| sgerus |
Hello All,
I just built my first tube amp based on the JE Labs 2A3 2001 edition.
It’s a 6sl7 grounded cathode - cathode follower capacitor coupled to the 2A3. I drive the amp from the pre-amp output of my Stereo receiver into 100db/w/m horn type speakers.
The amp sounds OK…. But just OK
I’m looking for ideas for a better front end.
The first choice is to stick with a tube that fist into the 8 – pin socket.
However I’m open to switching to a 9-pin tube as a last resort.
So, of the following configs, what do you like.
A. grounded cathode (just use ˝ of the tube)
B. SRPP
C. U-Follower
D. grounded cathode - cathode follower (as built)
E. OTHER
Thanks in Advance |
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| rcavictim |
I am a bit confused why you used a cathode follower cap coupled . I think I'd try parallelling both halves of the 6SL7 in a grounded cathode, plate coupled via capacitor to 2A3 grid. That would be very easy to obtain with minimal rewiring. You have not complained about a lack of sensitivity so obviously you have enough external drive available. This won't change much. It will get slightly better actually but not enough to hear. You may need to reduce R plate of the 6SL7 to as much as 1/2 original value as well as the common cathode R if you want the same tube current and operating characteristic as originally had with the first stage.
I am curious about the speakers you are using with it. Are they full range front horns? |
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| sgerus |
Bob,
My speakers are dual horn type 3 - ways... Klipsch KLF-20
Yes, the input sensitivity and output power are fine for my setup.
If I rememder correctly, 1.25V input = the 54V I need to drive the 2A3
(as built)
It's the preformance of the "horn sounds" I'm looking to improve.
Here is the link of the amp:
http://www.angela.com/catalog/how-to/SE.2A3.html
Thanks for the info
-Scott |
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| Gluca |
My pick-up:
B. Or you might consider a choke loaded 6C45pi (you'll need to change the socket).
Ciao
Gianluca |
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| dsavitsk |
| quote: | Originally posted by sgerus
I drive the amp from the pre-amp output of my Stereo receiver |
That's where I'd look if you don't like the sound. |
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| Tubes4e4 |
Hi Scott,
for simplicity, and to stay with two octal driver sockets, I would have a try at two paralleled 6sl7 sections per channel. Have a look at the EL34SE amp also shown at the Angela site to get the picture.
A problem is, that available B+ for the drivers in that 2A3 amp is a bit on the low side for 6SL7 anyway. 6SL7 sounds best with about 200V at plate, which would leave only 150V or so across the plate resistor in your circuit.
But at least it is worth a try, and a simple one to do, too.
Tom
P.S: You could also try something along the DC-coupled 6SN7 driver shown at that site implemented in the 300B SE amp. Again, no socket type change required. On second though, that even might be the better option, since it gives better driving capabilities (less driver Zo). The PT must be able to deliver 300mA more heater current at 6,3VAC, if you want to try this.
Tom |
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| sgerus |
Tom,
This amp started out as the JE Labs 6sn7-300B…
That amp sounded great but I gave up due to hum Problems which I thought where heater related.
I have since fixed the hum, changing to a 6sl7-2A3 amp in the process.
(Had nothing to do with the 300B heater).
So yes, changing to a 6sn7 is an option.
Here is what I’m thinking based on the replies so far:
1. Test with 6sl7 as SRPP, that’s easy and I have the parts.
2. Test as a U-follower…… even thought nobody has recommended that to this point!
3. Convert to 6sn7 per your suggestion
( which would be a good exercise for my next project ....)
I would still like to keep the input sensitivity around 1V.
Can I do that if I convert to the 6sn7? |
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| ToE |
I built the JE labs 2a3 srpp version which I enjoy very much (though I have some hum issues of my own I am chasing down...)
I agree with dsavitsk, your amp can't sound better than what your reciever is feeding it. A potentiometer on the input, I used a 100k on mine, feed it directly from your source and see how it sounds.
The JE labs deluxe 2a3 with a single 6sn7 for input and driver is another option. ( I plan to try this one myself...)
http://members.myactv.net/~je2a3/se300b.htm |
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| sgerus |
Hugh,
For what it's worth, here are some of the steps I went through to fix the HUM with my amp. This is a letter I sent to Derek Walton, who was very helpfull with the 300B amp.
Hello Derek,
Good timing, I was planning on sending you an update.
I got the hum under 2mV.... but this is no longer a 300B amp.
