Feel free to ask Myles

[myles_rose]

Originally posted by jetboy:

hi myles,

 

long time no chat but then Ive been pretty problem and question free!

 

anyway still read ya on the various boards and here too.

 

Got a rather simple question,

 

I picked up a used Holland lil jimi amp. Very nice, super clean the way it has been set up. Not a problem but...

 

I noticed on the amp label that it says el34/6l6 model and it has a bias pot and test probe inputs on the back. To my way of thinking this means that I might be able to run el34s and the like in the amp as long as I rebias it via the probes and pot?

 

The amp is seriously overbuilt tranny wise... what do you think?

 

My understanding is that Mike Holland was secretive in that no manual or layout was provided with his amps, there is not even a tube chart so I'm left guessing as to where v1 and v2 etc is. there is also a secret unmarked ¼ jack on the chassis.

 

Also the Holland amp co is out of business as heritage has taken over those designs (kind of).

 

Although I love the clean tone out of it as is, Im very curious as to what it would sound like with say el-34s or maybe kt66s in it.

Just rebias and use any EL34 or 6L6 (or 5881 or KT66).

 

Check the plate voltage off pin 5 of the output tube socket and we can calculate proper bias settings then.

[myles_rose]

Originally posted by Curly Dan:

Originally posted by Caevan O'Shite:

Originally posted by myles111:

"Rick Benson just walked in when I brought this up - they are great amps but he said be careful as there is asbestos all inside."

Yikes! Thanks for the heads-up, I think I'll pass! (There's no shortage of great amps to be had these days!)

Caevan,

as Myles will tell you, even Fender tweed Deluxes had the back panel covered with asbestos - pretty common material in those days

 

don't let that sour the deal

I fully agree.

[Shawners]

Thanx Myles for your input,

I've got a couple more questions. You suggested retubing my Soldano Decatone with Gt6l6s's in a #7, biased at 30ma , if I went with # 4-5's should I still bias at 30ma ? I want a little earlier break-up at lower volumes , or should I still get them at a #7??

Before I buy the 6l6S's , you said alot of Slo users love the KT66's in that amp...Why??

You probably picked the GT6l6S's because of the more aggressive tone I'm going for ,but I don't want to pass on the Kt66's ,if they have a majic vibe with Soldano.Wish I could by both than choose , but instead I'll listen to your more experienced voice of reason.

Thanx Myles, ...Shawners

P.S. Any info on what JJ Tubes is doing with this new long plate 12ax7 they are developing??

[myles_rose]

Originally posted by Shawners:

Thanx Myles for your input,

I've got a couple more questions. You suggested retubing my Soldano Decatone with Gt6l6s's in a #7, biased at 30ma , if I went with # 4-5's should I still bias at 30ma ? I want a little earlier break-up at lower volumes , or should I still get them at a #7??

Before I buy the 6l6S's , you said alot of Slo users love the KT66's in that amp...Why??

You probably picked the GT6l6S's because of the more aggressive tone I'm going for ,but I don't want to pass on the Kt66's ,if they have a majic vibe with Soldano.Wish I could by both than choose , but instead I'll listen to your more experienced voice of reason.

Thanx Myles, ...Shawners

P.S. Any info on what JJ Tubes is doing with this new long plate 12ax7 they are developing??

Still use 30mA but if you want faster breakup use #2,3,4. The lower the number the faster they will break up.

 

The KT66HP is just a "bigger" sounding tube - more lows, more mids, more round sounding.

 

I don't have any info on the JJ tube at this time.

[BillWelcome Home Studios]

Miles,

 

Don't know if you have any ideas for me or not...

 

Bought the THD UniValve, and bought a bunch of tubes from GT and got some from Messa.

 

With the Messa 12ax7a Russian 2 in the "input" and "V1" tube positions, I find the amp to be pretty bright.

 

I put in the Messa EL 84, and the tone is great, but I have the treble down at about 9 o'clock or less, while the bass and attitude are up around 1, 2 o'clock. Still, the (Duncan Fat Cat)P-90 treble pickup is too bright for my tastes. Neck pickup and blended pickups sound great.

 

With the GT GTE 34LS, a lot of the richness of tone seems to go away.

 

With the stock EL 34B, ... well, I like this least.

