| frankmalz |
Hi to all,
i am looking for Shindo 300B schematics.(Palmer etc.)
Has anybody a link or info about schematics.
Thank you very much
Frank |
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| ElectricHead |
| What do you want with the schematics of such nasty sounding amps? |
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| frankmalz |
Hi,
the Palmer is a highly regarded amp and maybe there is something to learn about the use of a 6SN7 in combination with a 300B using NFB .
Best wishes
Frank |
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| ElectricHead |
Well, the 6SN7/300B combi is a very good thing, I 'm using monos with 6SN7/300B SE NFB (I have many power-amps).
We have to seperate here between audiophiles and vintage tube addicts. Mr. Shindo is not interested in the best possible sound, he is a religous fanatic using only horrible sounding outdated parts. The people who believe that Shindo sounds good are people who do not have the slightest clue about parts and how they alter the sound. I've used my own monos in a listening test against the Palmer and the owner of the Palmer told me that it was the most horrible sounding amp he ever bought. I had the feeling that it was completely undynamic, lifeless with extreme problems in the freq. extremes. No bass no body no textures - 2D sound stage. Looking at the parts Mr. Shindo used it is self explaining - I would use the parts in the Palmer not even in an old tube radio. But rip-off is normal in the Audiophile scene, and the people of the german hifi-press are industry-paid disgusting idiots who do not understand the SLIGHTEST thing about circuits and electronics...
Best regards
ElectricHead |
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| yagas |
So, you claim that all the above you describe about the Palmer's sound are a matter of "selecting components" ?
Mic |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by ElectricHead
Well, the 6SN7/300B combi is a very good thing, |
Sorry, but that is not my experience. Usually you must plenty of parts that are distinctly non-neutral sounding to get anything approaching life or reality out of 6SN7 cascade 300B. I have herd them all, Reichert, JE, ANUK all the same stuff. Boring, congested and excessively euphonic, simply "pre-clear".
The Palmer was an exception, as it kills the charater of the 6SN7 by applying a good deal of negative feedback around the 2 6SN7 stages.
Shindo San's parts choices are controversial, agreed and they do not make for neutral sounding amplifiers, but that is not his point.
For Shindo gear I'd say around 50% of the sound is the parts used, another 30% are certain special tricks he applies (such as the feedback loop around the input/driver stage and the undersized output transformer in the Palmer, plus some I will not mention here), the remaining 20% are the schematic, hence having the schematic for Shindo gear is not particulary useful, without having the matching photos of the implementation too.
The sound of Shindo, it divides the spirits as they say, you either like it or not, few people can be anything except being polarised that way I noticed. I like Shindo Sound but in the long run it is a little too "chocolatey", for want of a better word.
Sayonara |
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| ElectricHead |
@Thorsten:
Well, you are right about the sound of the different implantation of the 6SN7. But please don't try to defend Mr.Shindo. I heard his completely unlistenable amp's espicially the Palmer. I'm tolerant to different tastes but a 300B amp without any bass or body (violins without wood) are not worth a discussion, not the mention the 2D stage like a cheap japanese transistor amp.
Without using Lundahl transformers, chokes & fast caps it is not possible to build a neutral and fast 300B amp, if you want to carry it further the speed and detail lane than one might also consider an EF86 instead of a 6SN7.
Looking at Shindo strictly scientifically it is a clear RIP-OFF period. |
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| ElectricHead |
| quote: | Originally posted by Kuei Yang Wang
...hence having the schematic for Shindo gear is not particulary useful, without having the matching photos of the implementation too.
Sayonara |
Yeah, that is right.
Good sound MUST have a material base, i.e.: An amp with mediocre parts can only sound mediocre, good parts don't mean automatically good sound. But without a kind of quality material standard you can't reach high levels of audiophilia. |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by ElectricHead
a 300B amp without any bass or body (violins without wood) are not worth a discussion, not the mention the 2D stage like a cheap japanese transistor amp. |
I am not sure what you heard and where, in what system context, but this does not sound like anything I'm familair from the few pieces of Shindo gear I am familiar with.
| quote: | Originally posted by ElectricHead
Without using Lundahl transformers, chokes & fast caps it is not possible to build a neutral and fast 300B amp, |
Lundahl transformers are okay, far from the best though. Solen SCR "Fast Caps" have no place in quality audio gear, their tone is revolting, even black gate are preferable to these.
