Dave Funk's Tube Amp School

[rooster]

OK, in the hopes of Dave returning here for a post, I have a question for him....

I have your book and always keep it handy. Too, I have all the period VG mag articles where you 'wrote' your book or displayed your book publicly - I'm not sure which came first but I think the later. Either way, I pesonally have learned much from your information sharing and I thank you.

OK, my question: Why doesn't the estate of KF publish or get permission to publish all of the articles that he wrote for them? I here recently pulled what I have of them - maybe 30 issues with Ken's articles - and reread them. Its still good stuff with plenty of character insight and amp tech info. So? I know you talked to him more than a few times and that you must know his wife and family. I would buy a book with everyone of those articles in it, no problem. Wouldn't this be a relatively easy thing to do - even on a small scale?

Please get back here and fill me in. And Dave? I realize you are not responsible for the well being of Ken's family and estate, but if the tables were turned, and it was you who passed way too early, wouldn't you appreciate it if one of your amp buds/fellow VG mag writer took an interest in your family's well being? I'm just saying.

[novosibir]

I have never seen a single informational post from Dave in any of the major forums that was just helpful.

He did, but it's already long ago! Maybe at a time, as TAG, TGP, HC, aso. still weren't alive?

Look here and scoll a bit down, then you'll find posts from Dave a few times:

http://xoomer.alice.it/augiuliv/amps/tech1.html

That's a part of this site:

http://xoomer.alice.it/augiuliv/amps/

Larry

[DonMarko]

Hi All.
First post, sorry its a bit off subject.
Hey Rooster A lot if not all of Ken's VG writings are in G.Webers second book "Tube amp talk for the guitarist and tech" as the Trainwreck pages.
Completely different to the Angela Inst Trainwreck pages in his first book.
I've been lurking around here for a while and I dont see these writings mentioned often.
Great forum.
Thanks
Mark

[rooster]

Ron - Didn't know that, thanks. How deep is it? For example, KF has a whole page and 1/2 dedicated to discussing home hi-fi, another review or two of things like the Klon Centaur and a Z amp or two. See what I mean? This kinda stuff can't be in the GW book, can it?

Anyway, how much $$ is the KF family seeing for this publication? I know for a fact that GW is not a very generous guy. Eh, well, thanks for the headsup, Ron. I will browse that book next time I find a copy, see what is up.

Dave?

[rooster]

Oh Oh Oh - I forgot to mention this. I also found a tidbit in the VG mag KF column where Ken talks about a contest put on by Marshall. It was a contest for 'the best blues tone from a Marshall amp', the prize was a new Bluesbreaker combo and a brand new LP Standard. Ken talks about his method of biasing and then goes on to say that - in particular - you want to keep the EL34 within the 30-40 ma range. ?? I find this pretty interesting because there seems to be a consensus here, beginning with Glen, to hit the 45ma mark. ?? So here is Ken saying something different. He also mentions in a different article that he like the Mullard EL84, but he equally likes 'the standard Sovtek EL84' (the 'M' version is not mentioned, BTW). He says it is almost as good sounding. Interesting, eh?

Oh. The amp that KF biased for his gtr playing friend, Dan (I can't remember), did win the contest with Dan's incredible playing apparently. All of which Ken used to stress his particular method of biasing.

.........I mean, wouldn't you like to read stuff like this and have it around to refer to?

[Dai H.]

I have never seen a single informational post from Dave in any of the major forums that was just helpful.

He did, but it's already long ago! Maybe at a time, as TAG, TGP, HC, aso. still weren't alive?

Look here and scoll a bit down, then you'll find posts from Dave a few times:

http://xoomer.alice.it/augiuliv/amps/tech1.html

That's a part of this site:

http://xoomer.alice.it/augiuliv/amps/

Larry

yeah, he has but not in recent years as far as I know. Example:

UPS, ISP, OT Check, New TFunk Amp

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Posted by Dave Funk on August 05, 2003 at 21:21:02:

Been out of touch for awhile, and have some comments.

UPS doesn't suck. Their policy is if it breaks it wasn't packed right. Marking fragile on the box means NOTHING. If you want the best chance of no breakage... ship it red or blue. Reason? The DRIVER loads and unloads those packages from the trucks.