 

Is there a tube combo that might mellow out the tone a bit, withput taking the richness away?

 

Thanks,

 

Bill

[myles_rose]

Originally posted by bpark@prorec.com:

Miles,

 

Don't know if you have any ideas for me or not...

 

Bought the THD UniValve, and bought a bunch of tubes from GT and got some from Messa.

 

With the Messa 12ax7a Russian 2 in the "input" and "V1" tube positions, I find the amp to be pretty bright.

 

I put in the Messa EL 84, and the tone is great, but I have the treble down at about 9 o'clock or less, while the bass and attitude are up around 1, 2 o'clock. Still, the (Duncan Fat Cat)P-90 treble pickup is too bright for my tastes. Neck pickup and blended pickups sound great.

 

With the GT GTE 34LS, a lot of the richness of tone seems to go away.

 

With the stock EL 34B, ... well, I like this least.

 

Is there a tube combo that might mellow out the tone a bit, withput taking the richness away?

 

Thanks,

 

Bill

Bill, the Mesa Russian tube is an EH, and these are a bit shy on current, and can be a bit thin sounding.

 

Try an ECC83S.

 

The 6L6 tubes will give more low end in the UV in many cases than the EL34.

 

On the E34LS the amp likes #3-4, cranked up, and the attitude control at about 3:00 and the bass control about the same.

 

Treble down to about 10:00 or less.

[jetboy]

Thanks myles,

 

I got some info back from the guys at Heritage amps (they were with Holland before) and they gave me some values to use at the test points for el34s which Im trying right now. They had 30-37 mv for the 6l6 and 35-40 Mv for the el34s. Im using 38+ for a bit more grind.

 

If I get ambitious Ill pull the chassis and measure at pin 5, will this give me the plate voltage?

 

The test points supposedly give the current draw, according to Heritage. Have you got anything to go by that just uses the current draw, Id rather not have to pull the chassis if possible

 

for some reason in their info back they said not to use 5851s. Would that indicate that the plate voltage is too high for that type tube? I have that question into heritage now.

 

I know there is a formula for this, can I use the info I got from heritage as to current draw, and the wattage dissapation of the tube to infer plate voltage or is this something that just needs to be measured?

 

Thanks again. Have a good turkey day!

 

Originally posted by myles111:

Just rebias and use any EL34 or 6L6 (or 5881 or KT66).

 

Check the plate voltage off pin 5 of the output tube socket and we can calculate proper bias settings then.[/QB]

[myles_rose]

Originally posted by jetboy:

Thanks myles,

 

I got some info back from the guys at Heritage amps (they were with Holland before) and they gave me some values to use at the test points for el34s which Im trying right now. They had 30-37 mv for the 6l6 and 35-40 Mv for the el34s. Im using 38+ for a bit more grind.

 

If I get ambitious Ill pull the chassis and measure at pin 5, will this give me the plate voltage?

 

The test points supposedly give the current draw, according to Heritage. Have you got anything to go by that just uses the current draw, Id rather not have to pull the chassis if possible

 

for some reason in their info back they said not to use 5851s. Would that indicate that the plate voltage is too high for that type tube? I have that question into heritage now.

 

I know there is a formula for this, can I use the info I got from heritage as to current draw, and the wattage dissapation of the tube to infer plate voltage or is this something that just needs to be measured?

 

Thanks again. Have a good turkey day!

 

Originally posted by myles111:

Just rebias and use any EL34 or 6L6 (or 5881 or KT66).

 

Check the plate voltage off pin 5 of the output tube socket and we can calculate proper bias settings then.

[/QB]

Plate voltage is measured at pint 3. Pin 5 will be your bias voltage, around -50 or so volts.

 

Today's 5881s are really 6L6 tubes so I do not see the harm in using them. The NOS Tungsols would also work quite nicely as would the other NOS 5881s at a proper bias setting.

 

I personally feel their bias recommendations are too high. You will get a wider playing range if the tubes are biased a bit cooler just out of crossover notch distortion.

[jetboy]

Hi Myles you were right.

 

I just got some more specific info. The previous info was from a generic sheet that had referred to.

 

The specific info was that the plate voltage was 470mv and that I should be biasing from 25-29 for the el-34 which makes much more sense according to everything else I've been looking at. Also turns out they were saying that they did not recommend the kt88-6550 tubes as they drew too much voltage.

