Hi guys,
Came across an interesting blog & wondering has anyone build an amp base on the description in this blog :
truefi: DHT tubes
Thks
Came across an interesting blog & wondering has anyone build an amp base on the description in this blog :
truefi: DHT tubes
Thks
There are a lot of WE 91 type clones out there which were build based on the circuit of WE or (mostly) cut the first pentode out, as the original had ultry low input voltage sensitivity.
Joe Roberts, who edited the old Sound Practices magazine, drew up a modified, 2-stage 91-A clone that sparked a minor rage in the early 90's. It's still a great circuit.
Hi Guys, thanks for the reply. What's also interesting about this blog is that he encourages the use of triode connected nos pentode/tetrode output tube citing that it sounds better then present day 300B tubes.
Hi Sumotan, where did you find reference to WE-91A using anything other than 300-B output tube?.
FWIW, I'm ordering pair of NC-20FII and FC-30-3.5S from Osawa-san this week, finally compare the ISO OPT to MM S-9.
EDIT: I've since found the link which hints at what you are referring to. I can pick it apart by using HIS extremes, stating 10-20k for a pair of WE 300-B, and I don't see any mention of modern day 300-B types. For a SE amplifier, I have found a well sorted pair of JJ 2A3/40 run as 300-B to be quite the thing, and at 75 times less than his upper 'estimate' for the original types. Works out to ~USD0.056/hr based on 10,000 hr service life.
Also, I would not be happy with the build quality as displayed within his pictures. I've seen this a few times, one notable German 'seller' come to mind, I digress.
HK
FWIW, I'm ordering pair of NC-20FII and FC-30-3.5S from Osawa-san this week, finally compare the ISO OPT to MM S-9.
EDIT: I've since found the link which hints at what you are referring to. I can pick it apart by using HIS extremes, stating 10-20k for a pair of WE 300-B, and I don't see any mention of modern day 300-B types. For a SE amplifier, I have found a well sorted pair of JJ 2A3/40 run as 300-B to be quite the thing, and at 75 times less than his upper 'estimate' for the original types. Works out to ~USD0.056/hr based on 10,000 hr service life.
Also, I would not be happy with the build quality as displayed within his pictures. I've seen this a few times, one notable German 'seller' come to mind, I digress.
HK
Last edited:
Hi Hanze
Read the blog it's detail in there. It was this that made me curious as to how it would sound using other then 300B tube.
Read the blog it's detail in there. It was this that made me curious as to how it would sound using other then 300B tube.
Different tubes sound different.
I build a SEP amp using F2A and Tamura permalloy/ Lundahl iron. It lacks the sweetness of a real triode but I can live with that. Most important is, it makes forget the tube amp and let focus on music and its drama. Its very emotional, same as every 300B. But each tube has its own sound signature. If I change from Mullard EL84 driver to a Funken tube, that sonic signature is clearly audible. Each part of an amp is important, so never focus on only one part. You should have the whole concept of the amp in focus.
I build a SEP amp using F2A and Tamura permalloy/ Lundahl iron. It lacks the sweetness of a real triode but I can live with that. Most important is, it makes forget the tube amp and let focus on music and its drama. Its very emotional, same as every 300B. But each tube has its own sound signature. If I change from Mullard EL84 driver to a Funken tube, that sonic signature is clearly audible. Each part of an amp is important, so never focus on only one part. You should have the whole concept of the amp in focus.
Attachments
Not so expensive compared with commercial gear, it's way more fun, and there's resale (and possibly more if Hirata is any indication) in those items. I can't see any other way to try it out.. and life is getting shorter 🙂
HK
Very true Hanz life is really getting shorter. I've got still a handful of projects that needs to be build or completed . Lol Re 300B, I'm going 2 stage with Rod Coleman's shunt cascode drive. Hope to be able to start on this project by next year.
Cheers
Cheers
Heppy 80th Birthday will hit you squarely, mine did...
Hi,
Hello,
Over the Covid duration since March, 2020 I've been collecting OTs, ITs, tubes, caps, resistors, traffos for Coleman regs, wire, ...on and on. Much yet to build. Back to my 80th birthday...
I was sitting on the pot and I said to myself..."Holy **** Bozo, you're 80 years old, and then I muttered "you'd better get the F to work!" How?
Well, I've been alternatring between two Loftin-White amplifiers in my main systeme...1. 24A/45/JS-6123H, and 2. EL84/2A3/FS030, so I placed orders with Jac for EML 45 Mesh and 300B-25 Mesh pairs to spice up those amps. The 45 Mesh is playing nicely now and the 2A3 is on the bench. Groovin' with Dexter Gordon GO in the meantime.
Gotta' go now...more later...meantime, I'm resurecting a pair of Bruce Edgar midrange horns to try on my Lowther PM2As...thanks Joe Roberts (SP 6) and
Walter Clay.
Like I said, gotta' go, Best Robert
Hi,
Hello,
Over the Covid duration since March, 2020 I've been collecting OTs, ITs, tubes, caps, resistors, traffos for Coleman regs, wire, ...on and on. Much yet to build. Back to my 80th birthday...
I was sitting on the pot and I said to myself..."Holy **** Bozo, you're 80 years old, and then I muttered "you'd better get the F to work!" How?
Well, I've been alternatring between two Loftin-White amplifiers in my main systeme...1. 24A/45/JS-6123H, and 2. EL84/2A3/FS030, so I placed orders with Jac for EML 45 Mesh and 300B-25 Mesh pairs to spice up those amps. The 45 Mesh is playing nicely now and the 2A3 is on the bench. Groovin' with Dexter Gordon GO in the meantime.
Gotta' go now...more later...meantime, I'm resurecting a pair of Bruce Edgar midrange horns to try on my Lowther PM2As...thanks Joe Roberts (SP 6) and
Walter Clay.
Like I said, gotta' go, Best Robert