ISP? I use Orange County Online (OCO.NET). Being in CA they provide excellent service at excellent prices. When you call, you usually talk to the same guy, and they offer everything you could want.

Just got a SoundCity (Sounds Shitty?) that a friend bought at a NY guitar shop. Yes, it had low output and the OT was blown. Resistance checks won't do much. The real test is power output on the bench. This one did 10 watts. S/B 32. Want to test for primary impedance? Here's a simple test.

Attach a proper load impedance. Attach a 10K pot wired as a variable resistor (tie the center terminal to one of the side terminals) to one side of a signal generator with the second lead to one of the plate wires. Attach an AC voltmeter across the variable resistor, and another one across the transformer primary (plate) wires. Apply signal. Adjust the variable resistor until the voltage drop across it equals the voltage drop across the transformer. Measure the resistance across the variable resistor. That's the primary impedance.

The primary normally burns first as it has the smaller wire, and is usually the first winding on the former, meaning it's the most buried and therefore the hottest.

Classic signs of a blown OT. Low power out (therefore distorted). The inverter distorts before the output, meaning the output is now reproducing a distorted drive signal.

If you're trying out an amp and it has low distorted output, plan on replacing the OT before you figure on a fair price.

Working on a new amp. Spent a couple of days with a collector, and compared all three Trainwrecks, Soldano, Bruno, Trainwreck, Triggs, Dr. Z, Orange, old Laney, Sound City, Hiwatt, Matchless (no, actually we didn't bother), high voltage, and low voltage Thunderfunks, Vox, Kelly, Marshalls (actually we didn't bother with these either), and would rank them this way:

Clean: Triggs, Laney, Bruno
Dirty: Trainwreck, TFunk, Laney

Best all around amp? The Laney.
Best of the new amps? (TFunk guitar amps don't count) Bruno, and Dr. Z.

We also identified 6 qualities, which are:

Thonk, Howl, Sing, Chime, Crunch, Buzz

Buzz is bad. Chime comes from EL84's. The only amps to sing were the TFunks and the Trainwrecks. Singing is the harmonics that come when holding a note. The Soldano SLO-100 was fun, but didn't sing. Mike's circuit mixes out-of-phase clean into the dirty, and is suppose to control the distortion, and yes it does, and is probably why it doesn't sing.

Going back this weekend with a difference. I wired a couple of amps with outboard plugs to make transformer swaps, and will compare different winding designs. Early results show that a new VOX proto transformer I had made were excellent. Will take notes as well as record the sessions again. Will publish more later. The goal? Design a new two channel non-switching amp that has the best clean and the best dirty in the same amp. Interesting stuff to come.


Dave Funk

How to Tell What Speaker Impedence is Expected...

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Posted by Dave Funk on August 08, 2003 at 21:43:14:

In Reply to: How to Tell What Speaker Impedence is Expected? posted by Sue on August 08, 2003 at 19:45:23:

This is a good question. The first thing you need to measure is the output transformer's primary impedance. I recently explained a simple way to do this.

!!!THE AMP SHOULD BE OFF AND THE DC VOLTAGE DRAINED!!! The tubes can stay in.

1. Connect a speaker load of the expected impedance to the speaker jack.

2. Tie the center wiper terminal to one side or the other. It doesn't matter which side. The pot should be 10K. The taper doesn't matter. Tying the wiper to one side makes it a variable resistor.

3. Connect one lead of a signal generator to one side of the variale rsistor. It doesn't matter which side. Connect the other side of the variable resistor to one of the primary plate wires.

4. Connect the second lead of the signal generator to the other plate wire.

5. Attach AC voltmeters across both sides of the variable resistor and across both plate wires.

6. Measure the AC voltage across the variable resistor and the primary wires, and rotate the "pot's" dial until the AC voltage drop across the "pot" equals the AC voltage drop across the primary.

7. Turn off the generator and measure the resulting resistance of the variable resistor.

This is the tricky part, as you have to have some idea of what to expect.