 

So I can use 5881s or kT66s etc. Anyway thanks for the help.

 

Looks like getting the info to and from them directly is waaay more accurate.... Im guessing some stuff got lost in translation.

 

Originally posted by myles111:

Originally posted by jetboy:

Thanks myles,

 

I got some info back from the guys at Heritage amps (they were with Holland before) and they gave me some values to use at the test points for el34s which Im trying right now. They had 30-37 mv for the 6l6 and 35-40 Mv for the el34s. Im using 38+ for a bit more grind.

 

If I get ambitious Ill pull the chassis and measure at pin 5, will this give me the plate voltage?

 

The test points supposedly give the current draw, according to Heritage. Have you got anything to go by that just uses the current draw, Id rather not have to pull the chassis if possible

 

for some reason in their info back they said not to use 5851s. Would that indicate that the plate voltage is too high for that type tube? I have that question into heritage now.

 

I know there is a formula for this, can I use the info I got from heritage as to current draw, and the wattage dissapation of the tube to infer plate voltage or is this something that just needs to be measured?

 

Thanks again. Have a good turkey day!

 

Originally posted by myles111:

Just rebias and use any EL34 or 6L6 (or 5881 or KT66).

 

Check the plate voltage off pin 5 of the output tube socket and we can calculate proper bias settings then.

Plate voltage is measured at pint 3. Pin 5 will be your bias voltage, around -50 or so volts.

 

Today's 5881s are really 6L6 tubes so I do not see the harm in using them. The NOS Tungsols would also work quite nicely as would the other NOS 5881s at a proper bias setting.

 

I personally feel their bias recommendations are too high. You will get a wider playing range if the tubes are biased a bit cooler just out of crossover notch distortion.[/QB]

[BillWelcome Home Studios]

Like so many other guitarists, I notice a change in tonal quality when I plug into footpedals in front of the amp, compared to plugging directly into the amp.

 

So Im exploring possible solutions.

 

I find little gain circuits based upon FET, opamp, and other designs. Then I see (what appears to be) a passive impedance matcher. Hmmm

 

Now, Im trying to get my original tone, pushed through the effects, and not really make any changes. What avenue should I be persuing?

 

(If it matters, the pedals are all Fulltone, a wah, a univibe, and a distortion)

 

Thanks,

 

Bill

[PBBPaul]

Hey Myles,

 

I picked up a new project amp - an old Bogen PA head from the late '60s or early '70s. For tubes, it has a 6C4, 1 6EU7, 1 12AX7 and 2 6L6s. Do you have any recommendations on the preamp tubes? I'm looking (of course) for warmth and a nice fat overdrive.

 

Do you also have any recommendations or opinions on capacitors? I've used Sprague Atoms and Orange Drops before but found them to be a bit harsh.

 

And last question, what's your opinion on these NOS Sylvania 6L6G's? Are you familiar with them?

http://i1.ebayimg.com/02/i/02/e7/3f/5d_1_b.JPG

[jetboy]

a hopefully final question?

 

Im seeing various listings for power dissipation on el-34 tubes, some list them at 20 watts max and others at 25 watts. Is this variations in manufacturer or should they all be closer to 25 or 20 watts max.

 

Also what about the 6ca7 which are listed as 25 watt tubes, since they are supposed to be a direct replacement for the el-34 are they also more like 20 watt tubes or 25. The ones I have are not groove tubes but EH?

[myles_rose]

Originally posted by bpark@prorec.com:

Like so many other guitarists, I notice a change in tonal quality when I plug into footpedals in front of the amp, compared to plugging directly into the amp.

 

So Im exploring possible solutions.

 

I find little gain circuits based upon FET, opamp, and other designs. Then I see (what appears to be) a passive impedance matcher. Hmmm

 

Now, Im trying to get my original tone, pushed through the effects, and not really make any changes. What avenue should I be persuing?

 

(If it matters, the pedals are all Fulltone, a wah, a univibe, and a distortion)

 

Thanks,

 

Bill

Bill,

 

Pedals will load the amp differently and do all sorts of other things. It is pretty darn close to impossible to keeps and amp's original tone and feel when using pedals. Some amps do this better than others.

