Re: 6SN7 amp initial report

Phil S. schrieb:
"jh" <jh@xxxxxx> wrote in message news:gmmah0$7gf$1@xxxxxxxxxxxxxxxxxxxxxx
Hi Phil,

great....
Yes, feels good to get any sort of result that works. This, as you know, is a true Franken-amp.

Just a few /very little) comments
AFAIK the C12R has a lousy efficiency, the weber surely does not. If it's a real Blue Alnico clone, then it's supposed to be a very loud speaker. Might be th best result for "headroom"

OK, I will try the Weber next. Yes, AFAIK, it is Weber's clone of the bulldog, but no, this one is ceramic. The Alnico is rather expensive.

With the intermittent 6SN7, if pressing the glass in to the base helps, you might try to carefully resolder the pins. I've revived more than one tube...
Yes, pressing glass from the top makes it work. I don't understand what's involved here. I need to remove the base? How is that done without breaking it?

Hi Phil
I'd simply try to reflow the tube pins. If it works - ok, if not - nothing lost. The pins a re just small tubes with the wires coming from the base sticking through. If you've got a cold solder joint there, it will fix it, if the wire is broken at the base, it won't and you've got a nice tube for display....


With the distortion analysis (tubes vs transformers), i guess it's really time for a scope now. My first scope (that i really miss) was an old Tek 561? (i'm not at home to look what it exactly was) Two trace, differential input, max 20MHz. It served me really well for years, Real big mother, enough heat to warm a room, but great low level results, perfect for audio work. Really tough regarding abuse - applying 550V DC while in mV settings etc. I only realized what i lost, when I had the replacement. Also a tek, but a fairly recent one (2225 or something like that).
I bet they are dirt cheap, because they are much too slow for digital analysis. I bought mine in 93 for 120DM then (~60$) it was from an old university stock.

The language of scopes is confusing to me. This small explanation is helpful. You're saying I can get the kind that no one wants anymore. I started to watch auctions on eBay to see how the bids end. As for brands, you and Steve Cowell like Tek.

I've had/have two teks and have tried one cheap "sino all bells and whistle" scope for at least 15mins. REAL shitty flickery display, unstable, it just did not feel right. Sent it back immediately. Fortunately the TEK arrived from an ebay buy at the same time.

I know, that Steve advises against old tube scopes. I for myself have been a real happy camper with the (partly tubed) 561A. Especially the 3A3 diff amp is something i clearly miss. I know, that i'll recreate/reuse that plugin someday.
I never had any problems with the scope, until it simply refused to work. OK the guy i bought it from was xactly this grumpy old man with a basement full of TVs, VCRs and what not to fix and he told me that it was in perfect working order.
Beeing partly tube it's not one of those colossus scopes; it's about 2x the size of my TEK 2225

BTW the first and only probe that really failed her *was* the tek probe that came with the 2225. It also had that fixed ground wire which is always where don't want it to have.
My other probes *are* an assortment of cheapo probes ranging from 1:1/1:10, 1:10, 1:100. Never had real problems, other than a hook.

just my 02cts.

regards

Jochen

What else is OK? HP? BK? I thought it
would be nice to get a smaller "desktop" model. What's up with probes? They seem expensive.

regards

Jochen

Meanwhile, we are having an unseasonably warm day today, in the 60's (15C) and it will be calling me away from the workbench, which is in the basement.

Phil


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Relevant Pages

  • Re: 6SN7 amp initial report
    ... I'd simply try to reflow the tube pins. ... really time for a scope now. ... Also a tek, but a fairly recent one (2225 or something like ... BTW the first and only probe that really failed her *was* the tek probe ...
    (alt.guitar.amps)
  • Re: 6SN7 amp initial report
    ... I'd simply try to reflow the tube pins. ... really time for a scope now. ... Also a tek, but a fairly recent one (2225 or something like ... BTW the first and only probe that really failed her *was* the tek probe ...
    (alt.guitar.amps)
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