A 2-tube EL-84 or 6V6 should measure 6-8K.
A 4-tube EL-84 or 6V6 should measure 3-4K.
A 2-tube EL-34 or 6L6 should measure 4-5K.
A 4-tube EL-34 or 6L6 should measure 2-2.5K.

NOTE: Many 100-Watt Marshalls have 1.75K primaries.

If your results are way off, you have the wrong speaker load. Adjust and re-test.

If it's real low, the transformer's blown.

Dave Funk

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RE: (modified 0 times) rda69

Profile

Pretty much agree with Hogy. I've never heard a recone that sounded as good as an original. However, my opinion is that you can get pretty close with some of the Celestion recone kits. Never heard a Jensen recone that was even in the ball park with the '50s alnicos.
I've personally had good success repairing vintage speakers by removing the cone and repairing the voice coil. No significant change in tone. However, this takes forever and requires the hands and patience of a surgeon.

Dave Funk gave me the name of a guy that did this type of vintage speaker repair. I'll see if I can dig it up. Ted B., please chime in.


12-14-2000 09:42:16
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From: SpeedRacer
Date: 9/10/2005 1:45 AM
Subject: Re: weensy hijack

we ran chinese (Golden Dragon IIRC) biased to 35-38mA? with Simcha's hand wound prototype on Dave Stork's bench into a Tek dual trace scope and an HP dist analizer. We got to 5% THD at 65W at 1kHz after twiddling knobs and eq a bit. The recent issue Marshall OT did a lot less, and got very hot doing it. Simchas did not even warm up. 49W is still very good for clean from a 50W head. Dave Funk told me years ago to expect about 35W clean. Seriously!

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[bnwitt]

Dai,
I'm confused by your post. What are you saying in it?

[DonMarko]

Rooster,
The Marshall story is in there though not the other subjects you mentioned.Theres 140 pages in the trainwreck section covering his time at Ampeg,the history of TWreck,his troubleshooting methods,info on Vox,Marshalls,Ampegs,Gibsons,Hiwatt.Theres also some basic electronics info ,opinions on bias methods,and mods.He also mentions his own modded champ,maybe the first Dirty Little Monster.
It's well worth checking out just for the interview with Ken,Victor Frankenstein,Klaatu and the voices in Kens head.The Man seems to have had a quirky sense of humor.
Casper McCloud ,Derek Jan(Derek F I believe)and Les Krygier(not familiar with this guy) all contribute their TWreck stories.
Well worth the read.
Mark

[j-po]

Congratulations Dave and good luck. I guess the new responsibility won't allow you to post as much in this forum as you have been since you joined huh?

Good one and straight to the point!
And to think I have been feeling a bit bad for not being able to contribute to the forum like I have learned and downloaded.

[gearhead]

Rooster,
The Marshall story is in there though not the other subjects you mentioned.Theres 140 pages in the trainwreck section covering his time at Ampeg,the history of TWreck,his troubleshooting methods,info . . .

There's 140 pages of Ken F. authored articles in this?:
http://www.amazon.com/Tube-Amp-Talk-Gui ... bb_product

[Tubetwang]

more like 126...

There's 14 blank (no text or b&w tube pics) pages...

[rooster]

Don - OK, thanks again for pointing this out. Man, I really do have to wonder what - if any - $$ the family of KF saw for this publication. Ken would have been alive when this was published I think. Hm, on the one hand I appreciate that these articles were localized and published for the benefit of people like me. On the other hand why does GW get to benefit from 126 pages of Ken's work?

Well, I may never know what has happened here.

[Thunderfunk]

Ken talks about a contest put on by Marshall. It was a contest for 'the best blues tone from a Marshall amp', the prize was a new Bluesbreaker combo and a brand new LP Standard. [Ken also liked] the Mullard EL84, but he equally likes 'the standard Sovtek EL84' (the 'M' version is not mentioned, BTW). He says it is almost as good sounding. Interesting, eh?

Ken told me this story on the phone. He called a friend at Guitar Player and mentioned that (Dan ?) was going to win the "Woman Tone" contest. His friend was shocked as he had just come out a meeting where Dan was picked as the winner. His friend wanted to know how Ken knew this? Ken said that he had built Dan's amp for the contest.

