important market segment, money-wise. The reintroduction of most of previously no longer manufactured tubes were for this market. Maybe that's why the Gold Lion re-issues for 12AX7s and power tubes cost so much.

Unfortunately, the Hi-Fi community also gets wind of great NOS tubes and the prices go sky high. The Tong Sol 6550, 5881, any brand of 6L6GA, all of the Red Bank Tubes but especially the 5992 (6V6 on steroids) became expensive and scarce after articles in Vacuum Valley, the days of picking up these cheap tubes at Hamfests are gone. Black Plate 12ax7s, 5751 (SRV made the tube popular before the HI FI tube joined in) Baldwin, Hammond, Conn, Wurlitzer tubes likewise got expensive compared to 3 years ago.

A Chinese 12AT7 works fine as a reverb driver and as a PI in amps with a feedback loop. Sovteks (from which ever tube factory they source from) have there use too, but not in V1 position (although there are some 12ax7LPS NOS that are highly regarded). Valve Arts EL34B are worth a listen.JJ 12AX7 is an all around good tube. The STR (special tube requests) of TAD, Ruby, et al are worth a listen.

I have admiration for some current product tubes, and I commend JJ for reintroducing tubes such as the 7591 and KT77. The KT77, JJ got it right from backward engineering an original. Winged C makes a great 6L6.

However, JJ's 7591 (used in Ampeg and other amps) when tested produced only 15-19 watts instead of 25 Watts. Point in its favor the size is correct.

The current 7591 EH's were closer to the mark (within about 2-3 watts) and are an improvement over the 7591XYZ which were repinned 6L6s and not 7591s, but are quite a bit larger than the original tube.

JJ and EH's distortion figures were worse than the originals, however. Not so much of a problem with guitar and bass amps.

Great strides are being made in improving tube quality and reliability.

End of Hijack.

As to Hi Fi sourced resistors, I use Carbon Film resistors in the signal pathway, PRP Metal Films (also audio quality, and cost about $0.45) for preamp cathode resistors and occasionally in the signal pathway, and Metal Film (another Hi-Fi source) for the Anode resistor for V1 position. I use NOS Carbon Comp or recent production manufactured to the old specifications (not the newer, lower distortion variety) in some apropos places.

I wouldn't use a $3.00 (sometimes $4.25 or higher) for every resistor in an amp.

Best regards,

Steve

[diagrammatiks]

ya hi fi resistors can get very very pricey.

However! and this is a big difference when thinking about hi-fi versus guitar amp designs...

a lot of what's popular right now in hifi has very few components...as few as possible most of the time in the signal path.

[M Fowler]

I have so many parts bins with different types of resistors its getting darn funny looking for the one I want.

I try to get quantity buys from parts sources and sometimes ebay. Local techs are going to be my big source this year as I have already made plans to purchase one retired tech's stash of goodies. He used to wind his own transformers so I will see what has for trannies and chassis as well.

It all depends on what amp your building to me.

Mark

[leadfootdriver]

I've bought a bunch of the Baldwin labeled Sylvania 12ax7's from the 60's. They have strong gain with a wide response. They're pretty nice, with a beefy long plate structure. I think they're screened for quiet operation for the organs, but that could be hype.

That said, they kick the gain like no new production tube I owned. I have a few Raytheon black plates that are real articulate, but don't apear to be as robust as the Sylvanias. I have those in my mic pres.

So, I agree that NOS toobs are good. But I can't spend any more on the more popular brands like Mullard, Telefunken. The prices for those tubes are crazy.

[renshen1957]

I've bought a bunch of the Baldwin labeled Sylvania 12ax7's from the 60's. They have strong gain with a wide response. They're pretty nice, with a beefy long plate structure. I think they're screened for quiet operation for the organs, but that could be hype.

That said, they kick the gain like no new production tube I owned. I have a few Raytheon black plates that are real articulate, but don't apear to be as robust as the Sylvanias. I have those in my mic pres.

So, I agree that NOS toobs are good. But I can't spend any more on the more popular brands like Mullard, Telefunken. The prices for those tubes are crazy.

Hi,

The Baldwin tubes, in fact all the Organ (and Tubes for Hi Fi, too) were screened for low noise, microphonics, and generally read higher on GM than tubes that would have been used in TVs and Radios. Hammond owners often had service contracts that replaced the Tubes once a year. And Hammond sometime sourced its tubes from Mullard, but this was discovered long ago.