| quote: | Originally posted by ElectricHead
if you want to carry it further the speed and detail lane than one might also consider an EF86 instead of a 6SN7. |
EF86!!?? What for. Try an EL84 triode wired instead....Actually, you may wish to consider a design more like mine, if you want speed, detail, resolution, dynamics and a sound that is smooth, relaxed and makes you want to listen more:
http://www.jogis-roehrenbude.de/Les...-Loesch-Amp.htm
You might also check the recent D3a/300B DRD Amplifier thread for some ideas that I was able to input to Luis's design and realisation.
Key things to get a neutral sound from the 300B I found are:
No ECC99, 6SN7, 5687 et al cascade, absolutely NEVER EVER repeat the same valve twice in the driver stage.
Used as cascode this is another story, see penthode.
SRPP/Mu Follower et al is best avoided, it can do okay implemented with care, but usually it causes more problems than it solves.
Preferably ratchet up the Gm in the driver valve quite high and the anode impedance down, then SRPP et all are not needed, you have gain and drive readily available.
Never use more stages than absolutely needed.
Going 3-Stage (including powerstage) is okay if you use fairly powerfull low gain drivers (2A3, 45, 300B, 10, 205D, 6L6 et al) and low gain input valves, but most of the times 2 Stages (including powerstage) are preferable.
Example would be 6SN7 input and choke loaded 6BX7 driver, this is miles preferable to a resistor loaded 6SN7 cascade, but you start to cook seriously with a 417A or other highish Gm input valve and a 2A3 or KT66 as driver, IT/Choke loaded.
With Self Bias use the WE connection, if you don't you are missing the top 20...30% of the perfoirmance (dynamics, maturalism of sound) the Amplifier is capable of.
With fixed bias add a decoupled bypass to the last PSU capacitor.
The 300B requires DC Heaters (AC sounds foggy and indistinct - I need to try HF AC, that may be a happy middle) but these require utmost care in implementation in order not trade fog for severe glare and edginess.
Single stage pentode drivers (310A, EL84, C3m et al, the three mentioned I have build with) tend to have more delicacy and immediacy plus more than enough gain, tonal colours are rich and natural.
Triode drivers are a little more solid sounding and better on coarse dynamics, tonal colours are little bleached out.
Driver triodes need inductive or IT load = more delicacy, resistor load usually not recommended.
No Black Gates.
No PIO Coupling Capacitors.
No FastCap's.
If you can replace a resistor by a choke sensibly, do it.
Direct coupling usually swaps a good quality capacitor for a poor quality one, the results are unpredictable. If in doubt eliminate the cathode capacitor before a gridcoupling capacitor and remember, current flows in loops, if you do not give the signal current any other way to go the loop will complete through the Powersupply.
Output transformers with very high primary inductance for whatever resons do sound not right in the bass (and often equally crappy in the treble due to excessive leakage inductance), don't ask me why, but they don't (I suspect several things at work there, to early to talk much).
45's sound better than any 300B's, as do 10/10Y/VT25, if your speakers tolerate 1.5 - 2 Watt amplifiers.
Well, I'll add some if I remember any more.
Sayonara |
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| ElectricHead |
Jesus, quiet a lot of information from you.
1. I have a lot of schematics from you, I think you are very serious about sound quality so I really respect you.
2. Which transformers you consider better than Lundahl?
3. Black Gates are better than Solen? Oh come on.... please don't do that. The only problem the Solens have is the top... but there is a trick.... |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by ElectricHead
2. Which transformers you consider better than Lundahl? |
Various far eastern and european ones using medium - high nickel content.
| quote: | Originally posted by ElectricHead
3. Black Gates are better than Solen? Oh come on.... please don't do that. The only problem the Solens have is the top... but there is a trick.... |
The trick I prefer is simply not to use them. The locally available stuff is cheaper, better and more reliable.
Sayonara |
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| ElectricHead |
European? I've tried a lot of different trannies but Lundahl beats the hell out of the rest and even Tamura loses badly!