After testing the 300B amp with my receiver as a pre-amp and on the 98dB/w/m speakers, I came to the conclusion that:
1. I did not need all the power of a 300B
2. I did not need the low input sensitivity level of the 6sn7 input/driver.
3. Getting the HUM out became my top priority.
I returned the 300B tubes and changed the amp to a 6sl7 2a3
(JE Labs SIMPLE 45) with the PSU based in your deluxe amp.
I'm happy with the amp I ended up with... but I think the 300B sounded better!
Right now I'm planning my 2nd amp for next winter. Right now I'm thinking of a 6sl7 2A3 PSE.... or a 6sl7/300B.
Here are the steps I went through to get rid of the HUM
1. when I switched to the 2A3, I had to by a separate transformer for the 2A3 heater, I believe this helped a lot. My next project will go this way.
By the way, hum pots didn't help. I have the R/C on the heater transformer ct.
2. I re arranged the tube's to the the GZ34 away from the input tube.
The first amp had the GZ45-6sn7-300B in line.
The current amp has the 6sl7-2A3-GZ34 in line.
My next project will keep all the PSU components- all the AC and all the single-path far away from one another.
3. I re did the grounding... I will still send you photos in a couple of weeks.
4. Now I heat the 6sl7 from T1, grounding the 6.3vac dropped the sound level (hum?) a LOT, but didn't change the amount of mV I was seeing at the speaker
5. PSU changes: with the 6sl7 I only need 1.5 mV. So I figured out I was not drawing enough current through L2. My PSU is now choke input:
10H-50uF-10H-50uf(B+)-300R-30uF(B++)
THIS CHANGE LOWERED THE HUM A LOT. Before the psu changes, I was about 4.3mV. With the psu as described above, I'm under 2mV.
The meter reads 4.4 mV, but I read 2.7 mV with the amp off, so I guess the hum would be 1.7mV
Update 2/2/2006
Add 80v dc to 6sl7 heater ct.. Hum is now arounf 1mV |
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| SHiFTY |
I tried the 6SL7 SRPP, but it kills the bass, and runs out of puff. 2A3 needs a lot of drive voltage, which is why the cathode follower is a better driver. My version of this circuit sounded pretty good. I have also tried 6SN7 cascaded (like the 300B circuit) and that sounded pretty decent.
1/2 6SL7 sounds bad, it will not drive the 2A3 to full output.
In the end, the sound of a SET will depend on many things, the output transformers being most important. The driver stage is the next most important thing IMHO. |
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| sgerus |
Shifty,
Is your circuit the same as the JE Labs 2A3 SE?
If it's different, can you post your version of the circuit?
Also, what brand of 6sl7 are you using?
Thanks, Scott |
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| Dave Cigna |
I drove a 2a3 with 1/2 6SL7 for a long time and was pretty happy with it. I would try that first, then parallel both halves just to see if you like it better.
The sound of 6SL7's vary a lot by construction and brand. I like the round plate versions better than the flat plates. RCA in particular. I would normally leave tube rolling as the a tweak, but there really are big differences between 6SL7's
Also, as suggested, try running your source straight without the preamp.
5687/7119 type tubes also work very well as drivers for 2a3's, but they are 9 pins.
-- Dave |
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| arnoldc |
sgerus, I removed the volume control on mine. after dabbling with octals, I shifted to 9-pin drivers. two tubes I really liked are-
- 6072 in SRPP
- 417A/5842 single section driver
i like the 417A best, and currently drives mh 45 (plate choke loaded) and my 10Y/50/300B amp (resistor loaded) both with grid choke on power tube.
here's what my JE Labs 2A3 looks like without the volume pot-
| quote: | | I tried the 6SL7 SRPP, but it kills the bass, and runs out of puff. |
Shifty, mine is configured like that and I can't complain about bass. It's fast, and deep enough for my dance and techno vinyls. could it be that i'm still missing something? I don't have a subwoofer. My speaker is a pair of Altec 406-8Y in an Altec 604 cabinet which was custom made and unfinished, still. The mid-horns are Oxford and the super-tweeter is Fostex FT17H
Right now, my two amps use 417A/5842 drivers and I like them, however, I'm also planning to use a Pentode driver. Can somebody comment on what I came up with-
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| ToE |
Scott,
Thank you for your notes on hum reduction. I too have seperate 2.5vac heater supplies for each 2a3. My layout is well spaced between driver/ outputs and PS. I think I was too obsessive about running everything to the star ground. I'll try grounding stages locally, and running the local grounds to the star ground on the next go round.