I have some Lowery (another Organ company) 12ax7 Blackplates, but the Baldwins are stronger tubes. But judging by ebay the "Organ Tubes" tubes have been discovered, too. Raytheons, too. Soon the only tubes that haven't been discovered will be Delco, Ford, Hytron and other off label tubes.

I use EIs instead of Telefunkens (I keep the TF for my Hi Fi) made on the same machinery as the Telefunken tubes. EI isn't out of business, their website states the factory wasn't destroyed by a Nato bomb hit, but they aren't very active either. However, these are considered NOS tubes (pre-war). The price isn't crazy for these, but you have to either purchase selected tubes or do your own screening.

General consensus is the Re-issue Mullards 12ax7 aren't remotely like the originals, just Sovtek tubes with different chemicals. On the other hand, I have heard good things about the re-issued Tong Sol 5881 and 6550, maybe not equaling the NOS tubes but close enough for Guitar work.

[selloutrr]

part of the reason new production tubes dont last as long as NOS is that they don't handle the higher voltages as well as NOS.

[coolidge]

I use 1 watt PRP metal films, rated 500vdc, about 65 cents each, designed for audio and sound great. Its getting harder to source 2-3 watt power resistors with the required voltage rating, many of the 2-3 watts now are only rated 350vdc max.

What are your experiences with metal films? What do they do, or don't do to the sound that made you choose them?

They are quiet, accurate to 1% or better, and sound great. Not sure why some people feel metal films sound "sterile" these don't. I built a number of 1969 spec plexi's with them and everyone was quite happy. They also have long thick leads ideal for turret construction and don't cost an arm and a leg. I'm building a SLO 100 inspired amp now with them.

[coolidge]

part of the reason new production tubes dont last as long as NOS is that they don't handle the higher voltages as well as NOS.

Or people don't pay attention to the grid voltage ratings for new production tubes. While most EL34 are rated 800v on the plates many are only rated 400-450v on the grids. This is why I use SED Wing =C= tubes which are rated 500v on the grids.

[leadfootdriver]

I've bought a bunch of the Baldwin labeled Sylvania 12ax7's from the 60's. They have strong gain with a wide response. They're pretty nice, with a beefy long plate structure. I think they're screened for quiet operation for the organs, but that could be hype.

That said, they kick the gain like no new production tube I owned. I have a few Raytheon black plates that are real articulate, but don't apear to be as robust as the Sylvanias. I have those in my mic pres.

So, I agree that NOS toobs are good. But I can't spend any more on the more popular brands like Mullard, Telefunken. The prices for those tubes are crazy.

Hi,

The Baldwin tubes, in fact all the Organ (and Tubes for Hi Fi, too) were screened for low noise, microphonics, and generally read higher on GM than tubes that would have been used in TVs and Radios. Hammond owners often had service contracts that replaced the Tubes once a year. And Hammond sometime sourced its tubes from Mullard, but this was discovered long ago.

I have some Lowery (another Organ company) 12ax7 Blackplates, but the Baldwins are stronger tubes. But judging by ebay the "Organ Tubes" tubes have been discovered, too. Raytheons, too. Soon the only tubes that haven't been discovered will be Delco, Ford, Hytron and other off label tubes.

I use EIs instead of Telefunkens (I keep the TF for my Hi Fi) made on the same machinery as the Telefunken tubes. EI isn't out of business, their website states the factory wasn't destroyed by a Nato bomb hit, but they aren't very active either. However, these are considered NOS tubes (pre-war). The price isn't crazy for these, but you have to either purchase selected tubes or do your own screening.

General consensus is the Re-issue Mullards 12ax7 aren't remotely like the originals, just Sovtek tubes with different chemicals. On the other hand, I have heard good things about the re-issued Tong Sol 5881 and 6550, maybe not equaling the NOS tubes but close enough for Guitar work.

I bought a bunch of Ei's in the 90's, and they sounded great. But most of them were unpredictable with microphonics which is a shame. I still have 5 for reference.

[leadfootdriver]

I think I'm gonna' go with the 1 watt Takman Metal Films. They're pricey tho. I wanted to get enough for 2 builds, but the price goes up fast!

I priced them at Parts Connection. Is there a better vendor? http://www.partsconnexion.com/resistors ... _watt.html