P.S.: I like Blade Runner too, one of the the very few Science Fiction movies ever made. Are you reading Philip K. Dick? |
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| ElectricHead |
| What do you mean with locally stuff? I'm living in Germany, are you really trying to say I should use nasty sounding WIMA MKP's or endlessly slow and dull Siemens or Phillips caps? |
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| rdf |
| quote: | Originally posted by Kuei Yang Wang
No Black Gates. |
Hi KYW, do you mind if I ask what you consider to be the typical Black Gate sonic signature? I'm at ground 0.2 sorting out some of the things I hear playing with different circuits/parts. BG's have been one of the elements, mistakenly or not, I've considered 'a safe constant'. |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by ElectricHead
European? I've tried a lot of different trannies but Lundahl beats the hell out of the rest and even Tamura loses badly! |
Tamura (and Tango) make many series, note that I referred SPECIFICALLY to permalloy core transformers.
| quote: | Originally posted by ElectricHead
P.S.: I like Blade Runner too, one of the the very few Science Fiction movies ever made. Are you reading Philip K. Dick? |
I have read most of PKD's stuff. I am just revisiting the Strugatsky Brothers, their books come highly recommended as well as Tad Williams (Otherland Series) and William Gibson.
BTW, my tag line will likely change soon to this:
"Ich hörte, dieser Weg führe zum Ozean des Todes, und kehrte auf halbem Wege um. Seither dehnen sich vor mir Umwege, öde und krumm...."
| quote: | Originally posted by ElectricHead
What do you mean with locally stuff? I'm living in Germany, are you really trying to say I should use nasty sounding WIMA MKP's or endlessly slow and dull Siemens or Phillips caps? |
Locally to me means Ansar (Supersound) and ICW (ClarityCap). I also can get excellent quality Ducatti Motor run capacitors at my favourite local shop (Cricklewood Electronics) and next door is the best Indian/Nepalese curry joint in London....
Sayonara |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by rdf
what [do] you consider to be the typical Black Gate sonic signature? |
First, if you like them, don't let me put you off.
Secondly, in sonic terms they are bright, brash, with an unnatural "look how great I sound and how much fake detail I'm adding" style presentation, like the typhical "showroom" sound from loudspeakers with tipped up bass and treble that intionally impresses but tires in the lon g run.
One can partially offset this sound by using circuit topologies and other parts that make for laid back, overly soft and indistinkt sound, but it is essentially constantly fighting the various strong sonic signatures of the various parts to get something that sounds belanced, I find this too hard work and you don't halve pay for it too.
I will use the occasional BG Cap if I feel the need to brighten up a given design sonically, just as I'll use the occasional PIO capacitor to make the sound more laid back, but as a rule I prefer doing things from a neutral point.
Sayonara |
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| Peter Daniel |
Kuei, what I read here, this is a typical STD cap characteristic, and I have to agree with that. However, BG N (the red ones) are rather opposite, and when properly applied (with regards to orientation and usually smaller than normally used value) I can put them against most other "exotic" brands and would prefer them, mostly for lack of fake detail, the bass that is not tipped up and the trebles that never tire and are actually rather laid back.
I use standard BG only in GC PS, otherwise I don't like them much, same goes for FK type. However, I can't imagine voicing circuits without N types, all other elektrolytics I tried so far are simply too colored in comparison ( except for some Panasonics).
For coupling, the only caps that are substantially better than N type BG (IMO) are teflon V-Caps. Siemens MKV are OK too, but this is not the same league as V-Cap ( although I didn't try their best grade which really hard to find). |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by Peter Daniel
Kuei, what I read here, this is a typical STD cap characteristic, and I have to agree with that. |
I have tried others too and at leats in my applications (which are strictly Tube Gear and in places where large values are needed) alos the other series of BG's have this charateristic, some to a larger other to a lesser degree. I tend to take Elna silmic over BG in signal applications every day and in almost any applications, UNLESS I need to "liven up" the sound somewhere in the direction BG's pull it.
For coupling positions I have yet to find anything to better Silver Leaf / Mica capacitors. Secondly I like Tinfoil Film cap's, I found the differences between MIT PTFE types and Solen Polypropylene modest, if audible, but the difference compaed to Aluminum Foil & Polypropylene capacitors drastic.