I did try floating my HV supply and and using a regulated bench supply (HP-712b) for B+. I don't think I'll try this again until I have an isolation transformer, but it did prove my B+ supply is just fine and isn't adding any hum.
Next up is DC heaters, though I've read the sacrifice in sound quality isn't worth the gain of getting rid of the hum. Can't tell till I hear it myself.
I think I may try Tom's suggestion of parrallel 6sl7 sections myself. One reason I chose the JE labs 2a3 srpp as my first SE amp is all the options of drivers and circuits with minimal parts changes and costs. A new amp in an evening for a couple of bucks... |
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| rcavictim |
| quote: | Originally posted by ToE
Scott,
I think I may try Tom's suggestion of parrallel 6sl7 sections myself. |
Hey, that was MY suggestion first! :smash: |
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| Tubes4e4 |
| quote: | I'm also planning to use a Pentode driver. Can somebody comment on what I came up with-
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Yes, return the screen bypass cap to cathode instead of ground
:)
Tom |
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| analog_sa |
| quote: | Originally posted by Gluca
My pick-up:
B. Or you might consider a choke loaded 6C45pi (you'll need to change the socket).
Ciao
Gianluca |
This and ArnoldC's suggestions will take your amp out of the 6SL7 mediocrity and to a completely new level. Would your speakers be able to take the dynamics? |
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| arnoldc |
| quote: | Yes, return the screen bypass cap to cathode instead of ground
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Thanks Tom! Might as well tell me the logic behind it? |
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| James D. |
The screen grid 'works' with reference to the cathode not to ground, so if you return the sg voltage chain to the cathode and decouple the lower resistor you can dispense with the cathode bypass capacitor... and it sounds better.
I use a high Gm pentode with a VR tube between sg and cathode as I've found this sounds best. I've used 12GN7, D3a, EL84, PL802, C3m, C3g succesfully and they all sound better than any of the triode drivers I've tried.
Several others have built this circuit and all have found it better than previous attempts with triodes. The secret is to use a high Gm pentode.
If you want to use a low Gm pentode then use it as the first stage of a pentode Aikido and it will drive a DHT extremely well.
My favorite triode for driving a 2A3 is the 6N6P but the pentode is more open and transparent.
ciao
James |
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| arnoldc |
thanks james! i'm excited now about this Pentode-2A3 project :D
and oh, star grounding- I love it! I've tested all my amps with a friend's Avant Garde Duo and only the 300B has audible hum about a feet away from the horns. All use AC heating ;) |
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| Gluca |
----> James D: you mean you preferred the VR to the usual SG byapss cap?
It sounds interesting ... folks here and there reported and claimed that the screen voltage has to be flat and well regulated in order to enable a better perfomance.
Ciao
Gianluca |
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| JimW |
EL84 works very well! I set mine up so the the plate can never swing to a lower voltage than the screen - about 230v on plate, 150 on the screen. I intend to cap couple the screen to the cathode at some point - just haven't gotten around to doing that one. I used a simple voltage divider to obtain the screen voltage, although a gas regulator tube would be a nice touch. I am driving a 300B, has gobs of sensitivity, and good sounding el84s are not expensive (JJs are hard to beat). This should really kick butt driving a 2a3 while avoinding the difficulty of working with either hard to source or microphonic tubes. I tried the 6sl7/2a3 combo before, could never get it to my liking, although I was not using good NOS 'l7s. It sounded (and measured) rolled off in the highs. My present 2a3 amps are all transformer coupled pp (this may be the ticket!) and an SE variant of GRankins Baby Ongaku (with cheap iron). His driver circuit is a good one, and will not be the limiting factor in your amp, although many do not liKe 12at7. Good luck!
Jim |
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| rcavictim |
I recently built a two stage stereo SET amp using a 1619 DH octal base pentode with 2.5 volt fil on DC heat to drive an 809 DHT in A2, 6.3 volt fil also on DC heat. I used an interstage xfmer with +9 VDC G1 bias on the 809. The 809 and 1619 driver stand in series under a 625 volt B+ supply. Power for the drivers comes through the output tubes to minimize current load on the power transformer. ~375 volts plate to cathode from 420 volt plate supply on the 809. I have 200 volt plate supply on the 1619. A bit less on the plate through the I.T. I get 3.1 watts RMS per channel, similar to a 2A3. I could not get my pair of I.T.'s to match the 1619's well as a pentode and got much, much better results at a loss of gain by triode strapping the 1619 (1k R G2 to plate). In this mode this tube is really sweet and black silent! The amp turned out well and sounds very good.
