Well, what should I do with the T1RVT

zulu

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(Memo to file: hold on the cloth until the speakers are test-fitted to their ferlingheimers.)
That would be the gist of it, I do believe.
Eh ... you might want to avoid mentioning exactly why you need it
Agreed. It's best they not know every single detail.

"I got to modify, I got to modify, I've got to modify my new custom built speaker." What key is that in?
Admittedly my hunny isn't super-musical, but it's in c# plus abut 5-25 cents mostly monotone minor major 7 natural 3rd flattish 5, which adds to the "catchyness" or "bustin' chops" effect. Gotta love 'er.

Can I put the Mullards in???? Okay ... but before hitting a note, pour some Scotch or Stoly over ice ... keep it in easy reach.
'nuff said, I'll pick out a nice single malt for the occasion. Sounds like a dram good idea. If I spill it on my amp, who shall I hold liable, John?

Love a good customer service story, even about bell-ends. Weber USA quality speakers- now aint that America.
 

capnjuan

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zulu said:
... Sounds like a dram good idea. If I spill it on my amp, who shall I hold liable, John?
...... Coastie.

After you settle in with your revived amp and if you're still interested in wringing everything you can out of it without carving up the circuit, two further moves are updating the output transformers and changing out the inter-stage coupling capacitors. Neither offers the bang-to-buck ratio of caps/speakers/tubes but will still clean the signal up ... just not as noticeably as the other upgrades. After mentioning the output transformers, matching the 6GW8 output tubes to a suitable transformer poses some issues but it can be done.

The caps are more about flavor; they would change the amp's tenor but you'd enter the realm of "some say to-may-to ... some say to-maa-to" (but I'd like to point out that no one says lum-baa-go) or "does so ... does not ... does so". The existing caps are what Guild put in as a compromise between cost and function; what you have is what the amp did when it came out of the show-room. New coupling caps will not make it into a Supro, tweed-era Deluxe, or a black-face super reverb but they will alter the tone ... it's the for 'better or worse' part where the discussion steps off the end of the pier. I'll say this and move on; today's caps of whatever type are better-made and work considerably better (leave less tone imprint) than stuff from back in the day ... so it's a choice between memorializing the amp's original tone v. squeezing maximum performance out of what you have.

Some very conscientious people argue that if you want to screw around like that, buy a junker or build something ... don't 'wreck' something. These people also rarely admit to, somewhere along the line, having engaged in the conduct they now denounce ... that is, there's no partisan like a reformed partisan. Most recently, I've been using Mallory 150s or Weber/Mallory dupes ... metallized polyester film ... transparent, a little softer to my ear than polypropylene, compact, and inexpensive. At the other end of the spectrum is PIO/paper in oil ... I don't have any experience with them but if you want to max out what you have and take any chance of under-doing quality off the table, they are the way to go ... 5-10 time more expensive than Mallorys. John
 

zulu

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zulu wrote:
... Sounds like a dram good idea. If I spill it on my amp, who shall I hold liable, John?
...... Coastie.
somehow I think Coastie will find an exemption in the fine print.


Output transformers, inter stage coupling caps (hmmmm... with my paint-by-numbers amp tech experience, can you give me a hint as to what part of the circuit these are? at the inputs?),
food for thought J thanks. as far as Tomatoes, I prefer having the option of "t'mater" as well, depending upon company.

I've heard of people using/replacing tone caps in guitar wiring with those PIO caps.

I am itching a bit to start the Ampeg. Goal would be to use as a guitar amp (6L6 mod?), paired with a 2x12 cab (output step 16 to 8 ohms?), for stage use with effects pedals. I'll start a new thread soon with a rundown on the problems with the amp (ie, always ran it with 8 ohms or less load, oops), and I really appreciate your offer to help with it.

pour some Scotch or Stoly over ice
-out of curiosity, whats the preferred flavor over at juanzampz?

Z
 

capnjuan

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zulu said:
Output transformers, inter stage coupling caps ... I've heard of people using/replacing tone caps in guitar wiring with those PIO caps.
Hi Zac: the OTs are the two, smaller rectangular chunks on the tube deck .. more on them in a minute. Below is a rough match between the schematic and your amp ... not guaranteeing that I've ID'd all of the coupling caps in the photo:

Thundercaps.jpg


Brief lecture: downstream of the rectifier, all the power in the amp is DC ... the musical signal is AC like the typical sinusoidal waveform you see on an oscilloscope. Except for the trem section, each successive stage that the signal passes through amplifies the signal using DC power. Having been amplified, the signal is passed through a coupling cap to the next stage.

The reason a straight wire isn't used is the presence of DC. The AC signal passes through the coupling cap but the cap blocks the DC ... otherwise the following stage ... and all the stages thereafter, would receive and amplify the DC and that produces a highly undesirable screech. So ... what's needed is a way to connect stages but block DC ... interstage coupling caps. The term 'coupling' refers not to type but to application.