[myles_rose]

Originally posted by jetboy:

a hopefully final question?

 

Im seeing various listings for power dissipation on el-34 tubes, some list them at 20 watts max and others at 25 watts. Is this variations in manufacturer or should they all be closer to 25 or 20 watts max.

 

Also what about the 6ca7 which are listed as 25 watt tubes, since they are supposed to be a direct replacement for the el-34 are they also more like 20 watt tubes or 25. The ones I have are not groove tubes but EH?

Virtually all EL-34 tubes except the E34LS are 25 watt tubes. This includes the 6CA7. The E34LS (not the E34L) is a 30 watt tube.

[DanielT]

Hi Myles,

 

Thankyou for being available to answer our questions.

 

My question is about speaker impedence.

I gig with a Carvin Bellaire tube amp with 2 speaker outs and a switch for changing the load from 4 to 8 or 16 ohms. The speakers in the amp are 8 ohms, and I would like to also drive my 4-12 cabinet which is rated at 16 ohms.

What is my best course of action?

 

Thanks, Dan

[myles_rose]

Originally posted by DanielT:

Hi Myles,

 

Thankyou for being available to answer our questions.

 

My question is about speaker impedence.

I gig with a Carvin Bellaire tube amp with 2 speaker outs and a switch for changing the load from 4 to 8 or 16 ohms. The speakers in the amp are 8 ohms, and I would like to also drive my 4-12 cabinet which is rated at 16 ohms.

What is my best course of action?

 

Thanks, Dan

Dan,

 

I would not do that, although you can always set the selector to a lower value to drive a higher load with a slight drop in power. On your amp though there could be an issue as the output transformer is not as stout as some amps.

 

I would unplug the internal speakers and use the 16 ohm cab on the 16 ohm setting. You can also rewire the internal speakers to come up with a more proper value.

[WaterMan]

Myles,

 

My 12AX7 tube finally gave way in my ToneBone Classic distortion box. Do you have a recommendation(s) for a cool replacement tube?

 

Thanks!

[PBBPaul]

Myles,

 

My current project amp has a 6EU7 in V1, a 12AX7 in V2 and a 6C4 in V3 with 6L6 power tubes. I have no experience with the 6C4 and the 6EU7 preamp tubes and I didn't find any real info in your tube primer either. What are the typical characteristics of these? If I want to replace them, what should I look for? I don't have a schematic but I assume that the 12AX7 is the phase inverter. Is it odd for it to be in the V2 position?

 

By the way, I have this thing pretty well cleaned up now and other than some slight hum (my new caps aren't here yet), it sounds very good with a surprisingly nice, warm breakup from the GT 6L6C's that I popped in there.

[myles_rose]

Originally posted by WaterMan:

Myles,

 

My 12AX7 tube finally gave way in my ToneBone Classic distortion box. Do you have a recommendation(s) for a cool replacement tube?

 

Thanks!

I'd use a good 12AX7C.

[myles_rose]

Originally posted by PBBPaul:

Myles,

 

My current project amp has a 6EU7 in V1, a 12AX7 in V2 and a 6C4 in V3 with 6L6 power tubes. I have no experience with the 6C4 and the 6EU7 preamp tubes and I didn't find any real info in your tube primer either. What are the typical characteristics of these? If I want to replace them, what should I look for? I don't have a schematic but I assume that the 12AX7 is the phase inverter. Is it odd for it to be in the V2 position?

 

By the way, I have this thing pretty well cleaned up now and other than some slight hum (my new caps aren't here yet), it sounds very good with a surprisingly nice, warm breakup from the GT 6L6C's that I popped in there.

The 6EU7 is a dual triode and has about the same characteristics as a 12AX7.

 

I do not know this amp so I really cannot comment on it's layout. On the Fender Pro Tube series with 8 preamp tubes, V4 happens to be the phase inverter so it is not always the case of it being the last preamp tube for this use as the PI.

[DanielT]

Hi Myles,

 

Thanks for the insight on how to proceed with matching my 16 ohm cab with my 8 ohm combo speakers. I ended up rewiring the speakers in the amp in series so that they add up to 16 ohms and then switching the amp to 16 ohms. The result was truly glorious. I am not a high gain player, but even at the volume that I use, the added girth from the 4-12 cabinet is wonderful.