I mention this as a 1619 would give one a DH alternative to a EL84/6BQ5 as a driver for the 2A3 and it is a metal octal, basically a DH 6L6. |
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| James D. |
I've found with the high Gm pentodes that the VR tube definitly helps the sound when driving DHTs.
It doesn't make a difference with low Gm ones that I can hear. I tried 6B8-G, EF86, EF184 etc. and there a cap decoupling sg to the cathode sounds as good - provided it is a good cap and the right value (usually about 3-10uF not the often seen .1uF!
James |
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| Jaap |
I have a D3a or E810F => IT => 300B amp.
I have the pentode in triode mode.
Would it be better to take the pentode option ?
Would a CCS in the tail lead to better sound ?
Thanks,
Jaap |
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| Bas Horneman |
I think you might have to consider the fact that the 2a3 single ended might not be a good match for your speakers..(Efficiency does not tell the whole story of a speakers drive-ability)
Traditionally the classic Klipsch speakers worked best with pushpull amplifiers..( I read that somewhere) feel free to call me an armchair critic...I have been called that before. |
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| sgerus |
Bas,
Interesting comment that a push-pull amp might be better for my Klipsch speakers…
I’ll look into that. I’m in the planning stage for the next amp (next winters project).
Been looking into EL34 or KT88 types…. Seen lots of P-P designs.
Here is an update on the 6sl7 issue:
Decided to try the 6sl7 in parallel. First impression is it’s an improvement over the GC-CF configuration.
Here is what I ended up with:
330v B+
47K plate R = 205 V at the plate
680R cathode R = 1.8V at 2.78mA
If anyone can explain how the parallel setup works I would love to here it?
My understanding is that we still get about the same voltage swing but at 2 times the current?
The main benefit that the tube is operating in a zone where the curves are more linear? I.e. less distortion?
How do draw the loadline for a parallel configuration? |
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| rcavictim |
| quote: | Originally posted by Bas Horneman
I think you might have to consider the fact that the 2a3 single ended might not be a good match for your speakers..(Efficiency does not tell the whole story of a speakers drive-ability)
Traditionally the classic Klipsch speakers worked best with pushpull amplifiers..( I read that somewhere) feel free to call me an armchair critic...I have been called that before. |
Bas,
You have raised a very good point! Upon completion of my 3 watt 809 SET amp I was very pleased to discover that it mated well with my Ultor-X speaker design, my latest and the one I have commercial hopes for, but was surprised to learn that it fell flat on it's face with my original Ultor speakers which exibit similar high 90's-100 dB sensitivity. My crossovers and driver configuration, as well as number of drivers are different in both speaker designs as well as the acoustical loading imparted by the design on the drivers. There are so many factors at play that it is probably impossible to quantify them meaningfully so the best and easiest way is just to try the proposed combo and see how it sounds. Trying to predict sonic outcome is doomed to failure. |
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| Bas Horneman |
| quote: | | How do draw the loadline for a parallel configuration? |
Post on the audio asylum by Paul D. Scearce on plotting a load line
Posted by Paul D. Scearce on March 22, 2002 at 10:52:01
In Reply to: Load line posted by Bas Horneman on March 22, 2002 at 03:43:34:
From Ohm's law, impedance is V/I. To add an impedance line to a tubes plot, you need to find two points on the load and draw a straight line through them.
For a resistance coupled tube, start with the B+ voltage. If the plate of the tube is at that voltage, the voltage accross the load resistor is 0. From Ohm's law, current is V/R, in this case 0 ma. So the first point is at B+ v,0 ma. You can than pick any voltage less than B+ to find your second point. Lets pick 0 volts. If 0 volts appears at the plate of the tube, the voltage accross the load is B+ volts. Using Ohm's law again, current is B+/R, and your second point is B+/Rma,0v.
For example say B+ is 200v and the load is 20kohm. Draw one point at 200v,0ma and another at 0v,200/20ma(0v,10ma in other words). Then draw a straight line through these points. That is the load line.