Yes; PIO caps are popular in guitars as tone caps. One of many properties of caps is that, depending on size/uf value, they are frequency selective; small uf caps pass high frequencies but not lows and large uf caps pass low frequencies but not highs. In a guitar, as the tone cap is rotated from treble to bass, more and more high frequency is shunted to ground because it - and not the bass - pass through the cap because the cap is a smallish value; that is to say you aren't adding bass, you are bleeding off treble.

Since you only need 2 PIO caps for a two-pickup guitar (don't have to spend alot), lots of people put them in for the same reason they put them in amps ... the belief that they'll max out the tone ... as do the boutique amp makers like Clark and the others who use Sozos, Jupiters, and ????????? ?????????? ????? (various Russian brands). To be argumentative for moment, if those polycarbonates(?) in your amp and the Mallorys I use were so well thought of by the high-end crowd, they'd be using them and not PIOs, no?

The biggest risks (apart from burning your finger or nicking nearby insulation with a soldering iron) are that after so much work, your expectations aren't met and it's arguably 'violative'; you can justify all your moves to date as heavy maintenance, go further and anyone looking for a stock T1 RVT won't consider your amp or, if they do, discount it no matter how good it sounds.

The OTs: the reverb transformer is easier to find that the primary ... owing to those 6GW8s and their oddball internal resistance. The primary OT would probably have more affect on perceived volume and clarity although if you're going to do one, you might as well do both ... I mean if you don't but decide later you want to, it means dragging the chassis out one more time.

zulu said:
I am itching a bit to start the Ampeg. Goal would be to use as a guitar amp (6L6 mod?), paired with a 2x12 cab (output step 16 to 8 ohms?), for stage use with effects pedals. I'll start a new thread soon with a rundown on the problems with the amp (ie, always ran it with 8 ohms or less load, oops), and I really appreciate your offer to help with it.
Ok; sorry ... it's been so long ago ... B25 / 7027s? Whenever you wish.

Stoly .... although Absolut is ok too (burp :wink: ) J
 

zulu

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Still digesting this last post John. Meanwhile having fun with the amp. To date, I have not tried out any of my cool tubes from Coastie. waiting for the right moment. I have acquired a suitable beverage for the occasion, just waiting for some extended 'quiet' time.

Otherwise I'm lovin' it!

The Starfire is rockabilly/ surf / jazz heaven. The Strat is spaghetti western joy. My only humbucker guitar, the Nightbird, really brings out a nice smooth crunch at about %70 volume. With the amp tone controls near full, it will break up sooner.
The tele, eh, not so much, doesn't bring out the "teleness", but three out of four aint bad.

The only thing I would change about the amp right now would be to see if we could slow down the tremolo oscillations. Speed control works fine, just wish for a little slower trem in some cases. A very minor complaint.

Thanks again for everything John.
 

Bill Ashton

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John, your short monograph (this isn't a stereo amp, right?) on the coupling caps was great.

I think Don should start a section just on electronics tutorials...got lotsa spare time? :D
 

capnjuan

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Bill Ashton said:
John, your short monograph (this isn't a stereo amp, right?) on the coupling caps was great. I think Don should start a section just on electronics tutorials...got lotsa spare time? :D
Hi Bill; glad you found it useful (yes, mono :wink: ) When you consider that we ampistas are the lunatic fringe, we should just be grateful that Don and the others tolerate us.

Time?
 

zulu

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I told capnjuan I'd pay a buck a question, but he likes to trade, so now he has a listing battleship.
 

capnjuan

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zulu said:
... The only thing I would change about the amp right now would be to see if we could slow down the tremolo oscillations.
Well ... at first I was going to apologize for having missed this post until I realized that I hadn't missed it all ... I'd ducked it ... :oops: :lol:

As a famous philosopher once said: "A man's got to know his limitations ..." and adjusting trem speed exceeds mine ... This is results of a Search on the Hoffman Bulletin Board dealing with slowing down trem speed. As usual the discussion focuses on Fender amps but the reading is good. It can be done but my suggestion would be to join/long in, introduce yourself ... (no point in saying you're a noob if your question is going to expose you as one so) ... 'Hi; my name is Zac (optional: 'I'm a noob') and I was wondering what parts I can change to slow down the tremolo in my Guild T1 RVT ...' Don't forget to give them the link.

There's some possibility of getting a little scorn (you'll be in the Land where Fender is the one true Amp) ... there are some very strong people there and if you get a response you don't understand, send me a PM. The only other comment I have 'is how slow might be too slow' (or not slow enough) and I think - but am not sure that - if you slow it down, you loose the fastest speeds ... this may not matter ... and might not be true anyway. Good luck! J
 
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