 

Thanks again for the advice.

[Morgan Meader]

Hy Miles,

 

Great thread! Pun intended.

 

Forgive me if this question has been asked before. I wasn't able to find it here.

 

I'm trying to understand more about tubes and tone and how to get my Peavey Classic 30 to break up at lower volumes. It has never been retubed because I don't use it as often as the 65Twin with a tubescreamer but I want to use it more.

 

I'm after a Cream era Clapton overdrive tone.

 

What does the third 12ax7 ( power stage driver ) actually do to the tone and can I change it to get the clean channel to break up earlier? Do the pre amp tubes have an effect on the clean channel tone?

 

Thank you for any advice you can offer.

[myles_rose]

Originally posted by Morgan Meader:

Hy Miles,

 

Great thread! Pun intended.

 

Forgive me if this question has been asked before. I wasn't able to find it here.

 

I'm trying to understand more about tubes and tone and how to get my Peavey Classic 30 to break up at lower volumes. It has never been retubed because I don't use it as often as the 65Twin with a tubescreamer but I want to use it more.

 

I'm after a Cream era Clapton overdrive tone.

 

What does the third 12ax7 ( power stage driver ) actually do to the tone and can I change it to get the clean channel to break up earlier? Do the pre amp tubes have an effect on the clean channel tone?

 

Thank you for any advice you can offer.

Ckeck my website, lots of this info thre.

 

The phase inveter in your amp (V3) as a 12AX7 will cause the amp to break up quickest. If you use a hand selected PI with more gain the amp will drive harder more quickly.

 

If you use an ECC83S in v1 the amp will be more agressive.

 

If you use EL84S #2-3 rating in the output it will also get dirty faster.

[PBBPaul]

Myles,

 

Have you ever heard of an RCA variant of the 6L6 called a 7552? It seems to have a metal base with Coke-bottle shaped glass.

[myles_rose]

Originally posted by PBBPaul:

Myles,

 

Have you ever heard of an RCA variant of the 6L6 called a 7552? It seems to have a metal base with Coke-bottle shaped glass.

The only 7552 that I know of is not anything like a 6L6:

 

http://www.pmillett.addr.com/tubedata/HB-3/Miscellaneous%20Types/7552.PDF

[PBBPaul]

I saw that one too. Here is the one I'm talking about:

 

http://i7.ebayimg.com/03/i/03/07/d2/7b_1_b.JPGhttp://i11.ebayimg.com/03/i/03/07/8e/f2_1_b.JPG

Hence my confusion.

[myles_rose]

Originally posted by PBBPaul:

I saw that one too. Here is the one I'm talking about:

 

http://i7.ebayimg.com/03/i/03/07/d2/7b_1_b.JPGhttp://i11.ebayimg.com/03/i/03/07/8e/f2_1_b.JPG

Hence my confusion.

I'd need to see these on a curve tracer. They look like Chinese KT88s that have been screened with some sort of RCA copy of a logo. The 7552 would look to be a funny sort of date code and not a tube type.

[PBBPaul]

Very interesting.

 

Thank you.

[BillWelcome Home Studios]

Miles,

 

Just got a Reverend Goblin, powered by two EH 6V6GT tubes. Would you be looking for another tube besides the EH? If I'm going to get tweaky, I might as well get real tweaky....

 

Bill

[myles_rose]

Originally posted by bpark@prorec.com:

Miles,

 

Just got a Reverend Goblin, powered by two EH 6V6GT tubes. Would you be looking for another tube besides the EH? If I'm going to get tweaky, I might as well get real tweaky....

 

Bill

Bill,

 

The EH's are some of the best current production 6V6 tubes but you may find a pretty nice improvement with some of these:

 

NOS JAN Hytron 6V6GTY (brown base)------------------$ 52 Per matched pair

------------------------------------------------------------------------$ 25 Per single tube

 

NOS GE 6V6GT and 6V6GTYs---------------------------------$ 50 Per matched pair

------------------------------------------------------------------------$ 24 Per single tube

 

These are from Mike at www.kcanostubes.com and are not too pricy, last much longer than any production new 6V6 and sound just terrific with a lot of dynamics and articulation.