The process is similar for a transformer coupled tube, except now there is a fair amount of dc current flowing when the plate is at B+. Using your output stage for an example, the bias conditions are probably about 100 volts on the plate at 60ma per section. (Since grid voltage is represented as a negative number on the plots, plate voltage is read from the plate to the cathode.) So draw a point at 100v, 60ma. When the plate is at 0 volts, 100 volts would appear accross the ac load, so current will be 100v/3.2Kohm or 31.25 ma. (Two sections are used in parallel, so each section will see a load of about twice the primary impedance). Add the ac current to the bias current, and draw a second point at the resulting current along the 0volt line on your graph-about 0v,90ma. Now draw a straight line through the two points for your load line.
This line passes through the grid voltage lines of the tube, so you can tell what the plate voltage will be for any grid voltage. Bear in mind this is only an approximation, but it should give you a fair idea of how the tube will opperate.
Hope this helps
Paul |
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| Bas Horneman |
| quote: | | You have raised a very good point! Upon completion of my 3 watt 809 SET amp I was very pleased to discover that it mated well with my Ultor-X speaker design, my latest and the one I have commercial hopes for, but was surprised to learn that it fell flat on it's face with my original Ultor speakers which exibit similar high 90's-100 dB sensitivity |
Were can I read about your Ultor-X speakers? |
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| arnoldc |
| Bas, your post about the plotting the loadline is the textbook (basic) one. Does it actually tell you how to plot for a *parallel* section? I don't see that. :confused: |
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| Bas Horneman |
| quote: | | Does it actually tell you how to plot for a *parallel* section? |
You are right..this post can't be shown in isolation..thanks for pointing that out. I had a transformer with a primary impedance of 1.6k.
Thus when calculating the current through each section one has to double the load ...
| quote: | | so current will be 100v/3.2Kohm or 31.25 ma. |
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| Tubes4e4 |
Hi sgerus,
| quote: |
How do draw the loadline for a parallel configuration? |
Two methods:
1) Just use the plate curve sheet for a single tube and double the current values on the Y-axis. This method is useful if you are looking for suitable loads by trying several loadlines. It gives direct readout of power into load, distortion, etc.
2) Just use the plate curve sheet for a single tube and double the the plate load value to draw the load line for a single tube. Po results derived from the loadline must be doubled of course, since two tubes are working in this condition. This method is useful if you are stuck with a given load value (for example, an OPT you have already).
Tom |
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| rcavictim |
| quote: | Originally posted by Bas Horneman
Were can I read about your Ultor-X speakers? |
Bas,
Until they are available in the marketplace I won't be releasing any detailed technical descriptions. The only existing pair are the large, full-range, hi-efficiency speakers which were in my avatar until recently. |
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| sgerus |
Thanks Tom,
It’s starting to make sense.
I used your 2nd method, WITH one CHANGE.
Here is the actual setup for a 6sl7:
330V b+, 47K, 205V at plate, -1.88V @ cathode, 680R =2.76mA (Parallel)
To draw the LL, I doubled the plate R, AND DOUBLED THE CATHODE R.
So the LL is from 330V@0mA to 0V @ 3.5mA
The -1.88V curve lines up with 1.38mA, (based on the 2* cathode R)
Does this sound right….. finally.
Ps back to the original question of this thread:
the 6sl7 in parrallel is a big improvement over the GC-CF I started with |
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| Sheldon |
| quote: | Originally posted by sgerus
It's the preformance of the "horn sounds" I'm looking to improve.
-Scott |
Browsing this thread and interested in the general driver discussion. But I'm not sure what you're after here. Do you mean your speakers have "horn" sounds as in talking through a megaphone? If that's the case, you may improve the amp in many ways, but I don't see how it solves that kind of problem, which is the result of reflections in the horn. Or do I just misunderstand? If the latter, nevermind.
Sheldon |
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| arnoldc |
| quote: | Ps back to the original question of this thread:
the 6sl7 in parrallel is a big improvement over the GC-CF I started with
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hi sgerus, i just want to ask if you ever wired your 6SL7 driver as SRPP and compared it with paralleled 6SL7?
sheldon, you are right. i myself is using horns (mid horn to be exact) on my speakers. i believe some larger horns were made for movie houses and would not sound "normal" for home use, unless you have a room as big and treated as a movie house. they refer to that character as the "horny" (sic) sound. mine is not horny :D |
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| ryssen |
| quote: | | hi sgerus, i just want to ask if you ever wired your 6SL7 driver as SRPP and compared it with paralleled 6SL7? |
I kind of wonder 2. :confused: :cool: |
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| sgerus |
No, I never compared SRPP to the parallel 6sl7.