My current system has a Silver Mica Coupling Cap and a heavily bypassed MKP in the phonostage and one more Silver Mica coupler in the power amplifer. The rest is MKP. No BG, no teflon....
Sayonara |
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| rdf |
Thanks both for the relaying your experiences! For me the toughest parts of circuit tweeking are visualizing (auralizing?) the target, determining if a change was detrimental or exposed an underlying flaw, and finally getting a handle on how others hear and value similar changes to make best use of advice. Right now I'm working at cleaning up reproduction of sibilants on a grid-biased, trioded E180F RC coupled to an SE EL84. The latter is cathode biased with a 100uF BG-N across the resistor so your comment caught my eye. The other caps are an ancient 0.025 uF TRW Polystyrene foil from the kit box up front and a .1 Russian telfon interstage.
I recall reading you prefer the silver micas from diyhifisupply. I'll try the pair of .1 uF 100 volt silver micas I have floating around, admittedly cheapies from Sayal in Toronto, give them a break-in and run interstage to get at least a sense of the direction. Replacing a PIO with the TRW made a world of improvement up top. Will also dig up some Elnas. Thanks again. |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by rdf
Right now I'm working at cleaning up reproduction of sibilants on a grid-biased, trioded E180F RC coupled to an SE EL84. The latter is cathode biased with a 100uF BG-N across the resistor so your comment caught my eye. The other caps are an ancient 0.025 uF TRW Polystyrene foil from the kit box up front and a .1 Russian telfon interstage. |
First, what opertaing points do you use? Especially the E180F can sound bright and steely if the anode current is too high, try 6mA or less, given that you probably have a low anode voltage as well.
Secondly, both E180F & EL84 are very high transconductance, stick 1K gridstoppers on anything that looks like a grid (screen, suppressor etc.), even if you triode wire the valve. Also, if you triode wire remember to take any freely available suppressor grid to the anode, rather than the cathode.
Thirdly, go for fixed bias on the output stage as well and as the EL84 has loads of gain and transconductance apply cathode feedback from the output transformer secondary (observe correct polarity) to the cathode of the EL84, in other words connect the EL84 cathode to the output transformer secondary so that you attain negative feedback.
Forth, the EL84 is extremely eay to drive, try an unbypassed cathode resistor to bias the E180F, if you get too much top end rolloff add a small value silver mica "tuning capacitor" across this unbypassed cathode resistor to get any drooping trebel response back up.
Fifth, remember the that output stage current loop is completed through the powersupply. The final powersupply capacitor matters a lot sonically. You can add a modest value (22..47R) series resistor after the final electrolytic capacitor with a largish motor run film capacitor (22uF or larger) to ground as effectively "decoupled bypass" capacitor.
You might find that with only one coupling capacitor and one PSU capacitor plus local feedback in both stages for better linearity will make this a wholly different animal.
| quote: | Originally posted by rdf
I recall reading you prefer the silver micas from diyhifisupply. I'll try the pair of .1 uF 100 volt silver micas I have floating around, admittedly cheapies from Sayal in Toronto, give them a break-in and run interstage to get at least a sense of the direction. |
Beware, Silver Mica are in my experience the capacitors closest to a piece of wire... This can be a bad thing.
Sayonara |
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| Peter Daniel |
| quote: | Originally posted by Kuei Yang Wang
Beware, Silver Mica are in my experience the capacitors closest to a piece of wire... This can be a bad thing.
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That could be a good thing if your stereo is built from a piece of wire, unfortunately it's not.;)
Silver mica from Sayal is not worth even trying. I like to quote that post when it comes to silver mica, as it's very close to how I feel about those caps: http://www.diyaudio.com/forums/show...2664#post262664 |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by Peter Daniel
Silver mica from Sayal is not worth even trying. |
I would advise to try it anyway.
As much as I respect Jonathan (we had lengthy and friendly exchanges over at the joe list in the elder millenias and I learned a lot) he writes in the context of all solid state direct coupled, high feedback circuitry (as incidentally do you), while I write from the context of transformer coupled output usually low/no feedback circuitry, though my testing was done in a wire bypass test setup, so are about absolute neutrality, not about what happens in a given circuit.
So I suspect the differences in opinion and experience are quite explainable.