Here's the missing part. WHY did it give the woman tone? Because it had three gain stages. And why did it need the third gain stage?

On the tubes, yes Ken did like the "standard" Sovtek EL84's. I recently heard from a Trainwreck collector that Ken also liked the newer EL84's. Not sure if he meant the -M's or the -EH's. And then there' the JJ's.

I doubt the 45mA statement. He might have been throwing you off. I go with 30mA.

As for GW, Ken helped GW alot, basically writing his "repair" columns for him. GW came from selling Kirby vacuums and meat door-to-door. A good salesman, but otherwise not from an amp background. Ken helped him get his first amp working. GW's amps, THD, and Thunderfunk all appeared at the Chicago NAMM Show in the Summer of 1990. I thought they were both crazy, reproducing tweed amps. I wanted to do something different. I would have made a lot more money doing what they were doing. Selling a known commodity. GW's evil ways have caught up with him as he's in poor health. Ken sent me a letter saying he never should have been involved with GW. The Bible warned him about playing with pigs. GW stopped paying Ken for the Climax amp, and owes the estate over $95K. Ken was going to sue GW but his lawyer advised him that the trial would be in Texas, and Texans always win in Texas. Ken never wanted to go after Peavey or Fender for alluding to his trademark. He considered it free advertising. TM Stevens is in a new Warwick ad saying he's "Thunderfunkin'" with Warwick. Hmmmmm. I don't mind. As for Ken's "book" that's for Ken's family to handle. (Mother, sister, brother?) I don't think they're doing anything but defending the trademark. I've never talked to them.

I can't tell you what Ken thought of Dumble, but I must say I can hear a distinct tone. He did say some were good and some were junk. Then there's personal and business dealings stuff that's just gets nasty. Ken was a very honest guy.

I heard that Brad Paisley paid $20K for his Trainwreck. It was the cheapest he could find.

As to my posted earlier comments about our amp shootout, I stand by the good review of the DR Z's, BUT they have a nasty sub-harmonic in distortion mode. They do have nice sounding transformers though.

Ken never liked Mercury. He used Pacific, and I know (I have a letter) that he used Heyboer power, and "probably" Heyboer outputs also. (The letter doesn't say). As I remember, the spec for the rocket transformer was M6, and the Express was M19.

It's not that I don't post here as much as I don't post much anywhere.

Dave

[dr. who]

this is kinda funny... I was begging funkalicous to give a course a little more than a year ago for the d'style amps, and he finally conceded to allow me to purchase an amp from him, and fly to his hometown, and see the amp being build by him during the evenings when he wasn't doing his regular job. That was about the closest that he could get to a course. And now you are trying to knock a guy for offering the type of service that people like myself have been looking for. Yes some of us here would pay to have someone show us the correct way to do lead dress etc so that the basic ideas of building an amp with good sound are the core curriculum. This helps us to start building new ideas off of Howard's ideas, instead of copying howards schematics and trying to self learn what makes these amps work well. My only problem with dave funk is that he teaches so damn far away.

[Thunderfunk]

Just got off the phone with Michael Griffin of ESP Power Cords, and thought to write to you guys about his detachable power cord that makes a very noticeable improvement in the sound of ANY amp, mixer, etc. Not your computer though. He found that any wire larger than 20ga saps frequencies. So he bundled a bunch of 20ga wires together to make one huge reference power cord. They sell for $180 and are worth it. I bought three and within a week they were all gone. I didn't even intend to sell them. They just kinda found new homes. One engineer who works for Meyer ('nuff said) refused to return it. We just did an AB test at CPE Sound and it was startling. Now your results will vary depending on the power wiring of your venue, but the principle is that the power cable is an extension of the transformer's power leads. Now, CPE Sound, being a brand new rehearsal studio, has excellent, heavy duty AC service, and yet it was startling to hear the difference. And it wasn't just me, but everyone in the room looked shocked. Check out ESP power Cords at the NAMM show, or just call up and buy one.

248-375-2655

http://www.essentialsound.com/

(This is an unpaid endorsement).

Dave