I tested SRPP just a little.... I didn't like it, but I only listened a short while.
Based on my VERY LIMITED testing and experience, I would say that just using 1/2 the tube was better than SRPP of the GC-CF I just tried.
Gets back to the KISS method!
But.... I ended up with something that sounds GREAT
6sl7 in parallel driven by a 3mA constant current source.
I did some back to back testing of the R loaded tube vs. the ccs
and, in spite if the fact a had to add one SS stuff, I LOVE THE SOUND WITH THE CCS
The normal R loaded 6sl7 had an output of 1V=39V,
with ccs, 1V=51V. And the distortion with the ccs is way lower!
So in my case, just over 1V will drive the 2A3 (-54V bias) with ccs,
compared to about 1.33V without the ccs.
Sheldon.... back the my first post. My problem with the GC-CF config
was that I didn't like the way the amp sounded when I listened to horn type instruments, saxaphone, trumpet ect.
(I really need to write better next time)
If anyone wants the details on the ccs, let me know or see
tubelab.com (10m45 chip)
Thanks to all that replied.
-Scott |
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| arnoldc |
Scott, thanks for the info on the 6SL7. Did you use 2k2 or 1K for the resistors?
re: CCS- that chip was also used by pete millet with great results. i'm going to order a couple from DigiKey. |
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| sgerus |
| quote: | Originally posted by arnoldc
Scott, thanks for the info on the 6SL7. Did you use 2k2 or 1K for the resistors?
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Arnold... if your asking what the cathode R is for the parallel / ccs:
Cathode R = 680R which at 30mA = about -2V
The ccs replaces the plate R, My ccs is set up like this:
330V B+ into A
1K Resistor from K to the plate(s)
4.7K Resistor from G to the plates(s) |
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| ryssen |
I have seen some schema´s that have a cap between driver and the grid of the powertube,some doesnt have one.How do I know if it´s
safe to remove it,must be beter if there isn´t a cap,or isn´t it? :xeye: |
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| sgerus |
I dont know how well css works without the cap.
I had the cap on from my normal (non-css) setup, so I just left it in there. |
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| arnoldc |
sgerus, I'm so sorry i was not clear. i meant the resistors on the SRPP :( I was wondering what makes some dislike the SRPP. What made you? About the sound.
ryssen, I'll make an assumption that those you saw without a capacitor are what is called "directly coupled" and comes in various flavors such as Loftin-White, Monkey, Free Lunch, etc. |
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| sgerus |
Arnoldc,
When I was in srpp, I had 330v B+, two 2.2k, one for the bottom cathode to ground, the other between the top cathode and the bottom plate.
The heater ct was at around 87V
I gave this a very short listing test.... and didn't like it.
Sounded kind of dead.
But, dont rule out srpp based on my very limitted test.
Who knows, maybe it would sound better with 1K resistors?
One thing I will say,FOR ME, the parrallel config sounds better than the
grounded cathode-cathode follower or just using 1/2 the valve!
2 reasons to use the parrallel config over srpp, gc-cf:
1. you don't have to bias up the heater (I know, no big deal, 3 more parts)
2. Just using a single stage... with the output from the pate... |
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| ryssen |
I have a 6B4GSE amp with SRPP 6SL7 driver,when I read this trhead I got curious and connected the 6SL7 as ordinary single drivers,and the sound is less detailed less midrange,but the bass is the same.I tried
it with a 6SN7 but now the bass is almost bomy,wish I could have a switch between SRPP and single driver.Anyway I think I´m going back to SRPP.Wish I could try 6H30,6C45 or Ecc99.But that means metallwork :dead: Is there any other octal triod I could try? :rolleyes:
By the way,is there any benefit in driving the 6SL7 harder nearer its max ratings? |
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| arnoldc |
I guess it's really a matter of preferences then. I like the 6SL7 SRPP for its detail and slam, I also liked the 6072 SRPP on Gordon Rankin's Bugle 45. But now I tend to use single-triode drivers, such as the 417A/5842 because I like their sound and they are high current drivers (relative to the 6SL7).
ryssen, try the 6SL7 SRPP with 1K resistors. It will give more "balls" to it :D |
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| ryssen |
| quote: | | ryssen, try the 6SL7 SRPP with 1K resistors. It will give more "balls" to it |
I already have 1k,I meant even lower? :xeye: |
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| arnoldc |
| :eek: sorry, I didn't realize that you have 1k already. I didn't mean lower. |
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