Sayonara |
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| rdf |
| quote: | Originally posted by Kuei Yang Wang
First, what opertaing points do you use? Especially the E180F can sound bright and steely if the anode current is too high, try 6mA or less, given that you probably have a low anode voltage as well. |
Thanks for that! First though I should clear up a "posting-from-work" ommission. That should have read an E180F grid-leak biased with a TRW in front, the leak resistors 10 Meg Caddock spares from an earlier project. To my ear this has so far provided the cleanest top end performance. The plate load (today) is an IXYS chip surounded with stopper resistors and with 10-turn trim pot to facilitate easy bias current changes live. Prior to that it was VR90 regulator driving 150H Hammond chokes as plate loads, which sounded very good. They're only rated for 8 ma however so the IXYS's went back in to try something higher. The current right now is in the 12 ma range with around 110 volts on the plate. With the chokes it was between 7 and 8 depending on tube and 80-90 on the plates.
Regarding the EL84 op point it might be easier to say what wasn't tried. If it was between 8 and 12 watts standing dissipation and between 130 and 270 ohms in the cathode, it did time. Tubes include EH, Sovtek, JJ and the Anthony Welsh Russkie jobs. I keep gravitating back to about 255 volts plate-to-cathode with around 40 ma plate current (180 ohms) more on feel than anything else.
| quote: | | Secondly, both E180F & EL84 are very high transconductance, stick 1K gridstoppers on anything that looks like a grid (screen, suppressor etc.), even if you triode wire the valve. Also, if you triode wire remember to take any freely available suppressor grid to the anode, rather than the cathode. |
Of those suggestions only the EL84 is without gridstopper. Already did time with the front end pseudo triode, very impressive frequency response (flat to 120 kHz into load if I recall) but again sounded better to me in true triode. The scope shows both plates clean as a whistle to 60 MHz at least. I'll revisit the stopper for the output and intend to play around with variations of g2 and g3 anode strapping on the E180F. However this might be another one of those things which on revisit makes me wonder what I could have been thinking the first time.
| quote: | | Thirdly, go for fixed bias on the output stage as well and as the EL84 has loads of gain and transconductance apply cathode feedback from the output transformer secondary (observe correct polarity) to the cathode of the EL84, in other words connect the EL84 cathode to the output transformer secondary so that you attain negative feedback. |
That is interesting, I had considered that form of cathode feedback but not fixed bias. I'll give it a shot. Certainly the E180F won't break a sweat over the extra drive. Since I have these Hammond 156C 150H chokes laying around, what do you think of the following for a grid supply?
rect - cap - IXYS CCS - 156C - resistor in parallel with cap - grid resistor
The current through the active CCS sets the voltage across the final resistor, which doesn't need to be any higher than 1500 ohm to arrive at a reasonable grid bias voltage using a reasonable current of 8 ma or less. The 156C creates an very benign load for the chip as well. Should be very quiet if nothing else.
| quote: | | Forth, the EL84 is extremely eay to drive, try an unbypassed cathode resistor to bias the E180F, if you get too much top end rolloff add a small value silver mica "tuning capacitor" across this unbypassed cathode resistor to get any drooping trebel response back up. |
I tried the E180F with cathode degeneration before converting to gridleak. The gain went up on removing the bypass cap, which I take to be an indicator of Bad Things. It's something I meant to revisit but converted to gridleak. It seems to really like having its cathode hard grounded. Save for the usually SE low frequency stuff the amp's hiss is at the limits of audibility with an ear pressed to the dust cap of a 12" Tannoy Gold.
| quote: | | Fifth, remember the that output stage current loop is completed through the powersupply. The final powersupply capacitor matters a lot sonically. You can add a modest value (22..47R) series resistor after the final electrolytic capacitor with a largish motor run film capacitor (22uF or larger) to ground as effectively "decoupled bypass" capacitor. |
Right now the two EL84's share two 60uF and one 40 uf ASC motor runs (for a total of 160 uF) with 6 uF Solen fastcap bypasses. I don't like the Solens in a coupling position but they appeared to help here. There's also a shipment of 100 uF Japanese ASC's on the way. No electros anywhere to be seen, even the first cap of the LCLC supply is a 30 uF Solen I had laying around. What capacitance would you consider 'enough'. I also have a pile of supply chokes around and may 'Y' off to right and left after the first LC section.
| quote: | | You might find that with only one coupling capacitor and one PSU capacitor plus local feedback in both stages for better linearity will make this a wholly different animal. |
Let's hope! Since the output stage appears to be the main limitation at this point - the front end measures more linear by a factor of 20 - I'll start there.
| quote: | Beware, Silver Mica are in my experience the capacitors closest to a piece of wire... This can be a bad thing.
[/B] |
Dismaying, yes. Bad, never. The iron's heating up right now. Thanks again for your input, very greatly appreciated. |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by rdf
an E180F grid-leak biased with a TRW in front, the leak resistors 10 Meg Caddock spares from an earlier project. To my ear this has so far provided the cleanest top end performance. |
Generally agreed, but in power amp input stages gridleak bias may be too variable and non-linear, no matter how much I tend to like it.
| quote: | Originally posted by rdf
Of those suggestions only the EL84 is without gridstopper. |
Add it.
| quote: | Originally posted by rdf
The scope shows both plates clean as a whistle to 60 MHz at least. |
But that is with resistive load on the bench. What about playing music into a speaker?
| quote: | Originally posted by rdf
what do you think of the following for a grid supply? |
Bit overdone, but will do no harm....
| quote: | Originally posted by rdf
I tried the E180F with cathode degeneration before converting to gridleak. The gain went up on removing the bypass cap, which I take to be an indicator of Bad Things. It's something I meant to revisit but converted to gridleak. It seems to really like having its cathode hard grounded. Save for the usually SE low frequency stuff the amp's hiss is at the limits of audibility with an ear pressed to the dust cap of a 12" Tannoy Gold. |
Something does not sound right here. Did you use the cathode degneration with nthe CCS load or the choke?
| quote: | Originally posted by rdf
Right now the two EL84's share two 60uF and one 40 uf ASC motor runs (for a total of 160 uF) |
Sounds fine to me. I did not know how far you took things.
| quote: | Originally posted by rdf
Let's hope! Since the output stage appears to be the main limitation at this point - the front end measures more linear by a factor of 20 - I'll start there. |
Yes, I'd think so too.
Sayonara |
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| rdf |
The increased gain with degeneration could have been oscillation above 60 MHz. Wiring in the silver micas last night I noticed g3 was tied directly to plate in converting it from pseudo triode. No stopper resistor. Since it's something I wanted to try anway it was connected to g2 with 820 ohms (value at hand), g2 remains connected to anode with 1000 ohms. This one change dropped the plate voltage from ~110 to ~70 vdc. I recall reading somewhere oscillation can manifest itself as an increase in gain. That would certainly explain both behaviours.
There was just enough time last night for a quick listen. Interesting indeed. The changes appears to have had a substantial effect at the extreme top. Sibilants are very fast, distinctly different between male and females, individuals and location and have a greatly reduced tendency to shift from 's' to 'sh'. Sounds promising.
Thx again. |
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| alexg |
RDF,
Would you mind sharing the schema of your E180F/EL84 circuit?
I want to do an EL84 amp and I have a pair of 6688 (E180F) to try as drivers.
Thanks. |
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| rdf |
| Hi Alex. Sorry, that was a transitory design long ago dismantled. The general topology would have been 5K:8 transformer, 300-325 VDC on the EL84 plate at ~32 ma (I prefer high and cold for the reduced high harmonic distortion components), an IXYS CCS on the plate of the trioded E180F driver and an LED cathode load. My guess is a green LED with ~2 ma plate current. That circuit has been rebuilt so many times it's a now a 9002/6CW5! |
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| alexg |
| quote: | Originally posted by rdf
Hi Alex. Sorry, that was a transitory design long ago dismantled. The general topology would have been 5K:8 transformer, 300-325 VDC on the EL84 plate at ~32 ma (I prefer high and cold for the reduced high harmonic distortion components), an IXYS CCS on the plate of the trioded E180F driver and an LED cathode load. My guess is a green LED with ~2 ma plate current. That circuit has been rebuilt so many times it's a now a 9002/6CW5! |
Thanks.
I will try a triode strapped 6688 driving an EL84.
I just finished an triode strapped EF86 driving an EL84 in parafeed and I like what I am hearing.
Thanks. |
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